Yesterday while inspecting my trees, I noticed a significant amount of dropped foliage below my nectarine trees, I also noticed purple/brown discoloration at the edges of many leaves that are still on the trees (photos below). My trees are at the shuck split/drop stage and the leaves are only about 30-40% of the full size. Have not seen this before, any one familiar with this condition? Could it be because of the dormant copper spray that I did during bud swell? I used NuFilm sticker for the first time this year, so could it have kept the copper ions long on the swollen buds until they started breaking and some got on the small leaflets causing them some phytotoxicity?
No I doubt it is the copper, as the leaves are not sprayed, the exterior of the bud is hard. It looks like fertilizer burn to me. If not it is the roots that are in trouble for whatever reason?
Fertilizer burn? Does the fertilizer have to touch the leaves for that to happen? I fertilized about 3 weeks ago with one pound of granular 10:10:10 per tree, which is less than the 1.5 pound that Penn State recommends for 3rd leaf trees.
No just the roots.
You can’t go by that. If the trunk is as thick as your bicep, then that would be OK. Hard to tell from a photo and I can’t see the whole tree. It does not look like a fungus, it’s not insect damage. It is a root problem of some sort. Being too wet or too dry could be it too.
If I’m right and it is fertilizer burn, you’re fine, it will recover. The most common symptom of fertilizer burn is brown edges on leaves.
I read that watering the tree can help it recover from fertilizer burn, do you have experience with that? I rarely water, because the soil is clay and is always wet enough.
Yes that should help. It could also be sun burn, drought stress, or herbicide drift. The copper could cause this too, but I don’t see it, if not directly on the leaves. And if you used a liquid product, which are extremely weak, I don’t see it. Captan can cause burn too. Hopefully it is fertilizer burn, as your tree(s) will recover 100%. Fertilizer is a salt, and it dries the trees out, so the thinnest part of the leaf dries out and turns brown. So yes water is helpful.
Whatever happened the growth generally looks good so its not a major cause for concern. I also don’t think its copper, I have sprayed copper/nufilm for many years at very late dormant stages and never saw any effects. Fertilizer burn seems like a reasonable theory.
I am inclined to the fertilizer burn, because I do not see these symptoms on my other trees (pluots and cots) which were not fertilized! I thought I am adding the right amount of fertilizer, but maybe not. I guess I should have watered after adding the fertilizer… Nectarine foliage seem more sensitive to copper than pluots or cots, that’s why I initially suspected copper phytotoxicity.
You still could be right, and is a reasonable cause for it. . Hey I burned and even killed more plants from fertilizer than is probably in your yard. 2 years ago I killed a couple blueberry plants this way. It’s not easy to tell what is enough and what is too much? I so can’t tell I switched to organic fertilizers for my trees as too much rarely results in burns. Organics are much more forgiving.
It’s all part of learning, now you know what it looks like. Try 1/2 pound in the future. But I would not add any anytime soon.