Infected seeds are one of the main pathogen transmission vehicles, and they are responsible for significant losses in production fields; phytosanitary defense depends on the inoculum and climatic factors. Thus, in this study, it was aimed to identify climatic variables of the regions that propitiate the production of Brachiaria brizantha ‘BRS Piatã’ seeds infected with phytopathogenic fungi. Temperature and rainfall data were obtained from 10 production fields, and phytosanitary quality of the seeds was evaluated with the filter paper method; the means were compared using the Kruskal–Wallis non-parametric analysis. Principal component analysis was performed to determine the relationship between the climatic variables and seed phytosanitary quality. Sites with maximum temperatures higher than 30 °C, mean values close to 25 °C, and rainfall less than 82 mm during harvest were favorable to the incidence of Fusarium spp. The incidence of Bipolaris sp. in the seeds of Piatã grass was favored by temperatures around 19 and 20 °C during the maturation phase. The highest incidence of Exserohilum sp. occurred at the sites in which the temperature during harvest was close to 20 °C and accumulated rainfall, between 167 and 181 mm.

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is one of the major diseases of cotton. Preventive methods to manage this disease should be adopted what includes the seed treatment with biocontrol agents as a good alternative. This work aimed to evaluate the efficiency of biological products based on Trichoderma spp. and Bacillus subtilis in the control of Fusarium oxysporum f. sp. vasinfectum (Fov) applied in seeds and seedlings of cotton. The experiment was carried out at the Laboratório de Fitopatologia of the Centro de Ciências Agrárias, of the Universidade Federal de Paraíba (CCA-UFPB), located in the city of Areia, Paraíba - Brazil. The disease transmission of the seeds to the seedlings was evaluated. After the transmission test, cotton seeds of the variety Mocó (Gossypium hirsutum var. Marie-gallante (Watt) Hutch.), BRS 286 and Topázio cultivar (Gossypium hirsutum L.) were submitted to the treatments T1 - Control, T2 - Trichodel^® (0,5 mL); T3-Trichodel^® (1.0 mL); T4-Trichodel^® (1.5 mL); T5-Trichodel^® (2.0 mL); T6-Bactel^® (2.0 mL); T7-Bactel^® (2.5 mL); T8-Bactel^® (3.0 mL); T9-Bactel^® (3.5 mL) diluted in 100 mL SDW; T10 - Fungicide Captana (240 g / 100 kg of seeds) and inoculated with Fov. The pathogen incidence of the seeds was evaluated seven days after the inoculation (DAI). To evaluate the biological control of Fov in the seedlings, the treated seeds were submitted to the following inoculation methods: 1 - inoculation of the substrate with a pathogen conidia suspension; 2 - immersion of the seeds in the conidia suspension and 3 - direct contact of the seeds with the pathogen mycelium. Twenty-one DAI the disease severity and percentage of seedlings with vascular darkening were evaluated. It was observed a transmission rate of 64.0 to 89.0% of the seeds to the seedlings. Trichodel^® reduced the incidence and severity of Fov in the cotton seedlings and was the most efficient product.

Grapevines are propagated by grafting, but the rootstocks used in commercial plantations are susceptible to several diseases. In this study, we focused on a novel root and trunk rot disease of grapevine plantlets that show symptoms during cold storage, before field establishment. Our objectives were to study the aetiology, symptomatology, plant resistance responses, and mode of action of the pathogen that was initially identified as Fusarium. The characterisation of this pathosystem was performed by isolation, pathogenicity assays, genetic diversity studies with BOX-PCR, and identification by sequencing a fragment of the tef1 gene. Scanning electron microscopy and X-ray spectroscopy were used to study the mode of action and plant resistance responses. The results showed that 12 species of Fusarium, initially isolated from both healthy and diseased plantlets, and classified into 4 species complexes, were pathogenic to grapevines. Comparative analyses between diseased and healthy roots showed typical resistance responses in diseased plantlets, including tyloses formation, translocation of Ca, and accumulation of Si. Field experiments confirmed that 100% of the diseased plantlets died within 90 days of transplantation. This study contributes to a better understanding of root and trunk rot disease under cold storage and provides insights for the development of management strategies.

A antracnose, causada por Colletotrichum truncatum é uma das principais ameaças a produção de feijão fava, com isso, medidas de controle devem ser tomadas, visando minimizar os problemas ocasionados por essa doença, como o uso de controle biológico a partir do emprego de Trichoderma spp.. Esta pesquisa objetivou-se avaliar o potencial antagônico de cepas de Trichoderma spp. sobre Colletotrichum truncatum, in vitro. Foram selecionados cinco isolados de Trichoderma spp. (TCH01, TCH02, TCH03, TCH04 e TCH05) no antagonismo a C. truncatum. Para testar o potencial antagônico das cepas de Trichoderma sobre o patógeno, foi realizado o teste de confronto direto através da metodologia de cultura pareada, no qual foi avaliado a classificação do agrupamento dos isolados do antagonista e exames microscópicos a procurando sinais de micoparasitismo. Foi realizado também o teste de antibiose, onde avaliou-se medição do diâmetro das colônias, porcentagem de inibição do crescimento micelial, taxa crescimento micelial, contagem de esporos e porcentagem de inibição da esporulação. Pelo teste de confronto direto, todos as cepas de Trichoderma spp. foram agrupados na classe 1, ou seja, os mesmos cresceram sobre a colônia do patógeno, ocupando toda placa. Também observou-se que os antagonistas possuem potencial contra C. truncatum no teste de antibiose, com inibição do crescimento micelial e esporulação variando de 74,7% a 82,0% e 78,7% a 89,3%, respectivamente. Todos as cepas avaliadas apresenta potencial antagônico sobre Colletotrichum truncatum.