Gardening Articles: Edibles :: Fruit & Nut Trees
High-tech Dust Foils Pests (page 2 of 2)
by Barbara Richardson
Highly refined and powdery-white kaolin clay is the active ingredient.
A positive side effect of the white film is its ability to reduce the ultra-violet and infrared rays that reach the plant, while allowing visible light and gasses through. Plants stay cooler and photosynthesize more efficiently, resulting in greater vigor and larger harvests, a key benefit in very hot, arid climates. Some growers reported yields twice as high on particle film treated crops compared to crops under conventional management. Encouraged by this, researchers are now working with a prototype film that protects plants from frost damage by creating a barrier between ice crystals and plants' tender tissues.
Surround may sound like a home garden panacea, but there are caveats. First, it must be applied as a preventative to be effective. It can't control a pest that's already established. Though in general it doesn't generally harm pests' natural enemies, researchers in one location found that it interfered with beneficial insects. But they are confident that with proper timing of sprays, particle films will be more helpful than not. The product is not labeled for use on crops that it cannot be cleaned from easily, such as lettuce. Researchers in cool, cloudy regions are testing the product to make sure light reduction doesn't adversely affect harvests.
Usually you can't tell where you've sprayed a crop with pesticide. But when you use this special particle film, marketed to home gardeners as Surround At Home, plants have an eerie, ghostly white look. But it's really only scary to the pests it foils.
Surround washes off, but not as readily as you might imagine. In fact, we found that it sticks surprisingly well, to leaves through rains but also to patio decks and furniture. We recommend you cover anything nearby that you don't want speckled with white.
You'll need about 1/2 pound or 3 cups of the material to make 1 gallon of spray, which is enough for one full size tree. Use any type of pressure sprayer, and shake the sprayer constantly to keep the mixture agitated and evenly distributed. It mixes well with most other pesticides with the exception of horticultural oil, and can even enhance their performance. Expect to pay between $3 and $5 a pound, depending upon quantity.
Barbara E. Richardson is a horticulturist and the community manager at National Gardening Association.
Photography by Sabin Gratz/National Gardening Association.