Occurrence of Tegolophus brunneus and Phyllocoptruta oleivora (Acari: Eriophyidae) on the main citrus belt of Brazil and the differential toxicity of the acaricides to these species.

Abstract

Many mites of the family Eriophyidae are important pests worldwide. In citrus crops, the eriophyid Phyllocoptruta oleivora stands out for the economic losses caused. The pest's injuries cause the darkening of leaves, twigs, and fruits, making them unfit for the fresh fruit market and affecting plant productivity. Another species that causes similar symptoms was described in Brazil recently, the brown citrus rust mite, Tegolophus brunneus. Although studies have not been performed with this species, growers and technicians have attributed the rise in rust damages in Brazil to T. brunneus, affirming that this mite is more aggressive and resistant to acaricides than P. oleivora. In this study, the distribution of T. brunneus in the main Brazilian citrus belt and the differential toxicity of the acaricides sulfur and abamectin were evaluated for both species. Infested fruits were collected from different orchards in many municipalities, covering the main citrus species and cultivars grown, aiming to show the main T. brunneus hosts. It was observed that only plants of Tahiti acid lime (Citrus latifolia) were infested by T. brunneus, whereas P. oleivora infested all citrus cultivars and species evaluated (Citrus spp.). In our study, T. brunneus and P. oleivora were never observed coinfesting the same fruit/leaf or plant. The acute toxicity test of sulfur and abamectin as acaricides showed that T. brunneus has greater tolerance to abamectin than P. oleivora. However, the acute toxicity of sulfur was similar for both species. These results showed T. brunneus specificity to infest Tahiti acid lime, causing important damage to this crop, and suggest that attention should be paid to managing this mite using abamectin.