I have a 3 year old honey crisp apple tree. It has a lot of leaf damage as illustrated in picture 2&3. Picture 1 shows a larvae I found in the leaf pictured with it. I found one other larvae in a curled up leaf; both larvae appear to be all green under a 10x magnifier.
The honey crisp is set up as an esplanier. Over it, on a trellis, is a wisteria; could that be adding to my tree’s problem?
Also, I’d like to know the best time to spray it and with what. In January this year I used neem oil.
tree’s dormant stage.
You could have some type of apple leaf roller enjoying your apple leaves. Based on the photos of the larvae you discovered - green bodies with a green head. These may be pandemic leafrollers. Here is a Pacific Northwest Pest Management handbook site with some information regarding these insects and potential controls.https://pnwhandbooks.org/insect/tree-fruit/apple/apple-leafroller
You should continue to pick off and remove curled up leaves that contain larvae or pupae. In late winter or in March/April or before pink appears in buds (bud development Stages 2-3), you can spray with horticultural mineral oil. During bud development stages 3-6 and at petal fall, you can spray with Neem oil and other controls as described in the PNW site above. Do NOT spray anything during bloom time as it could be very dangerous to pollinators. The bud development stages for apples are described here. https://pnwhandbooks.org/sites/pnwhandbooks/files/insect/tree-
Always follow the label instructions.
It is possible that cracks in the Wisteria branches above your apple may provide overwintering locations for pandemic leaf roller larvae. Leafroller larvae have also been found on many trees and shrubs such as alder, hawthorn, big leaf maple, rose.
How did the leaves become so damaged from larvae ?
We’re larvae inside each of those leaves before they grew to their adult, albeit holey, self?
The leaves are the food for the more mature larvae and they roll the leaves together for shelter and for feeding.