SURVEY OF SCALE INSECTS AND MEALYBUGS INFESTING SOME AVOCADO CULTIVARS AND THEIR ASSOCIATED NATURAL ENEMIES IN EGYPT

Abstract

The present work was conducted for one year (January - December, 2013) on six avocado cultivars cultivated in new reclaimed lands at Borg El Arab (Alexandria Governorate), El Bostan (Beheira Governorate), El Sadat (Menofiya Governorate) and Sarapium (Ismailiya Governorate). The study was conducted to survey the scale insect and mealybug species and their associated natural enemies as well as the degree of infestation on avocado trees. The obtained results revealed eight species of scale insects and Mealybugs. Two coccid species [Coccus hesperidum L. and Pulvinaria psidii (Mask.)], Four diaspidid species [Hemiberlesia lataniae (Sign.), Aulacaspis tubercularis (Newst)., Aonidiella aurantii (Mask.) and Aspidiotus nerii Bouche] and Two Pseudococcid species [Pseudococcus longispinus (Targ.-Tozz.) and Ferrisia virgata (Ckll.)]. Associated parasitoids were Coccophagus scutellaris on C. hesperidum, Aphytis lepidosaphes, Habrolepis aspidioti and Marietta leopardina on H. lataniae, Encarsia citrina and Habrolepis diaspidi on A. tubercularis and Anagyrus spp. on P. longispinus. Also, associated predators were Rodalia cardinalis on C. hesperidum and two coccinellid predators (Cryptolaemus montrouzieri and Scymnus syriacus) on P. longispinus. H. lataniae was the most abundant (56.8%) followed by F. virgata (42.5%) , A. tubercularis (39.8%) , P. longispinus (31.7 % ), C. hesperidum (26.6%), P. psidii (15%), A. aurantii (15%) and A. nerii (14.3%). Hass cultivar proved the highest infestation rate in the four localities followed by Boothy and Waldim cultivars. Fuerte, Gwen and Lula cultivars had the lowest infestation rate.