Non-crop plant to attract and conserve an aphid predator (Coleoptera: Coccinellidae) in tomato

Pest control is an important ecosystem service that can be enhanced by increasing plant diversity. One of the simplest forms of plant diversification is making use of the occurring weeds that may benefit natural enemies of crop pests. We investigated the interaction between tomato plants, beggar-ticks (Bidens pilosa, Asteraceae), a common weed in Brazil and elsewhere, and the native ladybird beetle Cycloneda sanguinea, an important predator of aphids. The predators occurred on beggar-ticks in the field, independent of the presence of aphids, confirming that they obtained some benefit other than aphid prey from the plants. Predators were attracted to volatiles of clean, flowering beggar-ticks, and volatiles of flowering tomato plants plus flowering beggar-ticks were more attractive than volatiles of tomato plants alone. In the absence of aphids, C. sanguinea did not oviposit on tomato plants, beggar-ticks, or a combination of the two plants, but adult survival was higher on a combination of both plants than on tomato plants alone. These results show that the management of an abundant plant species in agricultural crops has potential for increasing pest control.