Apricot Leaves Cupping and Dropping Off

Q. My Blenheim apricot tree is not doing well. A few branches have lost all their leaves. Other leaves are starting to curl and cup. This year it had plenty of apricots but few leaves. I thinned them out since the tree is young. I thought this would also help the tree put more energy into leaves.

Note: since this response we have looked at the tree and determined the leaf cupping and marginal burning was probably due to stinkbug feeding when the leaves were first emerging from the buds.

A. First thing, I see you have wood mulch. Please pull it back 12 inches from the trunk. The symptoms you sent to me could be that. The cupping is because the outside edges of the leaves dried up and the leaf was still growing so the inside of the leaf still expanded while the dead edges did not.

The edges of the leaves dying could be lack of water, salt damage, wind damage, damage from sprays. The lack of water could be either from a lack of applied water, damage to the trunk (mechanical or borers).

Salt burn can be from applying fertilizer too close to the trunk and/or heavy rate of conventional fertilizers in the irrigation basin. Always keep fertilizer at least a foot from the trunk. When watering the fertilizer into the soil try not to flood the basin around the tree if you put a considerable amount of high nitrogen fertilizers such as ammonium sulfate or urea in the planting area. Urea or even “hot” manures like chicken or other poultry manures can cause problems like this if they get too close to the tree.

Wood mulches surrounding young fruit trees and left in contact with the trunk can cause the trunk to rot effectively choking the tree at its base and causing it to act like it is not getting enough water (leaf scorch), dieback or death. This is called collar rot, crown rot or Phytophthora rot.

Upon inspection of the tree if you have pulled the mulch back, inspected the trunk just above soil level and see no problems, inspected the trunk and see no signs of borer damage and ruled out possible damage from fertilizers then perhaps we can look at any sprays you might have applied and possible spray damage to foliage and fruit or damage from strong winds. Fruit trees do perform better with some windbreak in their growing area that either slows the wind down or causes it to be diverted to a different place.