Leaf holes can be used to identify common garden pests and diseases.
Leaf holes can be caused by insects, disease, and chemical or physical damage. Many rose bush leaves exhibit holes caused by their own thorns. Wind whipped branches can also cause holes in leaves. In these cases, there’s really nothing you can do. Chemical damage is usually caused by herbicide overspray. Using chemical herbicides more carefully (or not at all) can prevent this from happening. The signs of pest and disease damage, however, can be used to fight back.
When a leaf has a hole in it, photosynthesis is reduced, the plant may be weakened, and it becomes more vulnerable to other pests and diseases. Use the information below to learn how to identify the cause of leaf holes in your garden or landscape plants.
Irregularly shaped holes and complete defoliation, with the leaf midvein generally left intact are usually caused by:
Irregular holes, chewed stems, leaf chlorosis (yellowing), and wilting
This recipe for disaster indicates the presence of cucumber beetles. Cucumber beetles can be striped or spotted and they nearly always cause significant plant damage.
If your grape leaves look as though a tiny, knife-wielding slasher attack occurred, it was probably the Western grape rootworm (Bromius obscurus). Leaf slits are usually 1/4 to 1/2 inch long. Individually, these slits are usually too small to seem important, but the combined effect can be devastating to the leaf. Damage is also seen in the berries.
Once you identify the cause of holes in your leaves, you can select the best treatment. This list is by no means exclusive, but it should give you a good starting point. If you have other causes of leaf holes, please tell us in the comments below!
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