Antagonist potential of Trichoderma indigenous isolates for biological control of Phytophthora palmivora the causative agent of black pod disease on cocoa (Theobroma cacao L.) in C te d＊Ivoire

作者：J Mpika; IB Kebe; AE Issali; FK N’ Guessan; S Druzhinina; M Komon Zelazowska; CP Kubicek; S Ake

来源：African Journal of Biotechnology, 2009.

The biodiversity of Trichoderma isolates from cocoa rhizosphere in cocoa production areas of C te d＊Ivoire, and their antagonist potential with Phytophthora palmivora using in vitro assays and bioassays, were investigated and screened for field trials. A total of 135 isolates were analysed at the species level by using sequence analysis of ITS1 and 2 of the rRNA region and a fragment of translation elongation factor 1a (tef1) gene. Sixty-four isolates were identified as T. virens, 60 as T. harzianum, 7 as T. spirale, two as T. asperellum and two unidentified. Forty-three Trichoderma isolates were in vitro confronted with P. palmivora on agar plates, and their antagonist activity was further evaluated by the damages on leaf discs and detached pods. Twenty-five isolates reduced the mycelial growth of P. Palmivora more than 50%. The isolate T17 assigned to T .virens was the best to reduce mycelium growth upto 97.9%. All of Trichoderma isolates with the exception of isolate T39 reduced foliar sensitivity to P. palmivora. Tweenty-six Trichoderma isolates reduced the pod sensitivity to P. palmivora more than 50%. Based on the combined analysis, T. virens T7, T. harzianum T40, T. asperellum T54 and T. spirale T4 isolates were selected for field trials.