I feel absolutely no guilt keeping a few caterpillars from becoming butterflies

Published 8:42 am Friday, March 20, 2020

I didn’t get to wait until spring officially arrived before taking on the earliest of spring insects I deal with every year.

There are two bugs that made me a believer in not waiting until I see them to take steps to hold down their upcoming damage.

One is the canna caterpillar and the other is the plum curculio that is more of a problem on peaches than plums. In both cases, there is no doubt the critters are going to be here every year. And there is no doubt that waiting until I see the actual insects to do something means I am too late. The damage is done by then.

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I’ve rarely seen the tiny female plum curculios that lay eggs just beneath the skin of new peachettes. But if I didn’t start spraying early and often, nearly every peach would grow and ripen with a worm inside. I’ve said many times over the years that a peach tree is the biggest pain in a gardener’s posterior because of insect and disease pests.

But you can’t buy a truly ripe peach at a store because a peach doesn’t ripen off the tree and ripe ones don’t hold up for shipping. So I start spraying as soon blooms are pollinated.

The caterpillars that cause canna leaves to unfurl with holes showing and which continue to wrap themselves in twisted leaves as they eat are larva of a small, rather plain-looking butterfly species.

I feel no guilt about preventing a few caterpillars from becoming homely butterflies. The problem with getting control of the caterpillars before they uglify the cannas is they are pretty much protected down in the whorl of leaves. Thus canna caterpillars are the only insects for which I use a soil-applied, granular systemic insecticide.

Water carries the insecticide through the roots to the leaves so the bugs get a dose as soon as they take a bite. Based on rainfall or watering, it takes time to get the insecticide up to the leaves, so applying such a product after leaves unfurl full of holes is the day-late, dollar-short routine.

When using a soil-applied, systemic insecticide for the first time, don’t even entertain a curiosity about using such on food plants like vegetables and fruits. No, there are no such insecticides for our food-growing plants.

Most of our other common plant insects can be handled by observation and treating if and when the bugs get near damaging levels. It does take close and regular inspections for some of them like aphids and spider mites, but gardeners need to be checking plants often anyway.

And for a lot of insects, there are organic, biological and conventional chemical choices. But some listed options are questionable. One current organic remedy for curculios is the same as I read 35 years ago: spread bed sheets on the ground beneath peach trees, beat on the limbs, quickly gather up the sheets and dispose of the bugs. It didn’t say how many days in a row.


Terry Rector writes for the Warren County Soil and Water Conservation District.