Efficacy of entomopathogenic nematodes against the tomato leafminer Tuta absoluta in laboratory and greenhouse conditions

The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an important pest of tomato crops in South America and it has recently arrived in Europe affecting tomato plantations. The susceptibility of T. absoluta larvae and pupae to three species of entomopathogenic nematodes (Steinernema carpocapsae, Steinernema feltiae and Heterorhabditis bacteriophora) was examined under laboratory conditions. Leaf bioassays were conducted to evaluate the nematode's capability to reach the larvae and kill them within the galleries. The efficacy of the three nematode species after foliar application to potted tomato plants was evaluated under greenhouse conditions. High larval mortality (78.6-100%) and low pupae mortality (< 10%) was determined in laboratory experiments. In the leaf bioassay a high level of larval parasitation (77.1-91.7%) was recorded revealing the nematode's capacity to kill the larvae inside the galleries. In the pot experiments nematode treatment reduced insect infection of tomato plants by 87-95%. The results demonstrate the suitability of entomopathogenic nematodes for controlling T. absoluta.