Seasonal adult occurrence of a coccidophagous ladybird, Telsimia nigra (Coleoptera: Coccinellidae), in citrus groves in central Japan

Abstract

A coccidophagous ladybird, Telsimia nigra (Weise) (Coleoptera: Coccinellidae), may play a significant role in suppressing the abundance of scale insects belonging to Diaspididae (Hemiptera: Coccoidea) in citrus groves in Japan, and therefore might need to be protected from pesticide applications. Seasonal changes in the abundance of T. nigra adults were monitored using yellow sticky traps set inside citrus tree canopies and by beating citrus foliage in citrus groves with different pesticide application levels in Shizuoka City, central Japan. Telsimia nigra adults were caught on sticky traps in pesticide-free, organic, and reduced-pesticide groves, with far more adults in a pesticide-free grove, but were rarely recorded in conventionally managed groves. A larger number of T. nigra adults were captured on the traps from late March to early May, with a peak numbers in early to mid-April in the pesticide-free grove, and afterward adults were continually detected in much smaller numbers until November. Some adults were trapped mainly in April–May and October in organic and reduced-pesticide groves, with more adults in the former months. Adults collected by beating citrus foliage tended to be more abundant in April and November in the pesticide-free grove. Thus, T. nigra adults occurred most abundantly in April–May and in smaller numbers in October–November in citrus groves in Shizuoka City. This result suggests that the application of pesticides that are harmful to ladybirds should be avoided in April–May and autumn to conserve T. nigra populations in citrus groves in central Japan.