Identification of natural enemies and investigation of their efficiency in control of Pulvinaria aurantii (Hom.: Coccidae)

Khazaeipool, Azam and Fathi, S.A.A and Aghajanzadeh, S and Davari, M (2008) Identification of natural enemies and investigation of their efficiency in control of Pulvinaria aurantii (Hom.: Coccidae). Masters thesis, University of Mohaghegh Ardabili.

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Abstract

Pulvinaria aurantii Cockerell is the most important pest of the citrus that damaged to these trees. In this research natural enemies of P. aurantii were collected and identified. Cryptolaemus montrouzieri Mulsaunt with the relative abundance 28.08 %, Chilocorus bipustulatus L. with 14.7%, Scymnus spp. with 2.75%, Propylea quatuordecimpunctata (L.) with 2.36%, Chrysoperla carnea Stephens with 15.88%, the number of P. aurantii parasitized by Tetrastichus sp. with 21.92% and the number of P. aurantii parasitized by Lecanicllium spp. with 14.3%, were included from total specimens that was checked. In the predatory efficacy experiments, in separated releases of each predator species, the female of C. montrouzieri was attacked more ovisacs of P. aurantii than C. bipustulatus. Also, latest instar larvae of C. carnea was not consumed from ovisacs of P. aurantii. But the latest instar larvae of C. carnea was consumed the highest 2nd instar nymph of P. aurantii in compare to one female C. montrouzieri and C. bipustulatus. In combined releases of predator species, the highest ovisacs of P. aurantii were attacked by release of one female of C. montrouzieri + one female of C. bipustulatus. In contrast, the highest 2nd instar nymph of P. aurantii were consumed by release of one female of C. montrouzieri + one latest instar larvae of C. carnea. Also in this research, the population densities of P. aurantii and C. montrouzieri were studied in three different citrus orchards during first of May to October in 2007 and 2008. 40 samples were taken randomly from each of the orchard weekly. In each sample the number of different developmental stages of P. aurantii and C. montrouzieri were counted. The population densities of P. aurantii and C. montrouzieri were significantly different in three orchards. These differences can be associated with different fertilization levels in three orchards.

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