Looking for preventive treatment. I had to burn
a few out recently or they would have killed the
trees.

Reply to post by Tom, on September 05, 2000 at 19:54:35:

Probibly fall web worm, but still nasty. Tent cat is a spring occurance, and prefer rosaceae family. any contact insecticide labeled bor catapillars will work I recomcend stuff like sevin because it breaks down fast and is not persistant (or vise versa).

as for preventative, you need to get a good drench to the twigs to kill the egg mass, not real practical. Best bet is a localized application to control active pest, monitor and follow up if needed.

Follow the lable because the label is the law!

Reply to post by Tom, on September 05, 2000 at 19:54:35:

You are probably seeing a species of webworm on the ash trees, as John suggested. These form fine silky webs around the leaves at the end of branches.

Although it looks horrible, they will not likely kill the trees, even if they are completely defoliated. Burning them can cause much more harm to the tree, and is dangerous, too. Leaves, twigs and next-year's buds will not take the heat.

There are many products that can be used for control, if it is deemed necessary. I suggest you contact your local Cooperative Extension office or a qualified local arborist to get a positive identification of the pest and for treatment recommendations for your area.

The International Society of Arboriculture maintains a current list of ISA Certified Arborists. The searchable list can be accessed at the ISA Web site, at:
http://www.isa-arbor.com

Reply to post by Tom, on September 05, 2000 at 19:54:35:

The easyist way you can elliminate the problem with the web worm is to have a reptible tree care specialist (preferably a certified Arborist) to spray the tree in the spring as early as possible with a Systemic insecticide or have the tree injected as early in the spring with microinjections which is a injector that is injected into the tree around the tree trunk about every 6 inches. This is your best bet because it is guaranteed for the entire growing season where as spraying is only good for about a month with a good Systemic and then you would have to repeat it. Good Luck