Standardization of rearing and assaying procedures for green lacewing, Chrysoperla zastrowi sillemi (Neuroptera : Chrysopidae)

Chrysoperla zastrowi (Green lace wing), a beneficial insect widely recommended for augmentative biological control programs against pest insects, is a generalist predator of aphids, insect eggs and a variety of soft-bodied arthropods such as caterpillars, leafhoppers and mealybugs. The production of these beneficial insects in large numbers under controlled conditions is necessary for their efficient use in biological control programs. In areas where insect-resistant GM crops are cultivated, these insects may be exposed to insecticidal proteins either by direct pollen-feeding or through their prey. Therefore, a rearing and assaying procedure is required to assess any non-target risks that may be associated with such exposure. We tested different procedures available in the literature and found that a yeast and agar-based diet developed for Chrysopa carnea larvae can be used as a supplemental food source for the multiplication of C. zastrowi. Accordingly, a laboratory rearing procedure for C. zastrowi was standardized by using the artificial diet and eggs of Corcyra cephalonica as a food source. A modified parafilm-based procedure was used for encapsulation of the diet. The encapsulated diet was used in the assays with second instar C. zastrowi larvae. Bioassays were done with different concentrations of insecticidal protein(s) incorporated into the artificial diet. The results indicated that the insecticidal protein(s) tested did not cause any negative effect on the development and survival of C. zastrowi larvae whereas 100 per cent mortality was observed in control treatment (chemical insecticide) after 48 hrs of larval release. This method can be used for testing non-target effects of novel insecticidal proteins on C. zastrowi.