Effect of Potassium Silicate Application on Populations of Asian Citrus Psyllid in Tahiti Lime

Abstract

Asian citrus psyllid [ACP (Diaphorina citri)] is one of the most serious threats to the global citrus (Citrus sp.) culture, and management of ACP has depended primarily on the application of chemical insecticides. The expression of resistance mechanisms to herbivory is a key component in integrated pest management in crop production in which silicon (Si) applications can play an important role in plant–insect relationships. The objective of the current study was to evaluate the application of Si to tahiti lime (Citrus latifolia) plants under natural infestations of ACP. Two experiments were conducted using 15-month-old seedlings and 2-year-old trees, respectively. Treatments were 1) foliar Si sprays (potassium silicate) at a dose of 2 mL·L–1, 2) soil Si application at a dose of 1 kg commercial product per plant, 3) combined soil and foliar applications of Si at the doses just listed, and 4) untreated plants (control). The application of Si treatments to both seedlings and trees affected ACP oviposition, causing a reduction of 60%. Applications of Si did not affect the nutritional status (macronutrients and micronutrients) of plants in either test, except that the foliar concentration of Si tended to be greater in the soil and soil + foliar treatments than in the other treatment in both seedlings and trees. Based on these results, we suggest that Si can be added as a component of ACP integrated pest management programs.