Utah Plant Pest Diagnostic Lab

Two Plum Trees

Question:

I planted 2 plum trees several years ago. The 3rd year I had a huge crop. The next 2 years the leaves had what I think is peach leaf curl or at least that's how it made the leaves look. I sprayed both years with no improvement. This year I've also sprayed but after blossoming, the leafing is very sickly, the leaves done even really form, they just make tiny clusters of pale spikes that look like tiny curled leaves. Is there anything I can so short of digging them out? Can they be saved or I am better off just starting from scratch? How to I make sure what is there doesn't contaminate the new trees? Thanks.

Answer:

I have 2 plum trees in my yard - planted 3 years ago. One is a Santa Rosa, the other an Ozark Premier. Every spring, the leaves on the Ozark Premiere look like what you are describing. The problem is aphids. As they feed on new growth, the leaves are damaged, so as leaves expand they are twisted and deformed. Aphids are then able to "hide" in the curling leaves, so it becomes very difficult to treat. The Santa Rosa plum is hardly affected at all!

Early this spring, I sprayed both trees with dormant oil. It really helped reduce the aphid damage on the Ozark Premiere.

Here is a link to more information about Leaf Curl Plum Aphid:
http://www.ipm.ucdavis.edu/PMG/r611301811.html

Posted on 16 May 2007
Maggie Wolf
Horticulture Agent, Salt Lake County