by in Garden.

What’s that white stuff on the plant leaves?

Visitors to our garden often ask us about the white powder on the leaves of various plants, and no wonder, it does look foreboding. But fear not, it is an organic insect repellent made from kaolin clay, a naturally occurring mineral.

We are using a product called Surround W.P. which is made from 95% kaolin clay. Mixed with water and sprayed onto plant leaves it dries to form a white film that repels bugs. Surround can help control a wide variety of pests on fruit trees as well as vegetables. In our garden we are using it on the cucumbers, squash, and bean plants.

Kaolin clay on the Sour Gherkins growing up the fence near the top of our garden.

The list of pests that Surround can help control is long and includes caterpillars, beetles, worms, and flies. The pests we have seen the most attacking our cucumbers, beans, and squash are Mexican Bean Beetles, Cucumber Beetles, Bean Leaf Beetles, and Squash Beetles.

Surround is not a pesticide, it doesn’t kill bugs, it repels them. It sticks to their body parts and encourages them to move elsewhere. At harvest time, the white film can be removed simply by rubbing it off or washing the produce.

We combine use of kaolin clay with good old bug patrol by our garden staff. Each day we look carefully on the underside of leaves for eggs and larva – squashing them as we find them. Adult beetles, which we squash as well, can be found on and under leaves, as well as along the stems of plants.