Host plant characteristics determine the success of natural enemies against the tomato leaf miner Phthorimaea absoluta

Abstract: Integrating host plant resistance with natural enemies offers a promising strategy for long-lasting management of Phthorimaea (= Tuta) absoluta (Lepidoptera: Gelechiidae), a
destructive invasive pest that poses a significant threat to tomato production globally. However, morphological resistance traits, secondary metabolites, and plant volatiles of tomato can also adversely affect natural enemies, potentially impacting the overall effectiveness of pest control. In this study, we assessed the performance of three natural enemies on six tomato genotypes with varying resistance levels to P. absoluta. First, we examined the performance of the egg parasitoid Trichogramma achaeae (Hymenoptera: Trichogrammatidae) on eggs laid by moths reared on the different tomato genotypes, either isolated or on the respective tomato genotypes. Second, we evaluated the performance of the larval parasitoid Necremnus tutae (Hymenoptera: Eulophidae) on tomato genotypes hosting P. absoluta larvae. Finally, we investigated the predatory capacity of Macrolophus pygmaeus (Heteroptera: Miridae) on tomatoes hosting P. absoluta eggs and larvae, all derived from moths reared on those genotypes, as well as the survival of M. pygmaeus nymphs on the different tomato genotypes, both in the presence and absence of P. absoluta eggs. The resistant wild tomato Solanum arcanum, exhibiting a high density of glandular trichomes, negatively affected the performance of all natural enemies. In contrast, all three natural enemies performed well on the P. absoluta-susceptible tomatoes, the resistant domesticated Corona F1, and the resistant wild S. neorickii, all exhibiting much lower densities of glandular trichome. The implications of plant defense traits in integrated management of P. absoluta are discussed.