Compatibility of pesticides used in strawberry crops with predatory mites Stratiolaelaps scimitus (Womersley) and Cosmolaelaps brevistilis (Karg).

Stratiolaelaps scimitus (Womersley) and Cosmolaelaps brevistilis (Karg) (Acari: Laelapidae) are predatory mites of soil-inhabiting pests, mainly small insects. Fungus gnats fly species are found in greenhouse strawberry production and may be controlled with predatory mites, being important to know their compatibility with the pesticides used in strawberry crops. In this study, the compatibility of seven commercial pesticides used in strawberry cultivation with the predatory mites S. scimitus and C. brevistilis was assessed in laboratory conditions. Survival and oviposition rates were evaluated between 0.5 and 120 h after treatment (HAT). The results demonstrate that lambda-cyhalothrin treatment resulted in the lowest survival rate for both mites in the first evaluations, being moderately harmful, while spinetoran was slightly harmful to C. brevistilis. On the other hand, abamectin, azadirachtin, azoxystrobin + difenoconazole, iprodione and thiamethoxam were harmless for both mites and, oviposition rate was significantly different only at 72 and 120 HAT for S. scimitus and C. brevistilis respectively. These results may be used to develop guidelines for the adoption of selective pesticides in integrated pest management programs that conserves predatory mites.

Suitability of edaphic arthropods as prey for Proctolaelaps bickleyi and Cosmolaelaps brevistilis (Acari: Mesostigmata: Melicharidae, Laelapidae) under laboratory conditions.

Soils are often complex habitats inhabited by a wide range of organisms, some harmful to plants and others beneficial, for example by attacking harmful organisms. Beneficial organisms include predatory mites, some of which have been commercialized for biological control of pest insects and mites. The objective of this work was to evaluate under laboratory condition the suitability of representative soil insect and mite pests, especially Aceria tulipae (Keifer), as prey to the soil-inhabiting predatory mites Proctolaelaps bickleyi (Bram) and Cosmolaelaps brevistilis (Karg). Predation, oviposition and survivorship of recently molted adult females of the predators were assessed in the dark in rearing chambers at 25 ± 1 °C and 75 ± 3% RH. Predation rate by P. bickleyi on A. tulipae was significantly higher than that by C. brevistilis (196.3 vs. 71.0 specimens/day). About 482 A. tulipae were preyed by each P. bickleyi at each day, when 500 A. tulipae were made available daily to the predator. Oviposition rate on that prey was also higher for P. bickleyi (4.2 eggs/day). For C. brevistilis, the highest level of oviposition was on Caliothrips phaseoli (Hood) (1.2 eggs/day). Survivorship was always higher for C. brevistilis (≥ 70%), given its ability to remain alive relatively long even in the absence of prey. High rates of survivorship of P. bickleyi were observed on A. tulipae, Bradysia matogrossensis (Lane) and Protorhabditis sp. Promising results were obtained for P. bickleyi on A. tulipae and even on other prey, justifying the conduction of complementary studies under field condition.