Adults disperse to apple and begin laying eggs in early June. Nymphs feed on the underside of mature apple leaves. Feeding by adults is not considered as important because they feed for shorter intervals of time and the stylets do not penetrate into the leaves as far as nymphal stylets. Stylets are inserted through mesophyll tissue up into palisade cells. Feeding occurs in one to two of the two to three cell layers of this tissue.
Visible injury can range from light stippling along the midrib to complete chlorosis.
The stylets radiate in several directions from the point of insertion, therefore substantial stippling may be associated with a relatively low number of feeding sites. Stippling may give an overly severe impression of the impact of feeding, because white areas result partly from reflectance of light by air that has entered injured areas, not simply from removal of leaf cell contents. An abundance of adults at harvest can also be a nuisance to pickers. Trees also may be examined in early June for the appearance of RLH adults migrating to apple from multiflora rose or brambles. The action threshold should be lowered to one nymph per leaf where the nuisance to pickers from adult leafhoppers is a concern during harvest.