Grape leafhoppers spend winter in plant debris around the vineyard until springtime when temperatures increase significantly. Grape leafhoppers feed on wild weeds shortly before they swarm into vineyards after bud break and as new green foliage appears.
In general, nymphs and adults are similar and both are sap-sucking insects that pierce into the soft tissues of plants. Grape leafhoppers feeding can lead to a wide spectrum of symptoms that vary from one variety to another, such as tiny yellow or white dots on leaves, curling or folding of leaves, yellowing of leaf edges, and even decreased rates of plant growth. It is important to note that as the season progresses, late-ripening varieties are more susceptible to grape leafhoppers.
Many leafhopper species can transmit important plant diseases such as Pierce’s disease (xylella fastidiosa) and different phytoplasmas comprising the “Grapevine Yellows” complex, such as bois noir (blackwood disease) and flavescence dorée. It is difficult to differentiate between leafhopper species with eyesight.
Monitor: It is easier and more cost effective to overcome infestations and successfully eliminate grape leafhoppers during the initial stage of infestation. Grape leafhoppers are most susceptible to insecticides during the nymphal stage.
Make it a routine to monitor crops regularly and search plants for the presence of leafhoppers.
Maintain a healthy plant: Weak plants are more vulnerable to damage from grape than healthy plants. Therefore, adequate irrigation and fertilization regimes are important.
Sanitation: Many weeds are hosts for leafhoppers. Clean weeds and wild grasses in and around the vineyard as often as possible. This is important since it can reduce the overall population of grape leafhoppers.
The following insecticides are used in one or more parts of the world: Flonicamid, buprofezine, imidacloprid, thiamethoxam, clothianidin, sulfoxaflor, bifenthrin, deltamethrin, chlorpyrifos, dimethoate, and *carbaryl.
(*Note that while carbaryl-based insecticides are still used in some countries, there are safer alternatives available today.)
Neem oil and mineral oil can be applied.
*Names marked in red are considered to be highly poisonous to beneficial insects
*Names marked in green are considered to be IPM (integrated pest management) compatible