Efficacy Evaluation of Biopesticides Derived From Entomopathogenic Fungi against Rind Borer and Twig Blight Disease of Citrus

The study focused on citrus rind borer (CRB) and twig blight disease (TBD) which is the dominant cause of low quality and high postharvest losses of citrus production in the Philippines. Egg laying of CRB started during flushing and flowering stage thereby larval stage are ready to infest on flowering stage and fruitlet formation. Almost 80-92% of fruits showed severe lumps due to CRB as a visible symptom which causes poor quality of rind. On the other hand, TBD of citrus imposed serious problems during fruiting season, usually this fungus mainly infect citrus plants during flushing stage. The two isolates of EPF (Beauveria bassiana and Isaria fumosorosea) were formulated as solid and liquid based biopesticides and tried to test the efficacy under field condition with different level of concentration against disease prevalence of TBD and level of infestation of CRB. Field trial condition showed that the two entomopathogenic fungi at 100% concentration of two formulated biopesticides induced significant difference than other concentrations (75%, 50%, 25%) in terms of disease incidence and severity of fungal pathogen that caused twig blight disease. In addition, in terms of population dynamics of citrus rind borer on percent damage, number of infested buds, percent damaged flower buds, number of infested fruits, number of fruit fall, and yield performance per kg per tree also showed significant difference at 1x1012 concentration level compared to treatments 1x106, 1x108, and 1x1010. Verification trials of the two formulated organic-based biopesticides under field condition showed that either B. bassiana or I. fumosorosea has a novel potential as biopesticide at 1x1012 level of concentrations in Satsuma, Ponkan, Calamansi and Pomelo trees under field condition.