Neem in the Conventional Lake Chad Basin area and the threat of Oriental yellow scale insect (Aonidiella orientalisNewstead) (Homoptera: Diaspididae)

Abstract

Oriental yellow scale (Aonidiella orientalisNewstead) infestation has threatened the survival of several species of economic trees, especially neem (Azadirachta indicaA. Juss), in the Conventional Lake Chad Basin (CLCB) extending across parts of Niger, Nigeria, Chad and Cameroon since its appearance in the sub-region in 1972. Although the scale was first officially reported in Garoua, Northern Cameroon only in 1985, it has since spread over 1 million square kilometers in the CLCB area and destroyed many neem and other economic trees. This paper highlights the implications of the biology and ecology of this scale pest for its successful control and the need for a proper understanding of the role of meteorological factors in seasonal variations of populations of the scale. It further proposes an integrated pest management scheme involving the augmentation of indigenous predators/parasitoids, controlled pruning of infested branches as well as the destruction of heavily infested whole trees, the development and planting of neem varieties that are resistant to the scale and the selective application of approved systemic insecticides, for the effective control of the scale in the sub-region.