Have you ever turned to advice from online gardening forums about damage on your garden plants? Chances are, you’ve asked one of these eight common questions about pesticides — and possibly encountered a common myth in response. In this blog, we separate pesticide fact from fiction to help you take a pollinator-first approach to garden management.

Do pesticides only kill pests? Are pesticides safe for beneficial insects?

Most backyard pesticides harm all bugs, both pests and pollinators alike. 

Pesticide treatments do not differentiate between specific pests and beneficial insects like ladybugs, bees, or other pollinators. One crucial example is the impact of pesticides in home gardens on caterpillars. Using pesticides on or near butterfly host plants can kill caterpillars before the grow up into butterflies. On top of harming butterfly populations themselves, this can hurt your backyard birds, too. Caterpillars are a nutrient-rich food source for many bird species, so this can lead to a decline in food for birds. 

Pesticides can also disrupt the beneficial insects that help keep other garden pests in check. Spraying for mosquitoes, for instance, can harm insects like ladybugs, which naturally control aphids and scale insects. Losing those predatory insects can disrupt the delicate balance of the ecosystem and lead to outbreaks of garden pests.

What should I do if something is eating my plants? Are they going to die?

You probably don't need to worry! Plants are resilient, and can handle some nibbling from bugs.

This especially true for native plants living in the right conditions. Last year, my pearly everlasting plants (Anaphalis margaritacea) were covered in webbing and looked close to death shortly after emerging. Upon closer inspection, they were teeming with hungry American lady (Vanessa virginiensis) caterpillars. I let them be. Two months later, the plants were huge, healthy, and beautiful! This plant species has had a relationship with larval butterflies for much longer than I’ve been alive and it can withstand the damage it's adapted for. 

Take a pause before deciding to intervene. You can follow our guide for how to respond to damage on your plants for more detailed steps!

How long do pesticides stay on plants? Are pesticides safe after a few days? 

Some pesticides can remain in the environment — and continue to harm wildlife — for days, weeks, or even months or years. 

Even if you sprayed pesticides in the past, residues may still be present on plants, in the soil, or on nearby surfaces. Pollinators that come into contact with these residues can still be exposed and affected. It's important to be aware of the persistence of pesticides and consider the potential hidden risks to pollinators even after some time has passed since application.

Are the pesticides I can buy in the store safe? 

Unfortunately, many pesticides are approved for use despite the risks they pose to pollinators and other organisms. 

There are several pitfalls in the pesticide approval process. When the US Environmental Protection Agency (EPA) decides whether to approve a pesticide, it weighs the risks to humans or non-target wildlife against the potential economic benefit of its use. 

One reason this happens is because testing is performed on single active ingredients, not the final products or combinations of chemicals that pollinators encounter in the real world, which can both be more toxic. On top of that, all of the EPA's tests are only done using European honey bees. Honey bees are quite different from the thousands of bee species that are actually native to North America. And, of course, honey bees are even more different than other invertebrates that are regularly exposed to pesticides, like butterflies and fireflies, making them a bad test of whether a pesticide will be harmful.

Are natural or organic pesticides safe to use?

While natural or organic pesticides tend to have lower environmental impacts than their synthetic counterparts, they can still be toxic to beneficial insects, so use them carefully. 

For example, neem oil, a naturally-occurring pesticide extracted from seeds of the neem tree (Azadiracta indica), has many effects. Neem oil can smother insects on contact, repel insects and reduce feeding on the plant, and prevent immature insects from maturing into adults. Because neem is toxic to the developing larvae of many insects, you should avoid using it on plants that butterflies lay their eggs on.

Follow our guide to using organic pesticides with caution so you can minimize harm to beneficial insects. 

Are mosquito sprays made from chrysanthemum flowers safe for bees and butterflies?

Not quite. Pest control companies can mislead consumers who are concerned about the environment by implying that their pesticides have a natural origin and are therefore safer.

There are two types of pesticide ingredients that have very similar names: pyrethrins and pyrethroids. While pyrethrins are organic pesticides derived from chrysanthemums, pyrethroids are modified versions designed to be more persistent in the environment and more toxic to insects. By implying that their pesticides come from flowers, these companies create an illusion of safety and eco-friendliness.

Always ask for the active ingredient of the proposed spray. Synthetic pyrethroids commonly used in backyard settings include bifenthrin, permethrin, deltamethrin, lambda-cyhalothrin, cypermethrin, and esfenvalerate.  All of these pesticides are highly toxic to bees and many other beneficial insects, and more persistent in the environment than the organic pyrethrins. 

Are herbicides and fungicides safe for pollinators? 

While insecticides are often the primary concern when considering pollinator safety, herbicides and fungicides can also pose risks to wildlife. 

It's important to consider the potential impact of all types of pesticides on pollinators. Herbicides can eliminate the flowering plants that provide essential food sources for pollinators. Even for plants that aren't killed, herbicides can mess up the amount of nectar and pollen they make, as well as the nutrients within them. You can keep your butterflies safe by using our guide on protecting pollinators from herbicides.

Even though many fungicides do not kill invertebrates directly, they can still harm their health. For example, fungicides can make bees' bodies more susceptible to other threats, including diseases, poor nutrition, and actual insecticides. Follow our guide on protecting pollinators from fungicides to avoid these problems.

What is the cheapest and easiest way to get rid of pests? 

Pesticides can seem like an easy way out, but often only treat symptoms, without solving the actual issues in your garden.  

Pesticides are costly from both an economic and environmental standpoint, and there are many other options to try before considering a pesticide. Given the potential for harm, pesticides should be used as a last resort only when other methods have failed and there is a significant risk to health or property. 

Discover how to treat garden pests with fewer pesticides (or none at all)!

Learn more

• Organic Pesticides: Minimizing Risks to Pollinators and Beneficial Insects
• Effective Mosquito Management
• Top 7 Reasons to Avoid Pesticide Use at Home
• Protecting Pollinators from Pesticides: Fungicide Impacts on Pollinators