This year red wasps have invaded my hanging baskets. What can I use to kill them that won’t kill my plants?
We get this question quite a bit. Fortunately there are a lot of options and none of them will hurt or damage your plants.
You see, years ago when the first generation of home and garden pesticides came to market, they were highly concentrated and contained solvents that were many times damaging to the plants being treated. These highly concentrated active ingredients would many times burn or damage the treated plant (which is why so many people think insecticides will kill plants). Actives like Malathion, Diazinon and liquid Sevin would in fact do harm to most any potted plant when used like you want to use. Not only that, but their nasty odor would linger for many, many days. Fortunately a lot has changed.
Today we have actives that are a lot less concentrated (instead of 40-60% active ingredient, 5-20% are the norm). Additionally they have solvents which don’t cause side affects like burning the leaves of a treated plant or hurting the plants root system These actives are first tested to make sure they won’t hurt the plants they’re intended to be sprayed on so that by the time they come to market, there will be directions indicating what if any plants are sensitive to it’s use along with any other important treating guidelines.
So for your problem, the good news is there are plenty of options that can be utilized. And the treatment is actually quite easy. Basically all you have to do is mix one of these products with water and apply it like you would with a watering can. In other words, you don’t have to spray the plant but instead just water it into the plants soil. We have several products that will work on wasps and can be used in your potted plants, but here are two that we know very well.
The first is the CYPERMETHRIN mentioned in our WASP CONTROL ARTICLE. It not only will kill any nesting in the soil, but it’s repellent action will also keep new ones from coming around. Mix it at the rate of 1/2 oz per gallon and it will only take 32-64 oz of the mixed spray to do the job.
Alternatively, you can use an organic product like MULTIPURPOSE INSECT KILLER. Use it the same way as the Cypermethrin. Once it filters through the soil and finds the wasps nest, it will both kill any alive in the nest and continue to work for a day or two. Since it won’t last long like the Cypermethrin, you will have to treat again in two days if you continue to see activity. This is because the organic actives just don’t last long like the more traditional products. But in the end, it can get you the same result.
Here are direct links to the information and products listed above:
Wasp Control Article: http://www.wasps.net/wasp-and-hornet-control
Multipurpose Insect Killer: http://www.bugspraycart.com/organic/liquid/multi-purpose-insect-killer-24-oz