Mosquitoes are a common summer nuisance, but they've become more worrisome since we learned more about how many mosquitoes carry the Zika virus, the West Nile virus and even encephalitis. In some towns and cities, mass pesticide spraying aims to significantly reduce the mosquito population. But what we don’t think about is the effect these measures have on other critters — namely bees.
Bees are integral to many of our agricultural crops. Not only do they produce honey, but they're responsible for the pollination of various fruits and vegetables, such as apples, cucumbers and berries. Without honeybees, farmers would experience a serious drop in supply or may not be able to produce any crops at all.
Unfortunately, many mosquito insecticides are harmful to bees, particularly field worker bees that venture outside the hive. These bees can travel up to five miles to collect pollen and nectar from certain flowers and plants. They can be exposed to pesticides that have been sprayed directly on the plants from which they forage, or by pesticide drift — when wind moves pesticide from the area to another.
Pesticides can kill the bees even before they make it back to the hive, and if they make it back, they infect their entire colony.
If you're trying to control mosquitoes at home, you don't have to spray your yard with pesticide, of course. There are plenty of natural ways to kill mosquitoes. But if your family is extremely concerned about disease-carrying mosquitoes — maybe you have kids, or you're trying to get pregnant, or someone in your home has a compromised immune system — and you're going to apply mosquito pesticide, there are a few ways to reduce the danger to bees.
1. Apply your pesticide directly to the ground. This greatly reduces the drift from aerial spraying. Granular pesticides are generally the least likely to drift and cause harm to foraging bees, according to the Department of Pesticide Regulation at Clemson University. If you can't avoid aerial sprays, then spray in the evening or at night when bees have likely returned to the hive.
2. Cover your hives. If you’re a beekeeper with hives to protect, best to cover the hives if you know when an aerial spray will be taking place. (Contact your local county health department to find out.) This can be done with burlap or another breathable material, which will allow the hive to get the air it needs while protecting it from harmful pesticides.
3. Try Mosquito Dunks. Each "dunk" contain BTI, a bacteria that kills mosquito larvae but is nontoxic to all other insects, birds and people. This is a great option if you have a bird bath or other similar water feature in your yard. And on that note, prevent standing water in your yard altogether, since this is where female mosquitoes lay their eggs.
4. Keep mosquitoes out of your yard in the first place. Keep an eye out for puddling rainwater and get rid of it. Also, a strategically placed fan can help keep mosquitoes at bay since they're weak flyers and can’t navigate well in the wind. Try a few different fans, settings and placements until you get the desired effect. Since mosquitoes like to hide in tall grass during the day, trim weeds and mow your lawn often.
If you are going to use a pesticide, know that some pesticides are more harmful than others. Check out this guide from Clemson University to find out which ones should be avoided.