Within-field distribution of Aphis gossypii and aphidophagous lady beetles in chili, Capsicum annuum

Understanding the spatial distribution of insect pests and their natural enemies can be very important for a successful integrated pest management approach. In Malaysia, Aphis gossypii Glover (Hemiptera: Aphididae) is the only aphid species colonizing and responsible for significant crop losses in chili, Capsicum annuum L. (Solanaceae). Several species of aphidophagous lady beetles (Coleoptera: Coccinellidae) occur naturally, of which three species [Menochilus sexmaculatus (Fabricius), Coelophora inaequalis (Fabricius), and Coccinella transversalis (Fabricius)] predominate in chili ecosystems. In this study, we investigated the spatial distribution of A. gossypii and associated lady beetle predators during two growing seasons of C. annuum, using Spatial Analysis by Distance Indices (SADIE). Both aphid and lady beetle populations were spatially aggregated, the strength of aggregation being strongest mid-way through the cropping cycle. We concluded that the aggregated distribution of adult lady beetles is driven by the spatial distribution of A. gossypii.