The appearance of holes and damage on cherry tree leaves often causes immediate concern. Accurately identifying the source of this leaf damage is the necessary first step because different problems require different solutions. A systematic approach to diagnosing the symptoms—whether the leaf is eaten completely, partially skeletonized, or damaged by disease—will prevent the application of ineffective treatments. Understanding the specific causes is key to successfully protecting the health of your cherry tree.
Pests That Chew Holes in Leaves
Some pests consume large, irregular sections of leaf tissue, leaving behind visible holes or ragged margins. This damage is created by larger chewing insects that use their mandibles to ingest the leaf material. The adult Japanese beetle is a common culprit, recognizable by its metallic green body and bronze wing covers. These beetles often consume the softer tissue between the leaf veins, leaving behind a lacy skeleton, though their feeding can also result in large, haphazard holes.
Another group responsible for direct consumption is caterpillars, the larval stage of moths and butterflies. Tent caterpillars are highly noticeable because they create large, silken webs in the tree branches where they congregate. These larvae emerge in spring and consume entire leaves or large chunks of foliage before maturing, contributing to rapid defoliation. Other beetles, such as the bronze beetle, can also create hundreds of small holes in the foliage during a brief period of active feeding.
Pests That Cause Leaf Skeletonization
Skeletonization is a distinct type of damage where the pest consumes the soft green tissue but leaves the tougher, fibrous veins intact. This results in a translucent, lacy appearance on the leaf, differing from pests that chew completely through the tissue. The most common pest causing this unique pattern on cherry trees is the sawfly larva, often referred to as the pear or cherry slug.
These larvae are small and slug-like, frequently covered in a dark, slimy substance that offers protection. They feed exclusively on the upper surface of the leaf, scraping away the chlorophyll-containing layers and leaving only the network of veins. While one generation causes damage in early summer, a second generation can emerge later, reducing the tree’s photosynthetic capacity. Repeated skeletonization rarely kills a mature tree but can weaken the plant over multiple years.
Damage That Mimics Chewing
Not all holes in cherry tree leaves are caused by pests physically consuming the tissue; some result from disease or other non-insect factors. Shot hole disease is a frequent misdiagnosis because the resulting leaf appearance strongly suggests insect damage. This condition is caused by a fungus, bacterium, or combination of pathogens that first create small, purplish-black spots on the leaves. As the infected tissue dies, the necrotic spot dries up and cleanly falls out, leaving behind a small, neat, circular hole, as if the leaf was peppered with fine shot.
The holes from shot hole disease are typically quarter-inch in diameter or smaller and are distinguished by their clean, circular margins, unlike the ragged edges left by chewing insects. This disease is favored by warm, wet spring weather, and while it can cause premature defoliation, it is usually not fatal to an otherwise healthy tree.
Sap-Sucking Pests
Other pests, such as aphids and spider mites, do not chew, but their sap-sucking activity causes leaf deformation, curling, or stippling. Aphids feed on the sap of new growth, causing the leaves to curl and become distorted, which may lead to premature leaf drop.
Immediate Steps for Pest Management
Once the specific cause of the leaf damage has been correctly identified, several immediate, low-impact actions can be taken to manage the problem. For large, visible pests like caterpillars or sawfly larvae, physical removal is an effective initial step. Larger insects can be picked off by hand and dropped into a container of soapy water to prevent their return.
For soft-bodied pests such as aphids or mites, a strong jet of water from a hose can physically dislodge them from the leaves and new shoots. If the infestation is more persistent, applying a horticultural oil or insecticidal soap offers a targeted approach. These products work by smothering the pests or damaging their protective outer layer, and they should be applied thoroughly, ensuring coverage of the leaf undersides.