Potencial antagônico de Trichoderma do bioma amazônico contra fungos fitopatogênicos de hortaliças em condições in vitro

Abstract

Biological control is gaining more space every day, becoming part of the management of various agricultural and forestry cultivars throughout the world. Agricultural production in the state of Amazonas has been developing gradually over the years, mainly with the help of small producers who contribute a significant share of production. One of the most discouraging factors is the occurrence of plant diseases, especially those caused by fungi. One of the biocontrol agents for phytopathogens most applied in research in the world are fungi of the genus Trichoderma, which are widely used in agriculture, and have played a determining role in changing the scenario of biological control of phytopathogens in Brazil. This study aimed to evaluate in vitro the potential of seven strains of Trichoderma sp. for biological control of vegetable phytopathogens. Were evaluating the strains Trichoderma aureoviride P5B (T1), T. brevicompactum P16D2 (T2), T. ceraceum P7D (T3), T. harzianum P14A (T4), T. inhamatum P21C (T5), T. reesei P27B2.3 (T6) and T. tomentosum P14C2 (T7). The study was carried from reactivation of fungi preserved by the Castellani method and subjected to paired culture testing, non-volatile metabolites and thermostability of the crude extract. For antagonism using the paired culture technique, the T1, T4, T6 and T7 antagonists were efficient against Colletotrichum theobromicola, with inhibition rates above 50%. In the assay against Alternaria japonica, only T7 stood out, with an inhibition rate of 64.76%. In relation to the Bell scale, the values obtained varied between 1 and 2, confirming that all strains showed potential for use in the biocontrol of these phytopathogens. For the antagonism tests of non-volatile metabolites, only the T2 lineage was efficient against phytopathogens, promoting mycelial growth inhibition rates in relation to the control above 60%. In the thermostability test, only the T2 lineage showed activity, also with inhibition rates above 60% against the phytopathogens tested. This study allows us to conclude that all strains tested have potential for use in the biological control of the phytopathogens confronted, with the T. brevicompactum P16D2 strain standing out in the three experiments, requiring further studies to determine its use in the field.