Population dynamics of the mango scale, Aulacaspis tubercularis (Newstead) (Coccoidea: Diaspididae), in South Africa.
Labuschagne T. I., Hamburg H. van, Froneman I. J.
Author Affiliation: Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit, 1200, South Africa.
Israel Journal of Entomology 29 : 207-217
Abstract : Ecological aspects such as population composition, population fluctuation and spatial distribution as well as the natural enemies of the mango pest Aulacaspis tubercularis were analysed using data gathered from 2 localities, Kaapmuiden (25°29?S, 31°24?E) and Nelspruit (25°27?S, 30°58?E), South Africa. An average of 350 females and 550 males were examined fortnightly for a period of 12 months to determine the frequency of the developmental stages and the percentage parasitism. Eight leaves per tree, 2 in each quadrant, were randomly picked to determine the relative abundance and the spatial distribution of the scale insects within the tree. Twenty randomly selected trees in an orchard were used for this purpose. The highest infestation rate occurred on the shady south-facing lower aspect of the tree. Population peaks of the pest occurred during different periods of the year in the 2 regions monitored. The population peak at Kaapmuiden, with a higher mean temperature, occurred in August, much earlier than at Nelspruit, where it occurred in November. Generations overlapped to such an extent that no developmental stage peaks could be detected. The indigenous parasitoid Encarsia citrina was incapable of controlling A. tubercularis despite percentage parasitism exceeding 80% at certain times of the year. The predatory thrips Aleurodothrips fasciapennis was probably recorded for the first time in Africa preying on Aulcaspis tubercularis.