Herbicide Damage?

richie

Hi everyone

I'd like to get people opinion who are familiar with herbicide damage.

Location: Central florida
Trees : Laurel oak
Background:
Local water board recently carried out engineering work from the other side of a canal adjacent to a homeowner. The water level of the canal has been lowered, the canal dredged and Brazillian pepper sprayed on the opposite side of the canal by helicopter.
Chemicals used: “Habitat” - active ingredient Imazapyr tank mix with Glyphosate

Helicopter pilot stated that spraying operations occurred on 4th May. Decline symptoms were first noticed by the homeowner on 14th May, =10 days later.

It was noted that the following trees in the area showed no signs of decline:
Bleeding heart tree (Indian Rosewood)?. This tree is positioned next to some of the declining laurel oaks. (tree is in foreground)
Carrotwood tree also appeared to be OK.

Younger laurel oak trees showed browning on outer canopy. The leaves wilted and fell off, leaving behind a bare outer canopy.

The photos show various states of decline after the helicopter was seen passing overhead during a spraying operation. In some of the pics some of the oaks definately have a "frazzled" look to the outer canopy. In some pics this appears to be more on the top of the canopy also.

There is probably no single cause, recent drought no doubt has played a part. I would like to know if the oak trees had accidentally been sprayed from above , could this have been the "tipping point" on the way to death?

Could it be that the younger oaks, and the more prolific tree species were able to deal with a bit a herbicide, but for the older, already stressed oaks, it was just too much? Or are we looking at another cause??

Thanks for your insight!

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Eric Frei

When was the canal water level lowered and by how much?

What about rooting depth of species unaffected if lower water levels is the cause? Shallow rooted species most likely to suffer.

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richie

Hi Eric
In pic #15 you can see in the background along the canal similar trees in good health. (you can also see in the background on the other side of the canal the dead Brazillian Peppers which have been sprayed)

The canal was lowered in March about 2 feet. As you can see there is still water in it. The homeowners love their trees and have a sprinkler system. I don't think its water stress. They have in previous years fertilized them also.
I was told by a Biological scientist that trees in good health can actually be more susceptible to herbicide damage than poor quality trees. This makes sense, thinking about the ways imazapyr and glyphosate block amino acid synthesis in vigorous new growth. This fits the symptoms of the frazzled look of the outer canopy i.e new growth.

I'm hoping arborists on here can tell me if they have seem similar symptoms linked to herbicide damage.

Thanks for any insight that you can give

Eric Frei

Looks like herbicide damage to me, why don't you take samples to a lab and get the proof you need. Take leaves, maybe a core sample .... perhaps ring them and ask what they need.

They're liable for the damage and would have public liability insurance to pay for the damage.

You then get the trees valued and get paid for damages, plus they should pay for any works including removals, stump grinding and replacement planting.

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Victor Lindsay

Send samples to the lab. I use, Tropical Research Lab, 18905 SW 280 street
Homestead, Florida 33031-3314, but you should your local extention office. Once you have prof, then present it to the Local water board. Get soil, root, leaf, and core samples. Additionally, ask the lab what samples you would need and how to send them to thier lab.

DON'T tell them you think the water board did something wrong...this could be very political.

I have seen trees die from using weed and feed on lawns here in the keys.

ArbTrain

Just think about the drift potential from the down draft of a 'chopper..unbelievably stupid application technique from lazy people. As stated above, you will need sample analysis to be sure.

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http://www.arbtrain.com.au