To grow apples successfully and achieve high yields, effective management of diseases and pests is crucial. Today, we're discussing the green leafhopper, which poses a common threat to young apple trees, especially in orchards intercropped with grains, fruits, and vegetables. So, what should you do if your apple orchard is infested with green leafhoppers? Let's find out.
Dealing with Green Leafhoppers in Apple Orchards
1. Characteristics of Apple Green Leafhoppers
Apple green leafhoppers, also known as Empoasca decipiens, mainly harm apple trees during the autumn when the female adults lay eggs. They pierce the bark of branches with their saw-like ovipositors to deposit eggs underneath, creating crescent-shaped wounds. Severe infestations can leave branches covered in scales, making them prone to winter freezing and shoot dieback. Young branches and saplings aged 1-3 years are particularly vulnerable.
2. Life Cycle of Apple Green Leafhoppers
Apple green leafhoppers undergo three generations per year. Eggs overwinter under the bark of apple trees and hatch into nymphs after apple trees sprout in April. The nymphs then move to nearby crops or weeds to feed. They breed for two generations on crops and weeds during the summer and generally do not harm apple trees during this period. In late September, the third generation of adults migrate to late autumn crops or vegetables to cause damage. By mid to late October, they fly back to apple trees to lay eggs for overwintering. Orchards with abundant weeds or intercropped with late autumn crops are more susceptible to infestation. Adult leafhoppers are phototropic and prefer to rest in damp, sheltered areas.
3. Control Measures for Apple Green Leafhoppers
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Minimize Intercropping: Avoid intercropping late-maturing vegetables like cabbage and radish in apple orchards. If intercropping is necessary, harvest before September to break the bridge that facilitates the mass migration of leafhoppers to apple trees.
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Whitewash Tree Trunks in Autumn and Winter: Before mid to late October, when leafhoppers lay eggs, whitewash the tree trunks using lime and lime-sulfur compounds. Optionally, add a small amount of insecticide. If there are signs of egg-laying on the trunk, crush the leafhopper eggs with a stick or other tools. In summer, use light traps to attract and kill adult leafhoppers.
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Chemical Control: Use 1500-fold dilution of 10% pyridaben wettable powder, 2000-2500-fold dilution of 2.5% cyfluthrin emulsifiable concentrate, 1500-2000-fold dilution of 4.5% cypermethrin emulsifiable concentrate, or 1500-2000-fold dilution of 2.5% bromocyclen emulsifiable concentrate.
Above are the methods for dealing with green leafhoppers in apple orchards. Green leafhoppers can damage various fruit trees, including apples, leaving the main stems or branches covered in lesions. In spring, branches often dry out due to excessive water loss. Therefore, growers should pay attention to prevention and control measures.
