Association of a native predator Chilocorus sp. (Coleoptera: Coccinelidae) with a new exotic mango pest, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae) in Ethiopia

Abstract

White Mango Scale Aulacaspis tubercularis Newstead, 1906 was reported for the first time in 2010 from mango orchards belonging to Green Focus Ethiopia Ltd in western Ethiopia. It was hypothesized that the pest could enter Ethiopia with mango seedlings imported by the same company. The present study surveyed natural enemies of the pest and their population dynamics in western Ethiopia. Larvae of Chilocorus sp. (Coleoptera: Coccinelidae) were found feeding ravenously on live mango scales. There was a statistically significant (p<0.05) positive correlation between the A. tubercularis and Chilocorus sp. populations in both orchards, implying that the predator was not suppressing the pest population. There was no significant difference in the mean numbers of the predatory larva populations between Arjo and Bako orchards (p>0.05). Populations of White Mango Scale and its predator showed remarkably similar fluctuations, with their abundancies reaching peaks during same months. It has been concluded that the native predator got associated with the exotic insect pest recently, and its population may gradually build up. It is suggested that implementation of Chilocorus sp. as a biocontrol agent would be a sound strategy in the management of White Mango Scale in western Ethiopia, together with other control options