Diagnosis: Probably herbicide injury (second time this week) This time: IMPRELIS!

Mrs. B from Royersford called yesterday concerned about her douglas fir trees. She told me one was turning brown at the top, and also the white spruces didn’t look so good. She reminded me that I had sprayed them to control a disease problem a few years ago and was wondering if maybe they had the same problem again or maybe bagworms or something. As soon as I saw them I knew that it was neither of those problems. I explained to her that similar symptoms on different species most likely indicated an abiotic problem, not a disease or a pest, which are usually host- specific. The way the young growth of the doug firs was wilted and killed made me think of herbicide poisoning. In fact, it looked exactly like the symptoms of poisoning from Imprelis, Dupont’s new turf weedkiller.

Douglas fir - Imprelis injury

Douglas fir – Imprelis injury

White spruce - Imprelis injury

White spruce – Imprelis injury

Douglas fir - Imprelis injury

Douglas fir – Imprelis injury

 

Douglas fir - Imprelis injury

Douglas fir – Imprelis injury

The story of Imprelis is a really interesting one, and it is soon going to be big news. Heres the condensed version. Last year Dupont introduced this completely new product with great expectations for its potential. It is extremely low in toxicity to humans and at the same time very effective at controlling broadleaf weeds. So it was immediately popular. But this spring, all over the country cases of dying evergreen trees were being reported, mostly white pines and Norway spruce. And it wasn’t long before it became evident that there was a connection between these injured trees and Imprelis herbicide . The thing that these mysterious cases all had in common was the turf around them had been treated with Imprelis. Dupont initially did not acknowledge responsibility, but just last week they pulled Imprelis from the market. I’ll try to get some of the news articles and Dupont’s statements up here soon.

Anyway back to Mrs. B’s trees. I told her my suspicion. She said “but I have a lawn company that just uses organic treatments.” I responded; “maybe so, but there are NO weeds in your lawn. There is no organic weed control that is truly that effective.” I suggested she call the lawn company and ask them what chemicals had been applied. And told her to google “Imprelis.”

Then I left to go visit another client. Before I even got to Limerick, Mrs. B called me to tell me what happened. She had called the lawn company as soon as I left, and they were completely upfront with her. They acknowledged that they had applied Imprelis on June 13. And they now know there is a big problem., and want her continued feedback.

Do you note the irony here? A person thinks they’re being environmentally responsible by choosing the supposedly “organic” option, and this is what happens to them. Drag.

Diagnosis: Probably herbicide injury

On Monday I checked on an ash tree for a client in East Greenville.  She said the leaves appeared to be wilting.

The ash tree

The ash tree

Well, they didn’t really look wilted to me, but they were distorted and curled.

The curled ash leaves

The curled ash leaves

The curled ash leavesThe curled ash leaves
I unrolled some of them to check for pests; none were there.  No aphids, no silk from any caterpillars.  There was an outdoor fireplace nearby.  But if that were the cause, I would expect the symptoms to be the worst closest to where the fire would have been.

 

 

 

 

 

Next to the ash is a young saucer magnolia.  Last year I treated it for a bad magnolia scale infestation; so while I was there, I examined it.  The scale was gone, but it too had a lot of distorted leaves.  And, like the ash, no pests, no aphids.

The magnolia

The magnolia

When trees of different species have the same symptoms, it’s probably abiotic – not a disease or a pest.  Pests and diseases are usually host-specific.
Near the ash and magnolia is a Kousa dogwood.  Same thing – distorted leaves.  And the type of distortion that is generally seen with certain herbicide poisoning.  That is, elongated parallel veins and interveinal chlerosis.

Kousa dogwood

Kousa dogwood

Kousa dogwood leaves

Kousa dogwood leaves

There is another ash a few hundred feet away also at the rear of the backyard.  It has the same symptoms, only even more pronounced.

The other ash

The other ash

Well, all the symptoms are consistent with the effect of herbicides, but the client’s lawn is definitely not weed free.  If that is the cause, the likely reason is spray drift from the hay field adjacent to the yard.  The field looks very clean, hardly any weeds.

The hay field

The hay field

So that is my theory – all the trees were damaged by herbicide drift from the application to the hay field.  And that is what I told the client.  And she confirmed that the field was recently sprayed.  She will ask the farmer to be more careful in the future.