Palmistichus elaeisis can parasitize lepidopterous pupae in the soil at different depths?

Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) is an important biological control agent, parasitizing pupae of several species of lepidopterans, and due to this, it is widely used in forest protection programs. However, it is not known whether P. elaeisis can parasitize the pupae of lepidopterans that pupate in the soil, such as Iridopsis panopla Prout, 1932 (Lepidoptera: Geometridae), which in recent outbreaks has defoliated an area of almost 200 hectares of eucalyptus plantations. Therefore, the objective is to evaluate the parasitism of P. elaeisis in pupae at different soil depths. For this, 25 previously mated P. elaeisis females were placed in containers containing soil (U 30%), and five pupae of Diatraea saccharalis Fabr. (Lepidoptera: Crambidae), which were placed at 4 different depths (1, 2.3, and 4 cm), and combined with two more factors (soil with and without litter). In a completely randomized design, the containers were kept in a climate-controlled room (temperature 25±1°C, RH 50±10%, and photophase of 13:11 h), with 5 replications. It was then evaluated the occurrence of parasitism in each treatment, and the number of emerged insects. Emergence values were submitted to Fisher's test at 5% probability. There was parasitism of P. elaeisis only in the pupae were up to 1 cm deep in the soil, both with and without litter, at other depths P. elaeisis was unable to access the pupae, although insects were found inside the soil, indicating that able to detect the pupae, but could not reach them to parasitize. Regarding the number of emerged parasitoids, in the soil without litter, there was the emergence of a greater number of P. elaeisis (x̅ = 395.8) when compared to the soil with litter (x̅ = 328.0). Therefore, P. elaeisis can only parasitize lepidopteran pupae that are up to 1 cm deep in the soil, and litter does not impede this parasitism.