ABSTRACT Tomato is an important economic crop due to its consumption and production worldwide. However, like other crops, it is susceptible to pathogens, being necessary agrochemicals to prevent diseases and improve the production of fruits. Among the sustainable alternatives to crop production, microbial inoculants are used as biofungicide and biostimulants for plant development. Thus, this work aimed to evaluate the biocontrol potential of seven Trichoderma spp. isolates (T1, T2, T3, T4, T15, T17, and T19) against tomato pathogens in vitro experiments, and their potential to improve tomato growth. The Trichoderma spp. antagonism was investigated against Alternaria sp. 003/09, Botrytis sp. 006/13, Fusarium sp. 007/09, and Stemphylium sp. A73. Dual culture, volatile, and diffusible compounds activity tests showed that all new Trichoderma spp. tested could reduce the mycelial growth of all tested pathogens, highlighting T15 and T17 isolates. Seed and soil inoculation revealed very contrasting results: Trichoderma sp. T17 showed a beneficial effect when inoculated in soil, reducing the percentage of yellowish leaves, and increasing dry weight and stem diameter. Inoculation of Trichoderma sp. T17 in the seed increases hypocotyl and radicle lengths, and the seed vigor index. Finally, the strains studied present the potential to be used to develop biocontrol products.

Resumo O objetivo deste trabalho foi avaliar o efeito do óleo essencial de Eucalyptus staigeriana sobre o crescimento micelial e a germinação de conídios de Colletotrichum gloeosporioides e Greeneria uvicola em uvas, assim como o seu potencial para o controle de podridões no período pós-colheita e o seu efeito nas propriedades organolépticas das uvas. O óleo essencial (OE) apresentou atividade antifúngica in vitro contra ambos os patógenos, com efeito fungicida sobre o crescimento micelial e sobre a germinação de conídios, nas concentrações de 1,0 e 0,5 μL mL−1, respectivamente. Os compostos voláteis do OE exibiram efeito fungistático sobre o crescimento micelial de C. gloeosporioides e efeito fungicida sobre G. uvicola. Na pós-colheita, o OE reduziu a incidência da podridão-madura em até 75 e 86%, nos tratamentos preventivos e curativos, respectivamente, e a incidência da podridão-amarga em até 54% no tratamento curativo. Como o OE não influencia significativamente as propriedades sensoriais das uvas, não afeta a intenção de consumo para uvas tratadas com o OE. O OE de E. staigeriana é eficiente para o controle in vitro de ambos os patógenos; além disso, também é eficiente no controle da incidência de podridões fúngicas no período pós-colheita, principalmente no tratamento curativo.

Abstract The objective of this work was evaluate the effect of Eucalyptus staigeriana essential oil on Colletotrichum gloeosporioides and Greeneria uvicola mycelial growth and conidia germination on grapes, as well as its potential for the control of postharvest rot diseases and its effect on the organoleptic properties of grapes. The essential oil (EO) showed in vitro antifungal activity against both pathogens, with fungicidal effect on mycelial growth and on conidia germination at the concentrations of 1.0 and 0.5 μL mL−1, respectively. The EO volatile compounds had a fungistatic effect on the mycelial growth of C. gloeosporioides and a fungicidal effect on G uvicola. At postharvest, the EO reduced the incidence of ripe rot up to 75% and 86% in the preventive and curative treatments, respectively, and the incidence of bitter rot up to 54% in the curative treatment. Since the EO does not affect significantly grape sensory properties, it does not affect the consumption intention of grapes treated with the EO. The EO of E. staigeriana is efficient in the in vitro control of both pathogens; moreover, it is also efficient in the control of the incidence of postharvest fungal rot diseases, mainly in the curative treatment.