Survival and virus transmission ability of grapevine mealybug on grapevine root remnants in soil
Preventing re-infection of newly planted, virus free grapevines on soil where vines infested with grapevine mealybug and infected by leafroll virus were removed is critical to a successful leafroll control strategy. The possibility that viruliferous mealybugs moving from remnant roots of infected grapevines may transmit the disease to developing roots of newly planted, virus-free vines has grave implications for the industry’s leafroll strategy. To date no research has been done to determine how long the grapevine mealybug survives on vine roots under local conditions and if it can transmit grapevine leafroll associated virus-3 (GLRaV-3).
This project aims to determine if and for how long grapevine mealybug, Planococcus ficus, can survive on grapevine root remnants in soil under local conditions, which conditions favour mealybug occurrence on roots and if grapevine mealybugs are able to transmit grapevine leafroll associated virus-3 (GLRaV 3) after surviving on root remnants for some time.
The survival and virus transmission ability of P. ficus on remnant roots of grapevines has not been studied. In order to develop a sustainable strategy to prevent leafroll infection of new vineyards when planted in soil where virus infected vines infested with mealybugs were removed, it is critical to know:
1. how widespread P. ficus occurs on grapevine roots in South Africa and which soil types favour its occurrence on roots
2. if and for how long it can survive on remnant roots in soil and
3. if it can transmit GLRaV-3 to healthy grapevines after surviving on remnant roots underground.