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Abutilon albidum, a cryptic Saharo-Canarian species, was thought to have been last collected in 1945 in Tenerife by E.R. Sventenius. In 2019, it was rediscovered in the same area. The characteristic features of the Canarian plants are discussed, especially in relation to the morphologically similar-looking and probably closely-related species Abutilon indicum and A. bidentatum. It is concluded that the plants from Tenerife and north-western Africa indeed represent a distinct species. The species is illustrated and a key for the identification of this and related species is presented.

Velvetleaf is an economically important weed in agronomic crops in Nebraska and the United States. Dicamba applied alone usually does not provide complete velvetleaf control, particularly when velvetleaf is taller than 15 cm. The objectives of this experiment were to evaluate the interaction of dicamba, fluthiacet-methyl, and glyphosate applied alone or in a mixture in two- or three-way combinations for velvetleaf control in dicamba/glyphosate–resistant (DGR) soybean and to evaluate whether velvetleaf height (≤12 cm or ≤20 cm) at the time of herbicide application influences herbicide efficacy, velvetleaf density, biomass, and soybean yield. Field experiments were conducted near Clay Center, NE in 2019 and 2020. The experiment was arranged in a split-plot with velvetleaf height (≤12 cm or ≤20 cm) as the main plot treatment and herbicides as subplot treatment. Fluthiacet provided ≥94% velvetleaf control 28 d after treatment (DAT) and ≥96% biomass reduction regardless of application rate or velvetleaf height. Velvetleaf control was 31% to 74% at 28 DAT when dicamba or glyphosate was applied alone to velvetleaf ≤20 cm tall compared with 47% to 100% control applied to ≤12-cm-tall plants. Dicamba applied alone to ≤20-cm-tall velvetleaf provided −1 + fluthiacet at 7.2 g ai ha−1 or glyphosate at 1,260 g ae ha−1. Dicamba at 280 g ae ha−1 + glyphosate at 630 g ae ha−1 applied to ≤20-cm-tall velvetleaf resulted in 86% control 28 DAT compared with the expected 99% control. The interaction of dicamba + fluthiacet + glyphosate was additive for velvetleaf control and biomass reduction regardless of application rate and velvetleaf height.

In order to discover novel plant growth regulators and herbicides with new modes of action for crops production management and improvement, a series of new urea derivatives were designed and synthesized. The bioassay results demonstrated that target compounds exhibited remarkable inhibitory activities in the growth of hypocotyls and taproots and good promoting activity in the generation of lateral roots on Arabidopsis and rice, and compound Y9k showed considerable inhibition effects on germination of Bidens and growth of Abutilon in the herbicidal assay. These results suggested that compound Y9k may be a potential lead structure as a novel plant growth regulator for plant type regulation and weed control.

Three new species of Callianthe (Malvaceae) from southern Brazil and northeastern Argentina are described, and illustrated: C. flava, C. maritima, and C. sulcatarinensis. Morphological descriptions, distribution maps, photographs, ecological notes, and a table comparing these species to two morphologically similar species, C. amoena and C. muelleri-friderici, are presented. Two of the three newly-described species, C. maritima and C. sulcatarinensis, so far are considered endemic and according to IUCN criteria, fit into the categories Endangered (EN) and Vulnerable (VU), respectively. A new combination C. costicalyx, based on Abutilon costicalyx, also is proposed.

Velvetleaf is an economically important weed in popcorn production fields in Nebraska. Many PRE herbicides in popcorn have limited residual activity or provide partial velvetleaf control. There are a limited number of herbicides applied POST in popcorn compared with field corn, necessitating the evaluation of POST herbicides for control of velvetleaf. The objectives of this study were to (1) evaluate the efficacy and crop safety of labeled POST herbicides for controlling velvetleaf that survived S-metolachlor/atrazine applied PRE and (2) determine the effect of velvetleaf height on POST herbicide efficacy, popcorn injury, and yield. Field experiments were conducted in 2018 and 2019 near Clay Center, Nebraska. The experiments were arranged in a split-plot design with four replications. The main plot treatments were velvetleaf height (≤15 cm and ≤30 cm) and subplot treatments included a no-POST herbicide control, and 11 POST herbicide programs. Fluthiacet-methyl, fluthiacet-methyl/mesotrione, carfentrazone-ethyl, dicamba, and dicamba/diflufenzopyr provided greater than 96% velvetleaf control 28 d after treatment (DAT), reduced velvetleaf density to fewer than 7 plants m−2, achieved 99% to 100% biomass reduction, and had no effect on popcorn yield. Herbicide programs tested in this study provided greater than 98% control of velvetleaf 28 DAT in 2019. Most POST herbicide programs in this study provided greater than 90% control of up to 15 cm and up to 30 cm velvetleaf and no differences between velvetleaf heights in density, biomass reduction, or popcorn yield were observed, except with topramezone and nicosulfuron/mesotrione 28 DAT in 2018. On the basis of contrast analysis, herbicide programs with fluthiacet-methyl or dicamba provided better control than herbicide programs without them at 28 DAT in 2018. It is concluded that POST herbicides are available for control of velvetleaf up to 30-cm tall in popcorn production fields.

A widely distributed infraspecific taxon, Abutilon indicum subsp. albescens var. australiense is collected after lapse of six decades from peninsular India and recognized here as distinct species, Abutilon australiense comb. et stat. nov. The detailed comparative morphology with its associated taxa has been discussed in the present article with updated nomenclature and typification.

summary We studied the effects of mycorrhizal infection by Glomus etunicatum Becker & Gerd. and P amendment (three levels) on growth and reproduction of Abutilon theophrasti Medic. Mycorrhizal infection increased total leaf area, but individual leaf size was more-affected than leaf number. Mycorrhizal infection decreased the time taken to initiate flowering, increased the total duration of flowering, and increased seed production by increasing the number of flowers produced, the proportion of flowers producing fruits, and the number of seeds per fruit. Seeds produced by mycorrhizal plants were also heavier and contained more N and P than those produced by non-mycorrhizal plants, P amendment generally had similar influences to mycorrhizal infection, but seed P content was far more plastic in response TO P amendment than to mycorrhizal infection. The various components of reproduction were not uniformly affected by either mycorrhizal infection or P amendment. The most phenotypically plastic reproductive components were fruit production and seed P content. The least plastic components were seed weight and seed N content.

The Linnaean names Malva abutiloides, Sida alba, Sida americana, and Sida triquetra are investigated. Sida alba is a nomen nudum and not validly published according to the Art. 38.1 of the International Code of Nomenclature for algae, fungi, and plants. Sida triquetra is a superfluous and illegitimate name, replacement of the legitimate Sida trisulcata by Jacquin. The name S. americana is lectotypified by a specimen kept at LINN (No. 866.25). For nomenclatural purposes, the names Abutilon dentatum (= A. abutiloides), Albutilon ramosissimum (= S. trisulcata), Sida tricuspidata (= A. abutiloides), and Sida lignosa (= A. abutiloides) were also studied. These four names are lectotypified by specimens preserved at US (A. dentatum), PR (A. ramosissimum), and MA (S. tricuspidata and S. lignosa).

Various author citations for the African species Abutilon bidentatum are usually used. According to the International Code of Nomenclature, its basionym was effectively and validly published on the printed labels of the Schimper exsiccata Iter Abyssinicum II n. 1003 and the type must be chosen accordingly. Cover: (c) Ina Dinter - www.centralafricanplants.org

Due to depressed corn and soybean prices over the last few years in the United States, growers in Nebraska are showing interest in no-tillage (hereafter referred to as no-till) conventional (non–genetically engineered [non-GE]) soybean production. Due to the increasing number of herbicide-resistant weeds in the United States, weed control in no-till non-GE soybean using POST herbicides is a challenge. The objectives of this study were to compare PRE-only, PRE followed by (fb) POST, and PRE fb POST with residual (POST-WR) herbicide programs for Palmer amaranth and velvetleaf control and soybean injury and yield, as well as to estimate the gross profit margins and benefit–cost ratio of herbicide programs. A field experiment was conducted in 2016 and 2017 at Clay Center, NE. The PRE herbicides tested in this study resulted in ≥95% Palmer amaranth and velvetleaf control at 28 d after PRE (DAPRE). Averaged across the programs, the PRE-only program controlled Palmer amaranth 66%, whereas 86% and 97% control was obtained with the PRE fb POST and PRE fb POST-WR programs, respectively, at 28 d after POST (DAPOST). At 28 DAPOST, the PRE fb POST herbicide programs controlled velvetleaf 94%, whereas the PRE-only program resulted in 85% control. Mixing soil-residual herbicides with foliar-active POST programs did not improve velvetleaf control. Averaged across herbicide programs, PRE fb POST programs increased soybean yield by 10% and 41% in 2016 and 2017, respectively, over the PRE-only programs. Moreover, PRE fb POST-WR programs produced 7% and 40% higher soybean yield in 2016 and 2017, respectively, compared with the PRE fb POST programs. The gross profit margin (US$1,184.3 ha−1) was highest under flumioxazin/pyroxasulfone (PRE) fb fluthiacet-methyl plusS-metolachlor/fomesafen (POST-WR) treatment; however, the benefit–cost ratio was highest (6.1) with the PRE-only program of flumioxazin/chlorimuron-ethyl.

Edamame [Glycine max(L.) Merr.] differs from grain-type soybean in several aspects, one being that edamame seeds are 65% to 100% larger than grain-type soybean seed. Crop seed size has implications for weed management in grain-type soybean; however, the extent to which this observation holds true for edamame is unknown. Because weed interference continues to be a barrier to domestic edamame production, the objective was to quantify the effect of edamame seed size on the crop’s ability to tolerate weed interference (CT) and the crop’s ability to suppress weeds (WSA). Five edamame cultivars plus one grain-type cultivar were each sorted to create “small” and “large” seed size classes. Seed lots were included in a split–split plot design, whereby an additional experimental factor was presence or absence of velvetleaf (Abutilon theophrastiMedik.). Crop and weed emergence and growth were monitored through 8 wk after emergence (WAE). Crop plants from large seed had higher tolerance toA. theophrastithan plants from small seed, as evidenced by crop height, area, and biomass. Edamame seed size had little effect on WSA; however, crop cultivars differentially reducedA. theophrastileaf area and biomass at 4 and 8 WAE. While both seed size and edamame cultivar influence early-season crop competitive ability, the magnitude of these factors on CT and WSA underscores the importance of considering them not as stand-alone tactics but rather as useful additions to a more comprehensive integrated weed management system.

Previous reports have underscored antagonism that may result from mixing glyphosate and glufosinate across a wide range of application rates and for various broadleaf and grass weed species, but no investigation has been conducted to characterize glyphosate absorption and translocation when combined with glufosinate. The objectives of this study were to evaluate herbicide efficacy and assess herbicide interaction and physiological response with combinations of glyphosate and glufosinate on common lambsquarters, velvetleaf, and giant foxtail. Greenhouse studies to determine interaction resulted in strong and persistent antagonism between glyphosate at 110 and 220 g ae ha-1 and glufosinate at 20 or 40 g ae ha-1 in giant foxtail, whereas only transient and reduced antagonism was noted for velvetleaf and common lambsquarters. Combining glyphosate and glufosinate increased the maximum absorption of glyphosate by 9% and 23% in velvetleaf and giant foxtail, respectively, compared with glyphosate alone. In velvetleaf, averaged over time, only 2.6% of the applied radioactivity translocated out of the treated leaf when glufosinate was mixed with glyphosate compared with 9.9% when glyphosate was applied alone. In giant foxtail, 21.6% of the [14C]glyphosate translocated out of the treated leaf when glufosinate was mixed with glyphosate compared with 52.4% when glyphosate was applied alone. Conversely, no change in the radioactive pattern of translocation was noted for common lambsquarters. These results suggest that reduced translocation of glyphosate is the physiological mechanism responsible for the antagonism observed between glyphosate and glufosinate in giant foxtail and, to a lesser extent, in velvetleaf.Nomenclature: Glufosinate; glyphosate; common lambsquarters, Chenopodium album L. CHEAL; giant foxtail, Setaria faberi Herrm. SETFA; velvetleaf, Abutilon theophrasti Medik. ABUTH.

Spent coffee grounds (SCG) represent a significant food waste residue. Value-added uses for this material would be beneficial. Gritty agricultural residues, such as corncob grit, can be employed as abrasive air-propelled agents for organically-compatible and selective shredding of weed seedlings within established crops. SCG were tested and compared with corncob grit for their ability to injure seedlings of two important weeds: waterhemp and velvetleaf. Waterhemp seedlings were controlled completely with as little as 0.5 g of SCG at an air pressure of 690 kPa. Velvetleaf seedlings were much larger than those of waterhemp at the time of grit application, better tolerated SCG abrasion, but still were damaged appreciably by 1 to 2 g of grit. SCG were at least as effective for abrading weed seedlings as corncob grit, whose value for this purpose in organic crops was demonstrated previously. Nomenclature: Tall waterhemp, Amaranthus tuberculatus (Moq.) Sauer; velvetleaf, Abutilon theophrasti Medik.

Good weed management relies on the proper timing of weed control practices in relation to weed emergence dynamics. Therefore, the development of models that predict the timing of emergence may help provide growers with tools to make better weed management decisions. The aim of this study was to validate and compare two previously published predictive empirical thermal time models of the emergence of Abutilon theophrasti growing in maize with data sets from the USA and Europe, and test the hypothesis that a robust and general weed emergence model can be developed for this species. Previously developed Weibull and Logistic models were validated against new data sets collected from 11 site‐years, using four measures of validation. Our results indicated that predictions made with the Weibull model were more reliable than those made with the Logistic model. However, Weibull model results still contained appreciable biases that prevent its use as a general model of A. theophrasti emergence. Our findings highlight the need to develop more accurate models if the ultimate goal is to make more precise predictions of weed seedling emergence globally to provide growers with universally consistent tools to make better weed management decisions., VE‐C and JLG‐A were supported by FEDER (European Regional Development Funds) and the Spanish Ministry of Economy and Competitiveness Funds (project AGL2015‐64130‐R).

An improved method for particle length measurement was used for six members of the genus Crinivirus. Particle measurements were conducted with a CCD-72S solid state camera, which was interfaced with a Zeiss EM 109 electron microscope, and analyzed using the analysis 2.1 Image Analysis Software. In comparisons of specimen preparation methods, the leaf dip method is more representative and reproducible than the antibody capture method or preparation from purified virions. Particle length (nm) ranges of whitefly-transmitted criniviruses are: Abutilon yellows virus (AYV), 800 to 850; Cucurbit yellow stunting disorder virus (CYSDV), 750 to 800; Lettuce chlorosis virus (LCV), 800 to 850; Lettuce infectious yellows virus (LIYV), 700 to 750; Tomato chlorosis virus (ToCV), 800 to 850; and Tomato infectious chlorosis virus (TICV), 850 to 900.

Reddish brown lesions were observed on the lower stem and upper root area of velvetleaf (Abutilon theophrasti Medik.) plants growing in an Illinois soybean field in June 2000. The lesions were similar in appearance to those caused by Rhizoctonia root rot of soybean. Stems and roots with lesions were cut into ≍5-mm pieces, surface-disinfested, and placed on 2% water agar at pH 4.5. The cultural morphology of the two isolates fit the description of Phomopsis longicolla Hobbs (1). Colonies on potato dextrose agar (PDA) were floccose, dense, and white. The undersides of the cultures were colorless. Stromata were large, black, and spreading. The pattern of stromata in one isolate was effuse, and most of the stromata were immersed or semiimmersed in the medium, whereas the stromata from the other isolate were massive and prominent. Neither isolate turned green on PDA. Alpha conidia were hyaline, ellipsoidal to fusiform, and guttulate. DAPI (4′,6-diamidino-2-phenylindole)-stained alpha conidia were uninucleate. Beta conidia and perithecia did not occur on either PDA or oat flakes on water agar from 1 to 10 weeks at 25°C under a 12-h photoperiod. The DNA sequences of the mitochondrial small subunit rRNA genes of the two isolates were identical and shared 100% sequence identity with two P. longicolla soybean isolates that we had identified previously. Pathogenicity tests were conducted in a greenhouse by cutting the stems of 3-week-old soybean and velvetleaf plants at the second internode. Mycelial plugs (4 mm in diameter) from the margin of 1-week-old cultures of the two isolates from velvetleaf and one from soybean were individually placed mycelial side down directly on the top of cut stems of 10 to 15 plants per isolate. Controls included noninoculated plants with and without PDA plugs. Plants were kept in a mist chamber in the dark at 25°C for 4 days and were then transferred to a greenhouse with a 16-h photoperiod at 24 ± 3°C. Stem lesions were measured 7 days after inoculation. The experiment was repeated once. Mean stem lesion lengths caused by the velvetleaf and soybean isolates were 23 and 20 mm, respectively, on soybean stems, while negative controls produced no lesions. Mean stem lesion lengths caused by the velvetleaf and soybean isolates were 23.5 and 12 mm, respectively, on velvetleaf stems. P. longicolla was reisolated from the stem lesions of five randomly collected plants. This is the first report of P. longicolla being isolated from velvetleaf and causing stem lesions on inoculated soybean and velvetleaf plants. Reference: (1) T. W. Hobbs et al. Mycologia 77: 535, 1985.

This study was conducted to determine the host range of Phytophthora capsici isolates from pumpkin and virulence of the isolates on pumpkin cultivars. The pathogenicity of P. capsici isolates from pumpkin was evaluated on 45 species of herbaceous plants, including 36 species of crops grown in rotation sequences with pumpkin and nine species of weeds that commonly grow in pumpkin fields in Illinois. Plants were grown in the greenhouse, and 4-week-old seedlings were inoculated by adding 5 ml of a zoospore suspension (2 × 105 spores per ml of water) onto the soil surface around the stem of each plant in the pot. Twenty-two crop species and two weed species became infected with P. capsici and developed symptoms. P. capsici was reisolated from all of the symptomatic plants by culturing tissues onto a semiselective medium (PARP). Also, P. capsici was detected in 87.5% of symptomatic plants by a polymerase chain reaction (PCR) method using PCAP and IT5 primers. Cucurbits and pepper were the most susceptible hosts of P. capsici. Five crop species or varieties, beet (Beta vulgaris), Swiss-chard (Beta vulgaris var. cicla), lima beans (Phaseolus lunatus), turnip (Brassica rapa), and spinach (Spinacia oleracea), and one weed species, velvet-leaf (Abutilon theophrasti), were found to be hosts of P. capsici for the first time. Six isolates of P. capsici were inoculated onto six pumpkin cultivars (three processing and three jack-o-lantern pumpkins) in the greenhouse and resulted in significant interactions between pathogen isolates and pumpkin types. P. capsici isolates were more virulent on jack-o-lantern pumpkins than on processing pumpkins.

Two strains of Colletotrichum coccodes, the wild type (DAOM 183088) and T-20a, engineered with the necrosis- and ethylene-inducing peptide (NEP1) gene for hypervirulence on velvetleaf (Abutilon theophrasti, Medik.), were monitored in planta for the first 2 weeks after infection. Real-time quantitative polymerase chain reaction (QPCR) was used to assess the extent of colonization of both strains on velvetleaf using SYBR Green chemistry. Quantification of both strains was successful as soon as the conidia were sprayed on the leaves and up to 14 days after infection. The increase in fungal DNA amounts corroborated with the appearance of necrotic lesions on velvetleaf leaves infected with the wild-type strain. The wild-type C. coccodes was more efficient at infecting velvetleaf than the transgenic T-20a strain. In addition, detection of host DNA allowed us to quantitatively monitor the decrease in plant DNA amounts in response to wild-type strain infection. Expression of the NEP1 transgene by conventional retro-transcription (RT)-PCR was absent from T-20a growing on either V8 agar or in planta, suggesting that the gene may be silenced. The application of QPCR to monitor fungal growth was proven to detect the target organisms in planta prior to the appearance of symptoms.

Abutilon theophrasti is a weed that is spreading worldwide and that has had to adapt to different combinations of environmental conditions. Wide interpopulation variability has been reported regarding dormancy and germination. This variability, controlled by the interaction of genetic diversity and maternal effect, could hinder the adoption of Integrated Weed Management (IWM) tools. A collaborative project was conducted to compare emergence dynamics of 12 European and North American populations under diverse environmental conditions. The main aim was to assess interpopulation variability and explain this according to environmental conditions in the seed collection sites. Seeds were sown at six experimental sites, and seedling emergence was monitored. The AlertInf model was tested to evaluate its ability to predict emergence dynamics of the different populations. A wide interpopulation variability was observed for emergence percentage and dynamics with consistent trends across sites and related to different seed dormancy levels. Populations from Catalonia, Iowa and Minnesota reached higher emergence percentage with earlier and concentrated emergence flushes probably due to low dormancy level, while populations from Croatia, Serbia and Hungary, given their low average emergence percentage, presented high dormancy levels. Good predictive accuracy of AlertInf model was obtained at the different sites, confirming the possibility of adopting it across a wide range of environmental conditions. Achieving a better knowledge of interpopulation variability can allow specific control strategies to be designed, facilitating the replacement of solely herbicide- based management with true IWM.

In the Caribbean Basin, malvaceous weeds commonly show striking golden/yellow mosaic symptoms. Leaf samples from Malachra sp. and Abutilon sp. plants with these symptoms were collected in Hispaniola from 2014 to 2020. PCR tests with degenerate primers revealed that all samples were infected with a bipartite begomovirus, and sequence analyses showed that Malachra sp. plants were infected with tobacco leaf curl Cuba virus (TbLCuCV), whereas the Abutilon sp. plants were infected with a new bipartite begomovirus, tentatively named Abutilon golden yellow mosaic virus (AbGYMV). Phylogenetic analyses showed that TbLCuCV and AbGYMV are distinct but closely related species, which are most closely related to bipartite begomoviruses infecting weeds in the Caribbean Basin. Infectious cloned DNA-A and DNA-B components were used to fulfilled Koch’s postulates for these diseases of Malachra sp. and Abutilon sp. In host range studies, TbLCuCV also induced severe symptoms in Nicotiana benthamiana, tobacco and common bean plants; whereas AbGYMV induced few or no symptoms in plants of these species. Pseudorecombinants generated with the infectious clones of these viruses were highly infectious and induced severe symptoms in N. benthamiana and Malachra sp., and both viruses coinfected Malachra sp., and possibly facilitating virus evolution via recombination and pseudorecombination. Together, our results suggest that TbLCuCV primarily infects Malachra sp. in the Caribbean Basin, and occasionally spills over to infect and cause disease in crops; whereas AbGYMV is well-adapted to an Abutilon sp. in the Dominican Republic and has not been reported infecting crops.

The supply of soil resources is critical for the establishment and long-term competitive success of a plant species. Although there is considerable research on the effects of water supply on crop growth and productivity, there is little published research on the comparative response of crops and weeds to limiting soil water supply. The objective of this research was to determine the growth and transpiration efficiency of corn and velvetleaf at three levels of water supply. One corn or velvetleaf plant was grown in a large pot lined with plastic bags. When seedlings reached 10 cm, bags were sealed around the base of the plant, so the only water loss was from transpiration. Daily transpiration was measured by weighing the pots at the same time each day. The experiment was conducted in the fall of 2007 and in the spring of 2008. Four replicates of each species–water treatment were harvested periodically to determine biomass accumulation and leaf area. The relationship between cumulative aboveground biomass and water transpired was described using a linear function in which the slope defined the transpiration efficiency (TE). Corn TE was greater than velvetleaf TE in all treatments during both trials. In the fall trial, corn TE was 6.3 g kg–1, 47% greater than that of velvetleaf TE. In the spring trial, TEs of both species were lower overall, and corn TE increased with declining water supply. Corn produced more biomass and leaf area than velvetleaf did at all water-supply levels. Velvetleaf partitioned more biomass to roots compared with shoots during early growth than corn did. The ability of corn to generate more leaf area and its investment in a greater proportion of biomass into root growth at all levels of water supply may enable it to more-effectively avoid velvetleaf interference under all levels of soil-water supply.

Field experiments were conducted in 2013 and 2014 to determine the influence of velvetleaf densities of 0, 0.125, 0.25, 0.5, 1, 2, 4, and 8 plants m−1of row on cotton growth and yield. The relationship between velvetleaf density and seed cotton yield was described by the hyperbolic decay regression model, which estimated that a density of 0.44 to 0.48 velvetleaf m−1of row would result in a seed cotton yield loss of 50%. Velvetleaf remained taller and thicker than cotton throughout the growing season. Both cotton height and stem diameter reduced with increasing velvetleaf density. Moreover, velvetleaf interference delayed cotton maturity, especially at velvetleaf densities of 1 to 8 plants m−1of row, and cotton boll number and weight, seed numbers per boll, and lint percentage were also reduced. Fiber quality was not influenced by weed density when analyzed over 2 yr; however, fiber length uniformity and micronaire were adversely affected in 2014. Velvetleaf intraspecific competition resulted in density-dependent effects on weed biomass, ranging from 97 to 204 g plant−1dry weight. Velvetleaf seed production per plant or per square meter was indicated by a logarithmic response. At a density of 1 plant m−1of cotton row, velvetleaf produced approximately 20,000 seeds m−2. The adverse impact of velvetleaf on cotton growth and development identified in this study have indicated the need for effective management of this species when the weed density is greater than 0.25 to 0.5 plant m−1of row and before the weed seed maturity.

Abutilon fruticosum is one of the endemic plants with high medicinal and economic value in Saudi Arabia and belongs to the family Malvaceae. However, the plastome sequence and phylogenetic position have not been reported until this study. In this research, the complete chloroplast genome of A. fruticosum was sequenced and assembled, and comparative and phylogenetic analyses within the Malvaceae family were conducted. The chloroplast genome (cp genome) has a circular and quadripartite structure with a total length of 160,357 bp and contains 114 unique genes (80 protein-coding genes, 30 tRNA genes and 4 rRNA genes). The repeat analyses indicate that all the types of repeats (palindromic, complement, forward and reverse) were present in the genome, with palindromic occurring more frequently. A total number of 212 microsatellites were identified in the plastome, of which the majority are mononucleotides. Comparative analyses with other species of Malvaceae indicate a high level of resemblance in gene content and structural organization and a significant level of variation in the position of genes in single copy and inverted repeat borders. The analyses also reveal variable hotspots in the genomes that can serve as barcodes and tools for inferring phylogenetic relationships in the family: the regions include trnH-psbA, trnK-rps16, psbI-trnS, atpH-atpI, trnT-trnL, matK, ycf1 and ndhH. Phylogenetic analysis indicates that A. fruticosum is closely related to Althaea officinalis, which disagrees with the previous systematic position of the species. This study provides insights into the systematic position of A. fruticosum and valuable resources for further phylogenetic and evolutionary studies of the species and the Malvaceae family to resolve ambiguous issues within the taxa.

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.

Velvetleaf, an annual broadleaf weed, is a common and troublesome weed of cropping systems worldwide. Laboratory and field experiments were conducted to determine the effects of environmental factors on germination and emergence of velvetleaf. Seeds germinated over a range of constant temperatures from 10 to 40 oC regardless of light conditions, but no germination occurred at temperature below 5 oC and beyond 50 oC. Seeds germinated at alternating temperature regimes of 15/5 to 40/30 oC, with maximum germination (>90%) at alternating temperatures of 40/30 oC. Germination was sensitive to water stress, and only 0.4% of the seeds germinated at the osmotic potential of -0.4 MPa. There was no germination at ? 0.6 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ³ 150 mM NaCl or ³ 200 mM NaHCO3 concentrations. However, pH values from 5 to 9 had no effect on seed germination. Seedling emergence was significantly affected by burial depth and maximum emergence (78.1-85.6%) occurred at the 1-4 cm depth. The results of this study have contributed to our understanding of the germination and emergence of velvetleaf and should enhance our ability to improve control strategies in cropping systems in central China.

A new species, Abutilon substellatum Phuph. & Poopath, is described and contrasted to its nearest ally, A. persicum (Burm. f.) Merr

An alternative method to other technologies to clean up the soil, air and water pollution by heavy metals is phytoremediation. Therefore, a pot culture experiment was conducted at the College of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran, in 2014 to determine the potential absorption of cadmium by Portulaca oleracea (Common purslane), Solanum nigrum (Black nightshade), Abutilon theophrasti (Velvetleaf) and Taraxacum officinale (Dandelion). The type of experiment was completely randomized design with factorial arrangement and four replications. The soil in pot was treated with different rates of CdCl2.H2O (0 (control), 10, 20, 40, 60, and 80 mg Cd/kg soil) and the plants were sown. With increasing concentration levels, fresh weight and dry weight of shoots and roots of all plant species were reduced. The reduction severity was ranked according the following order, P. oleraceaA. theophrastiS. nigrumT. officinale. Bioconcentration factor (BCF), Translocation factor (TF) and Translocation efficiency (TE%) was ranked according the following order, T. officinaleS. nigrumA. theophrastiP. oleracea. The results of this study revealed that T. officinale and S. nigrum are effective species to phytoremediate Cd-contaminated soil.

Tomato yellow leaf curl virus (TYLCV) causes huge losses to tomato production worldwide. In July 2011 and July–August 2012, we screened for potential TYLCV hosts in a tomato-growing area in Shandong Province, the core vegetable-producing region in China. PCR detection showed that 5 species of plants, Zinnia elegans, Acalypha australis, Gossypium hirsutum, Abutilon theophrasti, and Nicotiana tabacum, were infected. Full genomic sequences of the new TYLCV isolates were obtained and submitted for sequence analysis. Sequence alignment and similarity analysis showed that they all belonged to the TYLCV-IL strain.

Theoretical models predict that seed size and seed-bank persistence evolve interdependently, such that strong selection for one trait corresponds with weak selection for the other. This framework has been supported and rejected by empirical data, and thus, conclusive evidence is lacking. We expanded the seed size–persistence framework to include seed-coat thickness, a defence trait previously correlated with seed survival in soil. To do this, we usedAbutilon theophrastiaccessions with varied evolutionary histories and we quantified associations among seed traits including morphology, size, coat thickness, dormancy (percentage of viable seeds that fail to germinate under optimum conditions) and seed-bank persistence (percentage of viable seeds remaining after 1 year of burial). Statistical models were developed to test the hypothesis that combined measurements of seed-coat thickness and seed size better explain variability in seed-bank persistence than seed-size data alone. Results indicated that measurements of seed size (length, width, mass) were negatively correlated with coat:width ratio (coat thickness relative to seed width) and coat:mass ratio (coat thickness relative to seed mass). Accessions characterized by smaller seeds with proportionally thicker seed coats were more dormant and more persistent in soil than accessions characterized by larger seeds with proportionally thinner seed coats. Seed-coat thickness data improved the explanatory power of logistic regression models for seed-size effects on both seed-bank persistence and dormancy. These results indicate that supplementing seed-size data with seed-defence data may clarify previously reported contradictory results regarding trade-offs between seed size and seed-bank persistence.

A new record for Abutilon theophrasti is recorded for the first time in the flora of Libya. This widespread agricultural weed was collected from El-Hamra region (El-Qabel) in the Nafusa Mountain south of Tripoli. To facilitate further identification and future detection, a full description, habitat information, distribution map and distribution data are provided. A brief discussion about the most important threats posed by this species is presented.

Summary Weed seeds in and on the soil are the primary cause of weed infestations in arable fields. Previous studies have documented reductions in weed seedbanks due to cropping system diversification through extended rotation sequences, but the impacts of different rotation systems on additions to and losses from weed seedbanks remain poorly understood. We conducted an experiment in Iowa, USA, to determine the fates of Setaria faberi and Abutilon theophrasti seeds in 2-, 3- and 4-year crop rotation systems when seed additions to the soil seedbank were restricted to a single pulse at the initiation of the study. Over the course of the experiment, seedlings were removed as they emerged and prevented from producing new seeds. After 41 months, seed population densities dropped >85% for S. faberi and >65% for A. theophrasti, but differences between rotation systems in the magnitude of seedbank reductions were not detected. Most of the reductions in seedbank densities took place from autumn through early spring in the first 5 months following seed deposition, before seedling emergence occurred, suggesting that seed predation and/or seed decay was important. For S. faberi, total cumulative seedling emergence and total seed mortality did not differ between rotation systems. In contrast, for A. theophrasti, seedling emergence was 71% lower and seed mortality was 83% greater in the 3- and 4-year rotation systems than in the 2-year system. Results of this study indicate that for certain weed species, such as A. theophrasti, crop rotation systems can strongly affect life-history processes associated with soil seedbanks.

Robinson, D. E., McNaughton, K. E. and Bilyea, D. 2013. Comparison of sequential preemergence-postemergence and postemergence-alone weed management strategies during critical period of red beet ( Beta vulgaris L.). Can. J. Plant Sci. 93: 863–870. Weed management during the first 4 wk after red beet emergence is critical to prevent yield loss. The purpose of this research was to compare weed control and red beet tolerance of postemergence (POST) treatments alone (full, split- and micro-rates of pyrazon plus triflusulfuron) with sequential preemergence (PRE) applications of s-metolachlor followed by these POST herbicide treatments. The experiment was carried out for 4 yr as a randomized complete block with four replications. Of the POST alone treatments examined, control of velvetleaf (Abutilon theophrasti Medik.), redroot pigweed (Amaranthus retroflexus L.), common lambsquarters (Chenopodium album L.) and green foxtail [Setaria viridis L. (Beauv.)] was 98, 86, 97 and 62%, respectively. Much more consistent control of all species (i.e., greater than 96%) was measured where the sequential treatment of s-metolachlor was applied PRE followed by POST split- or micro-rates in all study years. Red beet density and soluble solid levels were not different than the weed-free check in any of the POST or sequential treatments. However, red beet yield in the POST single and split-rate treatments alone ranged from 9500 to 12100 kg ha−1, and was significantly less than in the weed-free check (19400 kg ha−1). Yields in the sequential treatments were comparable to the weed-free check. The results of this study confirm that a sequential treatment of PRE s-metolachlor followed by POST split- and micro-rate applications of pyrazon plus triflusulfuron can be safely applied to red beet and control annual weed species.

Weed emergence models require biological parameters such as base temperature for germination, determination of which is costly and time-consuming. Transferability of these parameters across different populations may therefore represent one of the main constraints for the development and practical use of emergence models at a large scale. A collaborative project was undertaken to assess the interpopulation variability of base temperature for germination in different European populations of velvetleaf and jimsonweed and evaluate possible applicative consequences in terms of weed control. Seeds were collected in Italy, Portugal, and Spain, and each population was then sown in every country, obtaining nine seed batches named as experimental lots. Base temperature for germination was estimated for each experimental lot to calculate lot-specific accumulation of growing degree days (GDD) under three dissimilar climatic scenarios. Threshold date (TD50) was calculated as the date when GDD accumulation of a given experimental lot surpassed the values corresponding to 50% of cumulative field emergence of seedlings. GDD accumulation and TD50were then used as indicators to identify differences among experimental lots within each climatic scenario. No significant differences were detected among base temperatures estimated for velvetleaf experimental lots or among their patterns of accumulation of GDD and TD50values within climatic scenarios. Each value of base temperature determined for a single experimental lot could therefore be adopted to model germination for all the lots regardless of the population of origin or cultivation site. In contrast, the population of origin affected the base temperature for jimsonweed, with significantly higher values for experimental lots of the Portuguese population. From an applicative perspective, differences among patterns of accumulation of GDD and TD50of several experimental lots within each climatic scenario suggest the need to use population-specific values as base temperature for germination and emergence modeling of jimsonweed.

Abutilon theophrasti and Barnyardgrass (Echinochloa crus-galli) are major weeds that affect cropping systems worldwide. Laboratory and greenhouse studies were conducted to determine the effects of temperature, pH, water and salinity stress, and planting depth on seed germination and seedling emergence of Velvetleaf and Barnyardgrass. For Velvetleaf, the base, optimum and ceiling germination temperatures were estimated as 5, 35 and 48 ºC, respectively. Seed germination was sensitive to drought stress and completely inhibited by a potential of -0.6 MPa, but it was tolerant to salinity. Salinity stress up to 45 mM had no effect on the germination of Velvetleaf, but germination decreased with increasing salt concentration. Drought and salinity levels for 50% inhibition of maximum germination were -0.3 MPa and 110 mM, respectively. Seed germination of Velvetleaf was tolerant to a wide range of pH levels. For Barnyardgrass, the base, optimum and ceiling germination temperatures were estimated as 5, 38 and 45 ºC, respectively. Seed germination was tolerant to drought stress and completely inhibited by a potential of -1.0 MPa. Salinity stress up to 250 mM had no effect on seed germination. Drought and salinity levels for 50% inhibition of maximum germination were -0.5 MPa and 307 mM, respectively. A high percentage of seed germination was observed at pH=5 and decreased to 61.5% at acidic medium (pH 4) and to 11% at alkaline medium (pH 9). Maximum seedling emergence of Velvetleaf and Barnyardgrass occurred when the seeds were placed on the surface of the soil or at a depth of 1 cm.

A facultative, microbial micro-community colonizing roots of Abutilon theophrasti Medik. supports the plant in detoxifying hydroxylated benzoxazolinones. The root micro-community is composed of several fungi and bacteria with Actinomucor elegans as a dominant species. The yeast Papiliotrema baii and the bacterium Pantoea ananatis are actively involved in the detoxification of hydroxylated benzoxazolinones by generating H2O2. At the root surface, laccases, peroxidases and polyphenol oxidases cooperate for initiating polymerization reactions, whereby enzyme combinations seem to differ depending on the hydroxylation position of BOA-OHs. A glucosyltransferase, able to glucosylate the natural benzoxazolinone detoxification intermediates BOA-5- and BOA-6-OH, is thought to reduce oxidative overshoots by damping BOA-OH induced H2O2 generation. Due to this detoxification network, growth of Abutilon theophrasti seedlings is not suppressed by BOA-OHs. Polymer coats have no negative influence. Alternatively, quickly degradable 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one can be produced by the micro-community member Pantoea ananatis at the root surfaces. The results indicate that Abutilon theophrasti has evolved an efficient strategy by recruiting soil microorganisms with special abilities for different detoxification reactions which are variable and may be triggered by the allelochemical´s structure and by environmental conditions.

Summary Soyabean (Glycine max) was grown at ambient and projected levels of atmospheric carbon dioxide (+250 μmol mol−1 above ambient) over two field seasons with and without the presence of a weed, Abutilon theophrasti, to quantify the potential effect of rising atmospheric carbon dioxide concentration on weed–crop interactions and potential yield loss in soyabean. Under weed-free conditions, elevated CO2 resulted in stimulations in soyabean seed yield and associated components, including pod number. At an approximate density of 6 plants m−2, A. theophrasti competition resulted in a significant reduction (−40%) in soyabean seed yield. Although differences in seed yield reduction by A. theophrasti were observed as a function of year, the relative decrease in seed yield with A. theophrasti biomass did not differ in response to CO2. Although careful weed management will be necessary if CO2-induced increases in seed yield for soyabean are to be achieved, these data suggest that soyabean seed yield may be more resilient in competition with A. theophrasti as a function of rising atmospheric levels of carbon dioxide.

The boundaries between the genera Bakeridesia and Abutilon have long been debated. Results from recent phylogenetic studies using the rDNA ITS in tribe Malveae strongly suggest that these two genera as currently delimited are polyphyletic. Some species previously included in each genus form a well-supported clade that is phylogenetically removed from both Bakeridesia and Abutilon. The congruence of morphological and karyological distinctions with this molecular evidence provides compelling support for recognition of the clade as a new genus, here described as Callianthe . In the present study we transfer 40 species to Callianthe based on ITS data (including the synapomorphy of a 25-base pair deletion in ITS2) and/or morphological evidence, including the character states of four or more ovules per carpel, toothed and/or lobed leaves, and petals with impressed veins (the latter is a synapomorphy). In addition, species of Callianthe share a base chromosome number of x = 8 (versus 7 in Abutilon and 1...

Abutilon is represented in the state of São Paulo by 18 species mainly distributed in the Atlantic Forest, especially in dense rainforest. This work includes an identification key, illustrations, and comments on morphology, habitat, geographical distribution and conservation status. A new species (Abutilon costicalyx), three new synonyms, and three new records for São Paulo are presented.

The GLM herbarium collection houses vascular plant specimens from Namibia collected between 1909 and 1913 by Fritz Schafer. Duplicates at Berlin-Dahlem (B) were partly destroyed during World War II, and further duplicates are known only in few cases at Zurich (Z) and Cape Town (NBG). At GLM we traced 27 type specimens of 20 validly published names, for eight of these names no further type material is known to have been preserved elsewhere. We typify the names involved and designate Schafer specimens preserved at the herbaria GLM or B, respectively, as lectotypes for Abutilon schaeferi, Anthericum apicicolum, A. diphyllum, A. glutinosum, Aster schaeferi, Gnidia suavissima, Hermannia seitziana, Lachenalia klinghardtiana, Lebeckia cinera var. schaeferi, Oldenlandia schaeferi, Pelargonium grandicalcaratum, P. squarrosum, Solanum schaeferi and Viscum schaeferi, and a Dinter specimen preserved at NBG for Pelargonium mirabile.

The lucky find of 934 carbonized seeds of Abutilon theophrasti Medic. in a storage jar at the Late Neolithic site of Hodmezővasarhely-Gorzsa, south Hungary, suggests that the seeds of velvetleaf were intentionally gathered, processed and stored by the inhabitants of this Tisza culture tell-site. Today this ancient fibre and oil plant, the seeds of which can be used for food and medicine, has become a pestilential weed worldwide. Until now, there has been no archaeobotanical record of velvetleaf. Conflicting reports as to the native origin of velvetleaf exist, including India, China and even the Mediterranean area. Since the progenitors of velvetleaf have not yet been found the centre of origin of the species is still unidentified. The huge floodplain swamps and flood-free loess-silt areas in the heart of the Pannonian plain provide this temperate species with suitable growing conditions.

Crop seedlings detect the presence of neighboring competitors by means of the red to far-red ratio (R/FR) of light reflected from the leaf surfaces of adjacent seedlings. Although previous studies have suggested that shifts in the R/FR initiate crop– weed competition, no studies have documented the R/FR of light reflected from weeds or explored how weed management practices may affect the R/FR. Experiments were conducted to test the following hypotheses: (1) the duration of R/FR signals reflected from the leaf surface of weed seedlings will vary among herbicides following treatment and will decline faster as the dose of a given herbicide increases, (2) the R/FR of reflected light will differ among weed species, and (3) the R/FR of reflected light will decrease as weed seedling leaf area and stage of development increases. Velvetleaf was used as a model weed species to examine herbicide chemistry and dose, and six weed species including Powell amaranth, velvetleaf, Eastern black nightshade, barnyardgrass, proso millet, and green foxtail were evaluated in order to characterize the R/FR of light reflected from their leaf surfaces. Results of this study confirm that the R/FR reflected from the leaf surface of weeds is affected by: herbicide chemistry, herbicide dose, weed species, stage of weed development, and distance of the weed from the crop. The relative decline in the R/FR (as a percent of the untreated control) was most rapid following treatment with paraquat, followed by glufosinate and then glyphosate. As glyphosate dose decreased, so did the reduction in the relative R/ FR. Based on reflected R/FR, weed species tended to be grouped into monocots and dicots, with the latter reflecting a lower R/FR per unit leaf area than the former. This disparity was attributed to the compact leaf arrangement and orientation of dicot weed canopies, which may contribute to the greater competitiveness of dicot weeds. Nomenclature: Glyphosate; glufosinate; paraquat; barnyardgrass, Echinochloa crus-galli L. Beauv. ECHCG; Eastern black nightshade, Solanum ptycanthum Dunal. SOLPT; green foxtail, Setaria viridis L. (Beauv.) SETVI; proso millet, Panicum milliaceum L. PANMI; Powell amaranth, Amaranthus powellii S. Wats. AMPO; velvetleaf, Abutilon theophrasti Medik. ABUTH.

The average mealy bug (Phenacoccus solenopsis Tinsley) population was maximum (2.69, 2.40 and 1.73 adults/plant) on Parthenium hysterophorus at wasteland, in or near field and weeds present near stacks at Muktsar. At Ferozepur, the mean mealy bug population was 1.10 adults/plant on cotton. On the weeds, near or in the field, the maximum population (5.94 adult/plant) was recorded on P. hysterophorus followed by Digeria arvensis (3.74 adults/plant). The population was 2.69, 2.66 and 2.86 adults/plant on Sida acuta, Abutilon theophrasti and Achryanthus aspera, respectively. On wasteland weeds, similar trend was observed, i.e. maximum population was on P. hysterophorus (7.31 adults/plant), while minimum (3.00 adults/plant) on S. acuta, during 2008. Similar trend was followed in 2009 in Muktsar and Ferozepur but the population was lower than the previous year. Among the weeds, P. hysterophorus was the most preferred host for multiplication. During carry-over studies all the stages and ovisac was maximum, follo...

Weed-suppressive soils contain naturally occurring microorganisms that suppress a weed by inhibiting its growth, development, and reproductive potential. Increased knowledge of microbe–weed interactions in such soils could lead to the identification of management practices that create or enhance soil suppressiveness to weeds. Velvetleaf death and growth suppression was observed in a research field (fieldA) that was planted with high populations of velvetleaf, which may have developed via microbial mediated plant–soil feedback. Greenhouse studies were conducted with soil collected fromfieldA(soilA) to determine if it was biologically suppressive to velvetleaf. In one study, mortality of velvetleaf grown for 8 wk insoilAwas greatest (86%) and biomass was smallest (0.3 g plant−1) in comparison to soils collected from surrounding fields with similar structure and nutrient content, indicating that suppressiveness ofsoilAwas not likely caused by physical or chemical factors. WhensoilAwas autoclaved in another study, mortality of velvetleaf plants in the heat-treated soil was reduced to 4% compared to 55% for the untreated soil, thus suggesting that suppressiveness ofsoilAis biological in nature. A third set of experiments showed that suppressiveness to velvetleaf could be transferred to an autoclaved soil by amending the autoclaved soil with untreatedsoilA; this provided additional evidence for a biological basis for the effects ofsoilA.The suppressive condition in these greenhouse experiments was associated with high soil populations of fusaria.Fusarium lateritiumwas the most frequently isolated fungus from roots of diseased velvetleaf plants collected fromfieldA, and also was the most virulent when inoculated onto velvetleaf seedlings. Results of this research indicate that velvetleaf suppression can occur naturally in the field and thatF. lateritiumis an important cause of velvetleaf mortality infieldA.

Controlled environment experiments showed that velvetleaf plants grown under drought stress or low temperature (LT) treatments had greater leaf epicuticular wax (ECW) deposition compared to plants grown in soil with moisture at field capacity (FC) or a high temperature (HT) regime. Light intensity did not affect ECW deposition; however, increasing light intensity decreased the leaf ECW ester content and increased the secondary alcohol content. Plants grown at an LT regime or under FC had leaf ECW with fewer hydrocarbons and more esters than those grown at an HT or drought stress regime. Velvetleaf absorption of acifluorfen increased as light intensity decreased for plants grown in adequate soil water content, while the opposite was true for drought-stressed plants. Velvetleaf absorption of acifluorfen was approximately 3 and 10 times greater, respectively, with the addition of 28% urea ammonium nitrate (UAN) in comparison to crop oil concentrate (COC) or no adjuvant, regardless of the environmental treatments. Plants absorbed more acifluorfen when subjected to the LT regime in comparison to the HT regime when UAN was the adjuvant, while the opposite was true when COC was the adjuvant. Velvetleaf absorption of acifluorfen was not affected by drought stress when COC or no adjuvant was used and varied between studies when UAN was used. Velvetleaf absorption of bentazon was greatest for plants grown under HT/FC or high light/FC treatments and least with plants grown under HT/drought stress or low light/drought stress treatments, regardless of the adjuvant. However, bentazon absorption was higher with the addition of an adjuvant and for plants grown at a high light intensity or FC condition compared with medium to low light intensity or drought stress treatments.

Velvetleaf is one of the most significant and fastest spreading alien weeds in Europe, and it is a difficult weed to control in conventional sugarbeet. Laboratory experiments were carried out in 2007 and 2008 and field experiments were carried out in 2006, 2007, and 2008 with the aim of finding effective herbicide combinations and optimum timing of control. Herbicides containing the active ingredients phenmedipham, desmedipham, ethofumesate, clopyralid, and triflusulfuron were all tested at different timings. Phenmedipham + desmedipham + ethofumesate gave 87% velvetleaf control in pot experiments when applied at the growth stages of velvetleaf cotyledons and one true leaf, but only 27 to 42% control in field trials. Triflusulfuron gave 76% control in pot experiments and 83 to 88% control in field experiments. The timing of the first and second herbicide applications was very important: the first application of herbicides must be at the cotyledon stage of velvetleaf. A 1-wk delay in first application reduced herbicide efficacy by 8%. A 5-d period between the first and second treatments gave 93% control, while a 10-d period between the first and second treatments gave only 77% control. Sugarbeet yield decreased by 60 to 86% due to competition with velvetleaf when a standard herbicide combination (phenmedipham + desmedipham + ethofumesate) was used, and the velvetleaf produced between 6,700 and 14,800 seeds m−2. Inclusion of triflusulfuron in the herbicide treatment significantly reduced velvetleaf seed production to between 200 and 4,700 seeds m−2. In most cases, inclusion of triflusulfuron increased sugarbeet yield. Better velvetleaf control occurred in years when the sugarbeet canopy developed early and the index of leaf area of sugarbeet was higher.

Abutilon grandifolium is reported for the first time for the flora of Egypt. The paper includes a comprehensive description, occurrence, comparison with closely related species, comments on habitat, and an updated identification key to the species of Abutilon in Egypt. In addition, photographs are given for easy identification.