Numerical response of Olla V-nigrum (Coleoptera: Coccinellidae) to infestations of Asian citrus psyllid, (Hemiptera: Psyllidae) in Florida

Data are presented on the relative abundance of the coccinellid Olla v-nigrum (Mulsant) in Florida citrus, before and after invasion by the Asian citrus psyllid, Diaphorina citri Kuwayama. Adults and larvae of O. v-nigrum were observed preying on immature psyllids throughout their range in Florida. Immature psyllids were eliminated by predation from many flushed citrus terminals that exhibited damage symptoms; pupae of O. v-nigrum and Harmonia axyridis Pallas were recovered from adjacent leaves. Olla v-nigrum, a relatively rare species before the invasion by D. citri, is now a dominant species throughout Florida in citrus groves where the psyllid is present, but remains rare in regions where D, citri is absent. The strong numerical response of this native ladybeetle to D. citri populations indicates that it is assuming a key role in biological control of the psyllid.