Biological efficacy against Diaphorina citri Kuwayama (Hemiptera: Psyllidae) of chemical compounds applied to the soil and foliage in Citrus latifolia Tanaka

Abstract

The citrus acreage of Mexico exceeds 532 000 hectares. This area is endangered by the recent detection of the bacterium Candidatus Liberibacter asiaticus in some states and by the wide distribution of the vector Diaphorina citri. The aim of this study was to evaluate the efficiency against D. citri of chemical compounds applied to the soil and foliage in Persian lime. Two field evaluations were made during 2011 with applications of spirotetramat and imidacloprid to foliage and soil, and of spinosad and avermectin only to foliage. In the first evaluation, the spirotetramat (400 mL/ha) and the imidacloprid (300 mL ha-1), applied to foliage, caused a decrease of nymphs of 78.8%-93.54% three days after the application. The Imidacloprid (300 mL ha-1), applied to the soil, the spinosad (0.1 L ha-1), and the avermectin (0.1 L ha-1), had 69.8%, 70.6% and 61.6% less nymphs than the control treatment. In the second evaluation, imidacloprid, applied to the foliage, decreased the population of nymphs in shoots by 81.9%.The lowest average of nymphs per shoot in various sampling dates was obtained with the spirotetramat and imidacloprid treatments applied to foliage; 89.6% and 87.5% less than the control, respectively. Of the products evaluated, the spirotetramat and the imidacloprid, when applied to foliage, exerted the greatest effect against D. citri.