As Dallas entomologist Mike Merchant predicted, a second generation of webworms has hatched to defoliate not only our trees but also our ornamental annuals, perennials and shrubs.
Dr. Merchant, with the Texas Agricultural Extension Service, theorized in June that the webworms' early seasonal appearance could mean a second and even a third generation of the pests could wreak considerable damage before a frost sends them into dormancy.
"They're called fall webworms because, most years, that's when they are at their worst," says Dr. Merchant.
His own sweet gum tree is full of the grayish-white webs and skeletonized leaves that are evidence of the caterpillar infestation.
Their webs are high above my back garden in huge old pecans and elms. But they also are eating the leaves of my dwarf Japanese maples, brugmansias, Confederate roses and other ornamental plants.
I eradicated many of the millions of snails and sowbugs that were my garden's nemesis earlier in the season by applying Sluggo Plus between rain showers, but now I have to mount another campaign against the innocuous-looking whiskery, white caterpillars.
The good news is that, unlike the infestations in my trees, I can reach the webworms eating my flowering plants. I pluck them off and throw them into the fish pond or the rolling trash bin, whichever is handy. I'd rather the garden chickens would eat them, but they are leery of the long, white filaments covering the caterpillars' bodies. No, the hens choose my hard-working earthworms in the compost heap.
"Webworms prefer pecans and mulberries, but they have a pretty wide host range," says Dr. Merchant. "This year there are so many of them that they're eating just about anything."
He sprayed spinosad, an organic product, on his sweet gum about two weeks ago, but without breaking open the webs first, to see what effect the product would have.
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"I don't think I got very good mortality on those caterpillars," he says.
Pyrethroid insecticides are an effective killer, he says, if they penetrate the webs, but they also will kill beneficial insects, such as bees, and butterflies. A hose-end sprayer, he points out, will not reach the treetops anyway.
"For most people, the best thing to do is grin and bear it," recommends the entomologist. "If a tree is defoliated this time of year, it is not going to die, if it is otherwise healthy.
"Figure this is a bad year for caterpillars, and move on."