Seasonal abundance of Aphis spiraecola, A. gossypii and Toxoptera aurantii on citrus nursery trees in Sicily

Abstract: In the period 2007-2014 an official survey was carried out in northern and eastern Sicily for the detection of Citrus tristeza virus on citrus trees cultivated in nursery conditions. The diffusion of aphids was also surveyed to better define the role of CTV vectors hosted by citrus nursery trees and to exclude the presence of Toxoptera citricidus (Kirkaldy), not yet detected in Italy. The seasonal observations of the three predominant species of aphids show that, in eastern Sicily on citrus nursery trees, A. spiraecola Patch is the most abundant aphid species; that T. aurantii (Boyer de Fonscolombe) is commonly detected on citrus young trees and that A. gossypii Glover, considered as an efficient vector of CTV, is currently present only in the northern production area. Spring and autumn are the preferred seasons for aphids’ attacks, due to the large availability of soft new sprouts. But nursery trees can host few individuals also in summer and winter.