Biological control of Pratylenchus brachyurus with isolates of Trichoderma spp. on soybean

Abstract

Pratylenchus brachyurus is an important species of nematode as it causes significant yield losses in soybean crops in Brazil. The efficacy of Trichoderma asperellum T00 and Trichoderma harzianum ALL 42 were evaluated as biocontrol agents against P. brachyurus. The experiments were conducted under greenhouse conditions using the BRSGO Caiapônia and BRS 8560RR cultivars of soybeans. The application of these two fungal species significantly reduced the population density (PD) and reproductive factor (RF) of P. brachyurus in the cultivar BRSGO Caiapônia. In contrast, the PD and RF values for P. brachyurus in the cultivar BRS 8560RR remained stable after treatment with both species. The treatment of P. brachyurus (J2) with non-volatile metabolites from T. asperellum T00 and T. harzianum ALL42 resulted in mortality rates of 41% and 65%, respectively. The exposure to T. asperellum T00 and T. harzianum ALL42 did not alter the height, the size of the roots (RL), or the fresh mass of the aerial part (FSM) of BRSGO Caiapônia. On the other hand, the treatment of BRS 8560RR resulted in an increase in plant height, with no differences in RL and FSM. The activity of defense-related enzymes was determined in leaves of the two cultivars. In general, it was observed that the enzymes β-1,3-glucanase, chitinase and peroxidase showed higher activities in cultivar BRS 8560RR, while phenylalanine ammonia-lyase activity was higher in BRSGO Caiapônia. This study demonstrated that these two isolates of Trichoderma have potential for use in biological control of P. brachyurus in soybeans.