Emerald Ash Borer Treatment

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JHarkness
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Emerald Ash Borer Treatment

Post by JHarkness » Sat Sep 01, 2018 12:36 pm

ENTS,

I have a number of exceptional white ashes on my property, some healthy, some in decline and quite a number long dead. Some of these trees are old growth, a number of them grow in what was once a sheep pasture but were spared as shade trees, several of these ashes are likely over 300 years of age, so they're very ecologically important trees, not to mention they have a very high aesthetic value. I noted some yellowing in the crowns of a few of them a few days ago, so I will be treating a small number of the healthiest trees in the next few weeks.

I have read some very conflicting information on EAB treatment, some people say that almost any tree can be saved, others say that once there is crown decline it's too late to do anything. I'm curious to know from anyone who has done EAB treatment before how various trees have responded to treatment. Also, is there a specific time of year when treatment is most effective, that said, would early September be too late for treatment in New York State, would I be better off waiting until next summer?

Also, my oldest white ash, roughly 10' in circumference and 130' tall, appeared dead this spring, it didn't leaf out at all when the other ashes did, but it started to leaf out and grow new branches from a number of it's larger limbs towards the end of May, it has grown quite a few 2-3' long branches over the summer and they all appear to be in good health, as of today it doesn't have any sign of die off, all the foliage is very healthy. Less than 10% of it's crown has foliage, but that is a big improvement from this spring when it didn't have any foliage or live twigs. That said, I'm inclined to treat the tree to kill off any of the remaining EAB, fortunately, it's trunk and lower limbs have not been affected at all by the pest, so I'm hopeful that it can be saved. Any thoughts on the matter?

I'm treating with Zylam, a dinotefuran based systemic insecticide, it is marketed especially for EAB treatment and supposedly has good results.

Joshua Harkness
"Be not simply good; be good for something." Henry David Thoreau

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Rand
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Re: Emerald Ash Borer Treatment

Post by Rand » Sat Sep 01, 2018 8:10 pm

JHarkness wrote:Also, my oldest white ash, roughly 10' in circumference and 130' tall, appeared dead this spring, it didn't leaf out at all when the other ashes did, but it started to leaf out and grow new branches from a number of it's larger limbs towards the end of May, it has grown quite a few 2-3' long branches over the summer and they all appear to be in good health, as of today it doesn't have any sign of die off, all the foliage is very healthy. Less than 10% of it's crown has foliage, but that is a big improvement from this spring when it didn't have any foliage or live twigs. That said, I'm inclined to treat the tree to kill off any of the remaining EAB, fortunately, it's trunk and lower limbs have not been affected at all by the pest, so I'm hopeful that it can be saved. Any thoughts on the matter?
There are a couple off older ashes in my neighborhood, that died back from the EAB in 2011, resprouted new suckers low down in the crown and have been hanging in there and even regrowing some since then. I'd give it a shot.

My parents had a bunch of ash trees, ~ 8" dia at the base that they treated for several years, but they started to decline anyway and they gave up. I cut them all down 3 years ago and let the root suckers grow back. They are ~ 2" in diameter now and ~10' tall. So far, so good.

As a general rule, the more ash trees in close proximity, the less likely they were to survive. The green ash was popular to plant in long rows along streets, and just like with the dutch elm, it was a major carnage. Seems like the ash trees in the woods fared the worst. I think I've seen 1 mature ash tree survive in that circumstance, and even that one was right on the edge.

Curiously there is an ash tree that started as a fence row tree in my parents yards, but has survived the plague with hardly a mark on it. It is in a chicken lot, so my pet theory is the birds come into that tree, before they raid the chicken feeders, and take out EAB on the way. That and the fertilizer doesn't hurt.

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JHarkness
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Re: Emerald Ash Borer Treatment

Post by JHarkness » Sat Sep 01, 2018 9:06 pm

Thanks Rand,

I will be treating the tree, any chance to keep it alive is worth taking, it's really a beautiful tree, I don't believe any other tree on my property says "old growth" like it does.

Interesting about your theory on the white ash. I would certainly believe that is true, I've observed here that the oldest ashes on old growth or mature second growth forests, and those near forest edges have the greatest survival rates, essentially where insect-eating bird populations are highest. I've noticed quite a few white-breasted nuthatches hanging out around some of my healthier ashes, so perhaps they're hunting the EAB.

I have noted a number of at least partially resistant ashes here, I checked on one tree today, the purpose being to remeasure it and inspect it for EAB, anyway, it's now 115.7' and shows no sign of EAB whatsoever, a nearby 92' tree, however, is experiencing moderate crown decline and all the other mature ashes at the site are long dead, there is, however a lot of white ash regeneration. My tallest tree got infested with it when it first arrived, it killed many of it's neighbors, but this tree recovered. Pileated woodpecker damage to some of it's upper limbs show how bad it's situation got, it's in much better health now, but it unfortunately has a new infestation and needs to be treated, it's immediate neighbor has absolutely no signs of EAB oddly enough. Two beautiful green ashes and a white ash planted along my driveway got EAB and died very quickly, but one white ash next to them is in perfect health, I thought lost all of my green ash to EAB, but as it turned out a couple seedlings made it and there's now a small green ash forest popping up on the edge of a wetland, one tree is now about 7" in DBH and almost 40' tall, again, in perfect health. I've seen very high regeneration rates following EAB and pretty good survival rates as well, though deer certainly have an impact on their survival.

I feel that there is hope for the species, I highly doubt the claim that we will lose 98% of our eastern ash trees is true, perhaps the mature trees, but on my property at least, if you include the young trees, the population of the ashes has actually gone up since EAB arrived here.
"Be not simply good; be good for something." Henry David Thoreau

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Rand
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Re: Emerald Ash Borer Treatment

Post by Rand » Sun Sep 02, 2018 12:59 am

I've seen very heavy ash regeneration in NW Ohio as well. It is technically classified as elm/ash swamp forest, so the ashes were a very common tree. They do seem to be moderately shade tolerant, and I think the ashes masted pretty heavily before they died, so there are a lot of seedlings beneath all the dead, mature trees. I think it was spring of 2011 when it seemed like every ash tree between Columbus and Findlay died en mass. Once the bark sloughed off, you could see borer galleries engraved on every square inch of the trunk, so there must have been a truly colossal population explosion the year before. I'm guessing at some point there will be another big flare-up to challenge the young trees. It'd be nice to think the native predators will keep it in check, but I'm probably just being hopelessly optimistic.

There is one very old tree in my grandparents woods, that has the very thick old-growth bark that you describe. I'll have to go back and see if it survived to test out your theory of thick bark resisting the bugs. It's a big ~4' dbh stove-pipe with a broken crown. It was probably the tallest tree in that woods at one time.

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JHarkness
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Re: Emerald Ash Borer Treatment

Post by JHarkness » Mon Sep 03, 2018 5:01 pm

Rand,

I'm secretly hoping that the ashes are going to make a big comeback in a few years, what I've seen is that the ash seedlings stay very small beneath their parent trees as they decline, once the parent trees are dead and have opened up light gaps, then the seedlings take off, what I've noticed is that it's very rare to find a sapling large enough for the EAB to infest in a forest that hasn't already lost much of it's mature ash, I'm hoping that a lot of the EAB will lose their food source and die off, I can't imagine that many of them will survive without ash trees to feed on and lay their eggs in, perhaps we will see a comeback.

Joshua
"Be not simply good; be good for something." Henry David Thoreau

DwainSchroeder
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Re: Emerald Ash Borer Treatment

Post by DwainSchroeder » Thu Sep 06, 2018 6:44 pm

After the last of the ash trees here in NW Ohio were dying off, about 5 years ago, I noticed one small ash tree in my woods that still looked healthy. It was about 10" diameter, 40' tall. Other ash trees this size were dead. I doubt if this tree had any special resistance; it was somewhat isolated from other ash and my guess is that it was just temporaily beating the odds and would have been eventually attacked within a year or so.

As somewhat of an academic endevour, I decided to try to save this tree. I applied a systemic chemical to the root zone each spring for three years. Two years ago I stopped the treatment, partly to save the money ($30/year), and secondly with the theory that the borers might now be gone from this area because their food source was gone. The tree is still thriving with no evidence of any attack.

But I am not so optimistic about the future in that I fear the borer will be back. There are zillions of small ash seedlings in the understory of the woods that I visit. (I think of them as arising from the last gasp of the dying old growth ash trees.) As these small seedlings become more mature another borer sweep could occur. Like all of you - I hope not. Maybe a natural agent will arise or one can be developed that will offer a solution. We'll see....

In the meantime I enjoy walking by that surviver. It's a beautiful tree.

Dwain Schroeder

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Rand
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Re: Emerald Ash Borer Treatment

Post by Rand » Sat Sep 08, 2018 6:22 am

Rand wrote:

There is one very old tree in my grandparents woods, that has the very thick old-growth bark that you describe. I'll have to go back and see if it survived to test out your theory of thick bark resisting the bugs. It's a big ~4' dbh stove-pipe with a broken crown. It was probably the tallest tree in that woods at one time.
I visited this tree last weekend. It's been on the ground for years, as most of the bark has sloughed off. I guess there was a reason I kinda overlooked it on my past trips.

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Rand
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Re: Emerald Ash Borer Treatment

Post by Rand » Sat Sep 08, 2018 6:48 am

DwainSchroeder wrote: But I am not so optimistic about the future in that I fear the borer will be back. There are zillions of small ash seedlings in the understory of the woods that I visit. (I think of them as arising from the last gasp of the dying old growth ash trees.) As these small seedlings become more mature another borer sweep could occur. Like all of you - I hope not.
The sprouts in my parent's yard have picked up a few EAB dings, so the pest is still lurking about, even if the population is way, way down. My Dad grudgingly admits that the 'second chance' has worked pretty well so far, but that there won't be a third.
Maybe a natural agent will arise or one can be developed that will offer a solution. We'll see....

Dwain Schroeder
Here's a post about biological EAB controls from a few years ago:

http://ents-bbs-org.nativetreesociety.o ... bbd#p33602

DwainSchroeder
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Re: Emerald Ash Borer Treatment

Post by DwainSchroeder » Tue Sep 18, 2018 6:00 pm

Rand,

Thanks for the information links about EAB natural control. It looks like there is some promising work going on.

I have often wondered about the fate of the ash seedlings presently growing in this area. (The mature ash are of course all dead.) My understanding and observation is that EAB don't attack small trees so if these small ash trees get mature enough to drop seeds (maybe in 20 years???) before the trees get infected, then maybe another generation of ash seedlings will go on, and then on again. But I would guess that each successive generation would get more sparse owing to increased shading competition from other tree species and just general loss of vigor and population. But maybe one of those natural predators will make this question moot.

Thanks,
Dwain

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Rand
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Re: Emerald Ash Borer Treatment

Post by Rand » Tue Sep 18, 2018 11:47 pm

DwainSchroeder wrote:Rand,

Thanks for the information links about EAB natural control. It looks like there is some promising work going on.

I have often wondered about the fate of the ash seedlings presently growing in this area. (The mature ash are of course all dead.) My understanding and observation is that EAB don't attack small trees
I don't think that is technically true. I suggested this idea to a state forester even before the big die-off, and he said it was known that the EAB can attack small saplings. There are two 2" dia saplings in my parents' yard that have dead spots in the trunk from EAB galleries. I think the case is that the population is just really low right now. Here on my side of Columbus there are a scattering of ragged looking survivors in the suburbs that are slowly growing back.
so if these small ash trees get mature enough to drop seeds (maybe in 20 years???) before the trees get infected, then maybe another generation of ash seedlings will go on, and then on again. But I would guess that each successive generation would get more sparse owing to increased shading competition from other tree species and just general loss of vigor and population. But maybe one of those natural predators will make this question moot.

Thanks,
Dwain
Yeah, I'm not sure how this is going to play out either. They do seem to be moderately shade tolerant though, and reproduce well in small openings created by selective cutting. Long term I'm more concerned about oak reproduction on the wetter sites in NW Ohio, as I see very few of them that can get started in these small openings. Regeneration seems to be dominated by ash, elm, basswood and sugar maple. And with the first two facing an early death, that doesn't leave much diversity.

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