Strategies for Biocontrol of Aphids in Greenhouse Vegetable Crops

Biological control in sweet pepper has been one of the success stories of the greenhouse industry for decades. This success is mainly based on inoculative releases of anthocorid predatory bugs and generalist phytoseiid predatory mites, which successfully control thrips, broad mites and whiteflies. One of the last obstacles for a completely pesticide-free cropping system are aphids. Sweet pepper in particular is often quickly damaged by aphids, mainly by the peach aphid Myzus persicae (Sulzer), the foxglove aphid Aulacorthum solani (Kaltenbach) and the cotton aphid Aphis gossypii (Glover), because of their extremely fast development in this crop. Biological control of these pests in sweet pepper is difficult and expensive, as effective control requires repeated releases of natural enemies. So far, aphid control strategies are mainly based on frequent releases of specialized aphid parasitoids and the predatory midge<br/>Aphidoletes aphidimyza (Rondani). Additionally, growers release chrysopid, syrphid or coccinellid predators to suppress high aphid densities. However, none of these natural enemies is able to establish in a crop without aphids. Biological control of aphids might be greatly improved by generalist predators that are able to establish in a sweet pepper crop prior to aphid infestations, because this can result in rapid responses to new aphid infestations and prevent establishment of aphids