Control Methods and Technical Key Points for the Tea Green Leafhopper (Empoasca flavescens)

The tea green leafhopper, also known as the small green leafhopper, is one of the most important insect pests of tea in Fujian Province. It mainly feeds by piercing and sucking the sap of tender tea shoots with adults and nymphs, and female adults lay eggs inside the stems of tender shoots, causing stunted growth of tea plants. The damaged buds and leaves curl and harden, and the leaf tips and margins become reddish-brown and scorched, affecting the yield and quality of tea.

This pest has multiple generations per year in Fujian Province, with overlapping generations. In low-mountain tea areas, it has 12 to 13 generations per year, with peak damage periods in May to June and September to October; in high-mountain tea areas, it has 8 to 9 generations per year, with peak damage periods in July to September. It overwinters as adults on tea plants, leguminous plants and weeds. It becomes active when spring temperatures rise to 10°C, and a ten-day average temperature between 16 and 26°C is suitable for its growth and development. Adults mostly lay eggs inside the tender stems between the second and third leaves of new shoots. This pest tends to seek tender growth and prefers to inhabit the undersides of buds, shoots and tender leaves. The population density is highest on the 2 to 3 leaves below the buds. After the third instar, nymphs and adults are active and can crawl sideways or jump. Based on analysis of the pest's occurrence and damage characteristics, historical data and weather conditions, the tea green leafhopper is expected to occur at moderate to heavy levels in Ningde, Fuzhou, Quanzhou and Nanping, and at moderate levels in other cities.

Control methods:

(1) Do not interplant leguminous crops in tea gardens, and remove weeds promptly when found.

(2) Harvest tea promptly, and remove eggs on tender shoots whenever found, which can significantly reduce pest population density.

(3) Chemical control: Select pesticides that are highly effective, low in toxicity, residue-free and free from export restrictions. When the pest population reaches 6 or more per 100 leaves, the entire tea garden should be sprayed; if below the control threshold, targeted treatment may be applied as appropriate. For control agents, choose 2.5% Uranus emulsifiable concentrate at 1000 times dilution, or 10% imidacloprid wettable powder at 3000 to 4000 times dilution, or 35% Saidan emulsifiable concentrate at 1000 times dilution, or 25% Actara water-dispersible granules at 15000 to 20000 times dilution for spray control.