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Phytophthora cactorum and Phytophthora nicotianae cause leather rot on fruit and crown rot (PhCR) of strawberry plants. Leather rot is not a common disease in Florida; however, up to 50% yield loss has been reported in harvests after intense rainfall events. PhCR is an important disease worldwide and is characterized by a sudden wilting and collapse of plants. Mefenoxam is the most effective and widely used fungicide to control both diseases. P. cactorum and P. nicotianae isolates from leather rot and PhCR have been collected from multiple strawberry fields in Florida since 1997, and the sensitivity of 185 isolates was tested at 0, 0.05, 0.5, 5, and 100 µg/ml. The 50% effective concentration (EC50) values of sensitive isolates ranged from 0.05 to 1 µg/ml. Resistance to mefenoxam (EC50 values >100 µg/ml) was found among P. cactorum isolates collected after 2015, but no resistance was found in P. nicotianae isolates. During the 2015 to 2016, 2016 to 2017, 2017 to 2018, and 2018 to 2019 seasons, resistance was detected on 9, 10, 21, and 23% of the isolates collected, respectively. Mefenoxam-resistant isolates originated from 3 of the 24 strawberry nurseries monitored. This is the first report of the occurrence of P. cactorum resistance to mefenoxam in Florida, suggesting that alternative control strategies are needed to avoid the increase of mefenoxam-resistant populations of P. cactorum in Florida fields.

Recently, the Florida strawberry industry faced unprecedented outbreaks of an emerging disease caused by the fungus

Phytophthora crown rot (PhCR) and leather rot (LR) caused by Phytophthora spp. are major threats to strawberry production worldwide. In the United States, these diseases are mainly caused by

A new Neopestalotiopsis sp. was recently reported causing outbreaks of leaf spot and fruit rot on strawberry in Florida, Georgia, and South Carolina. In contrast to other Pestalotiopsis pathogens, the new species appears more aggressive and destructive on strawberry. Current chemical options for management are disease suppressive at best, and affected growers have been experiencing major yield losses. In this study, we developed a molecular method based on polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) for identification of the new Neopestalotiopsis sp. from strawberry. Isolates of the new Neopestalotiopsis sp. collected in Florida; isolates of N. rosae, N. honoluluana, N. ellipsopora, N. saprophytica, N. samarangensis, and P. rhododendri; and isolates from South Carolina suspected to be the new Neopestalotiopsis sp. were included in this study. This method is based on PCR amplification of a β-tubulin gene fragment using a previously published set of primers (Bt2a and Bt2b), followed by use of the restriction enzyme BsaWI. The enzyme cuts the PCR product from the new Neopestalotiopsis sp. twice, yielding fragments of 290 base pairs (bp) and 130 and 20 bp in size, whereas fragments from other species are only cut once, yielding fragments of 420 and 20 bp. This method will aid research labs and diagnostic clinics in the accurate and fast identification of the aggressive Neopestalotiopsis sp. variant from strawberry.

Phytophthora crown rot (PhCR) caused by P. cactorum is one of the most damaging diseases of strawberry worldwide. Mefenoxam is one of the major fungicides currently applied to manage PhCR. However, the emergence and spread of resistant isolates have made controlling the pathogen in the field problematic. In the present study, using whole genome sequencing analysis, mutations associated with mefenoxam-resistant isolates were identified in six different genomic regions of P. cactorum. The 95.54% reads from a sensitive isolate pool and 95.65% from a resistant isolate pool were mapped to the reference genome of P. cactorum P414. Four point mutations were in coding regions while the other two were in noncoding regions. The genes harboring mutations were functionally unknown. All mutations present in resistant isolates were confirmed by sanger sequencing of PCR products. For the rapid diagnostic assay, SNP-based high-resolution melting (HRM) markers were developed to differentiate mefenoxam-resistant P. cactorum from sensitive isolates. The HRM markers R3-1F/R3-1R and R2-1F/R2-1R were suitable to differentiate both sensitive and resistant profiles using clean and crude DNA extraction. Our findings may contribute to a better understanding of the mechanisms of resistance of mefenoxam in oomycetes as well as contribute to the monitoring of P. cactorum populations for the sustainable use of this product.

Phytophthora crown rot (PhCR) is an important disease of strawberry worldwide.

Florida strawberry production is affected by two economically important Phytophthora diseases, Phytophthora crown rot (PhCR) and leather rot (LR), caused primarily by Phytophthora cactorum and P. nicotianae. Although products are available, chemical control is limited to mefenoxam, phosphites, and azoxystrobin, and resistance to mefenoxam and azoxystrobin has been reported. Both in vitro and in vivo assays were conducted to evaluate the effectiveness of eight different chemical classes on controlling PhCR and LR of strawberry. The fungicides mandipropamid, fluopicolide, oxathiapiprolin, and cymoxanil completely inhibited mycelial growth of both species at 1 µg/ml. The same fungicides controlled LR and PhCR caused by P. cactorum, in detached fruit and greenhouse trials, respectively, including mefenoxam-resistant isolates. However, for PhCR caused by P. nicotianae, only oxathiapiprolin and cymoxanil were effective in controlling the disease. Cyazofamid, fluazinam, propamocarb, and tebuconazole did not control PhCR caused by either Phytophthora spp. Except for tebuconazole, all fungicides tested reduced incidence of LR caused by P. cactorum in the detached fruit assay; in contrast, fluazinam, cyazofamid, and propamocarb had no effect on P. nicotianae. This study identifies four fungicides that could potentially be registered to manage both PhCR and LR of strawberry. The registration of additional fungicides with different modes of action would allow fruit and nursery growers to alternate products to reduce fungicide resistance risk.

In underdeveloped countries, zinc deficiency is a public health problem. The main foods consumed in these countries have low levels of the nutrient, making their consumption insufficient to meet the minimum daily requirements. Therefore, the aim of this study was to evaluate agronomic biofortification with zinc in curly lettuce cultivars. The experiment was carried out at the Universidade Federal de Uberlândia - Monte Carmelo Campus, using a complete randomized block design in a 4 × 5 factorial scheme with four replications. The factors consisted of four curly lettuce cultivars (Brida, Isabela, Thais, and Vanda) and five doses of leaf zinc (0, 400, 800, 1200 and 1600 g ha-1 of Zn). The following traits were evaluated: zinc leaf content, plant height, SPAD index, total fresh mass, stem diameter, head diameter, number of leaves per plant, and estimated average yield. Data were subjected to analysis of variance by the F test (? = 0.05) and means were compared by Tukey test at 5% probability and regression analyzes. According to the results obtained, the cultivar Thais can be considered the lettuce with highest leaf zinc content and the most biofortified. It is advisable to use 700 g ha-1 of leaf zinc to obtain biofortified lettuce with increased yield.

During the fall of 2020 and summer of 2021, symptoms of leaf rust were observed on blackberry plants of 'Kiowa', and breeding line 1734 (progeny of 'Natchez' and Arapaho') in a field trial at the University of Florida, Wimauma, FL. Symptoms consisted of small chlorotic spots (1 to 3 mm) on the upper side of the leaf, while the underside had yellow-orange pustules. Disease incidence was up to 100% on both 'Kiowa' and the breeding line 1734, and severity was up to 20% with most of the symptoms observed on older leaves. Two isolates were collected from 'Kiowa' and one from the breeding line 1734 for further investigation. Isolates were maintained and multiplied on healthy 'Kiowa' plants in growth chambers (25 ºC and 12-12 h photoperiod). Uredinia (n=30) were erumpent and ranged from 90 to 320 µm (Average=285 µm, SD=5.3 µm) in diameter. Urediniospores (n=50) were obovoid, yellow, and ranged from 24 to 36 μm long (Average=32 µm, SD=3.2 µm) and 22 to 30 μm wide (Average=28 µm, SD=2.5 µm). Based on morphology and literature, the pathogen was tentatively identified as Kuehneola uredinis (Link) Arth (Arthur 1906; Shands et al., 2018). Spores from a single uredinium of each isolate were collected with a needle and suspended in 50 µL of molecular biology-grade water yielding a final concentration of approximately 5 x 104 spores/mL. Two µL of each spore suspension was used for the PCR reactions. Two DNA fragments were amplified using the primers Rust2inv and LR6, and Rust18S-R and NS1 for the 5.8S-ITS2-28S gene region of rDNA (1,755 bp) and partial 18S gene region of rDNA (2,684 bp), respectively. The amplified products of the partial 28S gene region were sequenced with the primers LR3 and LR0R, and the 18S gene region with NS5, NS6, and NS4 (Aime 2006). DNA sequences were deposited in GenBank (accession nos. OK509845 - OK509848). BLASTn searches revealed that the isolates were 100% identical to

Made available in DSpace on 2022-05-01T09:30:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 During the winter, there is a high occurrence of downy mildew on lettuce caused by Bremia lactucae. This oomycete shows variability in virulence, so understanding the genetic structure of the pathogen population becomes essential for obtaining resistant cultivars. Thus, the objective of this study was to determine sexual compatibility in Brazilian populations of B. lactucae and investigate the occurrence of sexual reproduction of the pathogen on lettuce (Lactuca sativa) and prickly lettuce (Lactuca serriola). Leaf samples were collected in 33 municipalities in seven Brazilian states. The virulence structure of the populations was monitored using the EU-C sextet code. B. lactucae populations from the states of São Paulo, Paraná, Rio de Janeiro, and Rio Grande do Sul shared six of the 15 virulence factors evaluated. Twenty-five virulence phenotypes (v-phenotypes) were found, with the sextet codes 31-00-02, 31-16-02, 31-24-02, and 31-01-02 being more frequent. The predominance of some v- phenotypes indicates that clonal reproduction is still the main form of B. lactucae propagation. The genes and resistance factors of the cultivars Argelès (Dm38), Balesta, and Bartoli are recommended as suitable sources of lettuce resistance in Brazil. Natural occurrence of oospores was detected in most sampled locations, in lettuce and prickly lettuce plants. Virulence variability of Brazilian isolates is the result of the pathogen's ability to reproduce both sexually and asexually, with a prevalence of homothallic isolates; although the majority were of the predominant B2 mating type, there was a high incidence of predominant B1 in addition to B1 = B2. Department of Agricultural Production Sciences São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences, SP Department of Plant Pathology Gulf Coast Research and Education Center University of Florida Research Department – Lettuce Breeding Agristar do Brasil, SP Department of Botany Faculty of Science Palacký University in Olomouc Department of Agricultural Production Sciences São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences, SP

Made available in DSpace on 2020-12-12T01:50:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Lettuce downy mildew, caused by Bremia lactucae, occurs throughout São Paulo, the main lettuce production state in Brazil, during winter due to low temperatures and high humidity. Thus, the aim of this work was to monitor the races and virulence factors in São Paulo’s B. lactucae population from 2003 to 2015, and to compare the results with similar studies in other countries. Data from 582 isolates collected from Lactuca sativa cultivars in 33 municipalities of São Paulo were analyzed. Seventeen virulence patterns (races) were identified. Only few races have been stable over the years. The virulence factors v1, v2, v3, v4, v5/8, v7, v10, v11, v12 and v13 have always been present since the first screening in 2003 while the factors v6, v14, v15, v16, v36 and v37 were found in varying frequencies. The population diversity in São Paulo increased over time with five new races emerging in 2014 and 2015. However, the virulence factors identified are the same as previously described in other areas. The races of São Paulo state are similar to the new races from Australia, California, Europe and Japan, grouping in the same clade by analysis the virulence patterns. The genes Dm17, Dm18, R38 and the resistance factors of the cultivars Balesta and Bellisimo can be recommended as source of resistance to the pathotypes characterized to date in São Paulo. Gulf Coast Research and Education Center University of Florida, 14625 CR 672, 33598 Department of Crop Production School of Agricultural and Veterinarian Sciences São Paulo State University (UNESP), Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane - s/n – CEP: 14 Naktuinbouw, Sotaweg 22, 2371 GD Department of Plant Pathology School of Agricultural and Veterinarian Sciences São Paulo State University (UNESP), Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane - s/n – CEP: 14 Department of Crop Production School of Agricultural and Veterinarian Sciences São Paulo State University (UNESP), Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane - s/n – CEP: 14 Department of Plant Pathology School of Agricultural and Veterinarian Sciences São Paulo State University (UNESP), Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane - s/n – CEP: 14 FAPESP: 2002/13968-9 FAPESP: 2012/09705-4 FAPESP: 2014/10923-1 FAPESP: and 2014/11242-8

Due to the harmful potential and existence of numerous races of lettuce downy mildew (Bremia lactucae Regel), several countries carry out the monitoring of these races through the use of differential cultivars of lettuce (Lactuca sativa L.) The identification of resistance to other important diseases in these cultivars would be of great value for the lettuce’s breeding, allowing the simultaneous selection for diseases. Among soil pathogens, the most important are the root-knot nematodes (Meloidogyne spp.) due their damage and difficulty of control. Thus, the present work evaluated the resistance of these differential cultivars (C-Set) against the two most important nematode species for the crop, M. javanica and M. incognita. The experiment was conducted in a completely randomized design, with eight replicates and initial population of 1000 eggs and juveniles. The evaluations were performed by the criteria of reproduction factor and reproduction index, 75 d after inoculation. Data were submitted to ANOVA and averages were compared by the Scott-Knott test (p < 0.05). All cultivars are considered susceptible to M. incognita by the reproduction factor, ‘Argelès’, ‘Bedford’, ‘Design’ and ‘Grand Rapids’ are considered as slightly resistant by the reproduction index. However, to M. javanica ‘Argelès’, ‘Kibrille’, ‘Balesta’, ‘Colorado’, ‘Design’, ‘Bartoli’, and ‘NunDm15’ are classified as resistant by the reproduction factor and very resistant by the reproduction index, and can be used as resistance source for simultaneous selection to downy mildew and this species of nematode.

Made available in DSpace on 2019-10-06T16:55:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-27 The root-knot nematodes (RKN) challenge okra production (Abelmoschus esculentus L. Moench) worldwide and there are no reports of genetic resistance within the genus Abelmoschus. As an alternative, the compatibility for grafting of RKN-resistant malvaceous species with okra was assessed. Cotton (Gossypium spp.) genotypes are incompatible for grafting with okra. The kenaf (Hibiscus cannabinus L.), the false roselle (Hibiscus acetosella Welw. ex Hiern.) and the roselle (Hibiscus sabdariffa L.) are compatible. However, the rootstock must be sown five days after the scion to promote better grafting compatibility. The performance of grafted okra onto kenaf and false roselle was assessed in two experiments: RKN-free field in the open, and in the presence or not of Meloidogyne incognita race 3 in protected environment. The effect of grafting along time was addressed in the open field experiment. In RKN-free conditions, no differences were observed between rootstocks and self-grafted and non-grafted control. In the presence of M. incognita race 3, the resistant rootstocks provided superior plant development and production due low nematode reproduction. Therefore, grafting okra onto resistant rootstocks is a potential prophylactic measure to manage RKN. São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences

Phytophthora crown rot, caused mainly by Phytophthora cactorum but also by P. nicotianae, reported in 2018, is an important disease in the Florida strawberry annual production system. Mefenoxam is the most effective and widely used fungicide to manage this disease. However, because of pathogen resistance, alternatives to chemical control are needed. Phytophthora spp. were rarely recovered during the summer from soil of commercial farms where the disease was observed during the season. In a more detailed survey on research plots, neither of the two species was recovered 1 month after the crop was terminated and water was shut off. Therefore, Phytophthora spp. does not seem to survive in the soil over summer in Florida. In a field trial, asymptomatic nursery transplants harboring quiescent infections were confirmed as the major source of inoculum for these pathogens in Florida. Heat treatment of P. cactorum zoospores at 44°C for as little as 5 min was effective in inhibiting germination and colony formation; however, oospore germination was not inhibited by any of the tested temperatures in vitro. In the field, thermotherapy treatment of inoculated plants was shown to have great potential to serve as a nonchemical approach for managing Phytophthora crown rot in production fields and reducing mefenoxam-resistant populations in nursery transplants.

Rapid and accurate disease diagnosis is a prerequisite for an effective disease management program in strawberry production. In Florida, Colletotrichum spp., Phytophthora spp., and Macrophomina phaseolina are the primary microorganisms causing strawberry crown rot. Even though the diseases can be caused by different pathogens, symptoms are indistinguishable and equally devastating. To inform strawberry growers in a timely fashion of diagnostic results for effective deployment of chemical control practices, we developed a multiplex high-resolution melting (HRM) assay to rapidly and accurately detect the abovementioned pathogens. The multiplex HRM assays using three predesigned primer pairs showed high specificity for individual species by generating specific melting peaks without cross-reaction between primers or with other common strawberry pathogens. The amplification limit of the assay was 1 pg of Colletotrichum and Phytophthora and 100 pg of M. phaseolina DNA per 10-μl reaction. However, the presence of different melting peaks was observed in mixed DNA samples and was concentration and target DNA dependent. A crude DNA extraction protocol was developed to allow high-throughput screening by minimizing the inhibitory effects. Moreover, we applied the HRM assay to 522 plant samples and found high correlations between conventional pathogen isolation and HRM and between singleplex and multiplex assays. Altogether, this multiplex HRM assay is specific, cost effective, and reliable for the timely detection of strawberry crown rot pathogens.

Hemp is an annual herbaceous plant that is used for its fiber and oil in a variety of commercial and industrial products. In Florida, it is currently being explored as a new specialty crop. During a field trial from October to January 2019 in Wimauma, FL, a stem canker was observed on up to 60% of three-month-old plants of 'Eletta Campana', 'Carmagnola Selezionata', and 'Tygra'. Symptoms started on the main stems with light-to-dark brown lesions of different sizes and shapes. Over time, the lesions coalesced into large necrotic areas and bore pycnidia. Isolations were made from diseased stem tissues on General Isolation medium (Amiri et al. 2018) after surface disinfestation (Marin et al. 2020). The plates were placed in a growth chamber at 25°C under a 12/12 photoperiod. A fungus with white, floccose, aerial mycelium and pycnidia producing alpha and beta conidia was consistently isolated. Three single spore isolates were chosen for identification and pathogenicity tests. Pycnidia on PDA were globose to irregular and ranged from 170 to 250 μm long (210 ± 2.5, n = 50) and 140 to 220 μm wide (180 ± 2.7, n = 50). The alpha conidia were unicellular, hyaline, ellipsoidal to fusiform and ranged from 5.3 to 7.7 μm long (6.5 ± 1.6, n = 50) and 1.5 to 4.6 μm wide (2.8 ± 1.8, n = 50). The beta conidia were hyaline, elongated, filiform, straight or curved and ranged from 10.2 to 17.7 μm long (16.1 ± 2.2, n = 50) and 0.5 to 1.8 μm wide (0.8 ± 0.2, n = 50). Perithecia were not observed. Based on morphological features, the fungus was similar to anamorphs of Diaporthe spp. (Santos et al. 2011; Udayanga et al. 2015). DNA from the same three isolates was extracted using the FastDNA kit, and the ribosomal internal transcribed spacer (ITS), β-tubulin (TUB), and calmodulin (CAL) regions were amplified following Udayanga et al. (2014), and Sanger sequenced by Genewiz. Sequences were deposited in GenBank (accession no. MT497039 to MT497047 for ITS, TUB, and CAL). BLASTn searches revealed isolates 20-58, 20-59, and 20-60 were 96.34% identical to the epitype isolate

Made available in DSpace on 2021-06-25T10:16:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Lettuce downy mildew caused by Bremia lactucae is one of the main diseases in high humidity and low temperature conditions. The identification of virulence factors appearing in the pathogen population could help improve breeding programs against this disease. This study aimed to monitor and evaluate virulence dynamic changes in B. lactucae virulence among two Brazilian regions to recommend resistance genes for breeding programs. Isolates from São Paulo, Rio Grande do Sul, and Paraná states were assessed using the sextet code EU-C composed by 16 Lactuca spp. genotypes, between 2015 and 2016. To understand the population dynamics, the frequencies of virulence phenotypes and factors and the virulence complexity per isolate (Ci), phenotype (Cp), and Gleason (Ig), indexes were calculated. B. lactucae virulence from Paraná, Rio Grande do Sul and São Paulo were similar and shared nine out of the 15 evaluated virulence factors. In total, 90 isolates were analyzed, and 27 virulence phenotypes were found. The most frequent sextet codes were 31–00-00, 31–00-02, 31–01-00, and 31–01-02. The genes or resistance factors present in ‘Argelès’ (Dm38), ‘Balesta’, and ‘Bartoli’ could be used as sources of resistance by Brazilian lettuce breeders. Department of Crop Production School of Agricultural and Veterinarian Sciences UNESP- São Paulo State University (Unesp) Gulf Coast Research and Education Center University of Florida Department of Plant Pathology School of Agricultural and Veterinarian UNESP- São Paulo State University (Unesp) Department of Crop Production School of Agricultural and Veterinarian Sciences UNESP- São Paulo State University (Unesp) Department of Plant Pathology School of Agricultural and Veterinarian UNESP- São Paulo State University (Unesp)

During the 2020-2021 Florida strawberry season (October to April), strawberry (Fragaria × ananassa) plants showing leaf spots were observed on samples submitted to the Diagnostic Clinic at the University of Florida's Gulf Coast Research and Education Center. Disease incidence was up to 5% and observed on four different farms in Plant City, FL on cultivars SensationTM Florida127 and Florida Brilliance. All the samples were submitted early in the season (November) and shared the same nursery source in California. Symptoms consisted of circular or irregular lesions with purple or brown halos, eventually developing leaf blight with sporulation at the center on advanced lesions. Diseased tissues (0.5 mm2) were surface disinfested with 10% bleach solution for 90 s, rinsed twice in sterile deionized water, and plated on general isolation medium (Amiri et al. 2018). Plates were incubated at 25°C and a 12-h photoperiod. A fungus producing white mycelia with sparse sporulation of Botrytis-like spores was consistently isolated. Isolates were single-spored and grown on HA medium to induce sporulation (Leroch et al. 2013). Three isolates (20-291, 20-293, and 20-295) were selected for identification and pathogenicity assays. Resulting cultures on HA had profuse sporulation resembling gray mold. Conidia (n=50) were round to ellipsoid ranging from 9 to 14.6 μm long (Avg=10.8, SD=1.3) and 6.3 to 9.5 μm wide (Avg=7.7, Sd=0.7). No sclerotia formation was observed on GI and HA medium. Based on morphology, the pathogen was tentatively identified as Botrytis cinerea (Hong et al. 2001; Jarvis 1977). DNA was extracted from the same three isolates using the FastDNA kit (MP Biomedicals, Solon, OH), and the heat shock protein (HSP60), RNA polymerase II-binding (RPB2), and glyceraldehyde 3-phosphate dehydrogenase (G3PDH) genes were amplified (Staats et al. 2004). Sequences were deposited in GenBank (accession nos. MZ288746 - MZ288754). BLASTn searches revealed that isolates were 100% identical to B. cinerea reported causing leaf spot on strawberry in California; accession numbers MK919494 (HSP60, 996/996 bp), MK919495 (RPB2, 1131/1131 bp), and MK919496 (G3PDH, 877/877 bp). To test for pathogenicity, four one-month-old plants of 'Florida Brilliance' were used per isolate and control treatment. Spores were harvested from two-week-old cultures grown on HA medium, and the suspension adjusted to 106 spores/mL in a solution of 0.1% of Tween 20. Plants were spray inoculated until run-off and kept inside clear plastic boxes for 48 h. Control plants were sprayed with sterile deionized water. Afterward, plants were kept in a misting table in the greenhouse with a water regime of 3 s every 10 min during the day. Disease incidence was evaluated weekly, and the experiment repeated once. Two weeks after inoculation, leaf spots were observed in all inoculated plants, while controls remained healthy. Fungi morphologically identical to the original isolates were re-isolated from the diseased tissues. To our knowledge, this is the first report of B. cinerea causing leaf spot on strawberry in Florida. This disease was recently reported in California (Mansouripour and Holmes 2020), which is where the transplants originated from. Considering the disease was observed early in the Florida season, it is likely that it was introduced with transplants from the nursery. This pathogen is also the causal agent of Botrytis fruit rot, which is considered a major disease of strawberry, and a previous study has shown that populations resistant to multiple fungicides are introduced with transplants (Mertely et al. 2018, Oliveira et al. 2018). While Botrytis leaf spot is currently considered rare and of minor significance (Mansouripour and Holmes 2020), it could contribute to the spread of fungicide resistance to from nursery to strawberry fruit production fields. Efforts should be implemented to monitor its occurrence and spread considering the high variability and fungicide resistance profile of this pathogen.

During the 2019-2020 Florida strawberry season (October to April), a strawberry (

Made available in DSpace on 2022-05-01T00:03:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) For the lettuce crop, there is no specific or standard methodology to evaluate genotype resistance of lettuce against downy mildew. Therefore, the aim of this work was to compare three methodologies for the identification of resistance to downy mildew. The experiment was carried out at Universidade Federal de Uberlândia, Monte Carmelo Campus between 2017 and 2018. The statistical method used was a completely randomized design with 12 treatments (cultivar Solaris, used as a control; and 11 genotypes of lettuce F5: 6: UFU-Crespa 75 # 2, UFU-Crespa 189 # 2, UFU-Crespa 206 # 1, UFU-Lisa 66 # 3, UFU-Lisa 66 # 7, UFU-Lisa 215 # 3, UFU-Lisa 215 # 6, UFU-Lisa 215 # 10, UFU-Lisa 215 # 12, UFU-Lisa 215 # 13, UFU-Lisa 215 # 14) and four replications. The seeding of genotypes was carried out in transparent boxes and after 15 days the inoculation was performed using a spore suspension (1x104 sporangia/ml) and sterile deionized water for the controls. The disease progression was assessed by three methods: Mesquita, Dickinson & Crute and Horsfall & Barrat. The data were standardized and submitted to the univariate analysis of variance by the F test and multivariate analyzes. The univariate clustering results allowed the separation of the genotypes into two distinct resistance groups for the Dickinson & Crute and Mesquita methods. In the multivariate analysis, more formation of groups among genotypes with different levels of resistance to downy mildew in the Mesquita method was observed. The methodology proposed by Mesquita was more efficient in discriminating genotypes with different levels of resistance to downy mildew, separating them in a larger number of groups. Instituto de Ciências Agrárias Universidade Federal de Uberlândia, Campus de Monte Carmelo Gulf Coast Research and Education Center University of Florida Departamento de Produção Vegetal Universidade Estadual Paulista 'Júlio de Mesquita Filho' Departamento de Produção Vegetal Universidade Estadual Paulista 'Júlio de Mesquita Filho'

The objective of this work was to estimate the stability and genotypic adaptability of advanced lines and cultivars of curled green-leaf lettuce (Lactuca sativa), in different growing environments and seasons, using the REML/Blup mixed model. Ten genotypes, seven cropping environments, and two growing seasons were studied in 2015. Plant yield traits were evaluated, and data were subjected to the Selegen-REML/Blup software. Genotype stability and adaptability were analyzed using the harmonic mean of genotypic values (HMGV) and the relative performance of genotypic values (RPGV), respectively. The harmonic mean of RPGV (HMRPGV) was used to simultaneously estimate the stability, adaptability, and yield of breeding lines or cultivars. Considering the combined analysis of the two seasons for the set of traits, the lines L6, L7, and L8 were selected as promising ones and recommended for planting. The breeding lines selected for all season exhibit good yield and are considered superior to the commercial cultivars Vanda and Vera. Resumo: O objetivo deste trabalho foi estimar a estabilidade e a adaptabilidade genotípica de linhagens avançadas e cultivares de alface-crespa (Lactuca sativa), em diferentes sistemas de cultivos e épocas, pelo modelo misto REML/Blup. Foram avaliados dez genótipos de alface, sete sistemas de cultivo e duas épocas, em 2015. Avaliaram-se os caracteres de produção das plantas, e os dados foram submetidos ao programa Selegen-REML/Blup. A estabilidade e a adaptabilidade genotípica foram analisadas pelos métodos da média harmônica dos valores genotípicos (MHVG) e do desempenho relativo dos valores genotípicos (PRVG), respectivamente. A média harmônica do PRVG (MHPRVG) foi utilizada para estimar simultaneamente a estabilidade, a adaptabilidade e a produtividade das linhagens e das cultivares. Ao se considerar a análise conjunta das duas épocas para o conjunto dos caracteres, as linhagens L6, L7 e L8 foram selecionadas como promissoras e recomendadas para plantio. As linhagens selecionadas para todas as épocas apresentam bons rendimentos e são consideradas superiores às cultivares comerciais Vanda e Vera.

Botrytis cinerea, the causal agent of Botrytis fruit rot, is annually introduced into Florida strawberry fields by infected transplants. The disease can be managed by fungicide sprays throughout the season; however, previous studies have demonstrated that several chemical classes are no longer effective owing to B. cinerea resistance. The objectives of this study were to evaluate the effectiveness of preplant fungicide-dip treatments of strawberry transplants on reducing B. cinerea colonization and to evaluate fungicide sensitivity of surviving B. cinerea isolates. Transplants of two strawberry cultivars, Winterstar ‘FL 05-107’ and ‘Florida Radiance’, were dipped in 11 different fungicides. After the plant establishment period, eight leaves per plot were collected before and 14 days after treatment to evaluate B. cinerea incidence. Isolates (n = 139) obtained from the transplants were tested for fungicide sensitivity. Plant diameter was measured 47 days after planting. All treatments, including the controls, reduced B. cinerea incidence by at least 77% compared with predip incidence. However, fungicide-resistant isolates were recovered from all treatments tested.

Hemp is an annual herbaceous plant that is used for its fiber and oil in a variety of commercial and industrial products. In Florida, it is currently being explored as a new specialty crop. During a field trial from October to January 2019 in Wimauma, FL, a stem canker was observed on up to 60% of three-month-old plants of 'Eletta Campana', 'Carmagnola Selezionata', and 'Tygra'. Symptoms started on the main stems with light-to-dark brown lesions of different sizes and shapes. Over time, the lesions coalesced into large necrotic areas and bore pycnidia. Isolations were made from diseased stem tissues on General Isolation medium (Amiri et al. 2018) after surface disinfestation (Marin et al. 2020). The plates were placed in a growth chamber at 25°C under a 12/12 photoperiod. A fungus with white, floccose, aerial mycelium and pycnidia producing alpha and beta conidia was consistently isolated. Three single spore isolates were chosen for identification and pathogenicity tests. Pycnidia on PDA were globose to irregular and ranged from 170 to 250 μm long (210 ± 2.5, n = 50) and 140 to 220 μm wide (180 ± 2.7, n = 50). The alpha conidia were unicellular, hyaline, ellipsoidal to fusiform and ranged from 5.3 to 7.7 μm long (6.5 ± 1.6, n = 50) and 1.5 to 4.6 μm wide (2.8 ± 1.8, n = 50). The beta conidia were hyaline, elongated, filiform, straight or curved and ranged from 10.2 to 17.7 μm long (16.1 ± 2.2, n = 50) and 0.5 to 1.8 μm wide (0.8 ± 0.2, n = 50). Perithecia were not observed. Based on morphological features, the fungus was similar to anamorphs of Diaporthe spp. (Santos et al. 2011; Udayanga et al. 2015). DNA from the same three isolates was extracted using the FastDNA kit, and the ribosomal internal transcribed spacer (ITS), β-tubulin (TUB), and calmodulin (CAL) regions were amplified following Udayanga et al. (2014), and Sanger sequenced by Genewiz. Sequences were deposited in GenBank (accession no. MT497039 to MT497047 for ITS, TUB, and CAL). BLASTn searches revealed isolates 20-58, 20-59, and 20-60 were 96.34% identical to the epitype isolate D. phaseolorum AR4203 for ITS (KJ590738.1, 527 bp out of 547 bp), 100% for TUB (KJ610893.1, 459 bp out of 459 bp), and 100% for CAL (KJ612135.1, 522 bp out of 522 bp) (Udayanga et al. 2015). Their identity was confirmed by phylogenetic analyses using maximum likelihood and Bayesian inference methods. To complete Koch's postulates, pycnidia of the same three isolates were harvested and crushed in 2 mL Eppendorf tubes containing 0.01% Tween 20. Conidia suspensions were adjusted to 106 spores/mL. Three 5-week-old potted plants of 'Eletta Campana' and 'Carmagnola Selezionata' per isolate were inoculated using a 1 mL syringe with a needle by injecting 200 µL of the suspension into the stem. Plants were placed inside clear plastic bags for 48 h and maintained in the greenhouse. Control plants were injected with sterile deionized water and kept under the same conditions. The pathogenicity test was repeated once. Four weeks after inoculation, inoculated plants developed stem cankers from which the same pathogen was isolated, whereas controls remained healthy. To our knowledge, this is the first report of D. phaseolorum causing stem canker on hemp. This pathogen has been reported causing canker on sunflower and Phaseolus spp. (Gomzhina and Gannibal 2018; Udayanga et al. 2015; Vrandecic et al. 2009). This discovery may help shape future research into disease epidemiology and management for a crop in which very limited disease information is available at the moment.

Made available in DSpace on 2022-04-30T00:49:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 In recent years, a group of small watermelons has stood out with 1-3 kg in weight called mini watermelons. These watermelons, when grown under greenhouse conditions, require different management techniques. This study evaluated the performance of mini watermelon hybrids at different plant spacing. To this end, the experiments were conducted in a greenhouse using a substrate of coconut husk fibers with fertigation. The study design was a randomized block with 5 × 3 factorial treatments and four replicates. The factors evaluated included five mini watermelon hybrids (Beni Kodama, Ki Kodama, Smile, New Kodama, and Beni Makura) and three plant spacing configurations (E1 = 0.35 m, E2 = 0.50 m, and E3 = 0.65 m). Growth characteristics, production, and quality were evaluated using analysis of variance. There was no significant interaction between the hybrids and plant spacing for yield traits, physiological traits, and fruit quality. Fresh fruit mass, yield, transverse and longitudinal diameter and firmness presented significant differences for both factors, type of hybrid and plant spacing. In this study, despite the established competition in terms of spacing, the performance of hybrids was not negatively affected. Thus, we recommend the cultivation of hybrids spaced 0.50 m apart in coconut husk fibers, because it results in good yield and fruit quality, while facilitating plant management techniques. Universidade Federal Rural da Amazônia - Campus Capanema, Rua João Pessoa, no 121 Universidade Estadual Paulista - Campus Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane, s/n Universidade Estadual Paulista - Campus Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane, s/n

Universidade Estadual Paulista/UNESP-FCAV Department of Crop Science, Via de Acesso Prof. Paulo Donato Castellane - s/n

Made available in DSpace on 2018-11-12T17:27:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-03-01. Added 1 bitstream(s) on 2018-11-12T17:35:53Z : No. of bitstreams: 1 S1983-40632016000100111.pdf: 198356 bytes, checksum: 6091d1732431e63024b7909c962054bb (MD5) RESUMO O melão é uma das culturas de grande importância econômica no Brasil, especialmente para o Nordeste. Contudo, à medida que seu cultivo é intensificado, surgem problemas fitossanitários, dentre eles os causados por nematoides, cujo controle tem como medida mais efetiva o uso de cultivares resistentes. Objetivou-se avaliar a reação de genótipos de meloeiro quanto à hospedabilidade de Meloidogyne incognita e M. javanica. O ensaio foi conduzido em condições de casa-de-vegetação, utilizando-se delineamento inteiramente casualizado, em esquema fatorial 2 x 15, com seis repetições. Foram avaliados 15 genótipos de meloeiro, e o tomateiro 'Santa Cruz Kada' foi utilizado como padrão de suscetibilidade. Para avaliação da reação dos genótipos, utilizadram-se o número total de ovos e juvenis nas raízes e o fator de reprodução. Nenhum dos genótipos foi resistente a M. incognita. Oito genótipos foram classificados como resistentes a M. javanica e promissores para emprego em programas de melhoramento genético do meloeiro. ABSTRACT Melon is one of the most economically important crops cultivated in Brazil, especially in the Northeast region. However, as its cultivation increases, phytosanitary problems arise, including those caused by nematodes, which are most effectively controlled using resistant cultivars. This study aimed at assessing the reaction of muskmelon genotypes, in terms of resistance to Meloidogyne incognita and M. javanica infestation. The experiment was conducted under greenhouse conditions using a completely randomized design, in a 2 x 15 factorial scheme, with six replications. A total of 15 muskmelon genotypes were evaluated and the 'Santa Cruz Kada' tomato was used as a susceptible control. The total number of eggs and juvenile nematodes in the roots and the reproduction factor were used to assess the genotype reaction. None of the genotypes was resistant to M. incognita. Eight genotypes were classified as resistant to M. javanica and promising for use in melon breeding programs. Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Ciências Agrárias e Veterinárias

RESUMO Sob condições controladas em câmara tipo BOD, oito linhagens de alface crespa e a cultivar Solaris, foram avaliadas por meio de um índice de latência (IL) como medida da severidade do míldio, e a resposta de resistência por meio da porcentagem de plântulas com esporângios (PE), quando inoculadas com nove raças de Bremia lactucae isoladamente e com a única mistura de todas as raças. O IL e a PE nas linhagens foram inferiores aos apresentados na cultivar Solaris utilizada como padrão de suscetibilidade. As linhagens L1, L2, L3 e L4, foram altamente resistentes quando inoculadas (PE=0,0%) com às nove raças/mistura, as linhagens L5, L6, L7 e L8, dependendo da raça/mistura inoculada apresentaram alto nível de resistência (PE=0-4,6%), resistência incompleta (PE=6,0-15,1%), e a linhagem L5 apresentou reação heterogênea de resistência e suscetibilidade à raça SPBl:07 (PE=27,9% ). ABSTRACT Under controlled conditions in a BOD chamber, eight lines of green leaf lettuce and the cultivar Solaris were evaluated by means of a latency index (IL) as a measure of downy mildew severity, while the resistance response was assessed based on the percentage of seedlings with sporangia (PE) when inoculated with nine races of Bremia lactucae alone and with one single mixture of all races. The IL and PE for the lines were inferior to those shown for the cultivar Solaris, used as the susceptibility standard. The lines L1, L2, L3 and L4 were highly resistant when inoculated (PE = 0.0%) with the nine races/mixture; the lines L5, L6, L7 and L8, depending on the inoculated race/mixture, showed high resistance level (PE = 0-4.6%) and incomplete resistance (PE = 6.0-15.1%), and the line L5 presented a heterogeneous resistance and susceptibility reaction to race SPBl:07 (PE = 27.9%).

During the 2019-2020 Florida strawberry season (October to April), a strawberry (Fragaria × ananassa) fruit rot was observed in two fields (Plant City and Wimauma, FL) with up to 5% incidence on short-day cultivars SensationTM Florida127, and Florida Brilliance. Symptoms on pink and ripe fruit consisted of softening, discoloration, watery rot with white fuzzy mycelium, and initial sclerotium formation. Diseased tissue was placed on General Isolation (GI) medium (Amiri et al. 2018) and incubated at 25°C under a 12-h photoperiod. A fungus producing spreading cottony white colonies with dark sclerotia near the outer edges of the plates was consistently isolated. One isolate from each cultivar field (20-51 and 20-55) was selected for identification and pathogenicity tests. Apothecial production was induced following the protocol of Li and Rollins (2009), and apothecia (n=30) had an average diameter of 4.5 (3.5 to 7.2) mm. Sclerotia were 3.6 (2.5 to 6.2) mm by 4.5 (3.1 to 5.9) mm (n=30) in size. Dimensions of asci were 130.2 (115.1 to 160.5) μm by 8.5 (6.2 to 13.1) μm (n=30), and those of ascospores were 12.2 (10.8 to 14.6) μm by 6.8 (5.7 to 8.1) μm (n=30). Based on these morphological features, the pathogen was tentatively identified as Sclerotinia sclerotiorum (Lib.) de Bary (Maas 1998). DNA was extracted from the same two isolates using the FastDNA kit (MP Biomedicals, Solon, OH), and the ribosomal internal transcribed spacer (ITS) region was amplified using the primers ITS1 and ITS4 (White et al. 1990). Sequences were deposited in GenBank (accession nos. MT378215 and MT378216). BLASTn searches revealed that isolates 20-51 and 20-55 were 99.62% identical (526 / 528 bp) to S. sclerotiorum CBS 499.50 (MH856725.1). Immature pink fruit of SensationTM 'Florida127' were harvested, surface disinfested in bleach solution (0.08% NaClO) for 90 sec, rinsed twice with deionized water, then placed into styrofoam egg cartons inside clean plastic boxes (30x24x7 cm) containing 150 ml of sterile deionized water to maintain moisture, and kept at 25°C with a 12-h photoperiod. Ascospores and sclerotia were used for inoculation tests with three repetitions in an egg carton containing 12 fruit each per isolate and inoculation method. The experiment was repeated once. Fruit were inoculated by placing 20 μl of a 1 × 106 ascospores/mL suspension or a single sclerotium on the upper half of the fruit. Controls were included, by placing 20 μl of sterile DI water or fruit with no sclerotia. Evaluations were done 6, 10, and 15 days after inoculation (DAI). Control fruit remained healthy, while inoculated fruit developed symptoms of softening and discoloration. For ascospore inoculation, disease incidence was 55 (± 5) and 78% (± 4), for 6 and 15 DAI, respectively, whereas for sclerotia inoculation incidence was 100% 6 DAI. Morphologically identical fungi to the original isolates were re-isolated from the diseased fruit. No other fruit decay fungi were observed. S. sclerotiorum has been previously reported causing strawberry fruit rot in Washington state in the United States, England, Israel, and Scotland (Alcorn 1966; Maas 1998; McLean 1957). It has also been listed in the indices of plant diseases from Florida, North Carolina, and California as causing crown rot (Farr and Rossman 2020). To our knowledge, this is the first report of S. sclerotiorum causing strawberry fruit rot in Florida. The pathogen is an aggressive necrotroph with prolonged survival and affects several vegetable crops grown in Florida (Paret et al. 2018). Because only the strawberry beds are fumigated, sclerotia remaining in the alleys could serve as inoculum sources. Currently, the disease is rare and of minor significance to strawberry production. However, efforts should be implemented to monitor its occurrence and spread.

Made available in DSpace on 2021-07-14T10:53:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2017. Added 1 bitstream(s) on 2021-07-14T11:40:43Z : No. of bitstreams: 1 S1983-40632017000400440.pdf: 248406 bytes, checksum: 1732a3392a61a00c38a4cd31105ca06b (MD5) O uso de resistência genética é um dos métodos mais adequados para o controle de oídio das cucurbitáceas em melão, causado por Podosphaera xanthii ou Golovinomyces orontii. Contudo, muitas raças desses patógenos têm sido descobertas, o que pode comprometer a eficácia desse método. Fazem-se, então, necessários o constante monitoramento de raças de oídio e a busca por novas fontes de resistência. Objetivou-se identificar em nível de raça uma população natural de oídio das cucurbitáceas em casa-de-vegetação, bem como avaliar a reação de genótipos locais e exóticos de meloeiro à raça identificada. A identificação da raça foi baseada na reação de oito linhagens diferenciadoras (PI 414723, PMR 45, PMR 5, WMR 29, Edisto 47, Nantais Oblong, PI 124111 e Védrantais). Foram avaliados 59 genótipos de meloeiro, sendo 53 destes acessos de germoplasma e seis linhagens de melão rendilhado, além de duas cultivares (Louis e Fantasy). As plantas foram avaliadas com base em escala visual para lesões nas folhas. A espécie P. xanthii foi confirmada como o agente causal, pela visualização de corpos de fibrosina nos conídios e pela resistência da abóbora d’água (Benincasa hispida). A raça 4 foi identificada pela primeira vez no estado de São Paulo. Os genótipos A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 e Solarking mostraram-se resistentes à raça 4. Genetic resistance is one of the most suitable strategies to control cucurbit powdery mildew (CPM) on melon, incited by Podosphaera xanthii or Golovinomyces orontii. However, many races of these pathogens have been reported worldwide in recent years, what may compromise the effectiveness of this method. Thus, annual surveys of CPM races and the screening of germplasm for new sources of genetic resistance provide a vital support to melon breeding programs. This study aimed at identifying a natural population of CPM race under greenhouse conditions, as well as evaluating the reaction of local and exotic melon germplasm for CPM-resistance. CPM race identity was based on the reaction of eight race differentials: Védrantais, Nantais Oblong, PMR 45, PMR 5, WMR 29, Edisto 47, PI 414723 and PI 124111. Fifty-nine melon genotypes were evaluated, 53 of them being germplasm accessions, and six net melon elite-inbred lines, besides two net melon-type cultivars (Louis and Fantasy). Plants were evaluated using a visual scale for leaf lesions. The causal pathogen was confirmed to be P. xanthii, based on the presence of fibrosin bodies in conidia and the complete resistance response of winter melon (Benincasa hispida). Race 4 was identified for the first time in the São Paulo state, Brazil. Genotypes A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 and Solarking showed to be resistant to the race 4. Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agrárias e Veterinárias United States Department of Agriculture, Agricultural Research Service Universidade Estadual Paulista “Júlio de Mesquita Filho”, Faculdade de Ciências Agrárias e Veterinárias

The okra (Abelmoschus esculentus L. Moench) is one of the most important vegetables in the world and is a popular food item in many tropical and subtropical countries. Besides its cultivation for fresh consumption, okra also has potential industrial uses. Nonetheless, pests and diseases remain the most damaging factors affecting its crop yield. Among these, root-knot nematodes are the main pests limiting okra production. This study aimed to determine the responses of plant species of the Malvaceae family to Meloidogyne incognita and M. enterolobii root-knot nematodes, and to also assess the compatibility of the same with the okra commercial 'Colhe Bem IAC'. Resistance was evaluated using the reproduction factor in two commercial okra cultivars ('Colhe Bem IAC' and 'Santa Cruz 47'), five cotton (Gossypium hirsutum L.) plant genotypes (PRO 277, IAC 29-233, PR 136, IAC 24, and IAC 03-979), and vinagreira (Hibiscus sabdariffa L.) Other resistance-related traits measured were the percentage of healing, plant height, root length, rootstock stem diameter, scion stem diameter, number of leaves, total fresh weight, and fresh weight of the scion, rootstock, and root parts. While the cotton and vinagreira genotypes tested were resistant to both species of nematodes, okra cultivars were not. The okra, however, showed successful adaptation to grafting, which may offer an important physical resistance against attacks by root-knot nematodes, while vinagreira showed the greatest potential for use as rootstock for protecting okra crops.

During the last three seasons, approximately 1% of strawberry (Fragaria × ananassa) with symptoms of fruit softening and discoloration were observed in three fields in Florida. Fruit eventually became black and mummified with pycnidia embedded in the tissue that produced hyaline, aseptate conidia. Eleven isolates recovered from infected tissue were purified by growing them on 2% water agar (WA) with sterilized pine needles (Pavlic et al. 2004) and transferring a single conidium to a new 2% WA plate, by spreading a conidial suspension over the medium and selecting a single germinating conidium 16 h later. DNA of the 11 isolates was extracted from 2-week-old colonies and PCR was performed following the conditions of White et al. (1990) and Carbone and Kohn (1999). Two sets of universal primers, ITS1F/ITS4 and EF1-728F/EF1-986R, were used to amplify and sequence the internal transcriber spacer (ITS) and partial translation elongation factor 1-alpha (EF1-α) regions, respectively. Sequences compared with the GenBank database using BLASTn showed 99 to 100% identity with ITS and EF1-α sequences within the Neofusicoccum parvum/N. ribis species complex or Lasiodiplodia theobromae: N. parvum (MH057203 and KM921768; n = 2), N. kwambonambiense (n = 3), N. ribis (n = 1), N. brasiliense (n = 2), and L. theobromae (MH049696 and KX580762; n = 3). All sequences were deposited in GenBank with following accession numbers: N. parvum/N. ribis species complex (MH809520 to MH809527 for ITS, and MH809508 to MH809515 for EF1-α), and L. theobromae (MH809517 to MH809519 for ITS, and MH809505 to MH809507 for EF1-α). Mycelia of both groups on V8 agar medium were initially white and aerial, but Lasiodiplodia mycelia became light gray after 3 to 5 days and Neofusicoccum mycelia turned dark gray to olivaceous. Conidia of the Neofusicoccum group were aseptate, hyaline, oblong, and 15.0 to 22.9 × 6.1 to 10.4 μm (n = 25). Lasiodiplodia conidia were similar but larger, 22.6 to 33.0 × 13.0 to 19.4 μm (young conidia) and when mature, became brown, one septate, with longitudinal striations, measuring 25.9 to 34.8 × 14.8 to 19.6 μm (n = 25). Similar morphology was previously reported (Alves et al. 2008; Pavlic et al. 2009). To confirm pathogenicity, four isolates (two from N. parvum/N. ribis species complex, and two L. theobromae) were selected and incubated for 2 weeks at 23°C under continuous light until formation of pycnidia. Twenty mature strawberry fruit of ‘Florida Radiance’ were inoculated in the field (five fruit per isolate), by wounding the fruit with a forceps and placing a single pycnidium inside the wound. Field conditions during the incubation period ranged from 16 to 29°C and 65 to 80% relative humidity. Disease incidence was assessed 6 to 10 days after inoculation, and the experiment was repeated once. After 10 days, fruit inoculated with the N. parvum/N. ribis were completely dark and covered with pycnidia, whereas fruit inoculated with L. theobromae had 80 to 100% of its surface covered with pycnidia. All 20 inoculated fruit showed the same symptoms as described above. Both fungi were reisolated from inoculated fruit, fulfilling Koch’s postulates. N. parvum and N. kwambonambiense have been previously reported to cause a postharvest disease of strawberry in Brazil (Lopes et al. 2014). To our knowledge, this is the first report of N. parvum/N. ribis species complex and L. theobromae causing fruit rot in strawberry fields in the U.S. This study sheds light on the possible broad distribution of these pathogens on different hosts as N. parvum was recently reported in the same area causing shoot blight and stem canker on pomegranate (KC and Vallad 2016).

Made available in DSpace on 2022-04-29T07:32:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-23 The objective of this study was to evaluate the influence of tray type and substrate on the initial development of the mini watermelon hybrid 'Ki Kodama'. The following treatments were compared: Three types of tray, 128, 200 and 288 cells, and three types of substrate, Bioplant HT, Biofibra, Bioflora. Treatments were factorially combined. Evaluations were performed 30 days after sowing, and the following parameters were determined: fresh and dry weights of shoot, fresh and dry weights of root, seedling height, number of leaves, root length, stem and root diameters, and leaf and root areas. There was a significant interaction between tray and substrate treatments for fresh and dry weights of shoot and root, stem diameter, and leaf and root areas. For the factor tray, only the root diameter differed, and 128-cell trays showed better performance, while for substrate, height, root length and number of leaves showed significant differences, with Bioflora providing better development of seedlings. For the other parameters, the best performance was observed in 288-cell trays filled with Bioplant HT. The results obtained can be explained because the volume occupied by substrate in each cell varies, which causes root and leaf development also to differ. Thus, for the conditions under which the experiment was conducted, seedlings of mini watermelon 'Ki Kodama' should be grown in 128 or 288 cell trays, filled with the commercial substrate Bioplant Prata HT or Bioflora. Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista

Made available in DSpace on 2022-04-29T07:32:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-23 Reusing the substrate in subsequent crops has been proposed due to several advantages, especially economic and environmental ones. Furthermore, the electrical conductivity of the nutrient solution can directly influence the nutrient content present in the substrate, especially when it is reused, thus interfering with absorption by plants. In this way, the present study aimed to determine the feasibility of reusing the substrate and determine the optimal concentration of the nutrient solution in tomato cultivation. The experiment was conducted in a greenhouse at the Department of Vegetable Crops and Aromatic Medicinal Plants, belonging to FCAV-UNESP. The 'Paronset' hybrid was cultivated in pots containing coconut husk fiber as substrate. The nutrient solution was evaluated at five concentrations, namely 25, 50, 100 (original solution), 150 and 200% of recommended solution, and the substrate at two usage levels (new and reused). Fertigation was performed by dripping with nutrient solution as recommended. The characteristics evaluated were: Production per plant, yield, number of fruits per plant, average fruit weight, soluble solids, and transverse and longitudinal fruit diameter. There was no interaction between the reuse of the substrate and nutrient solution concentration; moreover, there was no difference between the characteristics evaluated for all treatments. Under the conditions of this study, the reuse of the substrate is recommended, at least once, and the use of nutrient solution at a concentration of 25% of the original for the cultivation of 'Paronset' tomato hybrid. Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Solos E Adubos Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Produção Vegetal Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista Departamento de Solos E Adubos Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista