What is defoliating my blueberry bush?

Asked June 30, 2014, 7:37 AM EDT

Something or things or eating my blueberry bush. Leaves are completely disappearing. Some crinkling and curling of the leaves. We looked at the bush in the dark last night and found a small green worm (see fuzzy pic) and also noticed spider webs. Have also seen some cocooning on under side of leaves. Blueberries seem to be okay, at the moment. See pics. Is this leaf roller damage? Suggestions for how to treat?

Montgomery County Pennsylvania insect issues blueberries

3 Responses

Hi:
In the areas without leaves, were there leaves there earlier and then definitely eaten, or did they not leaf out at all? There are a number of leafrollers and leaftiers (both caterpillars) that could be doing this. Usually they aren't considered pests. There are a couple of fruitworms (cherry and cranberry) that actually go into the fruit.

If you catch caterpillars when they are newly hatched and small, you can use Bacillus thuringiensis (BT), which is a bacterial spore that only works on caterpillars and is very safe to use.

Yes, there were definitely a lot more leaves, initially. Early on, they were browning up (almost overnight it seemed) and then falling off. I am wondering if there might be a couple things. It seems like something might be sucking the juice out of the leaves because they are crinkling and curling. But then there are also places where the leaves are chomped away. Do you think I should treat it with both BT and Sevin? Thank you so much for your help! -- Ann

Hi:
Is the wood still green on the twigs that lost leaves? You cut prune off a small one. If dead, it could be a fungal pathogen or delayed winter injury. Plant was able to leave out, but because the wood was damaged, the leaves couldn't be sustained.

If one of the leatiers, they won't do a lot of damage. (The browning and dropping are different.) You could just hand remove. Gives you the satisfaction of taking them out yourself! Sevin is a broad spectrum insecticide and is harmful to beneficial insects including bees, though your plants are past that.