Abdomen - Covered with a white waxy material giving a characteristic woolly appearance.
Aphids are found on both aerial portions and roots of trees. Greatest infestations of roots occurs during extremes of hot or cold weather. In spring the woolly aphids migrate from the roots to the tops of the tree where they may remain for the growing period. In autumn there is a considerable reduction in infestation with many aphids making their way to the roots. Under heavy infestations, colonies may persist on aerial parts of trees throughout winter. The wingless female are capable of producing large numbers of living young without mating. The nymphs move to all parts of the tree whereby they either establish new colonies or join existing ones.
Origin and History:
The woolly aphid can be a serious pest of apple and pear varieties. Infestations cause knotted and gnarled lumps and scars on older wood. These are usually coated over with white woolly secretions produced by the aphids. As young lateral shoots develop during the summer, the aphids migrate to the underside of them. They may cause severe injury to new wood and destruction to buds. Heavy aphid infestations can severely reduce the vigour of trees which become 'staggy' in appearance, with little fruiting or leaf bearing wood.
Management and Control:
The parasitic black chalcid wasp (Aphelinus mali) is an extremely effective controlling agent.
Insecticides are available for the successful control of woolly aphid infestations.
Collated by HerbiGuide. Phone 08 98444064 for more information.