THE DIVERSITY OF APHID IN ORANGE GROVES OF THE MITIDJA-COMPARING POPULATIONS LEVELSOF APHIS SPIRAECOLA PATCH AND TOXOPTERA AURANTII BOYER DE FONSCOLOMBE (HEMIPTERA: APHIDIDAE …

Abstract

The objective of this study, conducted in orange groves located at the eastern part of the plain of Mitidja was to determine the diversity and relative abundance of aphid species and estimate population levels of the most common and dangerous species in citrus. The weekly sampling conducted between April 25 and June 6, 2012, has identified 18 species aphid, the most dominant is Aphis spiraecola with 32.05% of the total, followed by Toxoptera aurantii with 17.31 %. These results have stimulated us to follow the evolution of these two species during the spring of 2013. To estimate their importance, 15 weekly collections were made between April 11and July 21, 2013 at the I.A.T.M.S. (Institute of Agricultural Technology Middle Specialized). Both species have appeared to orange tree on April 18 to a value of Average Weekly mean Temperatures (A.W.M.T.) equal to 16.46°C. During the following weeks the number of two species remains low. It was around June 9 to (A.W.M.T.) equal to 19.44° C, the colonies Aphis spiraecola actually grow, reaching their maximum level 7 July (A.W.M.T.=22.47°C) with 5542 individuals (37.84%). After that date, increased while the number of Aphis spiraecola fell sharply to permanently disappear from the arboreal stratum to July 21 (A.W.M.T. =25.30°)