Growth of Verticillium tricorpus—A Saprophytic Fungus and Potential Entomopathogen of Cocoa Pod Borer as Affected by the Medium and Light

Abstract

Cocoa pod borer (CPB) has endangered Indonesian cocoa. Use of entomopathogen in biocontrol of pests is considered to be environmentally friendly approach. Verticillium tricorpus has been reported to be a potential agent for controlling CPB. The aim of this research was to study the possibility in using alternative, easy and cheap media and also the role of intensity and quality of light for mass production of V. tricorpus. The experiments were laid out in split-plot design as factorial, where every combination treatment was replicated three times. Medium, in form of semi-synthetic and natural, was treated as the main plot, while light as sub-plot. Results of this study showed that for the growth and development of fungus V. tricorpus, the use of alternative natural media in form of a mixture of cocoa pod husk and maize was the best. Use of cocoa dextrose agar (CDA) as semi-synthetic medium was more suitable for the growth and development of V. tricorpus compared to potato dextrose agar (PDA). The semi-synthetic and natural media consisted of cocoa husk and maize are suitable for cocoa production area in Indonesia, where mostly cocoa is planted in lowland area and mostly is also suitable for corn but not for potato growing. Growth of the fungus colony especially on CDA medium reached its optimum condition when using white light with the intensity of 1,000 lux. This study proved that the requirement for light quality was different between growth and development purposes. Development of V. tricorpus until the production of conidia in optimal condition was reached with the use of yellow light with the intensity of 1,000 lux.