**Vineyard Leafhoppers** (e.g., **Grape Leafhopper** – *Erythroneura comes*) are small, wedge-shaped insects that are major pests of grapevines. The conflict is **photosynthetic reduction and disease transmission**: they feed on the underside of leaves by sucking cell contents (mesophyll), causing leaves to develop fine white stippling. Severe feeding reduces the plant’s photosynthetic capacity, which lowers the sugar content and quality of the fruit. More critically, certain species vector key **phytoplasma diseases** (e.g., Flavescence Dorée) that can devastate vineyards.
Taxonomy and Classification
Leafhoppers belong to the Order Hemiptera (True Bugs) and the Family Cicadellidae. They undergo simple metamorphosis.
Physical Description
Adults are small, 3 mm to 5 mm long.
- **Adult (Key ID):** Small, wedge-shaped body; often pale yellow-green with reddish markings; rapidly jump or fly when disturbed.
- **Nymph (Key ID):** Pale white or yellowish, wingless version of the adult; moves sideways or backwards (crab-like).
- **Damage ID (Key):** Fine, whitish or yellowish **stippling** on the leaf surface; leaves may turn brown or red prematurely.
- **Vector Status:** Key vector for phytoplasma diseases.
- **Conflict:** Agricultural (Viticulture).
Distribution and Habitat
Found worldwide in viticulture regions. Habitat is the foliage of grapevines, particularly feeding on the more protected undersides of the leaves.
Behavior and Conflict
The conflict is driven by their mobility and virus transmission.
- **Stippling:** The stippling is caused by the death of the mesophyll cells after the insect sucks out the contents.
- **Disease Spread:** They acquire phytoplasma when feeding on an infected vine and transmit it rapidly to healthy vines.
Management and Prevention
Management is **IPM focused on Vector Control**.
- Targeted application of insecticides to control the nymph stage (often the most susceptible) and suppress populations below the economic threshold.
- Removing infected vines to eliminate the source of the phytoplasma; managing weeds that serve as alternate hosts.
Conservation and Research
Research focuses on developing rapid molecular diagnostic tests for phytoplasma diseases and utilizing biological controls (e.g., parasitic wasps) against the leafhopper populations.