Biological performance of Trichogramma pretiosum with different egg densities of Iridopsis panopla

Iridopsis panopla Prout (Lepidoptera: Geometridae) has been causing damage to eucalyptus plantations in Brazil. Recently, it has been observed that adult females of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) parasitize eggs of I. panopla under field and laboratory conditions. The objective of this study was to evaluate the biological characteristics of T. pretiosum at different egg densities of I. panopla. The experiment was conducted at the Insect Biological Control Laboratory (LECOBIOL) of the Universidade da Grande Dourados (UFGD), at a temperature of 25±2ºC, relative humidity of 70±10%, and a 14-hour photophase. The experimental design was completely randomized, with five treatments representing the egg ratios per T. pretiosum female of 1:1, 3:1, 5:1, 8:1, and 10:1, with 15 repetitions each. An increase in parasitism was observed with higher egg availability, reaching 96.60±1.91% at the 8:1 ratio. The life cycle duration was 8.15±0.04 days. Parasitism viability remained constant, with an overall average of 98.8%±0.83. The number of parasitoids per egg decreased with increasing egg availability, with 3.98±0.16 individuals per egg when using 8 eggs of I. panopla. Overall, it was observed that an adult female of T. pretiosum is able to successfully parasitize and develop within a 24-hour period when utilizing 8 to 10 eggs of I. panopla.