An inexpensive immunomarking technique for studying movement patterns of naturally occurring insect populations

An immunomarking system useful for determining insect movement patterns was developed that allows the marking of naturally occurring populations of insects within large areas with inexpensive and readily available proteins that can be applied using standard spray equipment. Enzyme-linked immunosorbent assay (ELISA) protocols were developed to detect chicken egg albumin (as egg whites), bovine casein (as cows' milk), and soy protein (as soy milk) at levels <= 30 ppb. Field applications showed that all of the proteins were stable and detectable at high levels on apple leaves at least 19 d after application. When adult pear psylla (Cacopsylla pyricola Foerster, Homoptera: Psyllidae) walked across apple leaves with field-aged residues of the marker proteins plus either Sylgard 309, EDTA, or both, they acquired the mark over the 19-d test period an average of 78.9, 19.4, and 2.1% of the time for egg whites, milk, and soy milk, respectively. Two field applications of the three markers were applied to an apple orchard during the first generation flight of codling moth (Cydia pomonella L., Lepidoptera: Tortricidae). We found that 46.5% of moths captured within a 2.8-ha area (including 1.6-ha surrounding the treated areas) tested positive for at least one of the three proteins. The marker systems developed cost between $0.12 and $0.26 liter versus older immunomarkers (using purified vertebrate IgG) that cost roughly $500/liter.