Exploring native predatory hemipteran species for use as biological controls in Canadian vegetable production

Canadian tomato growers are faced with the challenge of controlling pest insects amidst increasing insecticide resistance and invasive species introductions. The use of native predaceous insects as biocontrol agents (BCAs) is gaining appeal due to their low ecological risk and regulatory ease, but few native species have been developed as BCAs to date. Through our survey of predaceous hemipterans in Ontario, we identified two native mirids (Dicyphus discrepans and D. famelicus) that are promising BCA candidates because 1) they are amenable to lab rearing and 2) another species in this genus has been successfully commercialized as a BCA in greenhouse crops. We will now characterize the life history (fecundity and longevity), functional response, and efficacy of these Dicyphus spp. against various tomato pests (such as aphids, lepidopteran eggs, whitefly, and spider mites). Fecundity and adult longevity will be measured by enumerating eggs laid and egg mortality twice weekly until the adults die. To assess functional response, we will quantify the number of prey consumed per adult in a 24-hour period over different prey densities. Efficacy will be determined by measuring the predators’ ability to control whitefly populations on tomato in the field over 12 weeks. These evaluations will provide the foundation necessary to develop these native predators as BCAs for commercial use by Canadian tomato growers.