Abstract:
In Cameroon, the expected cocoa production seems difficult to achieve in view of several factors including diseases and pests. Insect pests, particularly Sahlbergella singularis, commonly called mirids usually cause damage to the cocoa tree which result in the reduction of the abundance of young fruits by up to 10% and the reduction in the weight of ripe pods by 12%. To combat this insect, conventional insecticides are the only effective control method, but creating more problems than they solve: pollute the environment, risk for deterioration of human, animal, and plant health. It therefore appears urgent to develop biological control methods through the development of biopesticides which appears to be a first-choice alternative for concerns about respect for the environment and preservation of health. Hence the interest of our study which consisted of developing a biopesticide formulation whose active ingredient was isolates of the fungus Beauveria bassiana which are pathogenic towards mirids. This fungus was isolated from cocoa leaves. Five isolates of Beauveria bassiana were tested under controlled laboratory conditions on parameters such as fungal radial growth, spore production and viability as well as insecticidal potential against the fourth and fifth nymphal stages of mirids. The selected isolates were subsequently the subject of a compatibility study with a certain number of additives generally used in the development of biopesticides. The results showed that the germination percentage was between 75.83% and 97.41%. Of these five isolates, two IRADA21 and IRADA30 stood out with maximum growth on PDA medium on the fifteenth day of observation, respectively 3.67 cm and 3.07 cm, and a higher number of spores, 9.84.108 spores/ mL, and 1.12.109 spores/mL respectively. On the ninth day post-inoculation, the mortality of mirids presenting a fungal outbreak varied between 14% and 93% with the best rates for the two isolates mentioned above. On the other hand, the parameters mentioned above and evaluated in the presence of adjuvants such as glycerol, refined palm oil, Tensiofix and tween 80 also showed good compatibility between the latter and the two isolates chosen. Locally isolated Beauveria bassiana is virulent against mirids and appears to be an asset for biological control programs.
Audience Take Away:
- Why produce biopesticide
- How to produce biopesticide
- Benefits of the use of biopesticide
- The use of biopesticide on cocoa cultivation and security
- Potential Risks of the use of cocoa production and consumption
