Aggressiveness of the Fungi Responsible for Pod Rot in Cropping Systems Based on Cocoa Trees (Theobroma cacao L.) in Cameroon

Abstract

To evaluate the Aggressiveness of the fungi responsible for pod rot in cropping systems based on cocoa trees (Theobroma Cacao L.), 3 cropping systems having cocoa trees were characterized: Cocoa trees associated with fruits and forest trees (S1), Cocoa trees associated with plantains and palm oil (S2) and associated cocoa trees with coffee trees (S3). 150 pods were collected per year for isolation and in-situ pathogenicity tests. Three culture media called V6-agar, V8-agar and Potato - Dextrose - Agar (PDA) were made for the in-vitro culture of fungi associated with pods. The test was conducted using a random split split plots arrangement with 9 replicates. As results obtained: of the 8 mushrooms which were isolated from the pods, only 3 are responsible for the burps. It is about Phytophthora megakarya, Botryodiplodia theobromae and Colletotrichum gloeosporioides. Black pods disease caused by P. megakarya was the most aggressively from cocoa pods associated with fruits and forest trees at a decay rate of 5% during a dryng season and 55% during a rainy season. The lesion areas developed by P. megakarya ranged from 40 cm2 during a dryng season to 220 cm2 during a rainy season. Cropping system having cocoa trees associated with fruits and forest trees (S1) is the most vulnerable to the the Aggressiveness of the fungi responsible for pod rot.