Home Grown 271 September 15, 2004

There are some terrible insects in my walnut, mulberry and other trees. They are making bags over the ends of the branches. I talked to some neighbors and one said they were gypsy moths, another said these were tent caterpillars and another thought they were bagworms. So what are they and are they dangerous? How do I tell these insects apart?

First, the good part. These are Fall Webworms and only rate as less than 1 on the Richter scale of Pest Problems. Their damage is cosmetic and not harmful to the trees and they do feed on a big bunch of them. If you cut out or burn out these guys, you will have done one hundred percent more damage than they ever will. If you were able to remove every single one from your property, you will still see more next year. These guys came from some place off your property originally and can easily come back from some other location. They appear in late summer and early fall and their web always includes the ends of the branches with the leaves. They eat season-end leaves and don't touch next year's buds so the tree isn't weakened. There are several ways of sorting out the other leaf eaters. The first way is with a calendar. All these caterpillars show up at very specific times of the year. They don't get to take earlier or later appointments. The second way is by what kinds of trees they are in. Everybody has a menu preference and don't change. The third way will be by visual recognition. Do they have some kind of a web-like structure and what does it look like? Eastern Tent Caterpillars show up the earliest in the spring. They get into apple, crabapple, peach and plum trees. Occasionally, they are found in other kinds of trees. The web that they build is where two branches meet. They build a web from wood to wood. No leaves are included. Gypsy moths will hatch in late April to the middle of May. Their damage is visible in June and early July. They build no webs. They can feed on over three hundred kinds of trees and shrubs but oak, poplar and maples with maroon leaves all year are real taste treats. Bagworms are rarely found in Michigan and if they were, they would build a bag about two inches in length that hangs off the bottom of a twig. The bag is interwoven with bits of leaves, twigs and silk. They are a mid summer visitor. Of your four larval munchers, the only one to drum up any fear and loathing are gypsy moths. Currently, southern Michigan doesn't have a whole lot of them so be calm; the end isn't near.



I have a couple of cats that stay in the house all the time. I don't want to get them rabies shots because they never go out and come in contact with anything. My husband says I should get them the shots but he can't give me a real reason. Am I right?

I hope there wasn't money bet on this one. If you need one reason it is spelled b-a-t. There are always a small number of bats with rabies. This doesn't grow into an epidemic and wipe out the bat herd but it is always present. Bats can live in attics and accidentally get downstairs. Bats can accidentally fall down a chimney or get around a screen. Cats, being the legendary predators that they are, are on seek-and-destroy missions with bats in the house. There is no way to look at a bat and tell if it has rabies. That's why you should never handle a bat without heavy leather gloves. Once your king of the kitty-beasts kills the bat, you have no way of knowing whether the bat bit the cat. To save yourself any misery about not protecting you little fluffy friends, get all the shots the cat needs to prevent disease. Talk to your veterinarian.

Gretchen Voyle, MSU Extension-Livingston County Horticulture
Agent 517/546-3950

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