Suitability of two exotic mealybug species as prey to indigenous lacewing species

Abstract

Mealybugs (Hemiptera: Pseudococcidae) have spread throughout subtropical and tropical regions, causing severe losses to crop production that have prompted much interest in discovering effective biological agents against these pests. The Brazilian indigenous lacewing (Neuroptera: Chrysopidae) species Chrysoperla externa (Hagen) and Ceraeochrysa everes (Banks) were studied against two exotic mealybug species, Ferrisia dasylirii (Cockerell) and Pseudococcus jackbeardsleyi Gimpel & Miller. To assess the relative potential of these lacewing species as control agents against these two pests, we confined 1st-, 2nd-, and 3rd-instar lacewing larvae with 2nd- and 3rd-instar nymphs and adult female mealybugs to evaluate development, survival, reproduction and predation rate. Lacewing larvae at 2nd- and 3rd-instar preyed successfully on mealybugs of all ages, and second instar mealybug nymphs supported successful development of lacewing larvae irrespective of the predators’ age. However, 1st-instar lacewing larvae either failed to complete development or showed lower performance when fed only 3rd-instar or adult female of mealybugs of either species. Comparing the lacewing species, Ce. everes tended to produce more eggs, but showed delayed development and lower egg viability as compared to Ch. externa. Furthermore, in every case in which a significant difference in predation rate was detected, it was always superior for Ch. externa. Further studies to assess the establishment of these species and other lacewing species associated with these introduced mealybugs are reasonable to provide sustainable biological control.