Impact of floral margins on the abundance of natural enemies in tomato crops

Abstract

Conservation biological control involves manipulation of the environment addressed to providing additional resources to natural enemies. In tomato crops, some indigenous predators and parasitoids have already been reported to have an important role in the biological control of tomato pests. Most parasitoid species can feed on nectar and pollen in order to reach their maximum biological potential. This paper seeks to assess the effect of floral resources of five insectary plants in wildflower margins (Lobularia maritima, Sinapis alba, Moricandia arvensis, Fagopyrum esculentum and Achillea millefolium) on the abundance of natural enemies and pollinators and on the biological control of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in tomato crops. The results show that insectary plants increased the abundance of parasitoids, hoverflies, pollinators, predatory bugs (Anthocoridae) and predatory thrips (Aeolothripidae) in the floral margins. In contrast, no differences in the abundance of natural enemies were detected in adjacent tomato crops. The natural enemy Necremnus tutae (Ribes & Bernardo) (Hymenoptera: Eulophidae) was the main parasitoid responsible for T. absoluta mortality in tomato fields, but no differences were detected between natural margins and wildflower margins in adjacent fields. Overall, species of insectary plants with the greatest presence of natural enemies and pollinators were F. esculentum, L. maritima and A. millefolium. These plant species could be used to promote conservation biological control and ecosystem services at field and farm scale.

Keywords: wildflower margins, tomato, biological control, Tuta absoluta.