Be Mindful of Nature in Your Pest Control Choices

by Janet Anderson, PhD*

Birds, bees, butterflies, and other wildlife can be harmed by the pest control techniques and timing we use.  Always read and strictly follow the label directions and precautions before you use any pesticide.

No matter what insect control measures you use in your gardens and landscape, consider the impact on pollinators. There is a severe decline of insects worldwide, and in Vermont we have lost several of our native bumblebee species. If you feel you must use a pesticide, you should never apply a pesticide mid-day when bees and other pollinators are most likely to be active. Spraying in the evening is best because it allows the spray to settle and dry before pollinators are again active.

If possible, do not apply pesticides when the plants are in flower and avoid spraying the flowers.  Early control, typically before plants flower, usually results in better pest control than trying to control a larger infestation later in the season. This advice for protecting pollinators applies to natural and organic pesticides just as much as to chemical pesticides.  Some organic pesticides are very toxic to bees.

You can reduce use of pesticides by choosing resistant plant varieties whenever possible and tolerating some insect damage and/or disease. Native plants are more tolerant of insects, fungi, and bacteria that are also naturally occurring, although it is true that many of our toughest pests to control are the introduced ones, like Japanese beetles and Asian lily beetles. If you can tolerate some insect pests, these, especially native insects, may be important food for birds, especially baby birds which do not eat seeds.

Why rodenticides are dangerous to wildlife

Be particularly cautious in the use of pesticides for control of mice that can unintentionally kill other wildlife. Owls, hawks, raccoons, fishers, coyotes, as well as pets, are poisoned by chemical baits used to control rodents. Most of the chemical baits are anticoagulants that slowly kill the mouse or mole. A sick mouse is easier to catch than a healthy one, but the anticoagulant in the mouse’s body is still active. Any animal that chews or swallows a poisoned  mouse is also poisoned by the anticoagulant. It was a hard winter for many predators with the snow coming early and often deep; there were several reports of predators being sickened or killed by rodenticides, especially when they are stressed by the severe weather.

Some of the rodenticides require several doses to kill a mouse, but even a single dose may provide enough of the chemical to affect the predator and make it vulnerable to the severe weather or other predators. Traps that kill quickly or baits with traps that prevent the mouse from leaving the trap do not allow a sick mouse to poison another animal. Mice can get through very small spaces to get to outside, so it is not enough to use baits in your basement, attic, or barn and believe this is safe for wildlife.

Steps to control use of neonicotinoides in Vermont

We can all celebrate efforts in Vermont to prohibit dangerous pesticides EPA has overlooked. The Vermont House has passed a bill (H 205) that would make a class of insecticides called neonicotinoides restricted use except for control of ticks and fleas on pets and as seed treatments. If signed into law, homeowners will not be allowed to buy or use these insecticides that have proven deadly to many pollinators, including bees and butterflies, except for use on pets. The neonicotinoides are safely used as a few drops on the back of the neck of dogs and cats and have proven highly effective and much safer than the old flea collars.  Also, the use on pets will have no impact on bees, butterflies and other pollinator insects. Be sure you wash your hands immediately after petting an animal treated with any pesticide.

The bill is currently in the Senate where it has been favorably reviewed by the Agricultural Committee and is now before the Finance Committee. There will be lots of pressure from pesticide companies to weaken or eliminate this leadership action in Vermont. You may want to contact your Vermont senators and the governor to encourage support of H 205.

The National Pesticide Information Center ( has more information on how to reduce pesticide risk including risk to wildlife. This organization works with the Environmental Protection Agency to provide the most up-to-date scientific based information on pesticides, including pesticide poisonings and impacts on pollinators.


*Dr. Andersen retired to Barnard from the EPA where she managed natural pesticides. She has a PhD in Plant Pathology from University of Maine and a Master of Science from the University of California, Berkeley.


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