Corynespora cassiicola threatens soybean and cotton production in Brazil. The objective of this study was to evaluate cultural and morphological aspects of C. cassiicola isolated from soybean and cotton of different Brazilian regions, in culture media. The isolates were grown in PDA (Potato Dextrose Agar) and V8 juice agar media. The characteristics evaluated were: color, aspect, and growth rate of mycelia, as well as production and dimension of conidia, and number of septa per conidium. Culture media and isolates were compared using the Kruskal-Wallis or Tukey’s test at 5% significance level. The mycelia of the isolates were predominantly dark gray and light brown. C. cassiicola isolates grew better in V8 juice agar medium, presenting a higher mycelial growth rate. In PDA medium, the production of conidia was higher in isolates from cotton, compared with soybean isolates. There was great variation in the production of conidia in V8 juice agar medium, regardless of the host origin. Conidia length and width varied for isolate and culture medium. The isolates of C. cassiicola coming from cotton presented a higher number of septa per conidium when grown in PDA medium. The morphological aspects of C. cassiicola vary depending on the host of origin and the culture medium.

The present study aimed to isolate endophilic fungi from plant tissues (leaves, stems and roots) of beans, in addition to identifying them at the genus level. The experiment was conducted at IDR-Londrina. Bean samples were collected at the Londrina Research Station and at UENP-Bandeirantes. The leaves, stems and roots were separated, fragments of 5 mm diameter were cut and disinfested. They were later transferred to BDA culture medium. The plates were incubated at room temperature for seven days for growth of the microorganisms present. The presence and absence, colonization rate (TC) for each tissue and gender identification of fungi were evaluated. The experiment was conducted in a completely randomized design, with five replications. Forty-eight endophilic isolates were found, 13 in root, 17 in stem and 18 in leaf. CT ranged from 17-100% (leaf), 17-83% (stem) and 16-100% (root). The genus Alternaria sp. and Cladosporium sp. have greater specificity with the leaf and stem, Penicillium sp. root and stem. The genera Fusarium sp. and Aspergillus sp. are found in all organs, Curvularia sp., Nigrospora sp. and Thichoderma sp. demonstrated leaf specificity, Macrophomina sp. the root, and Colletotrichum sp. to the stem. Thus, the identified fungi present potential for future studies in their application in the biocontrol of various plant diseases.

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This study aimed to classify the different types of leaf lesions caused by target spot and quantify their incidence in plant tissues of soybean cultivars infected by Corynespora cassiicola isolates. The experiment was conducted in a randomized block design in an 8 × 8 factorial arrangement, consisting of eight C. cassiicola isolates and eight soybean cultivars. Soybean plants were inoculated by spraying fungal suspension on the leaflets at a concentration of 2 × 104 conidia mL-1. Target spot lesions were classified, assigning scores for each type of symptom observed. The incidence of lesions in plant tissues was evaluated 10 days after inoculation, recording the presence of lesions. Five patterns of lesions were observed, ranging from small (0.74 mm) to large (9.30 mm) necrotic spots. Symptoms capable of causing defoliation occurred in BMX Elite IPRO, BRS 284, BMX Garra IPRO, and Nidera 5909 RG when inoculated with ISO 1S, ISO 4S, and ISO 11S. The highest frequency of lesioned trefoils was verified in the upper and lower (3rd and 1st trefoil) strata of soybean plants. Lesions were detected in cotyledons, unifoliate leaves, petioles, and stems of plants from all cultivars evaluated in this study. The isolate ISO 4S caused higher incidence of lesions in petioles compared with ISO 2A and ISO 2S. Moreover, ISO 4S produced more lesions in the stems of BMX Potência RR and BMX Force RR than BMX Elite IPRO. The incidence of petiole lesions caused by C. cassiicola increased as the petiole insertion height into the main stem decreased.