Acaricides compatibility with the armored scale predator Rhyzobius lophanthae
2019
Kaspi, Roy | Madar, Reut | Domeradzki, Sylvia
Rhyzobius lophanthae Blaisdell (Coleoptera: Coccinellidae) is an important worldwide predator of armored scale species in citrus orchards. Laboratory bioassays were performed to test the impact of acaricides, commonly used in citrus in general, and sulfur pesticides in particular, on acute mortality of R. lophanthae adults and larvae. The lethal toxicity of six acaricides to R. lophanthae (abamectin, spirodiclofen, fenbutatin oxide, summer oil, and two sulfur formulations) were evaluated. In addition, sulfur formulations were also tested at various rates, as high as 8-fold the recommended label rate. Toxicity was tested in two situations: (i) direct spray applications and (ii) feeding and contact with dry residues on prey items (oleander scales, Aspidiotus nerii). The pesticide abamectin combined with summer oil was highly toxic to R. lophanthae adults and larvae in both direct applications and pesticide residue situations. In contrast, pesticides fenbutatin oxide, spirodiclofen, summer oil, and two sulfur formulations of all doses, were found to be harmless to both R. lophanthae adults and larvae. Our findings suggest that all tested pesticides except for abamectin, are harmless and may be considered compatible with R. lophanthae. Moreover, our data show that R. lophanthae was not affected by high doses of sulfur solutions.
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