Performance of Chysoperla rufilabris Burmeister (Neuroptera: Chrysopidae) feeding on eggs and first instars of Microtheca ochroloma Stål (Coleoptera: Chrysomelidae)

The production of crucifer vegetables on organic farms has been highly affected by the presence of the yellowmargined leaf beetle, Microtheca ochroloma. The use of generalist predators present in Florida might help organic farmers to reduce the economic impact of this pest on their crops. The green lacewing Chrysoperla rufilabris has been observed preying on M. ochroloma, but no studies have been conducted to evaluate the efficacy of this predator and the suitability of M. ochroloma as prey for C. rufilabris.  This study evaluated the killing rate, developmental time, and mortality of C. rufilabris when offered eggs and larvae of M. ochroloma at 10, 15, 20, or 25^oC and assessed prey preference among eggs and first instars of M. ochroloma and green peach aphid, Myzus persicae, nymphs. For the prey preference study, equal numbers of each prey type were offered and the number of prey killed within 24h was counted. The mean number of prey killed daily increased from 8.4 eggs and 4.0 larvae at 15^oC to 18.6 eggs and 10.2 larvae at 25^oC. Mean developmental time decreased from 75.5 d and 54.0 d at 15^oC to 26.6 d and 21.4d at 25^oC when fed eggs and larvae, respectively. Predator survivorship was reduced by 80% at 15^oC; no larvae survived at 10^oC. The predator showed a 5.2-fold preference for aphids over M. ochroloma eggs and larvae.