Using new egg parasitoids (<i><scp>T</scp>richogramma</i>spp.) to improve integrated management against<i><scp>T</scp>uta absoluta</i>

Abstract

This study is the first step of the T uta PI program (2011–13) to decrease the costs of Integrated Pest Management ( IPM ) strategies against T uta absoluta in F rance by investigating new beneficial insects. Currently, the association of predator/egg parasitoid ( M acrolophus pygmaeus and T richogramma achaeae , respectively) in IPM strategies are quite effective, but expensive. Sixty‐four new potential strains from 19 T richogramma species originating from different regions of the world (from the collection of T richogramma at INRA Provence Alpes Côte d'Azur ( PACA ), F rance) were studied in this work. A screening study was performed on T . absoluta eggs on isolated tomato leaves (for 24 h at 25 ± 1°C, RH 75 ± 5% and 16 h light : 8 h dark). The proportion of parasitized T . absoluta eggs varied greatly (between 0 and 73%) depending on the different strains used. Levels of parasitism by females, equal to or higher than that of T . achaeae, were observed in 14 of the strains tested among eight species (four from F rance, four from elsewhere in E urope). The proportion of females that parasitized T . absoluta eggs was significantly different between strains (from 0 to 100%). Experimental results allowed about half of the 64 initial strains to be eliminated before the next steps: tests on a larger scale (mesocosm, and then in the greenhouse and field).