Apple blister, also known as the apple leafhopper, is commonly referred to as "tired insects" or "oil sweat." It belongs to the order Hemiptera and the family Cicadellidae. This pest is widely distributed across China, Japan, and North Korea. Its main host plants include apple trees, sand cherry, jujube, and mountain vine.
Damage caused by apple blister is primarily due to the feeding behavior of nymphs and adults. When they feed on the sap of shoots and buds, the edges of the leaves curl into a tube-like shape. Although the damage is usually localized, the affected leaves often develop longitudinal wounds from both sides toward the back. In some cases, the leaves may be rolled up like ropes, leading to wilting and drying. The internal damage caused by the blisters is not visible from the outside, but over time, the damaged leaves gradually wither and die.
Morphologically, the wingless female is about 1.4–1.6 mm in length, with a nearly spindle-shaped body. It has a dark green or brown coloration, a black head, and bright red compound eyes. A prominent frontal tubercle is present. The winged female is slightly larger, around 1.5 mm long, with an oval body. Its head and thorax are dark brown, and it also has a noticeable frontal tubercle, along with 2–3 black hairs. Nymphs are small and resemble wingless forms, with a light green body. Some individuals have dark wing buds on their dorsal thorax, which are referred to as "fin bases," and these eventually develop into winged pupae. The eggs are long-oval, dark green, and shiny, with a length of approximately 0.5 mm.
In terms of occurrence characteristics, this pest can complete more than ten generations per year. Overwintering occurs in the buds of annual shoots, as well as in saw-cut mouths. In early April of the following year, the overwintering eggs hatch, and parthenogenesis takes place from spring to autumn. The peak damage period typically occurs in mid-to-late June. From October to November, sexual reproduction occurs, followed by mating and egg-laying. The eggs then enter the overwintering stage.
For prevention and control, the key is to apply insecticides carefully during the overwintering period. In western Henan Province, the hatching of apple eggs begins at the start of April, peaks in mid-April, and ends by late April. For application, it's recommended to use a spray that covers all parts of the tree—branches, leaves, and buds—ensuring thorough coverage. Spraying should be done consistently and effectively to maximize control. Regular monitoring and timely intervention are essential for managing infestations and protecting the health of the apple trees.
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