ABSTRACT
The biological control of Ceratocystis wilt of cacao (Ceratocystis cacaofunesta) may be a promising alternative not explored yet to control this disease. Twelve isolates of Trichoderma spp. were tested as biocontrol agents (BCAs) for C. cacaofunesta. In this study, the following items were evaluated: i) antagonism by in vitro confronting between BCAs and the pathogen and by inhibition of the pathogen’s spore germination by the antagonist’s secretome; ii) effect of BCAs on the pathogen’s perithecium formation over leaf discs; iii) effect of BCAS on Ceratocystis wilt control in cacao seedlings under greenhouse conditions. The tested BCAs inhibited 100% in vitro growth of the pathogen on the third day and reduced the pathogen’s spore germination. Trichoderma virens (T68), T. harzianum (2927), T. loningiopsis (Tc26) and T. atroviride (7CC) inhibited by 98.5 to 92.3% the pathogen’s perithecium formation. Isolates 7CC, T68, Tc26 and 2729 are promising as BCAs. In combined BCAs, greater inhibition occurred for treatments including T68. There was no evidence of the expected efficiency in tests with seedlings.
Keywords
Ceratocystis cacaofunesta; Theobroma cacao; biological control
