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Okra [Abelmoschus esculentus (L.) Monech.] is an annual herb of the family Malvaceae and has tremendous nutritional and industrial potential. However, the unknown genome size, variation in ploidy level makes it more challenging for okra breeders to enhance their genetic potential. In this context, the genetic analysis of allelic polymorphism and population structure analysis of okra germplasm is pivotal for its genetic improvement. In the present investigation, a total of 96 okra genotypes were undertaken for morpho-genetic diversity analyses using 13 morphological parameters and 65 SSR markers. Out of 65 SSRs, 50 primers were polymorphic and the mean polymorphic information content (PIC) value was 0.38. The polymorphic loci AVRDC OKRA 64 revealed a maximum PIC value of 0.71 and the number of alleles per locus varied from 2 to 7, with an average of 3.34 alleles per locus. The neighbour-joining (N-J) tree grouped the genotypes into three distinct clusters (I-III), of which Cluster I comprised of cultivated species, A. esculentus and A. caillei, while, Cluster II and III consisted of other related wild species. Furthermore, the population structure analysis distinguished the okra genotypes into two distinct genetic groups comprising cultivated (A. esculentus) and wild-type okra. The variability analysis based on 13 agro-morphological traits revealed that the genotype DOV-92 exhibited the highest per se performance for total fruit yield, followed by Pusa Bhindi-5. The PCA (Principal Component Analysis) analysis revealed that the first three components account for more than 50% of the total genetic variation. The present investigation deciphered a high morphological and genetic diversity in cultivated and wild okra germplasm. Thus, it could serve as important genetic resources for okra improvement programmes.

The root-knot nematode Meloidogyne luci generates serious damages on economically important crops. However, the knowledge on host status of cultivated plants to this nematode species is highly limited. In this study, 71 cultivars of 43 plant species and varieties from Alliaceae, Apiaceae, Asteraceae, Brassicaceae, Chenopodiaceae, Compositae, Cucurbitaceae, Fabaceae, Malvaceae, Poaceae, Rosaceae and Solanaceae families were screened for their host status to an isolate of M. luci in pot assays under controlled greenhouse conditions. Host status of plant cultivars was determined based on nematode reproduction factor. Of the tested cultivars, five cultivars were identified as non-hosts (Rf = 0), 20 cultivars as poor hosts (0

Summary A Bursaphelenchus sp. belonging to the B. idius-group was isolated from a bark beetle, Ernoporus corpulentus, which had emerged from dead twigs of Hibiscus tiliaceus collected in Okinawa, in the subtropical region of Japan. In addition to its group-specific characters, i.e., four lateral lines in both male and female and less developed capitulum and relatively broad blade of the male spicules, the species is characterised by a relatively slender female tail with various tip shapes. Molecularly, the species is close to B. fagi and B. tiliae based on SSU and D2-D3 LSU sequences, but can be clearly distinguished from these two species. The species is described and illustrated herein as B. hibisci n. sp.

The constant search for natural insecticides in the form of extracts from many plants has received attention, and many of these extracts have been evaluated for their effectiveness as insecticides. To determine the toxic effect of six plant species Arundo donax L. (Poaceae), Brassica campestris L. (Brassicaceae), Cynodon dactylon L. (Poaceae), Hura polyandra Baill. (Euphorbiaceae), Phytollacca icosandra L. (Phytolaccaceae) and Sida acuta Burn. (Malvaceae) on Trialeurodes vaporariorum W. (Homoptera: Aleyrodidae) (adult whitefly), we evaluated the mortality rate and the lethal concentration (LC50) of the methanolic and aqueous extracts under laboratory and greenhouse conditions in a culture of Lycopersicum esculentum Mill. (Solanaceae). Analysis of Variance ANOVA and a test of comparison of means (Tukey, a = 0.05) showed a tendency of the methanolic extract in the six species towards a higher mortality rate and LC50 compared to that of the aqueous extract, both under greenhouse and laboratory conditions. The methanolic and aqueous extracts of A. donax and P. icosandra showed a higher toxicity under laboratory conditions (39.5 y 40.5%, respectively) than under greenhouse conditions (23.3 and 26.3%, respectively). The Treatments did not interfere with the tomato yield; so we are able to confirm the effectiveness of A. donax and P. icosandra extracts in the control of T . vaporariorum , which represents an ecological alternative for pest control in open field crops.

Kenaf, Hibiscus cannabinus, is a fiber-enriched plant belonging to Malvaceae and is an important fiber crop. The features of kenaf of being fast-growing and fiber-enriched suggest the potential for the use of kenaf in biomass and materials. Here, we modified procedures for regeneration from kenaf explants in order to establish efficient genetic modification for improving the property of kenaf as a material. We tested several tissues of kenaf seedlings for callus induction and subsequent shoot regeneration by supplying several combinations of plant growth factors. We show the cotyledons to be the best tissue for efficient callus induction, and the rate for callus induction reached ∼98% on an improved callus inducing medium. We also show the efficient regeneration of kenaf from cotyledon-derived calli achieved by shoot induction on a shoot-inducing medium. We also achieved seed setting of the regenerated kanaf plants under a regulated growth condition in a chamber. Our efficient regeneration method and seed setting condition will enable the production of stably transformed kenaf that can improve the properties of kenaf as a material.

Urena lobata L. is a commercial species used for fiber extraction in the Brazilian states of Amazonas and Pará that presents relevant socioeconomic importance for the Amazon region. Despite its importance and wide distribution throughout Brazil, there are no data on the species response to global climate change. This study aimed to present the potential geographical distribution of U. lobata in the current period (2009-2019) and predict areas of climatic suitability for its occurrence in two future scenarios (RCP 4.5 and RCP 8.5), at two time intervals (2020-2050 and 2051-2070), in the face of global climate change. A total of 19 bioclimatic variables were obtained from the WorldClim database and four algorithms (Climate Space Model, Envelope Score, Niche Mosaic and Environmental Distance), from which the Envelope Score was the most representative model for the species to verify its occurrence along the Brazilian phytogeographic domains (Amazon, Caatinga, Cerrado, Pantanal, Atlantic Forest and Pampa). Vulnerability was observed for the species, since there were losses of favorable areas in the Amazon, Pantanal, Atlantic Forest, Cerrado and Caatinga, becoming practically extinct in the worst scenario (RCP 8.5), in the year 2070. However, for this same scenario and year, there was a significant area increase in the Pampa. RESUMO. Urena lobata L. é uma espécie comercial, utilizada para a extração de fibras nos estados do Amazonas e Pará, que apresenta relevante importância socioeconômica para a região Amazônica. Apesar de sua importância e vasta distribuição pelo Brasil, não existem dados sobre a resposta da espécie às mudanças climáticas globais. Objetivou-se apresentar a distribuição geográfica potencial de U. lobata no período atual (2009-2019) e prever áreas de adequabilidade climática para sua ocorrência em dois cenários futuros (RCP 4.5 e RCP 8.5), em dois intervalos de tempo (2020-2050 e 2051-2070), diante das mudanças climáticas globais. Foram utilizadas 19 variáveis bioclimáticas obtidas do WorldClim e quatro algoritmos (Climate Space Model, Envelope Score, Niche Mosaic e Environmental Distance), dos quais o Envelope Score foi o modelo mais representativo para a espécie, para verificar sua ocorrência ao longo dos domínios fitogeográficos brasileiros (Amazônia, Caatinga, Cerrado, Pantanal, Mata Atlântica e Pampa). Observou-se vulnerabilidade para a espécie, já que houve perdas de áreas favoráveis na Amazônia, Pantanal, Mata Atlântica, Cerrado e Caatinga, tornando-se praticamente extinta no pior cenário (RCP 8.5), no ano de 2070. Entretanto, para esse mesmo cenário e ano, observou-se aumento significativo de área no Pampa. Made available in DSpace on 2022-09-01T11:19:22Z (GMT). No. of bitstreams: 1 APA-2022-PredictionNaturalDistributionConservationUrenaLobataL.pdf: 4219267 bytes, checksum: bb2b97e552a3c74e23bd79fc26b63593 (MD5) Previous issue date: 2022

Balsa wood is used widely in the nautical, aeronautical and wind-energy industries because of its low-density and high-resistance. In the Brazilian state of Mato Grosso, speculative producers with little knowledge of the culture have established balsa plantations using non-standardized and non-selected seedlings. In this sense, research is needed to improve balsa cultivation under Brazilian conditions to better explore the resource. The present study evaluated the efficiency of the Pilodyn instrument for the indirect determination of the basic wood density (BWD) of balsa. Twenty 12-year old balsa trees cultivated in Alta Floresta, Mato Grosso, were probed with the Pilodyn instrument on both north and south faces of the trunk at the base and at 1.30 and 3.10 m from the ground. Wood discs were subsequently collected from the probed sites and BWD determined according to the water-immersion method. Data were submitted to the Shapiro-Wilk normality test followed by analysis of variance and Pearson?s correlation analysis with α=0.05. The BWD of balsa decreased in the direction from the base to the top of the tree. The penetration depth of the Pilodyn probe was inversely proportional to BWD with a correlation that was strong (R2=0.72) at heights of 1.30 and 3.10 m but considered weak (R2=0.46) at the base of the trunk. The reliability of the Pilodyn method was sufficient to allow the development of a linear equation that could be applied for the indirect determination of the BWD of balsa based on the penetration depth of the Pilodyn probe assessed at 1.30 m from the ground. | Resumo: O pau-de-balsa é amplamente utilizado nas indústrias náutica, aeronáutica e de energia eólica devido à sua baixa densidade. No estado de Mato Grosso, produtores especulativos de balsa têm estabelecido plantios sem conhecimento sólido da cultura usando mudas não padronizadas e não selecionadas. Pesquisas são necessárias para melhorar o cultivo de balsa sob condições brasileiras para melhor explorar este recurso. O presente estudo teve como objetivo avaliar a eficiência do instrumento Pilodyn para a determinação indireta da densidade básica da madeira (DBM) de balsa. Vinte árvores de 12 anos de idade cultivadas em Alta Floresta, Mato Grosso, foram avaliadas com o instrumento Pilodyn nas faces norte e sul do tronco, na base e a 1,30 e 3,10 m do solo. Discos de madeira foram posteriormente coletados dos locais sondados e o DBM determinado de acordo com o método de imersão em água. Os dados foram submetidos ao teste de normalidade Shapiro-Wilk seguido de análise de variância e análise de correlação de Pearson com α=0,05. Os valores de DBM da balsa diminuiu da base em direção ao topo da árvore, enquanto a profundidade de penetração do Pilodyn foi inversamente proporcional. A correlação entre a profundidade de penetração do Pilodyn e o DBM foi fraca na base do tronco (R2=0,46), mas forte (R2=0,72) nos pontos de 1,30 e 3,10 m. O método Pilodyn foi suficientemente confiável que permitiu o desenvolvimento de uma equação para a determinação indireta do DBM do pau-de-balsa considerando o valor da profundidade de penetração a 1,30 m como uma das variáveis. Made available in DSpace on 2022-06-01T17:24:14Z (GMT). No. of bitstreams: 1 2022-cpamt-essh-calibration-pilodyn-instrument-indirect-in-situ-determination-basic-wood-density-balsa.pdf: 517239 bytes, checksum: 7446f8309efacd5d215e733884c10903 (MD5) Previous issue date: 2022

In Colombia there is a large diversity of promising fruit trees, one of them is Matisia cordata. Sapoti species is appreciated by the consumers, although it is produced in small volumes by traditional productors. The objective of this research is to describe the floral and reproductive biology of sapoti, including floral visitors that act as biotic pollination agents. The study was conducted in two farms, between February/2016 and July/2017. In the first farm, floral buds were marked to follow the stages until fruit formation, pollination mechanism was studied, and floral visitors were collected for identification. In the second farm, flowers were marked to measure the floral nectar production. The duration from floral bud to ripe fruit was 269 days, the 2.7% of the flowers reached the fruit stage. Twenty-five floral visitors were registered, seven of which contacted the sexual whorls, specially Meliponini bees, hummingbirds and bats from Artibeus and Glossophaga genus. M. cordata is a prevalently allogamous species, it attracts diurnal and nocturnal animals, which can contribute to the pollination process. The flowers produced 1.6 ml of nectar with a sugar content from 6.2 to 11 °Brix. The sapoti flowers constitute an abundant and valuable resource for animals from the region.

Powdery mildew collected from Abelmoschus esculentus (Malvaceae) in Karaj (Iran) was identified as Golovinomyces bolayi, a species that was recently delimited from the G. orontii species complex. The fungus was identified based on morphological characteristics of its asexual and sexual morphs, and rDNA ITS sequence analyses. This is the first identification of Golovinomyces bolayi as the causal agent of powdery mildew on Abelmoschus esculentus globally. Earlier, closely related taxa from the G. orontii species complex were reported from okra from different parts of the world.

The family of enzymes 5-enolpiruvil shikimato-3-phosphate synthase (EPSPS) is found in plants and microorganisms. The substrates of this enzyme are phosphoenolpyruvate (PEP) and 3-phospho-shikimate and their products are phosphate and 5-enolpyruvylshikimate-3-phosphate that is the biological target of the herbicide glyphosate, which is used in genetically modified crops. The interaction between cultivated genetically modified plants (GMP) and wild plant species could be a transference source of transgenes. Presence of transgenes could be cause and adverse environmental impact on non-target organisms. Gossypium hirsutum genotype Bollgard II® is a GMP with tolerance to herbicide glyphosate and it has been cultivated during 20 years in Mexico and the possibility to gene flow primary in congeners of the Malvaceae family is possible. The objective of this study was to quantify and identify weed species associated to genetically modified cotton fields and to detect the present of glyphosate-insensitive EPSP synthases (CP4 EPSPS) in these species. The results showed that plants of the families Amaranthaceae, Asteraceae, Boraginaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, Malvaceae, Poaceae, Portulacaceae, Solanaceae and Zygophyllaceae are present in the study site. Twenty-five weed species belonging to these botanical families were collected and identified in the site. From these, two species of the Malvaceae family with potential risk of gene flow plants, Anoda cristata and Sida hederacea were identified in the site; however, the CP4 EPSPS protein was not detected in none of the collected weed species and only the GM genotype Bollgard II® was positive to the CP4 EPSPS protein in the study site.

The effect of different levels of spent engine oil application on germination, survival, growth, leaf anatomy, yield, nutrient content and heavy metals uptake of okra (Abelmoschus esculentus – ‘Clemson’ spineless variety and ‘OLA 3 Local’ variety) was assessed in the present study. Completely randomized design was used with five treatment levels of spent engine oil at 0 ml (control), 50 ml, 100 ml, 150 ml and 200 ml applied to 5 kg of soil. Data on germination, seedling survival, growth, chlorophyll nutrient and heavy metal content, as well as leaf epidermal features collected from the study were subjected to Statistical Package for Social Sciences (SPSS) analyses. Spent engine oil at 200 ml per pot significantly (P < 0.05) delayed seed germination for 4 days and reduced germination percentage by approximately 24% compared to the control. Plant height, number of leaves, leaf area, chlorophyll A, B and stomata area were reduced by 21.33-72.89%; number and dry weight of fruits were reduced by 67.4-13.58%. Number of stomata was increased on the adaxial surface by 57.73% and on the abaxial surface by 34.99%. Na, K, Cr, Cd and Fe contents increased by 0.0178-6.2698 mg/kg-1. The present study has shown that plant constituents and anatomy can be influenced by spent oil contamination. Contamination of soil with spent engine oil therefore should be avoided in order to ensure sustainable crop plant productivity and to reduce the risk of heavy metals toxicity for human beings.

Plant mapping has been included and evolving in cotton (Gossypium hirsutum L. [Malvales: Malvaceae]) research and management for over 100 years. Here we describe the structure and use of a plant mapping program (PMAPplus) that includes capabilities to record and manage insect injury to fruiting bodies by position and branch, compare it to existing programs (COTMAN and PMAP), and illustrate its use in cotton research that includes an assessment of insect injury. PMAPplus was modified from PMAP to allow entry of additional data on insect injury to squares and bolls and cotton boll rot and to produce output in a numerical and graphical format that can be customized to user specifications. Comparing use side-by-side, protocols of PMAPplus required more mapping time per plant than PMAP and COTMAN due to observing the additional insect injury data. But the added data were found useful in a planting date experiment that included evaluation of verde plant bug (Creontiades signatus Distant [Hemiptera: Miridae]) feeding on cotton that results in injury to bolls and is associated with cotton boll rot. PMAPplus graphical displays and output that was further analyzed statistically indicated that first position bolls in the middle branches of later planted cotton had the higher insect injury scores and incidence of boll rot, despite similar verde plant bug densities occurring on both plantings. The within-cotton distribution of verde plant bug insect injury helped explain the significantly higher yield from the earlier planting than from the later planting that was incongruent with the weekly insect monitoring data alone.

Green mirids, Creontiades dilutus (Stal) (Hemiptera, Miridae), are primary pests of cotton (Gossypium hirsutum) (Malvaceae) in eastern Australia. Severe infestations delay crop development and reduce yield through boll drop (fruit loss). Most cotton farmers employ crop consultants to monitor mirids and recommend pest management options. Effective pest management needs to account for both increased pest numbers within cotton (i.e. the production of mirid offspring), and the movement of mirids into crops (invasions). The objective of this study is to evaluate what is known about environmental processes that influence mirid invasions by assessing records on mirid infestations spanning the 1976/77 through 2015/16 cotton seasons. The primary records of mirid invasion are qualitative surveys conducted in 1993 and 2014 that asked consultants about their monitoring efforts. These qualitative surveys are supplemented by seasonal reports of pest pressures across eastern Australia, and sporadic field surveys that quantified mirid densities. Although each consultant monitored only a small portion of the overall agricultural landscape, there was agreement that the earliest seasonal mirid invasions were associated with squaring (flower bud forming) cotton, and were influenced by nearby vegetation. There was, however, substantial variation in the responses regarding local factors that may influence mirid invasions. The importance of distinguishing between mirid invasions and the production of offspring within cotton is discussed. Methods are proposed that would improve the spatial and temporal resolution of mirid monitoring efforts across the agricultural landscape.

The spatio-temporal relationships of thrips populations across weeds and cotton (Gossypium hirsutum L. (Malvales: Malvaceae) crops were studied across the agricultural landscape of the Namoi Valley, New South Wales, Australia. In a structured sampling program, the seasonal patterns of host plant use by Thrips tabaci Lindeman, Frankliniella occidentalis Pergrande and F. schultzei Trybom (Thysanoptera: Thripidae) were quantified in relation to their invasion of cotton crops. Plants of 69 species (in 20 families) were sampled; T. tabaci was the most numerous thrips species and was recorded from 31 plant species, F. occidentalis was less numerous but recorded from 35 plant species, and F. schultzei was present at very low densities on 25 plant species. Both T. tabaci and F. occidentalis were mostly collected from weeds flowering in spring and summer, when these plants were most abundant. The seasonal composition of thrips populations on cotton changed from predominately T. tabaci on seedling cotton to F. schultzei and F. occidentalis on mature flowering cotton later in the season. High T. tabaci abundance on early season cotton was attributed to the abundance of T. tabaci on the surrounding weed species, because the weed hosts on which it was recorded were plentiful then. In contrast, the patterns of F. occidentalis and F. schultzei abundance on cotton were not correlated with their abundance on weeds, but rather with the emergence of cotton flowers. The genetic relationships and cryptic species identity of thrips on cotton relative to those on the other host plant species sampled was investigated through the analysis of mitochondrial CO1 gene sequences. Thrips tabaci and F. occidentalis collected from cotton were genetically identical to conspecifics collected from weeds. This is consistent with these insects moving onto cotton plants from nearby source populations on weeds. Frankliniella schultzei is a species complex in Australia, two members of which are present in this region, but only the black species was found in these surveys. This study demonstrates that (i) weeds play an important role in the population ecology of thrips, particularly in T. tabaci infesting early season cotton crops, (ii) the role of weeds warrants consideration in relation to pest management strategies, and (iii) without considering the surrounding landscape (which needs definition relative to each pest species) invasions cannot be readily understood mechanistically.

Abelmoschus angulosus var. mahendragiriensis R.C.Misra var. nov., from a gorge in the Mahendragiri hills of Odisha in the Eastern Ghats is described and illustrated. Information about the type specimen, illustration, taxonomic affinities, distribution and ecology and field photographs showing vegetative and floral parts of the new variety along with an identification key with diagnostic characters in relation to other known varieties are provided.

Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians (Xcv), can be a disease of economic importance but it occurs sporadically in production fields in Florida. We investigated the role of weeds, irrigation water, and crop debris as potential inoculum sources for Xcv. Detection and identification of Xcv was facilitated using semi-selective media and PCR with two primers pairs. During field outbreaks of the disease, epiphytic populations of Xcv were detected on 13 weed species belonging in the Asteraceae, Amaranthaceae, Aizoaceae, Chenopodiaceae, Portulacaceae, Solanaceae, and Malvaceae families. In greenhouse assays, Xcv epiphytic populations on 12 weed hosts varied greatly. Bacterial leaf spot-like symptoms developed on Sonchus oleraceus and significantly higher populations of Xcv were recovered from this weed. Bacteria were also recovered from surface irrigation water monitored during a 4-month period covering two growing seasons at three commercial sites. In two seasons of survival studies on crop debris, Xcv was recovered up to 1 month after placement of diseased tissue on the soil surface but not detected in tissue buried 15 or 30 cm beneath the soil surface. Therefore, weeds and surface irrigation water may play a role in the survival of Xcv whereas crop debris may be limited as an inoculum source during the fallow period in Florida.

Biological invasions by exotic species are among the major threats to biodiversity worldwide. The pink hibiscus mealybug (PHM) Maconellicoccus hirsutus (Green 1908) (Hemiptera: Pseudococcidae) is an invasive mealybug species that has been reported in Brazil since 2010. This species is sometimes found in mutualistic association with ants, which help spread this pest and also prey on or remove its natural enemies. Here, we describe for the first time the interactions between ants and M. hirsutus in Brazil, focusing on cocoa trees, Theobroma cacao (L., Malvaceae), and on the ornamental species Mimosa caesalpiniifolia Benth (Mimosaceae), and hibiscus Hibiscus rosa-sinensis L. (Malvaceae), all in the state of Bahia, Brazil. We collected M. hirsutus and associated ants on 50 randomly selected plants of these three species at three sites. We found a high diversity of ants (46 species) in trophobiotic interaction with the exotic mealybug. The highest ant species richness was found on hibiscus, with 33 species recorded interacting with the mealybug. Thirty ant species were observed associated with M. hirsutus on cocoa trees. We found significant differences in the ant assemblages according to site and plant species. Mutualisms with exotic species can cause profound alterations in the communities where they are inserted. This description of ant—M. hirsutus associations in Brazil is an initial step towards a better understanding of the mechanisms by which these mutual interactions become structured in the Neotropics and of their impacts on environment and agriculture.

This paper reports the presence and characteristics of the bruchid Spermophagus niger Motschulsky as a major pest of roselle (Hibiscus sabdariffa L.) seeds during post-harvest storage in Burkina Faso. Samples of roselle seeds collected in farmers granaries at three locations in Burkina Faso at the beginning of crop storage were brought to the laboratory and held for 2 months. All seed samples were infested with varying levels of S. niger, though samples from Tougan and Dedougou were more highly infested than those from Ouagadougou. Infested seeds generally had only one insect emergence hole, with seed perforation rates ranging from 1.8% to 4%. Insect rearing in the laboratory provided an opportunity for a clearer discrimination of sexual dimorphism and a better morphological description of the species. Males were smaller and weighed less than females. Post-embryonic development, which took place entirely within the seed, included four larval instars and one pupal stage; these stages are common in the subfamily Bruchinae. Our preliminary observations will enable a better understanding of this previously little-known insect pest. Furthermore, these results offer baseline data for further into appropriate post-harvest management of roselle in West Africa.

The little-known use of okra grafting, mainly to incorporate nematode resistance, requires evaluation of interspecific compatibilities. This study aimed to determine the compatibility of the okra ‘Santa Cruz 47’ cultivar grafted onto different rootstocks of the Malvaceae family. The research was divided into two experimental stages, with the treatments consisting of non-grafted, self-grafted or grafted okra plants onto rootstocks of mallow, roselle and pima cotton. In the first stage, a completely randomized design was used, with four replications and seedlings grown in a humidity chamber. In the second stage, the seedlings were transplanted to a greenhouse and a randomized block design was used, with five replications. The results of the first stage demonstrated that the self-grafting provided the best results for the growth characteristics assessed, except for the diameter of the grafted region. There was no difference among the treatments for the graft survival rate. In the second stage, the use of roselle as a rootstock enabled an adequate vegetative development, but did not differ from the treatments of self-grafting and mallow rootstock for the graft survival rate. The treatments did not differ for fruit diameter, length and average mass. Grafts onto roselle were the most precocious ones, with estimated means for production per plant (478.75 g), commercial yield (10.07 t ha-1) and total yield (10.64 t ha-1) similar to those observed for self-grafted and non-grafted plants. Hence, among the assessed rootstocks, roselle was identified as the most promising one for grafting with okra.

Cercospora leaf spot, caused by the fungal pathogen Cercospora beticola, is the most destructive foliar disease of sugar beet worldwide. This review discusses C. beticola genetics, genomics, and biology and summarizes our current understanding of the molecular interactions that occur between C. beticola and its sugar beet host. We highlight the known virulence arsenal of C. beticola as well as its ability to overcome currently used disease management strategies. Finally, we discuss future prospects for the study and management of C. beticola infections in the context of newly employed molecular tools to uncover additional information regarding the biology of this pathogen. Taxonomy Cercospora beticola Sacc.; Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Capnodiales, Family Mycosphaerellaceae, Genus Cercospora. Host range Well‐known pathogen of sugar beet (Beta vulgaris subsp. vulgaris) and most species of the Beta genus. Reported as pathogenic on other members of the Chenopodiaceae (e.g., lamb's quarters, spinach) as well as members of the Acanthaceae (e.g., bear's breeches), Apiaceae (e.g., Apium), Asteraceae (e.g., chrysanthemum, lettuce, safflower), Brassicaceae (e.g., wild mustard), Malvaceae (e.g., Malva), Plumbaginaceae (e.g., Limonium), and Polygonaceae (e.g., broad‐leaved dock) families. Disease symptoms Leaves infected with C. beticola exhibit circular lesions that are coloured tan to grey in the centre and are often delimited by tan‐brown to reddish‐purple rings. As disease progresses, spots can coalesce to form larger necrotic areas, causing severely infected leaves to wither and die. At the centre of these spots are black spore‐bearing structures (pseudostromata). Older leaves often show symptoms first and younger leaves become infected as the disease progresses. Management Application of a mixture of fungicides with different modes of action is currently performed although elevated resistance has been documented in most employed fungicide classes. Breeding for high‐yielding cultivars with improved host resistance is an ongoing effort and prudent cultural practices, such as crop rotation, weed host management, and cultivation to reduce infested residue levels, are widely used to manage disease. Useful website https://www.ncbi.nlm.nih.gov/genome/11237?genome_assembly_id=352037, The hemibiotrophic fungus Cercospora beticola applies various virulence strategies to infect sugar beet and is currently only managed in‐field through integrated practices.

A severe epidemic of a leaf blight of cotton occurred in the state of Paraná, Brazil, during 1994 and 1995, causing up to 100% yield losses in some commercial fields of cultivar Paraná 3. The severity of the disease among fields was variable and cultivar-dependent. Attempts were made to identify the organism causing the leaf blight symptoms, which were characterized as circular to irregular dark brown to black spots turning reddish brown with age and varying between 2 and 10 mm in diameter. The older lesions showed cracks and/or holes in the center. Severely diseased leaves dried rapidly and abscised. Fructifications of a fungus in the genus Stemphylium were observed on young, as well as on old, lesions. The Stemphylium sp. was consistently isolated on potato dextrose agar from disease samples collected from five cultivars in 14 locations. In inoculation tests, the Stemphylium isolates from cotton were highly aggressive to cotton, tomato, potato, and blue lupines; whereas an isolate of S. solani from tomato was highly aggressive on tomato and potato but less aggressive on cotton. On the basis of its morphological, cultural, and pathogenic characteristics, the principal pathogen causing leaf blight symptoms was identified as Stemphylium solani. Epidemics caused by S. solani on cotton have not been reported previously in commercial cotton cultivation.

A screening program to find sources of resistance to Thielaviopsis basicola in cotton identified a diploid cotton (Gossypium arboreum, PI 1415) with apparent high resistance to this pathogen. Seedlings were obtained from self-pollinated seed taken from the resistant plant (PI 1415) and grown in growth chamber tests with the cultivars (tetraploid G. hirsutum) Paymaster HS-26 and Paymaster Tejas as controls. Seedlings were grown for 20 days in naturally infested field soil and evaluated for root growth and root necrosis. In all tests, PI 1415 had less (P = 0.001) root necrosis than the cultivars HS-26 and Tejas. A triadimenol seed treatment also resulted in less (P = 0.001) root necrosis for all three cotton genotypes, and the response was additive with level of disease resistance. Incorporation of the resistance factor from PI 1415 into tetraploid upland cotton may greatly reduce damage by black root rot, especially in combination with fungicide seed treatments.

The current epidemic of cotton leaf curl disease (CLCuD) in Pakistan started in 1988 with the natural host range limited to a few plant species in the family Malvaceae. However, we have observed expansion in the host range of the virus, and several non-Malvaceous plants were found to be infected with the virus. Characteristic symptoms of CLCuD such as leaf curl and enations have been observed on radish plants, primarily in kitchen gardens. However, in 1999, levels of infection of 10 to 90% were observed both in commercial fields and kitchen gardens in the Punjab province of Pakistan. Both symptomatic and nonsymptomatic samples were collected from five different locations. Total DNA was isolated, dot-blotted on nylon membrane, and a full-length clone corresponding to DNA A of cotton leaf curl virus was labeled with 32P dCTP and used as a probe for the detection of a begomovirus. Strong signals were observed in symptomatic plants while no signals were observed in nonsymptomatic plants. Infection with a begomovirus was further confirmed by polymerase chain reaction (PCR) using degenerate primers for DNA A (1). Primers specific for the two distinct begomoviruses associated with CLCuD were also used in PCR reactions (2), and products of the expected size were obtained from all symptomatic samples, confirming infection with begomoviruses similar to those associated with CLCuD. A full-length probe of a nanovirus-like molecule associated with cotton leaf disease (3), called DNA 1 was labeled with 32P dCTP and detected the virus only in symptomatic plants. Similarly, primers specific for DNA 1 (3) amplified a product of expected size when used in PCR. On the basis of symptomatology and the detection of specific viral components associated with the disease, we confirmed that radish plants are infected with Cotton leaf curl virus (CLCuV). Since radish is a short duration crop, infection of CLCuV in radish may not serve as a direct source of infection for the next cotton crop. However, it is a potential threat to tomato crops which overlap with radish in the Punjab province. The detection of CLCuD in radish is another example of the mobilization of begomoviruses to previously unknown hosts. References: (1) M. R. Rojas et al. Plant Dis. 77:340, 1993. (2) S. Mansoor et al. Pak. J. Bot. 31:115, 1999. (3) Mansoor et al. Virology 259:190, 1999.

The effects of chicken litter incorporated 28, 14, and 0 days before planting on Meloidogyne incognita in cotton and soil organisms were determined in the greenhouse. Treatments consisted of field soil amended with litter at rates of 0, 0.125, 0.25, 0.5, and 1% by weight. At 45 and 90 days after planting, numbers of M. incognita decreased as rates of litter increased. Microbivorous nematode densities increased as litter rates increased only in the first experiment. Plant growth increased as litter rates increased, regardless of when the litter was incorporated, or the presence or absence of M. incognita. Bacterial and fungal CFU fluctuated during both experiments, but generally had positive linear relationships with litter rate. Population densities of M. incognita decreased with increasing bacterial and fungal counts in amended soil. Bacterial genera identified from the litter-amended soil included Arthrobacter, Bacillus, Cellulomonas, Mi-crococcus, Pseudomonas, and Rhodococcus.

Kenaf (Hibiscus cannabinus L.) is a fast-growing, bamboo-like annual plant belonging to the Malvaceae. The stem, which ranges from 1.5 to 4 m, presents a source of high-quality cellulose fibers. The plant is being investigated in South Africa with a view to commercial production. In April 2001, at least 50% of 4- to 5-month-old kenaf plants grown from seed in trials near Rustenburg, Northwest Province, South Africa, were observed as having powdery mildew. Signs included extensive growth of white, superficial mycelium and emergent conidiophores on the abaxial leaf surface, followed by partial defoliation. On older leaves, the abaxial leaf surface was completely covered by powdery mildew, and chlorotic and necrotic patches were clearly visible on the adaxial surface. Symptoms were observed on all five planted cultivars (Everglades 41, Cuba 108, El Salvador, SF459, and Tainung 2), and no difference in disease severity was noted among cultivars. Leveillula taurica (Lév.) Arnaud (anamorph Oidiopsis taurica [Lév.] Salmon) was subsequently identified by the presence of endophytic mycelia, often branched conidiophores, and dimorphic conidia borne singly or in short chains (1). In 100 measurements of each type, pyriform conidia averaged 69 ± 5 × 18 ± 2 μm and cylindrical conidia averaged 62 ± 6 × 16 ± 2 μm. The teleomorph was not observed. The source of L. taurica for this reported outbreak is unknown, and powdery mildew was not observed in a field of mature cotton (Gossypium hirsutum L.) growing within 10 m of the kenaf plot. L. taurica was reported on kenaf in Texas in 1992 (2) and in Italy in 1995 (3). The pathogen can cause significant losses in seed yield and reduce seed quality in susceptible kenaf cultivars. Although L. taurica has been reported from Hibiscus sabdariffa in Egypt (4), to our knowledge this is the first report of the pathogen occurring on kenaf in Africa. References: (1) H. J. Boesewinkel. Bot Rev. 46:167, 1980. (2) C. G. Cook and J. L. Riggs. Plant Dis. 79:968, 1995. (3) S. Frisullo et al. Inf. Fitopatol. 45:37–41, 1995. (4) M. Khairy, et al. Phytopathol. Medit. 10:269–271, 1971.

Two field trials at Stillwater and Bixby, OK, evaluated the efficacy of solid matrix priming techniques, alone or in combination with fungicide seed treatment on seedling emergence and reduction of damping-off of okra in field soil naturally infested with Pythium ultimum. The following treatments were evaluated: thiram + carboxin (chemo-primed) (commercially applied), biological seed treatment (bio-primed) (Trichoderma harzianum isolate OK-110, 1 g suspended in 1% carboxymethylcellulose [CMC]), untreated seed (control), and a 1% CMC control. Chemo-primed seeds had a more uniform and faster emergence compared with untreated seeds at both field sites. Within 3 days, 92 and 78% of chemo-primed seeds had emerged at Stillwater and Bixby, respectively, compared with 84 and 71% emergence in the untreated control. Mean emergence of chemo-primed seeds was lower (P ≤ 0.05) than the untreated control. Chemo-primed seeds had greater vigor (P≤ 0.05) at both locations compared with either fungicide-treated or priming alone, at both locations. There were no differences (P ≤ 0.05) in yield among treatments at both locations. P. ultimum was consistently isolated from damped-off seedlings and surrounding soil at both locations. Isolates of P. ultimum were more pathogenic on okra in laboratory tests than isolates of Rhizoctonia spp., Fusarium spp., and other Pythium spp. also isolated from seed or soil.

Kenaf (Hibiscus cannabinus L.) (Malvaceae) is a source of high-quality cellulose fibers and is being investigated in South Africa with a view to commercial production. In April 2001, 20 to 30% of 5-month-old kenaf plants grown from seed in experimental plots near Rustenburg, Northwest Province, South Africa, were affected by gray mold caused by Botrytis cinerea Pers.:Fr. Infected plants displayed brown necrotic areas that girdled the stem, resulting in wilting and lodging in at least 50% of observed cases. Symptoms included extensive growth of mycelia and gray conidia on stem lesions. Microscopic examination revealed hyaline, one-celled conidia and conidiophores conforming to the description of B. cinerea. Plating of diseased stem tissue on malt extract agar (MEA) consistently yielded B. cinerea. Koch's postulates were satisfied by applying toothpick tips (5 mm) colonized by B. cinerea on MEA to the stems of 10 120-day-old greenhouse-grown plants of each of five kenaf cultivars. A colonized toothpick tip was placed on the stem of each of five plants per cultivar at a point ≍15 cm above soil level. Another five plants of each cultivar were wounded once using a sharp dissecting needle, and a colonized toothpick tip was placed on top of each wound. Corresponding control treatments consisted of five additional plants per cultivar, each wounded and mock-inoculated with sterile toothpick tips. Inoculation points were wrapped in Parafilm. The experiment was conducted twice. Developing lesions were measured after 7 days. Mean lesion lengths for the two treatments, nonwounded and wounded, on the five cultivars were, respectively: 32.4 and 35.2 mm for Everglades 41; 14.9 and 53.8 mm for Cuba 108; 39.5 and 55.8 mm for El Salvador; 19.0 and 44.3 mm for SF459; and 12.4 and 43.9 mm for Tainung 2. The Newman-Keuls multiple comparison test revealed no significant difference (P < 0.05) in means among cultivars for the wounded treatment. For the nonwounded treatment, Everglades 41 and El Salvador were significantly more susceptible (P < 0.05) than the three remaining cultivars. No lesions developed on control treatments. The fungus was reisolated on MEA from all artificially inoculated plants. The pathogen is reported to cause serious losses in yield and fiber quality of kenaf in Spain (1). This is the first report of B. cinerea on kenaf in South Africa, and its potential impact on kenaf production in this country should be taken seriously. Reference: (1) A. De Cal and P. Melgarejo. Plant Dis. 76:539, 1992.

A novel tobamovirus recently was isolated from hibiscus in Florida. Serological and molecular methods, including enzyme-linked immunosorbent assay (ELISA), dot-blot immunoassay (DBIA), tissue-blot immunoassay (TBIA), and immunocapture reverse-transcription poly-merase chain reaction (IC-RT-PCR) were compared to evaluate their usefulness for diagnosis of this virus. Each method was tested with partially purified virus preparations and tissue samples from infected hibiscus and Chenopodium quinoa plants. Indirect ELISA was more sensitive than double-antibody sandwich (DAS)-ELISA with all samples tested. The Florida hibiscus virus was detectable in hibiscus leaves and bark up to 1:12,800 and 1:6,400 dilutions, respectively, by indirect ELISA and up to 1:3,200 and 1:400 dilutions by DAS-ELISA. End-point dilutions of partially purified virus preparations from indirect and DAS-ELISA were 4 and 31 ng/ml, respectively. Florida hibiscus virus was detected by DBIA in sap from hibiscus bark and leaves at dilutions up to 1:400 and 1:800, respectively, showing that DBIA was less sensitive than either ELISA method. The virus also was detected reliably by TBIA from leaves and bark of hibiscus plants. The most sensitive method was IC-RT-PCR, which could detect as little as 500 pg/ml of virus in partially purified preparations and was 16- and 32-fold more sensitive than DAS-ELISA with hibiscus bark and leaf extracts, respectively. Over 600 hibiscus samples were tested by various combinations of these methods to validate their usefulness.

Three aspects of the infection process of a new tobamovirus species, Hibiscus latent Fort Pierce virus, recently isolated from hibiscus in Florida, were examined: (i) transmission efficiency of rub-, slash-, and cut-inoculation for two hibiscus cultivars, Pink Versicolor and Brilliant Red; (ii) distribution within infected hibiscus plants; and (iii) treatments to prevent infection during plant propagation and pruning. Rub-, slash-, and cut-inoculation methods were all effective and yielded infection rates of 66, 74, and 70%, respectively, in Pink Versicolor and 50, 56, and 38%, respectively, in Brilliant Red. Analysis of virus distribution in infected plants over time revealed that the virus moved from the place of inoculation to the roots and then toward the bottom (oldest) leaves of the plants. Virus was found in all leaves on branches of Brilliant Red plants at 210 days postinoculation, whereas it remained restricted to the bottom and middle leaves of Pink Versicolor plants at 290 days postinoculation. Although several treatments of tools reduced infection of hibiscus during experiments mimicking plant propagation and pruning, 10% (wt/vol) sodium hypochlorite and 20% (wt/vol) nonfat dry milk completely prevented infection.

Kenaf, Hibiscus cannabinus L. (Malvaceae), is being planted commercially in South Africa for the high quality cellulose fibers that it produces. In a January 2001 survey of 3-month-old kenaf plants grown from seed in experimental plots near Rustenburg, Northwest Province, 30% of plants were observed with severe wilting. Stems at ground level of all infected plants had sunken tan lesions, white mycelial strands, and small, dark brown, 1 to 2 mm diameter sclerotia. Isolations from diseased stem tissue on malt extract agar (MEA) consistently yielded a fungus conforming to the description of Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough). Pathogenicity tests were conducted by applying toothpick tips (5 mm) colonized by S. rolfsii on MEA to the stems of 120-day-old potted plants of 10 kenaf cultivars in the greenhouse. Five plants of each cultivar were wounded once using a sharp dissecting needle, and a colonized toothpick tip was placed on top of each wound. Control treatments consisted of five plants per cultivar each wounded and inoculated with sterile toothpick tips. All inoculation points were wrapped using Parafilm, and the experiment was conducted twice. Lesions were measured after 10 days. Mean lesion lengths for the 10 cultivars were as follows: Dowling (34.9 mm), Cuba 108 (38.6 mm), Gregg (41.1 mm), Everglades 41 (44.2 mm), SF459 (44.9 mm), Tainung 2 (45.8 mm), El Salvador (45.9 mm), Whitton (46.1 mm), Everglades 71 (46.4 mm), and Endora (54.0 mm). The Newman-Keuls multiple comparison test revealed that cvs. Dowling and Endora were significantly more resistant and more susceptible (P < 0.05), respectively, than the other cultivars. Lesions did not develop on control plants. The fungus was reisolated on MEA from all artificially inoculated plants. The pathogen is reported to cause serious losses in yield and fiber quality of kenaf (1). To our knowledge, this is the first report of S. rolfsii on kenaf in South Africa. Commercial plantings of kenaf in South Africa are expected to exceed 500 ha during the next 2 years, so its potential impact on kenaf production in this country will be significant if efficient disease control measures are not practiced. References: (1) J. M. Dempsey. Kenaf. Pages 203–304 in: Fiber Crops. The University Press of Florida, Gainesville, 1975.

Jaime-Garcia, R., and Cotty, P. J. 2004. Aspergillus flavus in soils and corncobs in South Texas: Implications for management of aflatoxins in corn–cotton rotations. Plant Dis. 88:1366-1371. Aspergillus flavus causes aflatoxin contamination in both cottonseed and corn. Corn–cotton rotations are common in South Texas, where reduced tillage frequently results in long-term residence of corncobs on soil surfaces. Corncobs are colonized by A. flavus either prior to harvest or while in the soil. This study sought to determine the potential of corncobs as sources of inoculum for cotton and corn in South Texas. A. flavus communities in corncob and soil samples were collected during the planting seasons of 2001 to 2003 from 29 fields extending from Calhoun and Victoria Counties in the north to the Rio Grande Valley. In order to assess persistence of A. flavus in corncobs, A. flavus communities in corncobs and soil were contrasted every 2 to 3 months in four fields throughout the 3-year study. To assess seasonal variation, similar contrasts were performed in two fields on a biweekly basis. The results indicate that corncobs are major sources of A. flavus inoculum. Corncobs from the previous season contained, on average, over 190 times more A. flavus propagules than soil from the same field, and 2-year-old corncobs still retained 45 times more propagules than soil. There was no significant difference in the incidence of A. flavus strain S on corncobs and soil. The quantity of A. flavus in corncobs decreased with corncob age (r2 = 0.54; P = 0.002).

The soilborne fungus Sclerotinia minor Jagger is a major pathogen of peanut (Arachis hypogaea L.) in North Carolina, Virginia, Oklahoma, and Texas. The pathogen attacks several winter annual weed species (1). Economic crops that are hosts to S. minor are seldom grown in rotation with peanut; therefore, its pathogenicity on weed species is of importance in understanding how inoculum densities are maintained between peanut crops. During September 2004, signs of fluffy, white mycelium, small, black sclerotia, and symptoms of bleached leaves and stems were observed on prickly sida (Sida spinosa L.) in a peanut field in Bertie County, NC. Plants of prickly sida with similar signs and symptoms were observed previously in a Chowan County, NC peanut field. Prickly sida is one of several weed species commonly found in peanut fields and rotational crops in agricultural areas of northeastern North Carolina. Cultivation and herbicides usually keep prickly sida under control in the early part of the growing season, but as the summer progresses into early fall, it can become prevalent, as was true in the two fields reported here. Symptomatic tissues were excised into 1- to 2-cm sections, rinsed in tap water, blotted dry, and placed on potato dextrose agar (PDA). The pure cultures with small, black irregular-shaped sclerotia ( Reference: (1) J. E. Hollowell et al. Plant Dis. 87:197, 2003. (2) M. S. Melzer et al. Can. J. Plant Pathol. 19:272, 1997.

Monfort, W. S., Kirkpatrick, T. L., and Rothrock, C. S. 2006. Effects of nocturnal soil temperatures and Meloidogyne incognita densities on cotton seedling growth and the interaction with Thielaviopsis basicola. Plant Dis. 90:519-522. Controlled studies were conducted to evaluate the effects of soil temperatures typical of field conditions during the first 6 weeks of the growing season in Arkansas and different population densities of Meloidogyne incognita on damage to cotton (Gossypium hirsutum) seedlings associated with the interaction between M. incognita and Thielaviopsis basicola. Treatments consisted of varying nocturnal temperatures that approximated the temperatures that occurred during the 2001, 2002, and 2003 growing seasons in southeastern Arkansas. Nocturnal temperatures in the study were as follows: high, the first week at 15°C, followed by 3 weeks at 17°C, 1 week at 21°C, and 1 week at 17°C (approximating the 2002 season); medium, 3 weeks at 15°C and 3 weeks at 19°C (approximating the 2003 season); and low, 1 week at 15°C, 1 week at 13°C, 2 weeks at 17°C, 1 week at 15°C, and 1 week at 17°C (approximating the 2001 season). Pathogen population densities were either 0 or 100 chlamydospores of T. basicola per gram of soil and 0, 2,000, 4,000, or 8,000 eggs of M. incognita per 500 cm3 of soil. Plant height and fresh top weight increased with an increase in nocturnal temperature across treatments. There were significant reductions in plant growth and development with T. basicola, but not with M. incognita, at these nocturnal temperatures, but decreased plant height and weight were seen where both pathogens were present in comparison with either pathogen alone. Trends of increased disease associated with T. basicola were observed with increasing inoculum rates of M. incognita, indicating that the interaction between T. basicola and M. incognita occurs even at soil temperatures below the minimum temperature reported as necessary for damage from M. incognita.

Moran, P. J., and Showler, A. T. 2007. Phomopsis amaranthicola and Microsphaeropsis amaranthi symptoms on Amaranthus spp. under south Texas conditions. Plant Dis. 91:1638-1646. Temperature, humidity, weed species and age, and inducible responses in the host are factors that could limit the efficacy of fungal bioherbicides. The influences of these factors on the efficacy of the fungal bioherbicides Phomopsis amaranthicola and Microsphaeropsis amaranthi against Palmer amaranth (Amaranthus palmeri), smooth pigweed (Amaranthus hybridus), and redroot pigweed (Amaranthus retroflexus) were investigated in greenhouse and field studies under south Texas conditions. Despite plants being given an initial dew period, the bioherbicides, applied individually or in combination, did not cause mortality on any pigweed species in greenhouse or field environments. In greenhouse experiments, fewer than 5% of the leaves in six- to eight-leaf A. palmeri plants developed necrotic lesions within 2 weeks after bioherbicide treatment and only 8% or fewer of the plants developed stem lesions. Disease incidence was significantly higher in A. hybridus and A. retroflexus, with as much as 94% of leaves developing necrosis and 95% of the plants having stem lesions. New leaf production was reduced by biobherbicide treatment in A. hybridus. Combined-pathogen inoculation caused leaf and stem lesions on mature (13 to 36 leaves per plant) A. hybridus and A. retroflexus. Summer and fall field inoculations with M. amaranthi on A. hybridus and A. palmeri produced disease incidence levels similar to or higher than those in greenhouse tests. Infection of A. palmeri by P. amaranthicola increased the peroxidase activity level nearly twofold compared with the controls. Neither pathogen influenced leaf free amino acid content. The high temperatures and low humidity of south Texas and interspecific variation in resistance, possibly linked to peroxidase induction, limited the efficacy of these bioherbicides.

Tomaso-Peterson, M., and Trevathan, L. E. 2007. Characterization of Rhizoctonia-like fungi isolated from agronomic crops and turfgrasses in Mississippi. Plant Dis. 91:260-265. Twenty-three isolates of Rhizoctonia spp. from agronomic crops and turfgrasses were characterized by cytological and pathological methods in order to establish the identity, pathogenicity, and virulence of Rhizoctonia spp. and anastomosis groups that occur on these hosts in Mississippi. Twelve isolates were identified as R. solani, including the five anastomosis groups (AGs) AG-1IB, AG-2-2, AG-4, AG-5, and AG-13. Rhizoctonia zeae, R. oryzae, and eight binucleate Rhizoctonia sp., including R. cerealis, also were identified. R. solani AG-4 isolates were consistently the most virulent isolates on all hosts in pathogenicity evaluations. Pathogenicity of AG-2-2 and AG-5 isolates, binucleate Rhizoctonia spp., and R. oryzae varied between hosts. Two AG-2-2 isolates from bermudagrass or wheat were determined to be clonal isolates, with numerous selfanastomosis reactions. R. solani (AG-1-IB) was pathogenic on all graminaceous hosts. R. cerealis produced sharp eyespot symptoms on wheat and corn and minimal symptoms on cotton and soybean. This is a first report of R. cerealis as a pathogen of corn. R. zeae isolates were pathogenic on all hosts, including cotton and soybean. These results indicate that a diverse group of Rhizoctonia spp. occurs as pathogens on a wide variety of agronomic crops and turfgrasses in Mississippi.

Kenaf (Malvaceae; Hibiscus cannabinus L.) is being commercially cultivated in Winterton, South Africa for its high-quality cellulose fibers with approximately 2,000 ha currently under cultivation. In 2004, 25% of 1-month-old kenaf plants grown from seed were observed in the field with severe wilting followed by lodging and mortality within 1 week. Isolations from diseased stem and root tissue on malt extract agar (MEA) consistently yielded Fusarium verticillioides (Sacc.) Nirenberg (2). Pathogenicity tests were conducted by inoculating kenaf seedlings with inoculum prepared from barley grains that had been colonized by the pathogen in vitro for 2 weeks prior to being finely ground in a laboratory mill. Fifty seeds from each of eight kenaf cultivars were incubated at 25°C on sterile filter paper to ensure germination and the absence of pathogens. Germinated seeds were sown in pots (400 cm3) containing steam sterilized loam soil (200 g) by placing 20 germinated seeds from each cultivar, with four replicates (5 seeds per pot), on the soil in each pot and covering them with 100 g of the same soil. Inoculum powder was sprinkled on the surface of the soil in each pot and covered by 100 g of soil. Pots were maintained in a glasshouse at an ambient temperature of 25°C. Sterile ground barley seeds served as the control treatment. Pots were watered daily with 20 ml of water and observed periodically for seedling emergence. The percentage of diseased seedlings was recorded after 3 weeks and the experiment was repeated. Wilting had occurred in 85% of seedlings when they were approximately 4 cm high and all diseased seedlings had died within 1 week thereafter. Subsequent examination revealed dark brown lesions girdling the stem and decayed roots in all instances. No symptoms developed on control plants. From means of combined data, the greatest seedling mortality was observed for cv. Gregg (65%) and the least for cv. Cuba108 (5%). Mean mortalities for the remaining six cultivars ranged from 30 to 55%. The pathogen was reisolated on MEA from all diseased seedlings. To our knowledge, this is the first report of F. verticillioides occurring on kenaf in South Africa. The only other report of Fusarium sp. causing serious damping-off of kenaf is from Iran (1). The potential impact of the pathogen on kenaf production in South Africa must be considered in the implementation of disease control measures. References: (1) J. M. Dempsey. Kenaf. In: Fiber Crops. The University Press of Florida, Gainesville, 1975. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006.

Cotton (Gossypium hirsutum) entries were evaluated for resistance to the whitefly (Bemisia tabaci biotype B) and cotton leaf crumple (CLCr) disease during the 1999 to 2001 growing seasons in the Imperial Valley of California. Entries were evaluated for densities of whitefly adults and nymphs, and for CLCr, by visual rating and squash/dot blot hybridization analyses. Differences in whitefly densities were detected among entries, but none were highly resistant, nor was there any correlation with CLCr disease severity. Entries AP 4103 and AP 6101 had relatively low whitefly densities and were highly susceptible (high CLCr disease severity ratings and viral titers), whereas NK 2387C and DPX 1883 also had low whitefly densities but were highly resistant (no symptoms or detectable viral titers). Other entries showed moderate CLCr resistance, which was independent of whitefly density. Geminivirus DNA-A and DNA-B components were consistently detected in cotton leaves with CLCr symptoms by polymerase chain reaction (PCR) with degenerate begomovirus primers, and full-length DNA-A and DNA-B clones were obtained. Cotton seedlings inoculated with these cloned DNAs by particle bombardment developed CLCr symptoms, and progeny virus was whitefly-transmissible. Sequence analysis revealed that these clones comprised the genome of a California isolate of the bipartite begomovirus Cotton leaf crumple virus (CLCrV-CA). Thus, CLCr disease in the Imperial Valley is caused by CLCrV-CA, and cotton entries with high levels of resistance were identified.

Sida is a genus of flowering herbs in the family Malvaceae, which includes several species that are weeds in Brazil. Plants of a Sida sp. exhibiting symptoms characterized by stunting, chlorosis, small leaves, and witches'-broom, indicative of infection by phytoplasmas, were found in a field previously cultivated with tomato, located in the region of Campinas, State of São Paulo, in December 2008. To demonstrate the presence of phytoplasmas in diseased tissues, DNA was extracted from shoots and leaves from three symptomatic and eight asymptomatic plants. Nested PCR was performed using primers P1/Tint followed by primer pair R16F2n/R16R2 (1). DNA fragments of 1.2 kb, corresponding to 16S rDNA, were amplified only for DNA from two symptomatic samples. Phytoplasma identification was initially carried out by restriction fragment length polymorphism (RFLP) analysis through digesting the PCR products with the restriction enzymes AluI, HhaI, HaeIII, HpaII, MseI, and RsaI. The two phytoplasma isolates found to be infecting a Sida sp. showed identical RFLP patterns, which were indistinguishable from the phytoplasma previously reported in association with hibiscus (Hibiscus rosa-sinensis) witches'-broom in Brazil (2). Nucleotide sequence alignment revealed that 16S rDNA of both phytoplasma isolates found in a Sida sp. (GenBank Accession No. HQ230579) shared 99.9% sequence similarity with 16S rDNA from hibiscus witches'-broom phytoplasma (HibWB) (GenBank Accession No. AF147708). HibWB is the representative of the 16SrXV group and it was proposed as a putative species nominated “Candidatus Phytoplasma brasiliense” (2). The disease is frequently observed in hibiscus plants used as ornamentals in the states of São Paulo (4) and Rio de Janeiro (2). “Ca. Phytoplasma brasiliense” has only been reported in Brazil to be infecting hibiscus (2,4) and periwinkle (Catharanthus roseus) (3). The presence of a phytoplasma belonging to group 16SrXV in a Sida sp. expands its natural host range. The role of this weed as a potential source of inoculum for crops should be investigated. References: (1) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) H. G. Montano et al. Int. J. Syst. Evol. Microbiol. 51:1109, 2001. (3) H. G. Montano et al. Plant Dis. 85:1209, 2001. (4) E. G. Silva et al. Summa Phytopathol. 35:234, 2009.

Isolates of Rhizoctonia spp. were obtained during the spring of 2007 from diseased cotton and tobacco seedlings showing damping-off symptoms. The sampled fields were located in the main cotton- and tobacco-cultivating regions of central and northern Greece. Among the 79 isolates obtained from cotton plants, 17 were binucleate and 62 were multinucleate whereas, among the 89 isolates obtained from tobacco plants, 87 were multinucleate and only 2 were binucleate. Characterization of anastomosis groups (AGs) was performed with hyphal anastomosis reactions using tester isolates of known AG groups. Anastomosis reactions in cotton mutlinucleate isolates showed that 54 of them belonged in Rhizoctonia solani AG-4, 6 in AG-7, 1 in AG-2, and 1 in AG-3. In the 87 tobacco multinucleate isolates, anastomosis reactions showed that 70 of them belonged in R. solani AG-2, 16 in AG-4, and 1 in AG-5. In addition, molecular characterization was carried out using the specific ribosomal DNA internal transcribed spacer region, in a randomly selected number of isolates. In cotton, the most prevalent AG was AG-4, with 18 isolates to the subgroup HG-I, 1 isolate to the subgroup HG-II, and 7 isolates to the subgroup HG-III, followed by AG-7 (7 isolates), AG-2-1 (1 isolate), and AG-3 (1 isolate). In tobacco, the most prevalent group was AG-2-1 (70 isolates), followed by AG-4 (6 isolates to the subgroup HG-I and 5 isolates to the subgroup HG-III) and a single isolate belonging to AG-5. Phylogenetic analysis showed that the isolates were distinctly separated based on their AG types. Pathogenicity and aggressiveness of the isolates to several hosts was determined. AG-4 isolates from either cotton or tobacco were the most aggressive on the hosts tested, while AG-2-1 isolates were of moderate aggressiveness and were not pathogenic on barley.

Kenaf (Hibiscus cannabinus L.; Malvaceae) is an annual fiber crop that has recently been introduced as a niche crop in Israel, and grown mainly at areas with high summer temperatures. It is advantageous in crop rotation in these areas since it can rapidly accumulate biomass under high temperatures when other crops (e.g., tomato, sunflower, corn, and sorghum) cannot be cultivated. Additionally, the fact that it can be irrigated with waste water makes it attractive under these climatic conditions. Broomrapes (Phelipanche and Orobanche spp.) are chlorophyll-lacking obligatory root-parasitic plants that parasitize the root system of many field crops and vegetables (1). Parasitism by P. aegyptiaca has economic impacts on various crops belonging to several botanical families (e.g., Solanaceae, Apiaceae, Fabaceae, and Asteraceae). This parasitic weed is common in most agricultural areas in Israel including the coastal plain, Yisre'el Valley, the Jordan Valley, and the Negev Desert. High infection levels by P. aegyptiaca have result in a severe yield losses and quality reduction in these crops. Parasitism of P. aegyptiaca on kenaf was observed in September 2012 in a field located in Bet-Shean Valley (Latitude 32° 30' N; Longitude 35° 30' E; 105 m), with an average density of 0.7 plant/m2, in a total area of 0.3 ha. This crop was planted on May 2012 in plots that were previously affected. Infection did not lead to visible symptoms or damage to kenaf, but allowed seed production by the parasite. In order to verify that kenaf was a host of P. aegyptiaca, 10 samples of kenaf plants infected with P. aegyptiaca were taken to the lab and the root systems of the plant and the parasite were carefully washed. Cross-sections of the connection between kenaf and the parasite were taken and inspected for xylem connections under a compound microscope (BX61, Olympus) equipped with high-resolution digital camera (DP-70, Olympus), under 40× magnification. A clear xylem connection between the weed's tubercles and kenaf roots was observed, confirming the development of functional Phelipanche haustoria. To our knowledge, this is the first report of kenaf as a host for P. aegyptiaca. Kenaf has been reported to induce the germination of O. cernua in India (3). Cotton, another member of the Malvaceae, has also been reported to stimulate seed germination of O. minor (4) and P. aegyptiaca (2). However, to the best of our knowledge, this finding reports the first occurrence of a Malvaceae crop as a host for P. aegyptiaca. References: (1) H. Eizenberg et al. Weed Sci. 55:152, 2007. (2) M. Ghotbi et al. Int. J. Agri. Sci. 2:62, 2012. (3) G. V. G. Krishnamurthy et al. Indian J. Weed Sci. 9:95, 1977. (4) Y. Ma et al. Agron. J. 104:569, 2012.

Background The cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), is a pest of upland cotton, Gossypium hirsutum L. (Malvales: Malvaceae), that attacks pre-floral buds (squares), leading to abscission and yield losses. In the Brazos Valley cotton production area of Texas (USA), P. seriatus exhibits a seasonal pattern of host use. In spring, eggs hatch from stems of the overwintering host, woolly croton, Croton capitatus Michx. (Malpighiales: Euphorbiaceae). During the growing season, individuals feed on a variety of host plants, including cotton. Adults return to woolly croton at season end to oviposit. We investigated if genetic differentiation exists between populations infesting cotton and those infesting alternative hosts, and whether woolly croton serves as a year-end site of admixture that could be suitable as a natural refuge for the purposes of insect resistance management. We combined high-throughput DNA sequencing with fine-scale spatio-temporal sampling to test (i) whether a population genomic approach would recover patterns of genetic variation consistent with earlier studies and (ii) if local genetic population structure was robust to seasonal changes in local habitat over time. Results We found high gene flow among populations of P. seriatus collected from different host plants in the Brazos Valley. We also identified temporal instability of the local population genetic structure, including the near complete loss of a genotypic group that had been previously abundant. Conclusion We support the status of woolly croton as a natural refuge that promotes year-end gene flow between genotypes infesting cotton and those infesting alternative hosts. © 2019 Society of Chemical Industry.

Common mallow (Malva sylvestris L.) is a perennial medicinal plant in the Malvaceae family, which is native to Asia, Europe, and North Africa. In July 2012, typical symptoms of anthracnose disease, with a disease incidence of ~70%, were observed on common mallow in the Medicinal Herb Garden of Shenyang Pharmaceutical University, Liaoning, China. The fungus mainly infected the stalks and leaves of M. sylvestris. Pinpoint, brownish lesions initially appeared at the flowering stage and the disease spread within the field. The lesions on stems gradually enlarged and became dark brown, elliptical, and slightly concave. Concurrently, acervuli and mucilaginous conidial masses of the pathogen appeared on lesions under moist conditions. Conidia were hyaline, one-celled, cylindrical with both ends rounded, and measured 10.0 to 12.5 × 2.5 to 4.0 μm (mean 11.3 × 3.3 μm). The fungus was isolated from symptomatic tissues. Small pieces from leaves and stems were surface disinfested with 70% ethanol and 1.5% sodium hypochlorite for 1 min, then rinsed three times with sterile distilled water, and cultured on potato dextrose agar (PDA) at 25°C. The colonies on PDA had initially white aerial mycelia, and later became greenish black with regularly whorled rings. To confirm Koch's postulates, five 3-month-old plants of M. sylvestris were inoculated with a conidial suspension (105 conidia/ml) prepared from PDA cultures incubated for 14 days. Five non-inoculated plants served as controls. The plants were maintained in the greenhouse at 22 to 25°C and about 75% relative humidity under natural daylight. Typical symptoms on inoculated plants were reproduced after ~10 to 14 days, whereas control plants remained asymptomatic. The pathogen was successfully recovered from symptomatic tissues and re-identified, completing Koch's postulates. The internal transcribed spacer (ITS) and large subunit -28S (LSU) region of rDNA was amplified with primers ITS1/ITS4 and NL1/NL4, respectively, and sequenced. Phylogenetic trees (ITS and LSU) that were obtained using MEGE3.1 with the neighbor-joining method showed that both of the isolates fall in the Colletotrichum trifolii clade. The representative sequences (ITS and LSU) were deposited in GenBank (Accession Nos. KJ155692 and KJ920935). The fungus isolated from symptomatic tissues was identified as C. trifolii on the basis of morphological, cultural characteristics, and sequence analysis (2). According to previous references, C. orbiculare and C. malvarum on Malvaceae were respectively described in America and Europe (1,3,4). However, the isolate from M. sylvestris significantly differed from those of C. orbiculare and C. malvarum in cultural characteristics and sequence analysis. In this paper, the results showed that M. sylvestris is a new host of C. trifolii. To our knowledge, this is the first report of mallow anthracnose caused by C. trifolii in China. References: (1) J. A. Bailey et al. Phytopathology 86:1076, 1996. (2) U. Damm et al. Fungal Divers. 61:29, 2013. (3) K. Hyde et al. Fungal Divers. 39:147, 2009. (4) L. Tosi et al. Plant Dis. 88:425, 2004.

Okra [Abelmoschus esculentus (L.) Moench], which belongs to the family Malvaceae, is widely grown in the tropics, sub-tropics and warmer areas of the temperate zones for its immature seed pods which are consumed as a vegetable. In China, okra pods are consumed as not only vegetables but also as a traditional medicine to cure dental diseases and gastric ulcers. During September 2018 to June 2019, extensive spots on okra leaves were observed in several commercial fields (approximately 2.0 hectares), with disease incidence of approximately 25%~50% in the Yanqing District (115°98'E, 40°46'N) of Beijing, China. Symptoms of the disease initially appeared as small pale brown spots with yellow haloes. As the disease progressed, some spots gradually coalesced, forming larger irregular dark brown lesions. The centers of the lesions became grayish white. A total of 13 small fragments (3 to 5 mm) excised from the lesion margins were sterilized in 1% sodium hypochlorite (NaClO) for 1 min, followed by three washes with sterile distilled water, and then placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 5 days. In total, 21 cultures were obtained and purified by single-spore subcultures on PDA for morphological identification. The colonies on PDA were whitish to gray, with cottony aerial mycelium. Conidiophores were fasciculate, olivaceous brown, straight or geniculate, uniform in width, multiseptate, and ranged from 286/span> to 711 μm (avg. = 578 μm, n = 50). Conidia were hyaline, slightly curved or straight, needle shaped, truncate at the base, and terminal at the tip, 3-17-septate, and measuring 52 to 231 μm (avg. = 182 μm, n = 50). The morphological features were consistent with Cercospora cf. flagellaris Ellis & G. Martin (Groenewald et al. 2013). Pathogenicity tests were conducted on potted okra plants cv. 'Jiayuan'. Twenty four healthy okra plants at the true leaf stage were sprayed with conidial suspensions (1 × 106 conidia/mL), incubated at a glass cabinet maintained at 25°C and 90% relative humidity (RH). To each leaf approximately 10 mL of conidial suspension was applied. Plants sprayed with water were used as controls. Seven days later, dark brown spot, which were identical to those observed in the fields, were observed on inoculated leaves, whereas the control plants remained healthy. C. cf. flagellaris was reisolated from symptomatic leaves, confirming Koch's Postulates. Genomic DNA was extracted from fungal mycelium using the Plant Genomic DNA Kit (Tiangen Biotech Co. Ltd., Beijing, China). The nuclear ribosomal internal transcribed spacer region (ITS), and portions of the actin (ACT), histone H3 (HIS3), and translation elongation factor 1-α (TEF1) genes were amplified using primers ITS1/ITS4 (Groenewald et al. 2013), ACT-512F/ACT-783R (Carbone & Kohn 1999), CYLH3F/CYLH3R (Crous et al. 2006), and EF1-728F/EF1-986R (Carbone & Kohn 1999). The resulting 542 bp ITS, 226 bp ACT, 410 bp HIS3 and 306 bp TEF1 sequences of isolate QK14091813 were deposited in GeneBank (Accession nos. MT949700, MT949701, MT949702 and MT949703, respectively). The ITS, ACT, HIS3 and TEF1 sequences shared 99.42% to 100% identities to previously published sequences of C. cf. flagellaris (Accession nos. MN633275 for ITS, MF680960 for ACT, MK991295 for HIS3, and MK991292.1 for TEF1, respectively). Multi-locus phylogenetic analyses (ITS, ACT, HIS3, and TEF1) were performed by neighbor-joining method using MEGA 7.0. The resulting trees showed that C. cf. flagellaris isolate QK14091813 (this study) nested within the clade that includes other isolates of C. cf. flagellaris with a 99% confidence level. To our knowledge, this is the first report of C. cf. flagellaris causing leaf spot on okra (Farr and Rossman 2020). The pathogen has a worldwide distribution and an unusually broad host range, which can be of great significance, and the plant protection policy of priority to prevention and synthetical prevention should be followed.

Seashore mallow (Kosteletzkya pentacarpos) is a flowering perennial halophytic herb belonging to the family Malvaceae that is found in marshes along the Atlantic and Gulf coasts of the United States. Fourteen accessions were collected from wild populations along the Atlantic (n = 8) and Gulf (n = 6) coasts of the United States and fatty acid profiles were determined from seeds cultivated in one or more of three controlled environments. Those growth environments were a greenhouse and field plots irrigated with freshwater and field plots irrigated with saltwater, all of which were located in Lewes, DE. Twenty-four of the 42 combinations were selected for fatty acid analysis. The principal fatty acid identified in all accessions was linoleic acid (53.1 ± 2.8%), with significant amounts of palmitic (20.7 ± 1.3%), oleic (13.7 ± 1.4%), and stearic (1.8 ± 0.5%) acids also detected. Additionally, significant amounts of cyclopropyl fatty acids such as malvalic (5.2 ± 0.7%) and dihydrosterculic (1.2 ± 0.5%) acids were also identified, along with trace amounts of sterculic acid. Minor fatty acids (

Programmed cell death (PCD) plays a critical role in the development of plant pigment glands, while H2O2, which is a kind of reactive oxygen species (ROS) produced by the aerobic metabolism of cells, acts as an important signal in this process. Here, we investigated the temporal and spatial dynamics of accumulated H2O2 in pigment glands of Gossypium hirsutum L. with 3,3-diaminobenzidine (DAB) staining, 2',7'-dichlorodihydrofluorescein diacetate (DCFH2)-DA fluorescent labeling and CeCl3 cytochemical localization techniques. The results showed that the pigment glands of G. hirsutum could generate H2O2, and the amount and localization of H2O2 varied at different developmental stages. At the early developmental stage, a small amount of H2O2 accumulated in the vacuole membrane of pigment gland cells. At the intermediate stage, a large number of H2O2 appeared in the vacuole membrane, while cell walls started to accumulate a small amount of H2O2. When pigment gland cell degraded, H2O2 mainly accumulated on the chloroplast envelope membrane of inner sheath cells. With the degradation of the sheath cells, H2O2 was detected in cell wall and the membrane of secretory vesicles which contains the preliminary contents of pigment gland. With the pigment glands completely maturation, H2O2 would disappeared. The accumulation sites of H2O2 are consistent with the process of PCD of individual gland cells, which started from the degradation of intracellular membrane and ended with the degradation of cell walls. Thus H2O2 probably plays an important role in the development of pigment glands. In addition, the development of pigment glands and the generation of H2O2 are not associated with the light, and no H2O2 was detected in the secretions of pigment glands.

This study investigated the olfactory responses of 3 thrips species [Frankliniella schultzei Trybom, F. occidentalis Pergrande and Thrips tabaci Lindeman (Thysanoptera: Thripidae)] to cotton seedlings [Gossypium hirsutum L. (Malvales: Malvaceae)] simultaneously damaged by different combinations of herbivores. Cotton seedlings were damaged by foliar feeding Tetranychus urticae Koch (Trombidiforms: Tetranychidae), Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), Aphis gossypii Glover (Hemiptera: Aphididae) or root feeding Tenebrio molitor L. (Coleoptera: Tenebrionidae). Thrips responses to plants simultaneously damaged by 2 species of herbivore were additive and equivalent to the sum of the responses of thrips to plants damaged by single herbivore species feeding alone. For example, F. occidentalis was attracted to T. urticae damaged plants but more attracted to undamaged plants than to plants damaged by H. armigera. Plants simultaneously damaged by low densities of T. urticae and H. armigera repelled F. occidentalis but as T. urticae density increased relative to H. armigera density, F. occidentalis attraction to coinfested plants increased proportionally. Thrips tabaci did not discriminate between undamaged plants and plants damaged by H. armigera but were attracted to plants damaged by T. urticae alone or simultaneously damaged by T. urticae and H. armigera. Olfactometer assays showed that simultaneous feeding by 2 herbivores on a plant can affect predator-prey interactions. Attraction of F. occidentalis to plants damaged by its T. urticae prey was reduced when the plant was simultaneously damaged by H. armigera, T. molitor, or A. gossypii and F. schultzei was more attracted to plants simultaneously damaged by T. urticae and H. armigera than to plants damaged by T. urticae alone. We conclude that plant responses to feeding by 1 species of herbivore are affected by responses to feeding by other herbivores. These plant-mediated interactions between herbivore complexes affect the behavioral responses of thrips which vary between species and are highly context dependent.

Sheep dietary selection from species-diverse Caatinga rangeland of semi-arid northeastern Brazil has not been documented. This study examined the botanical composition of the available forage and diets of Dorper x Saint Ines ewes on thinned Caatinga over-seeded with Cenchrus ciliaris and Urochloa mosambicensis. Sixty-three species from 23 families, dominated by shrubs and short trees of low forage nutritive value, were identified in the vegetation. The botanical composition revealed, on average, high presence of 29.2% Malvaceae and 13.0% C. ciliaris. Using the microhistological technique, sheep showed, on average, 59.6% preference for dicotyledons throughout the year. However, selectivity indexes indicated, on average, greater selection for Poaceae during the rainy season (1.5) and for dicotyledons in the dry season (1.8) with a year-round aversion for Malvaceae (0.3). These findings suggest that Caatinga vegetation management should include Malvaceae thinning and greater incorporation of grasses and herbaceous legumes to improve rangeland carrying capacity. Keywords: Brazil, continuous stocking, dietary selection, microhistological technique, principal components.DOI: 10.17138/TGFT(4)71-81

Velvetleaf (Abutilon theophrasti), an annual plant in the family Malvaceae, is an important source of fiber and medicine (Flora of China 2007; Su et al. 2010). Dark brown lesions were observed on the leaves of A. theophrasti in the Herbal Garden of Jilin Agricultural University (125.23°E, 43.47°N), Jilin Province, China, in July 2015 and 2016, respectively. The disease incidence was about 20%. The lesions appeared initially as small, light brown spots on the leaves. These enlarged gradually and coalesced with others to form large spots having irregular edges. Finally, the central portions of the lesions broke open leaving small holes on the leaves. A small piece of tissue was cut from the lesion margin of 30 leaves and then surface sterilized in 75% ethanol for 30 s followed by 1.5% NaClO for 1 min, washed three times with sterilized distilled water, and then dried on sterilized filter paper. Each tissue piece was incubated on potato dextrose agar at 25°C in the dark for 7 days. Colonies formed and were light olive (after 3 days) and then became dark olive (after 7 days). The growth rate (colony radius) ranged from 3.5 to 5.2 mm per day. Conidia were hyaline, aseptate, both ends were bent slightly, and measured 21.9 to 28.0 (25.4 ± 1.4) μm in length and 3.2 to 5.8 (4.3 ± 0.6) μm in width. The hyphae were hyaline, septate, and branched. Appressoria were light to dark brown, solitary, with the outline roundish to ellipsoidal, and 7.3 to 9.8 × 4.8 to 6.3 μm in size. Setae were dark brown, two to five septate, and measured 79.2 to 162.6 μm in length. The morphological characteristics corresponded to Colletotrichum truncatum more clearly and directly (Damm et al. 2009). To further confirm the identity of the pathogen, DNA was extracted from one single-spore isolate, CT12. The following loci were amplified according to Weir et al. (2012): the internal transcribed spacer (ITS) region of ribosomal DNA and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-tubulin-2 (TUB2), and chitin synthase (CHS-1) genes. The numbers of base pairs matching were 548/550 for ITS, 225/228 for GAPDH, 241/242 for CHS-1, and 683/683 for TUB2 compared with the sequences of C. truncatum in GenBank (KX621963 for ITS, MK359986 for GAPDH, MK118057 for CHS-1, and MH925229 for TUB2). Maximum likelihood analysis of the combined four gene sequences and reference sequences of Colletotrichum spp. from GenBank and the results of the phylogenetic tree showed that CT12 belonged in C. truncatum with 100% bootstrap support. Sequences of the representative isolate CT12 were deposited in NCBI GenBank (MG993325 [ITS, 558 bp], MH038172 [GAPDH, 225 bp], MH038171 [TUB2, 683 bp], and MH038173 [CHS-1, 242 bp], respectively). Conidial suspension (10⁶ conidia/ml) of CT12 was sprayed on 10 healthy, 3-month-old velvetleaf leaves, and sterilized distilled water was sprayed on 10 healthy 3-month-old velvetleaf leaves as a control. The experiment was conducted three times. All plants were incubated in a controlled incubator with a 12-h photoperiod and 90% relative humidity at 25°C. After 5 days, necrotic lesions occurred on the inoculated leaves but not on the control plants. The same fungus was reisolated from the infected leaf tissues. C. truncatum has been reported to cause anthracnose on soybean, pepper, tomato, eggplant, muskmelon, chickpea, grapes, and other plants (Damm et al. 2009; Diao et al. 2014). To our knowledge, this is the first report of C. truncatum causing anthracnose on velvetleaf in China. The identification of the pathogen will provide a theoretical basis for the identification and control of the disease and reduce economic losses.