Suitability of Asian citrus psyllid, Diaphorina citri, as prey for ladybeetles

Abstract

Given the apparent importance of ladybeetles as biological control agents of the invasive Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), a series of experiments were undertaken to assess the nutritional suitability of this pest as a prey item. Five species of Coccinellidae were shown to develop successfully on a diet of psyllid nymphs and four species produced viable eggs. Eggs of the flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were used as a reference diet. Larvae of Curinus coeruleus Mulsant, Cycloneda sanguinea L., Exochomus childreni Mulsant, Harmonia axyridis Pallas, and Olla v-nigrum Mulsant all had survival on a diet of D. citri nymphs not different from 100%, although developmental times were extended and adult dry weights were reduced relative to the Ephestia egg diet. Species were ranked (highest to lowest) for larval performance on the D. citri diet relative to the Ephestia egg diet as: E. childreni, 0.85; O. v-nigrum, 0.82; C. coeruleus, 0.80; H. axyridis, 0.71; C. sanguinea, 0.48. Most females of C. sanguinea ceased oviposition on the second day following transferal to the D. citri diet, but the fecundity and fertility of females of the other species were not different from those feeding on Ephestia eggs. Generation times on the Ephestia egg diet at 24 ◦ C (time to egg hatch + larval developmental time + pupation time + adult prereproductive period) were (mean ± SEM): C. coeruleus, 56.7 ± 1.32 d; C. sanguinea, 28.0 ± 0.88 d; E. childreni, 60.8 ± 1.96 d; H. axyridis, 32.2 ± 1.47 d; O. v-nigrum, 25.8 ± 1.12 d. Adult females of C. coeruleus, H. axyridis and O. v-nigrum consumed the most psyllids in one h, C. sanguinea was intermediate, and E. childreni consumed the least.