Codling moth, Cydia pomonella (L.), is the major pest of apple (Malus spp.) in the western United States and many other regions of the world. The codling moth granulovirus (CpGV) provides a selective and safe means of its control. We assessed the long-term stability and storage potential of two commercial formulations of CpGV, Cyd-X, and Virosoft. All assays were performed with individual C. pomonella neonate larvae in 2-ml vials on 1 ml of artificial larval diet that was surface inoculated with 10 μl of the test virus suspension. Baseline quantitative assays for the two formulations revealed that the LC50 and LC95 values (occlusion bodies per vial) did not differ significantly between the formulations. For year-long studies on Cyd-X stability, the product was stored at −20, 2, 25, and 35°C, and quantitative bioassays were conducted after 0, 3, 6, and 12 mo of storage. Cyd-X retained good larvicidal activity from −20 to 25°C, and it was the least negatively affected at the lowest temperature. Storage of Cyd-X at 35°C was detrimental to its larvicidal activity within 3 mo of storage. For longer term storage studies, Cyd-X and Virosoft formulations were stored at 2, 25, and 35°C, and assayed for larvicidal activity over a 3-yr period. For recently produced product, a 10-μl sample of a 10−5 dilution of both formulations resulted in 95–100% mortality in neonate larvae. Larvicidal activity for the Cyd-X formulation remained essentially unaffected for 156 wk when stored at 2 and 25°C, but it began to decline significantly after 20 wk of storage at 35°C. The Virosoft formulation stored at 2°C also remained active throughout the 3-yr study, but it began to decline in larvicidal activity after 144 wk at 25°C and 40 wk at 35°C. The information reported in this study should be useful to growers and commercial suppliers for avoiding decreases in CpGV potency due to improper storage conditions.
Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.