Native plants feeds insects, and insects in turn feed birds, fish and mammals, according to Lynn Markham, UW-Extension land use specialist based at UW-Stevens Point.
“Insects matter in many ways,” Markham said during a UW-Extension webinar on how pesticides affect pollinators and songbirds in yards.
But the use of pesticides in residential settings can negatively impact beneficial insects, including pollinators, such as bees, moths and butterflies.
“Our insect pollinators need need three things to survive,” Markham said. “They need food, they need shelter and they need protection from insecticides.”
Pesticides are one of the four Ps driving the decline of bees, one of the most studied pollinators, Markham said. The other three Ps are pathogens, parasites and poor nutrition.
The general category of pesticides includes insecticides, fungicides and herbicides. Each type can be hazardous to pollinators.
Insecticides designed to kill unwanted insects can also kill or harm beneficial insects, Markham said. Fungicides have the potential to negatively impact bee nutrition, and herbicides can kill the nectar- and pollen-providing flowers pollinators rely on.
“Ideally the pesticides would harm only the target pest and then break down into harmless substances,” Markham said. But that isn’t the case.
Instead pesticides can cling to plants, get into insects and the animals that eat them, be tracked into homes, drift in the air, stick to people applying pesticides and contaminate water, Markham said.
Damage to non-target species caused by insecticides can take 10 to 20 years or more to become fully apparent, Markham said. DDT was banned after decades of use as the pesticide was determined to cause harm, including to bald eagles, whose eggs were made brittle by the chemical, contributing to population decline.
Toxicity of pesticides to birds has decreased over time, something that coincides with lessened use of the insecticide category of organophosphates, Markham said.
But over the same period of time, toxicity of pesticides to pollinators and aquatic invertebrates has significantly increased — linked particularly to use of pyrethroid insecticides around aquatic invertebrates and neonicotinoid insecticides around pollinators.
While it’s hard to say if residential neonicotinoid use is directly having a harmful effect on birds, Markham said, if the use of those pesticides is killing insects, then the birds will have fewer insects to eat.
“Insects and particularly caterpillars that are easy for baby birds to eat ... constitute a substantial part of the diet of many bird species during the breeding season and are indispensable for raising offspring,” Markham said.
“Everything is connected,” she said. “When you exterminate the bugs, you’re actually exterminating the birds as well.”
There are options for people who want to make their residential lawn more hospitable for pollinators, which can in turn support bird populations.
Pavement and mowed lawns don’t provide habitat for pollinators, Markham said.
Pollinators can be helped by having a lawn with diverse plants that bloom throughout the season, she said.
Communitywide initiatives like “No Mow May” can also help provide pollinator habitat, Markham said.
In vegetable gardens, pest control options less harmful to pollinators can include crop rotation, cover crops, row covers and insect traps, such as hanging pails of vinegar combined with sugar and a banana peel, Markham said.
For people specifically looking for mosquito control, more natural options include removing standing water, using fans or screened-in porches, creating spaces for natural predators of mosquitoes, such as bats, swallows, dragonflies and damselflies, or using biological mosquito control products in standing water.
Minimizing use of pesticides and weed and feed products is recommended, but for those who determine that pesticide use is their best option, Markham encouraged careful reading of pesticide labels.
She also said that consumers can and should go beyond labels to examine how damaging a particular pesticide is to pollinators. The National Pesticide Information Center at Oregon State University (npic.orst.edu) and University of Massachusetts Extension (tinyurl.com/3h85nnjy) can both provide additional information on if a pesticide ingredient is harmful to pollinators if such information isn’t on the product label.
Banning neonicotinoid use or requiring pesticide labels to include impacts on pollinators are national policy items that could also have benefits, Markham said. Neonicotinoid bans have been introduced at the federal level four times in the last decade but have never passed.
A few states have implemented policies that prohibit consumers from buying neonicotinoid pesticides, while allowing farmers and pesticide applicators to still use the products, Markham said. Some individual communities have also taken steps to limit or eliminate the use of pesticides.
Some food and garden retailers have also taken steps to eliminate or phase out of the use of neonicotinoids in the products they sell, Markham said.