Efficacy of endophytic wild strains of entomopathogenic fungi against the tomato leafminer Tuta absoluta Meyrick) (Lepidoptera: Gelechiidae) in tomato plants

Abstract

Background: Tomato (Solanum lycopersicum L.) is a vegetable of great economic value. The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a serious pest of tomato. Its control is difficult due to the protection of the larvae in the galleries they create its fast resistance development too many active ingredients and due to its many generations per year. Many entomopathogenic fungi (EPF) have been reported as endophytes for various plant pathogens and pests. In this study, the endophyticity of Beauveria bassiana Balsamo (Vuillemin) (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) isolated from the soils of Crete against larvae of T. absoluta in tomato plants was examined. Results: As a result, the EPF isolates of Crete decreased both the distance of larval travel from the egg to the opening of the gallery and the weight of the T. absoluta larvae, but also colonized the tomato plants. The entomopathogenic fungi were isolated from tomatoes again. Mycelium began to appear 7 days later and had developed completely after 12 days at 25 ± 2 °C and in 95% RH. Interestingly, the period between the hatched egg and the emerged first instar T. absoluta larvae was affected significantly by the different treatments, but not by "repetition" or "plant". Interestingly, the distance was further significantly shortened after treatment with M. anisopliae isolate Crete and B. bassiana isolate Crete and the commercial strain. The development period of T. absoluta larvae varied significantly among the treatments, but not by repetition in time or plant. The treatments caused a significant variation in the weight of T. absoluta pupae. The lowest weight was recorded in the plants colonized by M. anisopliae isolate Crete. Conclusions: The study demonstrated the ability of the B. bassiana and M. anisopliae from Crete to colonize the tomato plants and the wild strains of Crete affect the distance of larvae. With the presence of endophytic EPF, the period between the hatched egg and the emerged first instar T. absoluta larvae was decreased, as does the weight of the T. absoluta pupae.