Leonardo de Jesus Machado Gois de Oliveira

O presente trabalho analisou a qualidade da água, a abundância e a diversidade de fungos filamentosos aquáticos no Rio Tocantins, na zona urbana de Imperatriz (MA), identificados por morfologia e estrutura molecular. As coletas da água foram feitas em diferentes pontos do Rio Tocantins, entre setembro e outubro de 2021 (período de estiagem); em fevereiro (período chuvoso) e junho (período de estiagem) de 2022; e entre janeiro e maio de 2023 (período chuvoso), com o uso de frascos de vidro esterilizados de 500 ml. As análises macro e microscópica dos fungos aquáticos isolados permitiu a identificação de 8 gêneros (Trichoderma, Penicillium, Cladosporium, Fusarium, Aspergillus, Curvularia, Alternaria e Aphanomyces) e de características de hifas e conídios. A partir da identificação molecular, foram determinadas as espécies Aspergillus flavus, Penicillium expansum, Penicillium rolfsii, Cladosporium sp., Fusarium incarnatum e Trichoderma sp. pertencentes ao clado Harzianum. Sete gêneros pertencem ao filo Ascomycota. Também notou-se a presença de fungos comuns em solo, como Trichoderma e Fusarium.

Cowpea is one of the main crops in family agriculture, especially in the Northeastern region of Brazil, and it is expanding to other regions in Brazil. The use of seeds with low physiological and health quality is reflected in the plant development and consequently yield, making it important to study the seed physiological and health quality. The objective of the present study was to assess the physiology and health of traditional and biofortified cowpea seeds. The traditional cowpea varieties (Angelim, Mercado and Manteguinha) and the biofortified cowpea cultivars (BRS Aracê, BRS Xique-Xique and BRS Tumucumaque) were assessed for the following physiological parameters: water content (WC), first count (FC), germination test (G), germination speed index (GSI), seedling emergence in the greenhouse (E), emergence speed index (ESI), seedling aerial part and root length (APL and RL) and electric conductivity test (EC). The seed health quality was assessed by the Blotter Test. The water content present in the seeds of the traditional and biofortified varieties ranged from 10% to 14%. All the traditional and biofortified varieties showed high germination and emergence value in the greenhouse. The germination and emergence speed indexes indicated the BRS Aracê and BRS Xique-Xique cultivars as the most vigorous. In the health tests the highest indexes were the storage fungi Aspergillus sp., Cladosporium sp. and Penicillium sp., with the highest prevalence in the BRS Tumucumaque variety, which was probably related to the higher water content present in this variety.

Essential oils have been widely studied because they are natural sources of substances that have antimicrobial properties. In fruit growing, especially in mango crop, anthracnose (Colletotrichum gloeosporioides) is considered the main disease because it causes series of damages in the fruit production chain and, in this sense, essential oils can be an option in this disease control. The objective of this study was to evaluate the effect of essential oils obtained from the leaves of Chá-de-moça (Pectis brevipedunculata) and Melosa (Dizygostemon riparius) in the in vitro and in vivo control of the C. gloeosporioides fungus, in seedlings and mango fruits. The in vitro bioassays were performed by testing the effect of different concentrations of essential oils (0, 1, 2, 3 and 4 µl/mL) on the reduction of mycelial growth of the C. gloeosporioides fungus. Additionally, the anthracnose control in mango seedlings (Tommy Atkins, Constantina, Comum and Rosa cultivars) was evaluated by foliar application of essential oils at 4 µl/mL concentration. Disease control in fruits of the same mango cultivars was evaluated at 3 µl/mL concentration of essential oils. The evaluation was carried out by measuring the average diameter of the colonies, for the in vitro treatment, and the lesions for the in vivo treatments, in two diametrically opposite directions. There was a decrease in the fungus mycelial growth in all tested concentrations. There was a decrease in the disease severity from the sixth day after the oils application in Tommy Atkins cultivar seedlings, when treated with both essential oils at 4 µl/mL concentration. As for preventive treatments with fruits, it was observed that all cultivars achieved a reduction in severity from 54.83% at 3 µl/mL concentration with the use of both essential oils. Given the results obtained, it was observed that the essential oils P. brevipedunculata and D. riparius can be a viable alternative in the anthracnose control in mango culture.