Perspectives on Tuta absoluta management: tomato genotypes and natural enemies

Abstract: Combining host plant resistance and natural enemies is a promising approach to
replace chemical insecticides for controlling Tuta absoluta (Meyrick) (Lepidoptera:
Gelechiidae), an invasive pest threatening tomato production worldwide. However,
morphological resistance traits, secondary metabolites, and plant volatiles can also influence
natural enemies and thus the overall level of pest control. Our study aims at characterizing the interaction between T. absoluta – tomato varieties – and natural enemies. Therefore, we
assessed the resistance of 19 tomato varieties against T. absoluta. Tomato varieties affected the oviposition potency, larval mining time, larval development time, leaf area damaged, pupal weight and the emergence of adult T. absoluta. Wild tomatoes Solanum arcanum and S. neorickii, along with domesticated Corona F1, showed particularly detrimental effects.
Trichome density extended larval establishment time but did not influence female oviposition. We then evaluated the performance of the egg parasitoid Trichogramma achaeae Nagaraja and Nagarkatti (Hymenoptera: Trichogrammatidae) and the larval parasitoid Necremnus tutae (Reuter) (Hymenoptera: Eulophidae) on six varieties (four domesticated ones and the wild tomatoes S. arcanum and S. neorickii) differing in their level of resistance. While domesticated plants and S. neorickii had insignificant impact on parasitoid efficacy, S. arcanum negatively affected both species due to its high glandular trichome abundance. Our findings reveal the complex interaction between host plants and natural enemies.