Study to determine occurrence and impace of Asian ladybird, Harmonia axyridis (Pallas) in Western Cape winelands.
Achiano, K A
Achiano, K A
The presence of the highly invasive Asian or harlequin ladybird, Harmonia axyridis (Pallas) was recently confirmed in South Africa. This ladybird is primarily an aphid predator. If any of these beetles are crushed with the grapes, the wine becomes tainted. Once wine is tainted, not even filtering, treatment with activated charcoal or heat treatment can rid the wine of the unpalatable flavours. At present the only known breeding populations in the Western Cape are in wheat lands in the vicinity of Riviersonderend and Swellendam. Many vineyards in the Swartland and Overberg regions are situated in the vicinity of wheat fields, or even surrounded by them. Various grains (wheat, rye, Triticale, oats) are cultivated in vineyards as winter cover crops. These grains are often attacked by aphids, and these aphids may attract harlequin ladybirds into vineyards.
In view of the possible negative effects that harlequin ladybird infestations may have on wine quality and on biocontrol of vine pests, research will be conducted to determine the following:
1. The distribution of harlequin ladybirds in the Western Cape winelands,
2. The possible effect of harlequin ladybirds on populations of local natural enemies particularly predatory ladybirds,
3. Whether indigenous parasitoids that attack local predatory ladybirds also attack harlequin ladybirds,
4. Whether grains sown as winter cover crops play a significant role in attracting harlequin ladybirds to vineyards.
Achiano, K. 2011. Population study of Harmonia axyridis (Coleoptera: Coccinellidae) on vines in the Western Cape, South Africa. Presentation at the 9th Winetech Grapevine Virus Workshop. 24 May, ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa.