Field Assessments to Control the Lesser Mealworm (Coleoptera: Tenebrionidae) Using Diatomaceous Earth in Poultry Houses.

Control of the lesser mealworm (Alphitobius diaperinus Panzer, 1797 [Coleoptera: Tenebrionidae]) is usually conducted with chemical insecticides, which have limited efficacy as well as environmental and health risks. Diatomaceous earth (DE) is safe and effective in controlling many insects including lesser mealworm. However, little is known of DE efficacy against this pest. Thus, an assessment of DE was conducted for the first time in commercial broiler houses in Brazil, with the aim of developing a strategy for the use of DE in the control of this insect. The efficacy of DE was determinate to a minimum concentration, and the application was directed to the most infested sites. The DE applied to the entire poultry house (280 g/m2) was verified to control the insects. DE was also comparable to chemical treatments, with a reduction of 80% in the insect population. DE controlled the lesser mealworm and is recommended for application at a concentration of 280 g/m2 when applied to the surface of new poultry litter, before the first lot of birds is housed. Thereafter, DE should be reapplied before the housing of each lot of birds, in the same concentration, only in the housing area and under the feeders and near the walls and pillars. In addition to being a control strategy, DE can be an important tool in the management of lesser mealworm insecticide resistance.

Potential Side Effects of the Entomopathogenic Fungus Metarhizium anisopliae on the Egg Parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) Under Controlled Conditions.

The purpose was to evaluate the side effects of strains Metarhizium anisopliae (Metsch.) Sorokin sensu lato Unioeste 43 and M. anisopliae sensu stricto ESALQ 1641 on Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under controlled conditions. A free-choice test for parasitism was performed, with the confinement of T. pretiosum females mated with cards (1 × 5 cm) containing age-standardized Anagasta kuehniella Zeller eggs, either sprayed with a fungal strain (109 conidia/ml) or 0.01% v/v Tween 80 (control). For the no-choice tests, T. pretiosum females mated were confined with cards sprayed with fungal strains before or after parasitism, and cards with fungal applications at different times. The number of parasitized eggs, percentage of emergence, longevity, egg-to-adult period, sex ratio, total and confirmed mortality by the fungus, and longevity of females that parasitized previously sprayed eggs, were assessed. Histological analysis of immature phases was also performed. The fungus was repellent to T. pretiosum in the free-choice test, while in the no-choice test, fungal applications before and after parasitism did not affect the number of eggs parasitized by T. pretiosum or the sex ratio of emerging adults. However, both strains affected adult emergence rates, the egg-to-adult period, and longevity. Overall, both M. anisopliae strains had minor effects on these biological parameters of T. pretiosum under controlled conditions. Hyphae were not detected in histological observations of immature stages of the parasitoid.