Stuff raining down from hickory tree

easyworldjuliaJuly 18, 2013

Our hickory trees are raining tiny pellets. Our deck and outdoor furniture are covered and I have swept a number of times. This "raining" has been going on continuously for days. They've already dropped most (I hope) of their nuts, which was a challenge, and now this! This stuff sounds just like rain coming down.

We've lived here since fall of 2010 and this is the first time we've experienced this.

What the heck is it? And how long does it go on?

Thanks in advance!

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Dave in NoVA • 7a • Northern VA


Sounds like squirrels are feasting on the nuts to me.

That's one reason I removed a large hickory from our yard. Too much debris.

    Bookmark   July 18, 2013 at 12:17PM
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ken_adrian Adrian MI cold Z5

give us a pic.. and we will give you a guess..

otherwise.. your definition of STUFF.. is close enough


    Bookmark   July 18, 2013 at 12:18PM
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rhizo_1 (North AL) zone 7

Agree that we need pictures of the "stuff ". You DON 'T want our imaginations to go to work on your mystery!

    Bookmark   July 18, 2013 at 3:16PM
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Are you seeing any leaves skeletonized or stuck together or a web spanning several of them? The trees are hosts to webworms like the ones on black walnuts. Sometimes they are easier to see if you step back from the tree. You may see a place where the leaves are encased with something that looks like spider webs.

    Bookmark   July 18, 2013 at 3:26PM
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beng(z6 western MD)

Caterpillar frass? (another name for wormsh*t)

    Bookmark   July 18, 2013 at 6:24PM
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Omigod, Beng. It could, indeed be caterpillar frass. I smushed one of the pellets today and it smeared just like velvety poop--a gorgeous, jewel-like green...little tiny turd.

How the heck many caterpillars could be up there? It is coming down fast and furious. I had just hosed off a chair today and stopped to answer a phone call and by the time I got back to the chair 15-20 mins. later, there was a layer of the stuff on it--maybe 100 pellets.

It's getting dark now, but I will take a photo tomorrow. Thanks everybody for you input...

    Bookmark   July 18, 2013 at 8:03PM
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beng(z6 western MD)

gardenspirit, I wouldn't worry unless you see significant defoliation. Hickories are host to quite a few butterfly/moth larvae (which feed quite a few caterpillar-hunters -- birds, wasps, etc).

    Bookmark   July 19, 2013 at 10:57AM
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Yep--I think it must be caterpillar frass. Note the smear of green--that's where I smushed one. I must admit, till I took this photo, I didn't even notice all the leaf litter along with it. There must be millions of caterpillars but the tree looks fine from what I can see. I think they may be so high up in the tree that I can't tell from looking at the leaves closest to the ground that anything is going on.

The "rain" of frass is continuous. The deck was just swept and washed yesterday afternoon and it is already covered in the areas beneath the hickory tree. Very annoying, but worse would be if the tree is being decimated. Any idea how long this could go on??? The deck needs to be sealed but no way to do it till this is over with...

    Bookmark   July 19, 2013 at 2:32PM
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beng(z6 western MD)

Yes, frass. Good fertilizer, at least (running away)...

Can't last forever, but you're right -- no sealing until it stops. Hopefully the worm-eaters will put a dent in the production. Hickory Horned Devil?

Here is a link that might be useful: Hickory_Horned_Devil

    Bookmark   July 20, 2013 at 9:05AM
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saccharum(z9 FL)

That does look like caterpillar frass. There are some species that like hickory in particular and can cause heavy defoliation, such as the walnut caterpillar. Even when they completely defoliate a tree, it usually recovers with no major trouble.

It can be hard to say how long it will go on, though. If it's the walnut caterpillar, they often have two generations per year in your range, and the second generation (which emerges around late July) tends to be the worse one. Other species may only have one generation per year, so you might be seeing the last of it. See if you can spot any wandering caterpillars.

    Bookmark   July 20, 2013 at 9:08AM
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Well, it is that time of year for walnut caterpillars and yellow-necked caterpillars. They're voracious little buggers, feasting in huge clusters. I caught them defoliating a smoketree last week, but it was small enough to treat with a sprayer. Bt worked wonders. Now I am keeping a close eye on the crabapples because those are usually the ones they hit first.

It's amazing how much frass caterpillars can generate. I saved about a dozen tomato hornworms last year for a master gardener who pupates them for school science classes. Overnight, the box they were in was deep in doodoo and I had to clean it out. I guess if they have to live in it very long, they die.

    Bookmark   July 20, 2013 at 9:46AM
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Caterpillars = bird food.

Perfect for this time of year when chicks are in the nest.

And I agree with the free fertilizer. The tree will be fine, no need to bring out the pesticides.

    Bookmark   July 20, 2013 at 5:44PM
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esh, the problem with the webworms that thrive on Juglans and Carya is that only a few species of birds will tackle the webs. I think Ovenbirds are one. If you don't have them around, the webs protect the caterpillars. The best defense is the Nuthatches and Chickadees that eat the eggs laid in the cracks of the bark.

    Bookmark   July 20, 2013 at 7:29PM
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If the birds can't get to the web and the caterpillars get to stay, does their activity kill the tree?

Is there some reason - besides aesthetics - that a homeowner can't let nature take its course? Native tree, native bug, native ecosystem ....

    Bookmark   July 20, 2013 at 7:47PM
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saccharum(z9 FL)

The vast majority of the time, it's not a serious problem for the tree. Now, if they were to completely defoliate it for two years in a row, I might start to worry about the third. But that's not common; natural enemies (predators, parasitoids, and pathogens) generally knock the population down.

My bet is that it's not webworms in this case. With that much frass, you'd expect the nests to be pretty obvious.

    Bookmark   July 20, 2013 at 10:00PM
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Walnut caterpillars don't create webs. They just cluster in hordes on branches and defoliate them very quickly. Birds don't get rid of them either, at least not in my experience. We nearly had two bald crabapple trees a few years ago.

I tried blasting them off with a strong spray of water, like you'd do with sawfly larvae. A half hour later, they were marching back up the trunk -- thousands of them. It was like a Hitchcock movie.

So I got out the Bt and nailed them.

If you noticed your trees had mobs like this, you might want to deal with them too...

Here is a link that might be useful: Walnut Caterpillars

    Bookmark   July 20, 2013 at 10:07PM
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I would let them be. One of my blueberries was just completely defoliated and I watched them do it over a period of 4-5 days.

To me, it's all part of the natural process. I'm sure the birds get some. I happen to think that as gardeners we have a role to play in supporting the environment. We have the plants in our yard but they don't belong to us. They are part of a bigger community. Our attempts to control nature appear to be doing more harm than good when you look at the bigger picture. And sometimes we don't even know the end result of our actions.

    Bookmark   July 20, 2013 at 10:41PM
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The reason I speculated about the webworms is that they are not really noticeable unless the webs are close to the ground. If you back up and look at the tree from a distance, and you know what to look for, they can be seen. The walnut worms often fall under the tree, and if you have 3 masses, you will find 100 worms over the course of time. They climb back up the tree, but for a time you will find several individuals under the branches. The OP said nothing about finding any worms at all, so I am assuming none are falling.

esh, I have watched bagworms since moving to PA some 30 years ago. Like many insects, they come in cycles, with some years having plagues, and some years having few. In this area, a substantial portion of the tree cover is J. nigra, and a lot of the old farmsteads have J. regia near them. Hickories are not as common, but not rare.

There seems to be a feedback loop between J. nigra and the webworms. The years the worms are bad, the leaves are shed earlier, and the shedding starts not long after the webs get going. The defoliation is not caused by the worms eating the leaves, but the tree actually seems to try to starve the worms by losing its leaves. I'm not sure that that is possible, but from my amateur observations, it seems to happen.

When I first moved here, one of the 3 trees was a J. nigra, and it also lost the leaves in Sept. (Black Locust and Cherry were the other 2) I planted other trees and shrubs (probably in the neighborhood of 150-200 species trees / shrubs), and the birds showed up. When I started, the most common birds I saw were pigeons, house sparrows and starlings. Now I rarely see those, but many other species have appeared. I noticed that when nuthatches (we call them treecreepers) and chickadees started living here, my webworm problem was cut by 75%. These 2 bird species seem to spend an inordinate amount of time examining the bark of the walnut where webworm eggs (and other leaf predators) hide through the winter.

The last few years have seen my tree stay green until the frost, which was something I had never seen before. Trees near town don't share this characteristic, and after the leaves fall, the trees are decorated with grey hanging remains of the nest, with shed skin and frass weighing them down. Sometimes they persist through the winter, the webs holding them tight to the bark.

Enemies of the webworms besides the birds? Hurricanes. The years we get a good blow from those winds (every couple of years), a good number of the branches that host the worms are knocked down. It is not uncommon to walk under a walnut after a hurricane and see the ground covered in webs. After they are knocked down en masse, they make their home on the ground, but the grass doesn't support webworms,

Before people who go through real hurricanes jump on me, let me say that what we get are winds of 45-50 mph, not hurricanes force winds, but winds from a hurricane. The storms are almost always below hurricane force when the hit Penna., but we get sustained 40-50mph for several hours. Enough to knock the webworms twigs out of the trees.

    Bookmark   July 21, 2013 at 7:24AM
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saccharum(z9 FL)

Very interesting observations, Dzitmoidonc!

    Bookmark   July 21, 2013 at 9:01AM
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esh, people are learning. But, there will always be those who think their trees trump everything. (see recent EAB post >>> honey bees are toxic to Imidicloprid and Dinotofuran, not to mention associated soil run-off possibilities) And there are people who are so paranoid of insects-catapillers et al, that they're willing to cut down the tree ( large healthy trees) to rid their world of insects. I've met them.

    Bookmark   July 21, 2013 at 9:37AM
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Yep. They're walnut caterpillars. They started falling out of the trees day before yesterday (till then, we didn't see a one) and they match the photo at the link you posted, MulchMama (thanks!).

No interest in poisoning them. I have confidence that the ecosystem of our woods is healthy. I'm not picking up stress from the trees and my sense is that they'll be fine.

My only issue in the present is how much of a mess they're making.These wooly boogers are giving new definition to the term "poop deck."

IS it good fertilizer?????

Thanks for everyone's input!

This post was edited by gardenspirit on Mon, Jul 22, 13 at 1:03

    Bookmark   July 22, 2013 at 12:56AM
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