KENNEWICK -- Last week, a frustrated gardener came in and said that the spinosad pesticide product that he purchased wasn't doing anything to control the aphids on his roses.
I wasn't surprised.
Spinosad is most effective in controlling chewing insects, such as caterpillars, leaf beetles, leaf rollers and thrips. Aphids are a sucking insect. There are other materials that are much more effective against aphids.
While it's sometimes hard to find knowledgeable staff at stores that sell pesticides, the pesticide label is a great source of information. It will tell you what types of plants you can use the product on, how to apply the material and what type of pests it will control.
This gardener's spinosad container was empty, so he gave us the label. Did you know that pesticide label print is so minuscule that just trying to read it can be frustrating?
If you can decipher the tiny print, you should able to find out what pests the product supposedly will control effectively. I could find no aphids listed on the label anywhere. If the type of target pest that's troubling your plants is not on the label, don't buy it -- even if the store clerk says it "should work."
The label will give instructions for the amount of material to use for application and how to mix it. In addition, the label will provide you with any special precautions you should take to protect yourself, your plants or wildlife. Even if a material is considered "organic" and relatively benign, it can pose a hazard. Spinosad, as noted on the label, is highly toxic to bees. The label warns not apply it to blooming plants.
Another part of the label that should be heeded is the minimum number of days you must wait from your last application until you harvest the fruits or vegetables. This varies with from crop to crop. For example, you must wait seven days to harvest apples after spraying them with this spinosad product, but you only have to wait one day after treating tomatoes.
Even if a material is designated as an "organic" material, it doesn't mean you can eat treated crops right after application. For any type of insecticide or fungicide, check the label when treating food crops for how long you must wait.
This spinosad label also directs you as to the maximum times you may use it in one season on the same plant and the minimum days to wait before reapplying it. These are aimed at preventing insects from building up resistance to the material.
So what should the "frustrated" gardener used instead of spinosad to kill aphids on his roses. If he wanted to use an "organic" or less toxic material, I would recommend an insecticidal soap or neem oil product. Thorough coverage of infested plants is crucial in achieving success with these.
Since this is a nonfood crop, there are other nonorganic, more toxic products that also will kill aphids effectively. Products containing acephate, cyfluthrin or imidacloprid should provide good rose aphid control.
When selecting any pesticide product, read the entire label, even though the print is much to small to make this easy. Make sure the pest is listed on the label. Make sure the type of crop or plant is listed on the label. Read and follow all precautions for that product's safe use in your garden and landscape, whether the material is organic or nonorganic. This will protect your garden from pests and you from becoming a frustrated gardener.
* Marianne C. Ophardt is a horticulturist for the Washington State University Benton County Extension Office.