Coast Gardener
Garden Information and
Misinformation?
The Coast Gardener Newspaper and Web Column
- October 27, 2008
It seems this fall we have had an extraordinary amount of homeowner calls concerning insect pests. Caterpillars, leaf miners, and scale insects to name a few. Since I am a horticulturist and I do not have a vast background in insects, I have had to do a lot of reading and research. I have uncovered some interesting answers to pesticide questions and some myths that need to be reported correctly.
Scale insects have been very active this fall. These insects spend the majority of their lives under a protective shell where they feed undisturbed. Sooty mold grows on the honeydew exuded as a result of scale feeding with other damage being distorted growth and death of branches.
So, why are there so many scale insects this fall? One reason may be surprising and is related to mosquito eradication efforts. The primary insecticide sprayed, actually fogging, for mosquitoes is permethrin (related to the botanical insecticide pyrethrum) and this seems to have an impact on the predatory insects that would normally feed on the scale insects. The heaviest scale infestations seem to be correlated to area nearest the fogging route.
Speaking of botanical insecticides, I read that since these were natural products only the insect pests are affected and harmless to mammal and amphibians populations. Not true, it cannot be assumed that botanicals are safer than other pesticides. In fact, Mother Nature produces some of the most toxic chemistry.
Since we are talking about pesticides, can you name the most flagrant environmental pesticide polluter? It is not the local golf course, greenhouse/nursery, or even large agricultural producer. It is the homeowner, your neighbors, and maybe the person in the mirror.
Most people know the old saying that an ounce of prevention is worth a pound of cure. Many consumers take this one a step farther. If an ounce of prevention is good, then a pound of prevention is even better. This is a popular view when using pesticides in the landscape, be it the home lawn, flower garden, and yikes, even the vegetable garden. Overuse can harm beneficial insects, render veggies inedible, and increases the chances accidental poisoning.
Please, please, please, when using any pesticide follow the label instructions and wear the recommended personal protective equipment.
Written by Dr. Gary R. Bachman, Assistant Extension Professor of Horticulture, Coastal Research & Extension Center.