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Large Willow does not look healthy

Posted: Tue Aug 12, 2014 11:40 am
by moormansd
I have a very large (about 30 inch diameter) Willow next to my creek. I have noticed over the last couple of years that it is not looking very healthy compared to other Willow’s in my town. The leaves have a yellow-green color rather than the dark green I see on other trees. It seems to have dropped more leaves throughout this summer than I recall during previous years.

I do not know if it is related, but I noticed that many of the leaves (at least at ground level) have been munched on and upon closer inspection found a good number of small black beetle like bugs. Not sure if this is a disease or insect issue. I would love to able to bring this tree back to the beautiful specimen it used to be. The leaf is about 3 inches long and half an inch wide (to help give you an idea of the size of the bug).

Please see attached photo.

Thanks, Shawn
Willow Tree.jpg
Leaf and bug
Willow Tree.jpg (10.96 KiB) Viewed 1255 times

Re: Large Willow does not look healthy

Posted: Fri Aug 15, 2014 5:01 pm
by lorijones
The beetle looks like the Imported Willow Leaf Beetle but unless you have a heavy infestation, this is probably not the cause of the yellowing of the leaves. The adult beetles chew holes and notches in the leaves and the larvae feed on the tissue between the veins leaving the leaves skeletonized and brown. A heavy infestation can leave the whole tree looking brown and dead while a lighter infestation can cause the tree to just look slightly brown due to partial skeletonization of the leaves by the larvae. Check the dropped leaves to see if they have been skeletonized by the larvae of this beetle. If they are just yellow, the beetle may not be the cause of the tree's decline. There are chemical controls for this beetle but the problem is that the tree is close to a waterway and most of the control products are very toxic to aquatic organisms and should not be sprayed or used near bodies of water.
The tree could also have a vascular disease. There is no good control except to feed the tree with Espoma Tree-tone (15 lbs per 100 square feet of root area) and keep the tree well watered.

If this tree is very important to you, I would strongly suggest that you contact Bartlett Tree Experts ( and have them come out to assess the tree. They should be able to diagnose the problem and recommend a course of action. I think this would be the best idea.

Re: Large Willow does not look healthy

Posted: Wed Aug 20, 2014 8:49 am
by moormansd
Thanks for the quidance. The leaves on the ground are NOT showing signs of being eaten by the bug, so it does not appear to be a heavy infestation. I did notice that one particular 3" diameter branch and it's descendants all have very yellow leaves as apposed to the lighter green of the rest of the tree. I have a call in to the arborist and will report back on their findings. Thanks again.

Re: Large Willow does not look healthy

Posted: Wed Aug 20, 2014 10:05 am
by lorijones
Oh good! I'm glad you decided to consult an arborist. Thanks for keeping me posted. Hopefully they can recommend something to help your tree and get it healthy again.

Re: Large Willow does not look healthy

Posted: Wed Sep 10, 2014 5:27 pm
by moormansd
Arborist confirmed beetle, but states condition mostly due to a fungus. Recommended injecting for beetle but holding off on fungicide and instead injecting fertilizer in the hopes that the tree will be strong enough in the Spring to fight the fungus on its own. Did not seem concerned about the pesticide and nearby creek due to the proposed injection application method. Unfortunately the quote for all this is way out of my budget. I will have to skip the pesticide but am hoping I can takle the fertilization on my own (I am fairly handy). Breadth of tree corresonds to about 2,000 sq ft on the ground. Can you provide some guidance on the fertilizer type, amount and application. I know the typical fertilizer contains nitrogen-phosphorus-potassium, but when they fertilize sod in our area they skip either phosphorus or potassium (I need to confirm which). I suspect it is because we have enough of it in our soil. Regarding watering, that could be a challenge as the tree is at least 1000 yards from the nearest faucet. I assume I could rig a small pump to pull from the creek that is 20 ft away, but then I would need to figure out how to get power down there ;-).

Re: Large Willow does not look healthy

Posted: Thu Sep 11, 2014 5:14 pm
by lorijones
Fertilizing trees, shrubs and perennials is MUCH different than fertilizing the lawn. Grass is a nitrogen hog and thus turf fertilizers are high in nitrogen. Recently they have removed the phosphorus (P - the 2nd number in the N-P-K fertilizer analysis) from most of the lawn fertilizers.
You would not want to fertilize your trees and shrubs with a lawn fertilizer. We would recommend using Espoma Tree-tone to fertilize your willow. There are detailed application instructions on the bag but here is Espoma's recommendation:

Feeding Established Trees
Trees should be fed twice each year: in early Spring before growth starts and in Fall after leaves drop but before ground freezes. Use the following rates:

Your tree is over 6 inches in trunk diameter so according to the label you should use 6 lbs. per inch of trunk diameter

Feed large trees (over 6" trunk diameter) as follows:
  • 1. Make a series of 3 inch wide holes, 12 -18 inches deep, 2-3 feet apart, under the drip line of the tree (outer edges of branches).
    2. Divide the Tree-tone evenly and pour into holes.
    3. Backfill holes with soil and water thoroughly.
Getting water to your tree is obviously going to be a problem.