Tuesday, October 01, 2013
Pest of the month: Asian Woolly Hackberry Aphid
Several years ago, one of the members of my bonsai club showed me a bonsai infested with woolly aphids. I couldn’t investigate what species it was at that time, but last month I have come across some woolly aphids on Chinese Hackberry (Celtis sinensis) (images above). This time I had the opportunity to identify the species. Images below show microscope sild specimens of winged and wingless adults, which have to be prepared for species identification. It turned out to be the Asian Woolly Hackberry Aphid (Shivaphis celti), an exotic species recently introduced to Australia. Woolly aphids such as Asian Woolly Hackberry Aphid can be a real nuisance. They quickly multiply and draw large amounts of plant sap to secrete a sugary substance or honeydew and deposit it on the plant’s surface. It is intended as ant food in exchange for protection ants provide to the aphids. However, in the absence of ants honeydew gets infected with sooty mould fungus, which blackens the leaves. Don’t let it happen and kill woolly aphids with an insecticide as soon as you notice them on your bonsai.