Ladybeetles as predators of pest and predacious mites in citrus

The acceptability of Panonychus citri (McGregor) (Tetranychidae) as prey for adults and larvae of four coccinellid species, Cycloneda sanguinea L., Exochomus childreni Mulsant, Harmonia axyridis Pallas, and Olla v-nigrum (Mulsant), was evaluated. Also, three beneficial predacious species, Euseius mesembrinus (Dean), lphiseiodes quadripilis (Banks) and an Amblyseius sp. (Phytoseiidae), were evaluated for their acceptability as prey for H. axyridis adults. Adult females and early larval stages of C. sanguinea, E. childreni, H. axyridis, and O. v-nigrum readily consumed adult P. citri females when these were presented on leaf disk arenas in Petri dishes. The most voracious mite predator was H. axyridis. Adult female H. axyridis consumed an average of 15.14 ± 1.9 female P. citri in 24 h, and first-instar larvae consumed 6.1 ± 0.7 in 60 min. Only H. axyridis was tested with predaceous mites as prey. First-instar H. axyridis larvae consumed one or two adult Amblyseius sp. in three out of eight trials, and a single E. mesembrinus female. No 1. quadripilis females were eaten by H. axyridis larvae. Adult female H. axyridis did not consume adult female phytoseiids of any species under similar conditions. If predacious phytoseiids are generally unacceptable as prey for coccinellids while P. citri is selectively consumed, then coccinellid predation would likely have a net beneficial effect in contributing to suppression of tetranychid mite populations in citrus.