Managing leafhoppers in BC vineyards: Identification, monitoring, and control

In late April and May, adults emerge from leaf litter and begin feeding on nearby plants, often congregating in higher numbers along the vineyard edges. Yellow sticky cards can help monitor these emerging adults and identify potential reservoirs and entry points, though they provide only relative infestation levels for that specific area.

As grapevines leaf out, adults migrate throughout the vineyard. By late May and June, females lay eggs on the undersides of leaves. WGL lay single eggs, while VCL lay clusters of eggs averaging 2–6. Eggs begin hatching in mid-June to July, forming the first generation. By July and August, these nymphs become winged adults and start producing the second generation.

Leafhopper nymphs and adults damage grape leaves by sucking out the contents of individual leaf cells. At low numbers, this causes stippling on grape leaves while heavy feeding leads to browning, drying, and premature leaf drop. Excessive leaf loss reduces photosynthesis, which can delay fruit maturity, lower yield, and affect fruit quality. High leafhopper populations also leave sticky excrement that concerns table grape producers, and large swarms can bother pickers during harvest, making their work more difficult and unpleasant.