Avalação do silício no comportamento alimentar da cochonilia-branca [Planococcus citri (Risso) (Pseudococcidae)] em cafeeiro

Abstract

Several researches focusing the use of silicon in plants have demonstrated an increase of plant resistance to stress and pests. This work aims to determine the effect of silicon, applied as calcium silicate (CaSiO3) on mealybug probing behavior by using the technique of Electrical Penetration Graphs (EPG). The citrus mealybug, [Planococcus citri (Pseudococcidae)], and coffee plants cvs. Catuaí and Catucaí were used in these experiments with silicate applied in plant pots at rate of 1 g of calcium silicate/250 g of soil/pot. The mealybug probing behavior showed that on treated plants, the mealybugs reached the phloem vessels, their feeding site, at similar time than untreated plants, demonstrating absence of mechanical barrier to stylet penetration after silicate application. In addition, other parameters associated with phloem and xylem phases were not significant, either comparing cultivars or silicate treatments. By consequence, calcium silicate applied in soil at these rates did not affect the citrus mealybug probing behavior in coffee plants.