Antimicrobial Potential of Trichoderma strains for brown rot control of cocoa pods

INTRODUCTION
The cocoa (Theobroma cacao L.) is a tree of the Malvaceae family, producing cocoa beans, intended for the chocolate, cosmetic and pharmaceutical industries. In Cameroon, this crop is facing attacks from Phytophthora megakarya, responsible for brown pod rot, leading to a drop in the organoleptic and nutritional quality of the beans, or even the almost total loss of the harvest despite the use of synthetic fungicides.Therefore, research of secondary metabolites from endophytic fungi is an alternative to resolve the problem.

OBJECTIVE
The aim of this study is to evaluated the antimicrobial Potential of Trichoderma strains for brown rot control of cocoa pods

METHODOLOGY
5 isolats of endophytic fungus have been isolated from theroots, trunks and pods of the varieties Forastero, Trinitario and Criolo. Secondary metabolites of strain have been obtained by fermentation in liquid medium. Bioactivity of crude and organic extract has been evaluated by poison method on the growth of Phytophthora megakarya. Endophytes mycoparasitism capacity was evaluated with the 5 strains against the phytopathogen. Chemical and biochemical screening was also done to analyse the chemical and enzymatic composition of extracts respectively.

RESULTS
The crude extract show total inhibition of radial growth of P. megakarya significantly. The extract from ethyl acetat reduced the radial growth of P. megakarya significantly compared to control, while the methanol extract has a poor activity against P. megakarya. Mycoparastic activity of endophytes and particular Trichoderma is manifested morphologically by the overgrowth upon the mycelial growth of the pathogen.

IMPACT OF THE RESULTS
Trichoderma can be used as a biological control alternative having both a preventive and curative action against brown rot in cocoa pods.

Key words: Theobroma cacao L., Phytophthora megakarya, Trichoderma, Endophytic fungi and biological control.