Princess Kay Plum diseased leaves - Ask Extension
We planted a Princess KayPlum this past spring. We’ve kept it well-watered, but it is showing signs of disease. Several leaves have numerous lacy ho...
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Princess Kay Plum diseased leaves #878062
Asked July 20, 2024, 7:04 PM EDT
We planted a Princess KayPlum this past spring. We’ve kept it well-watered, but it is showing signs of disease. Several leaves have numerous lacy holes in them. We DO have those nasty Japanese beetles in our rose bush, but I haven’t seen any on the new plum. Any ideas what could be happening? Thanks
Larimer County Colorado
Expert Response
Hi Krisann,
Yes, all plums (ornamental and edible) are a host for Japanese beetles and this does look like their feeding injury. They make the leaves look "lacy". They may only be occasionally feeding and finding other plants that are more tasty in your landscape.
Hand picking can be very effective, if you're able to reach most of the leaves. You can also use BeetleGon or BeetleJus (mixed with 4 oz per gallon of water) and spray it on the tree. This might be hard to get good coverage, depending on the size of the tree, but it stops the beetles from feeding and they die of a horrific stomach ache (and prevents them from mating). https://www.gurneys.com/product/beetlejus-for-ornamental-and-vegetable-pests
You would need to reapply this every few days because the product breaks down in UV light.
Or you can just let the beetles take their course. The tree will still survive; it will just look bad for the rest of the season.
Yes, all plums (ornamental and edible) are a host for Japanese beetles and this does look like their feeding injury. They make the leaves look "lacy". They may only be occasionally feeding and finding other plants that are more tasty in your landscape.
Hand picking can be very effective, if you're able to reach most of the leaves. You can also use BeetleGon or BeetleJus (mixed with 4 oz per gallon of water) and spray it on the tree. This might be hard to get good coverage, depending on the size of the tree, but it stops the beetles from feeding and they die of a horrific stomach ache (and prevents them from mating). https://www.gurneys.com/product/beetlejus-for-ornamental-and-vegetable-pests
You would need to reapply this every few days because the product breaks down in UV light.
Or you can just let the beetles take their course. The tree will still survive; it will just look bad for the rest of the season.
Thanks very much for your reply.
I called the nursery where we purchased the tree and they, too, say it’s the dang Japanese Beetle. They are suggesting a Tree & Shrub drench which is mixed with water and poured at the base of the tree. They said that they’ve had success diminishing beetle damage with this drench.
I think we’ll try this first.
Thanks again for your help,
Krisann Corcoran
Hi Krisann,
What product do they recommend and what is the active ingredient? There are some things that can work, but they may harm beneficials, like pollinators, if applied where there are flowering plants below the tree.
The benefit of the BeetleGon/BeetleJus is that it only affects Japanese beetle and other pest insects. It's not harmful to beneficials.
But please proceed with what you feel is best. The soil drench will need to be thoroughly watered in and it will take time for the product to make its way to the leaves of the tree.
What product do they recommend and what is the active ingredient? There are some things that can work, but they may harm beneficials, like pollinators, if applied where there are flowering plants below the tree.
The benefit of the BeetleGon/BeetleJus is that it only affects Japanese beetle and other pest insects. It's not harmful to beneficials.
But please proceed with what you feel is best. The soil drench will need to be thoroughly watered in and it will take time for the product to make its way to the leaves of the tree.
Thanks for the advice!
