The efficacy of Fusarium spp. as an entomopathogen against Aphis gossypii (Homoptera: Aphididae) and the influence of mancozeb on Fusarium spp. in chilli (Capsicum annuum L.)

Chilli pepper (Capsicum annuum L.) is a valuable horticultural crop whose productivity is significantly hindered by aphid infestations, particularly Aphis gossypii (Homoptera: Aphididae). This pest inflicts direct damage through sap extraction and indirectly diminishes yield by transmitting deleterious viruses, such as pepper yellow leaf curl virus (PYLCV), which can cause substantial yield losses or complete crop failure. Currently, aphid management relies predominantly on synthetic insecticides, raising concerns about environmental sustainability, human health and the development of resistance. Therefore, there is an urgent need for environmentally sustainable alternatives that are based on biological control agents. Entomopathogenic fungi represent a promising solution and Fusarium spp. have been identified as potential aphid pathogens. This study investigated the potential of Fusarium spp. as a biological control agent against A. gossypii on chilli plants and evaluated its efficacy under varying fungicide treatments and conidial concentrations. Laboratory experiments were conducted at the Laboratory of Pests and Diseases, Faculty of Agriculture, Hasanuddin University, using a completely randomised design. Six conidial concentrations (120000; 12000; 1200; 0.120; and 0.012 ppm) and a control were applied, with five replications per treatment. Aphid mortality and infection symptoms were recorded to assess pathogenicity. These results indicate that Fusarium spp. exhibited significant pathogenicity against A. gossypii, with aphid mortality increasing in a concentration-dependent manner. Fungicide exposure affects fungal efficacy, underscoring the importance of compatibility in integrated pest management systems. Overall, Fusarium spp. demonstrated strong potential as an effective biological control agent to support sustainable chilli production and enhance the quality of chilli commodities in Indonesia.