Iowa State University’s Extension entomologists are asking you to be careful about harming honeybees as you get out an about in the warm weather and tend to your plants. Entomologist, Laura Jesse, says insecticides were one of the things mentioned in a recent report on the decline of the honeybee population across the U.S.
Jesse says it’s not easy to protect bees while you are trying to rid your garden of pests. “Bees are insects, and yet we have insect pests, so insecticides in general will harm bees. One class of insecticides that we’re concerned about right now is a class called neonicotinoids,” Jesse says.
She says this class of insecticides is very toxic to bees. And she says the neonicotinoids are systemic. “With most of our spray insecticides where you’ve got caterpillars, aphids and things, you spray it on and it dries. As long as you aren’t treating the plant when it’s flowering you are very unlikely to harm pollinating insects,” Jesse explains.
“Whereas with the systemic insecticides you can be putting it on long before the plant flowers and the insecticide is in the pollen and nectar. And we don’t know how much is in the pollen and nectar and for how long.” Jesse says you should determine if the damage to your plant is merely cosmetic, or there is still a problem that needs to be treated.
“The first step is kind of look –there are still insects here it might be worth treating — and then consider other options. In the case of aphids, you can often blast a lot of them off with a hose and then come back with maybe a soap-based insecticide,” Jesse says.
She says always go through the other options before you move in with insecticides. Sometimes people miss the window to treat the insects that have done the damage, but spray anyway. “We call it a revenge spray, where you spray after the damage is done.”
Some people might be afraid of being stung and spray bees anytime they see them. Jesse says that’s not a good strategy.
She says honeybees and bumblebees are not that aggressive, while the yellow jackets are probably the most aggressive. But Jesse says yellow jackets eat a lot of insect pests and are very beneficial. Jesse says if you have questions you can call her or others at the Iowa State Plant and Insect Diagnostic Clinic at 515-294-0581.