Population dynamics of white mango scale, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae) in Western Ethiopia

Mango (Mangifera indica L.) is the third most important fruit crop in the tropics following citrus and banana. It is consumed as a fresh fruit and different forms of preparations for its multifaceted nutritional values. Mango production in Ethiopia is constrained by infestation of white mango scale (WMS), Aulacaspis tubercularis Newstead. White mango scale was recorded from Ethiopia for the first time in 2010, in a mango orchard in Loko in the western part of the country. This study was conducted from June 2013 to May 2014 to document the population dynamics of white mango scale in Western Ethiopia. Randomized Complete Block Design was used for the sampling in two mango orchards, Arjo and Bako.  Scale population peaked in April at Arjo and in May at Bako showed marked decline with decreasing precipitation. Abundances of eggs, crawlers and sessile stages of the scale showed significant differences among most of the study months (P0.05). The abundance of sessile scales was significantly higher at Bako than at Arjo (P0.05). In both study areas, white mango scales were significantly more abundant on the upper leaf surfaces than the lower (P0.05). At Bako, male scale numbers were significantly higher than those of the females (P0.05). The study found that the decline and build-up of white mango scale populations are affected by rainfall, whereas the effects of other environmental factors on scale numbers need to be investigated. Key words: Developmental stages, fluctuation, infestation, orchard, rainfall, sessile.