Tom
Weeping cherry trees fall prey to all types of pests and diseases. Before you can treat the problem effectively, you are going to have to figure out exactly who is doing the damage. Aphids, Japanese beetles, and Oriental fruit moths should all be on your short list of primary suspects. Tent caterpillars and spider mites can cause problems as well. All of these pests enjoy feasting on the leaves and branches.
Japanese beetles are perhaps the easiest to spot. The adult beetles are 3/8 inch long, and metallic green with copper-brown wing covers. The leaves usually look like lace when they finish munching on them. Adult beetles can be shaken from plants onto drop cloths and drowned in soapy water. This is best done in the early morning when they are likely to be feeding. In their larvae form, Japanese beetles overwinter deep in the soil as grubs and pupate in the early summer. Applying milky spore or parasitic nematodes to your sod will help control populations in this stage.
If new leaves appear twisted or curled and are covered with a sticky coating (honeydew), you're looking at an aphid infestation. Ants feed on honeydew and may be present in larger numbers than normal. Aphids usually leave my midsummer, so if an infestation isn't severe, you may just want to wait it out. Otherwise, use a strong spray of water from the garden hose to knock them off the tree. Natural predators like lacewing or lady beetles can also be introduced to help control aphid populations.
If growing shoots wilt and die, you could be looking at an infestation of Oriental fruit moth larvae. Slit the stem below the wilted portion and look for a pinkish-white caterpillar. Horticultural oil can help smother eggs and larvae.
Good luck!
Ellen
Here are the questions asked by community members. Read on to see the answers provided by the ThriftyFun community.
Something is eating my leaves in my weeping cherry tree.
Ron
I also have just planted a dwarf weeping cherry that now has pinholes in its leaves. The only insects I have noticed are several yellow jackets it seems to be attracting?