For Release September 5, 2004

Don't Confuse Cause and Effect

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

Everyone is familiar with the concept of cause and effect. You drop a hammer on your foot, it's going to hurt. You throw a pebble in the water, it'll make a splash and ripples will go out in all directions. An effect created by an obvious cause. Nature is full of causes and effects. Unfortunately, we often get them confused and assume that the effect is actually the cause.

How many times have you heard the folk lore that if the squirrels are busy burying acorns its going to be a hard winter? The assumption is that the squirrels "know" that it's going to be a hard winter so they are busy caching extra food. There is a cause and effect involved, but let's get it in the right order. Squirrels will busily prepare for winter. They will keep burying nuts as long as there are nuts to bury. If the squirrels are busy burying acorns, it means that it was a good year for acorn production. Which may, or may not mean it's going to be a hard winter.

Or consider our friend the woolly bear caterpillar. It's ability to forecast winter weather is legendary. The caterpillar is covered with coarse stiff hairs, these hairs being black at each end of the caterpillar and brown in the middle. Folklore states that the wider the brown segment, the milder will be the winter. Here we have a cause, the width of the brown band, and an effect, the severity of the winter. Or do we say an effect and then a cause?

In reality, can we have an effect before we have a cause? I doubt it! What if we saw an all black woolly bear? Does it indicate a very brutal winter approaching. Or does it simply mean that we have a caterpillar who is genetically programmed to be all black? Sorry folks, but the truth is that the amount of brown and black on the true woolly bear is a function of diet and environment.

Wide black bands signal a caterpillar that lived in a moist environment and wide brown, a dry environment. Subsequently, the food sources in each would be somewhat different as well. As for the all black version, it's a different species. There are about three closely related species in this group of moths, the Banded Woollybear, the Saltmarsh Caterpillar and the Giant Leopard Moth. The larvae are black and brown banded, all yellow and all black, respectively.

One misplaced cause and effect that I face on a regular basis has to do with lawns and weeds. A plant will be brought into my office with the pronouncement that it is taking over the lawn, killing the grass and it must be killed. Very few weeds can actually take over a lawn and kill the grass. The sudden emergence of the weed is a result of a lawn that became thin and weak. Most plants that we call weeds need an opportunity to get started in a yard. They often need bare soil and space. Once given that, they will grow rapidly. But they did not kill the grass. The grass dying gave the weed a chance to become established.

Weeds in a yard, even crabgrass, aren't a problem, they are a symptom. The problem is a lawn that is not aggressive and competitive. Now is the time of year to fix that. Fertilize your lawn and overseed thin spots. Make sure you are mowing the grass as tall as you can, usually three to three and a half inches. Fall is the time of year to really make a difference. The cause, a thick aggressive lawn. The effect, few if any weeds. Cause and effect, keep 'em straight!

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