I am having a problem with evergreen bagworms around the city's (Huntsville) baseball fields on eastern redcedar and baldcypress. On a few of the trees, it has gotten to where they just have "tufts" of needles at the tips of the branches.

I may have a problem with each of the solutions:

Bt - The city doesn't have a sprayer that will reach the tops of the trees and I don't want to lug a pump sprayer up a ladder (it would be a trombone sprayer of course ).

Trichogramma - On a typical day, it is extremely windy. The park in and of itself is very large. It is next to the airport, several large Prison pastures, and I-45 all of which are quite open. The wind is present enought to affect the trees overall shape and lean (not to the point of bristlecone pine or coastal live oaks, but we may get there yet). Will this wind cause problems with using the wasp as control?

All comments welcome. This is the fist time I have had a need for either of these products, so I don't have any hands-on.

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May the forest be with you.

Plain old paper wasps will eat a ton of caterpillars. If you know of anyone with a wasp eradication program, they are hurting themselves more than they know.

It's interesting to see trees affected by tent caterpillars in the neighborhood. You'll drive down the road and all the trees in one area are full of tents. Then you'll pass a few houses with no tents at all. That pattern alternates. I know I live in one of the clean areas and I have paper wasps everywhere I can get them.

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David Hall
Moderator
Dirt Doctor Lawns Forum

Wasps can knock out a caterpillar population but they have to be there and get to the caterpillars. I have seen them take out a huge tent caterpillar nest in an hour and a half...not a single resident left. They are great allies but not necessarily dependable or good in cold weather.

Since it is still cool, the wasps aren't around much yet, so Bt is probably your best defense right now. Spray it as high as you can get it, with a little molasses, and then do it again according to the directions on the bottle. Make sure you do this in the evening; UV rays kill the bacteria and render it useless. I have seen sprayers just for trees that will shoot up 30 feet at Lowe's stores. It depends on the water pressure more than anything else.

There are a couple of other organic controls that would work in a pinch but really Bt is the best choice. I doubt your friends would appreciate you spraying garlic pepper tea up in the air!

Kateh

We have 20 ac. E. of Bonham, but live in Plano. Last April the infestation of worms stripped nearly all cedar elms and a lot of other trees. They did come back except for a couple. We noticed yesterday the thin spider-web-like strands that these worms make & are worried that the whole cycle is happening again! We have no clue if the beneficial wasps will work again in due time or if we didn't get enough out there last year & should put out more??? HELP!
Plano Patty

Check out the following:

http://www.dirtdoctor.com/radio.php?id=317

http://www.dirtdoctor.com/dallasnews.php
(Scroll down to the very last question on the page).

http://www.dirtdoctor.com/view_question.php?id=217

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Nadine Bielling
Moderator
Gardener Exchange Forum

The Laws of Ecology:
"All things are interconnected. Everything goes somewhere. There's no such thing as a free lunch. Nature bats last." --Ernest Callenbach

The trichogramma wasps only work on the eggs. If the moth is able to lay the caterpillar eggs in the tree, then the tiny wasps should be able to find them.

I've read and it makes sense that if you're buying wasps, it is best to get them earlier than you think you need them so that they can start multiplying. You can never afford to buy as many as you need, but they will multiply by themselves if you get them out early enough. Each generation multiplies by a factor of 100.

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David Hall
Moderator
Dirt Doctor Lawns Forum

Yup! Do the wasps now. Save the BT for when the leaves are there. It only gets the caterpillers when they eat those leaves... it does not kill them directly.

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...Bill