Effect of no-risk insecticides on the green lacewing, Chrysopa oculata (Neuroptera: Chrysopidae)

The green lacewing Chrysopa oculata (Neuroptera: Chrysopidae) is a common lacewing species in the southeastern US. It is a critical natural enemy contributing to arthropod pest management in fruits, vegetables, and field crops. Both adults and larvae of C. oculata are voracious predators and prey on various soft-bodied arthropods such as aphids, mites, and other insect pests. However, the widespread application of insecticides, including reduced-risk and no-risk formulations, increases concern about the potential impact of insecticides on the C. oculata population. The study aimed to find the lethal and sub-lethal effects of no-risk insecticides on C. oculata. We tested the impact of two insecticides using 10% and 100% of the high label rate for vegetables of horticultural oil and insecticidal soap, with distilled water as the control. We reared the colony of C. oculata initiated with field-collected adults in an environmental growth chamber under controlled temperature, photoperiod, and relative humidity. We used twenty-four-hour-old eggs, newly emerged second-instar larvae, and adults with six replicates of five individuals each for eggs and larval studies and 15 pairs for adult experiments. We treated the adults and larvae to treatment through contact, ingestion, and residual exposure, and eggs via contact exposure. We evaluated 24-, 48-, and 72-hour mortality of adults and larvae for direct effects and longevity, fecundity, and fertility of adults, larvae to adult developmental time, survival, adult sex ratio of larvae, and developmental time and survival from egg to adult emergence of eggs. We will discuss some of the results in detail.