Not too long ago, using a drench product to prevent insects was primarily a greehouse or growing operation option. However, since about 3 years ago, applying a soil drench to trees and shrubs has become a popular and effective way to deliver long lasting insect protection easily and safely to larger trees and shrubs.
The first true consumer drench product was Bayer Tree and Shrub Insect Control which was introduced in about 2004. This product is mixed in a watering can or bucket according to the height of the tree or the number of shurbs you want to treat. The mixture is applied at the root flare of the tree (not at the drip line) and is absorbed by the tree, eventually making it "bugproof" for up to a year. Bayer worked hard to pitch this technology to dealers and consumers. The product got a lift when it was recommended by Michigan State University for control of the Emerald Ash Borer, a very destructive pest which appeared in the Detroit Metro area in 2002, and which has since destroyed or caused to be destroyed over 16 MILLION ash trees.
In late 2006 the patent on Bayer's "Merit" the active ingredient in their drench product expired, opening the door to a number of additional manufacturers to produce the active ingredient - Imidacloprid - at a lower cost. This has made this fairly expensive product a much more palatable price lately. The active ingredient is available in Bonide Product's Annual Tree and Shrub Insect Control for significantly less than last year's Bayer retail price.
The best time to apply drench type systemic insecticides is in the fall. This is a little counterintutive to most gardeners, but simply put, if you apply it now, it will be stored in the roots of the tree or shrub until it makes its way back to the crown of the tree in the spring as the sap rises. This moves the insecticide to the tips of the branches and into new leaves and shoots to provide protection during the growing season. I have used these products successfully in both southern and northern climates and I have to tell you, it works.
You can find these products at garden centers and home stores almost all year long. Don't apply the product to frozen soil or to soil which is saturated, as it will not be effectively taken up if you do.
Drenches provide excellent control of aphids, certain borers, leaf miners, Japanese Beetles, and many other tree destroying pests. Unfortunately, Merit is less effective on caterpillars that turn into moths and butterflies so it is not an effective control for Gypsy Moth or Eastern Tent Caterpillars.
So next time you're in your local garden supply outlet look for these new products to provide your trees and shrubs with a bug free year next year.
SG
Brilliant article, thanks for the read. I was just wondering if anyone can help me with a question I have on gardening while im here. I have been looking at the Garden Groom (in the link in my name) and I was just wondering if anyone has had an experience with it? Im a little concerned about using electric trimmers as im not as young as I used to be! Thanks - Lou
Posted by: Garden Groom Midi | July 25, 2008 at 09:22 AM