Desempenho biológico e custo de produção de Trichogramma pretiosum RILEY (HYMENOPTERA: TRICHOGRAMMATIDAE) visando ao controle de Iridopsis panopla PROUT (LEPIDOPTERA: GEOMETRIDAE) em eucalipto

Abstract

Iridopsis panopla Prout (Lepidoptera: Geometridae), recorded in 2021 in eucalyptus plantations in Brazil, poses a challenge to existing control strategies due to its adaptability and ability to cause damage to the crop. The aim was to make the first record of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) parasitizing I. panopla eggs in eucalyptus plantations in Mato Grosso do Sul, Brazil, evaluate the biological characteristics resulting from this parasitism under controlled and field conditions, and discuss the efficiency and costs of Trichogramma spp. production. To evaluate T. pretiosum in commercial eucalyptus plantations, newly emerged adults from the collection of the Laboratory of Insect Biological Control (LECOBIOL) at the Federal University of Grande Dourados (UFGD) were distributed at densities of 18,000, 36,000, 54,000, and 72,000 per hectare in nine points per hectare. Under controlled conditions, the biological characteristics of T. pretiosum were evaluated when offered at 5 densities of I. panopla eggs per female of T. pretiosum (1:1, 3:1, 5:1, 8:1, and 10:1). To discuss the efficiency and costs of Trichogramma spp. production, the absorption and variable costing method was used, addressing various cost parameters in Trichogramma spp. production and quality. The unprecedented record of T. pretiosum naturally parasitizing I. panopla eggs stands out as a significant milestone in this study. Parasitism rates are promising, especially when applied at a density of 72,000 females per hectare. I. panopla eggs are suitable for T. pretiosum reproduction, as evidenced by laboratory analyses. Optimizing the costs associated with large-scale production of Trichogramma spp. involves a focus on the productivity of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) host diets and process automation. Packaging for releasing Trichogramma spp. is an important cost component but ensures the quality of applications, as well as proper dosage based on parasitism and parasitism viability estimates. Additionally, as an alternative during periods of low demand for Trichogramma spp., selling E. kuehniella eggs can ensure profitability when produced on a scale above the breakeven point (BE).