Avaliação de nematóides entomopatogênicos (Rhabditida: Steinernematidae e Heterorhabditidae) e interação com o predador Macrolophus basicornis (Stäl) (Hemiptera: Miridae) no manejo integrado de Tuta absoluta (Meyrick) (Lepidotera: Gelechiidae) em cultivo de tomate

Abstract

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an important pest in the protected cultivations of tomato in South America and in part of Europe. Strategies of biological control using entomopathogenic nematodes (EPN) and predators have been successfully studied. The objectives of this work were to determine the virulence and efficiency of the EPN Steinernema carpocapsae and Heterorhabditis amazonensis JPM4 over T. absoluta and the interaction of these nematodes with the predator Macrolophus basicornis. The evaluation of the virulence over T. absoluta was performed in five concentrations of infective juveniles (JI)/mL for both nematodes. The applications were performed on the caterpillars inside the mines and on the pupas. The best virulence was obtained with 1500 JI/mL for both nematodes in larvae and pupas. The mortalities found for the larvae and pupas were, respectively, 94 and 13% with S. carpocapsae and 68 and 8% for H. amazonensis isolate JPM4. We also found the efficiency of these EPN after the foliar application of the tomato plants infected with T. absoluta and maintained in greenhouse and in laboratory (fitotrom). The foliar application of the S. carpocapsae and H. amazonensis nematodes in greenhouse presented an efficiency of 86% and 84%, respectively, without significant difference between the nematodes. In fitotrom, the mortalities for T. absoluta with S. carpocapsae and H. amazonensis JMP4 were of 93 and 87%, respectively. These results show the potential these nematodes present over T. absoluta. To determine the interaction of these nematodes with the M. basicornis predator, the adults and the different stages of nymphs were placed in direct contact with the nematodes, with and without chance of choosing, providing the female M. basicornis with larvae inoculated with the nematodes. It was verified that, from the second nymph instar up to the M. basicornis adult, the predators were susceptible to the nematodes. The higher mortality of the adults was obtained by the S. carpocapsae (28%). In the tests with and without chance of choosing, the female M. basicornis feeds on either healthy or infected larvae without exhibiting significant differences in intake or presenting mortality. Thus, these natural enemies may be considered effective in controlling T. absoluta, and may be used among the tomato integrated management packages.