Pest control in the Kentucky vegetable garden sometimes seems like a Cold War-era arms race. Just when you get ahead of one problem, another ruby-throated ninja stem annihilator (don’t worry ... this is a made-up pest!) emerges on the horizon.

Sometimes it seems that it would be easier to just chuck the whole thing and take up tennis for the remainder of the summer. But other times there emerges a reminder that simple and low tech can provide some answers. Such is the case with kaolin clay.

Use of kaolin clay and other mineral elements has been practiced for more than 2,000 years. Taking a nod from observations of animals taking dust baths to rid themselves of insect pests, both the ancient Chinese and Egyptians used various minerals and dusts as crop protectants.

Kaolin clay is a naturally occurring soil mineral that is harvested, pulverized and packaged for application to fruit and vegetable crops. It repels, irritates, discourages and annoys a wide range of insects and also reduces fungal disease.

In some instances it has been shown to help reduce sunburn on crops and in areas of intense sun (particularly in the Southwest) has been shown to result in a net increase in crop photosynthesis. Sounds kinda like aspirin for the garden. And it just may be that good.

For the last several weeks, Maggie Dana, a Middlebury College student participating in Louisville’s FoodWorks internship program, has been working at Yew Dell Botanical Gardens. She is interested in food production and organic gardening and has been working with kaolin clay this summer with excellent results.

When asked about the benefits of the clay, Dana responded, “One of the great things about using the kaolin clay is that you don’t have to use nasty chemicals and spray suits to apply the material.”

Indeed, the clay, mixed with a little detergent to help it flow and stick to the leaves, is no more toxic than a handful of clean soil.

“The other nice thing is that it’s easy to see when you have to reapply the clay,” Dana added. The dried clay leaves a white film on the leaves. And since it is easily washed off by rain and needs to be applied to new leaves as plants grow, constant application is required.

Application of the kaolin spray requires strict attention to detail. One leaf missed, even the lower surface, leaves an open window for pests. And considering the long list of voracious pests that attack some veggies in the garden, you have to plan to be out there regularly (Dana recommends every two weeks without rain washing off the clay) and immediately after a heavy rain so as not to leave that window open even a crack.

Of course, the clay sprays don’t mix well with overhead irrigation. Drip irrigation avoids having your overhead irrigation water washing the clay off the leaves.

Yew Dell’s garden manager, Ann Mattingly, says that this has been a banner year in Yew Dell’s vegetable plantings. She assigns the lack of pest problems this year primarily to use of the kaolin clay.

Knocking on a nearby wooden garden bench, she said, “This has been the best year we’ve had in the vegetable garden since I’ve been here,” as she looked over her shoulder for one of those ruby-throated ninja stem annihilators.

Kaolin clay is available from a variety of garden centers and farm supply sources locally and online.