Determining the time required after the start of feeding by grapevine mealybug crawlers before systemically-applied imidacloprid kills or stops the insects from feeding.
At a Winetech Grapevine Virus Workshop the question was asked whether a mealybug crawler carrying leafroll virus can transmit it to a virus free grapevine treated with imidacloprid before the insecticide takes effect and kills the mealybug. Research by Dr. K. Krüger has shown that an infected crawler can transfer the virus within 15 min after it starts feeding. If systemically applied imidacloprid does not stop the insect from feeding and/or kill it in a shorter period than the virus transfer period, such insecticide applications will not protect virus-free vineyards from becoming infected if virus-carrying mealybug crawlers enter the vineyard. This has serious implications for the industry’s grapevine leafroll control strategy.
The aim of this project is to determine how soon after a mealybug starts feeding on a treated grapevine the imidacloprid takes effect and stops the mealybug feeding before it dies.
Allsopp, E. 2013. Can grapevine mealybug transmit grapevine leafroll-associated virus 3 to grapevines treated with imidacloprid? Poster presented at the 18th Congress of the Entomological Society of Southern Africa. 30 June – 3 July 2013, North-West University, Potchefstroom, South Africa.