How a Popular Pesticide Threatens Bees, Butterflies, and Human Health

The Hidden Fallout of Neonicotinoids

Neonicotinoids, often called “neonics,” have become one of the most widely used classes of insecticides in the world.

Initially praised for their effectiveness and lower toxicity to humans compared to older pesticides, neonics are now under growing scrutiny for their unintended and far-reaching consequences.

Mounting evidence—much of it from leading research institutions like Cornell University—shows that these chemicals pose a significant risk to pollinators like bees and butterflies, and may even impact human health through food and water contamination.

A Closer Look at Neonicotinoids

Neonicotinoids are synthetic chemicals that mimic nicotine and act on the nervous system of insects. When applied to seeds, soil, or foliage, these compounds are absorbed into every part of the plant—leaves, pollen, nectar, and even fruit. This systemic action means that insects feeding on treated plants are poisoned, even if the pesticide was applied months earlier.

While this approach was meant to target harmful pests, it turns out beneficial insects, especially pollinators, are especially at risk. In fact, research at Cornell and other institutions has shown that neonics persist in the environment far longer than originally expected and can travel through soil and water, exposing a much wider range of organisms.

Bees on the Brink

Honey bees and wild bees play an essential role in pollinating crops and native plants. Yet over the past two decades, both populations have experienced dramatic declines. While many factors are involved—such as habitat loss, disease, and climate change—neonicotinoids have emerged as one of the key drivers of pollinator collapse.

Cornell University’s Pollinator Health Research Program has conducted extensive studies showing that even low, sublethal doses of neonics can impair bees’ memory, navigation, and foraging behavior. This means bees may leave the hive and fail to return, unable to find their way back. Neonics also weaken the immune systems of bees, making them more vulnerable to viruses and parasites like the deadly Varroa mite.

One striking finding from Cornell’s work is that neonicotinoids don’t have to be applied directly to flowering crops to cause harm. Because these chemicals move through the environment, wildflowers and other plants near treated fields can also become contaminated. Bees feeding on these flowers are unknowingly exposed, leading to chronic poisoning.

The Butterfly Effect

Monarch butterflies and other native pollinators are also suffering. Monarch populations have plummeted by more than 80% over the last few decades, and while habitat loss is a major factor, pesticide exposure adds a significant burden.

Cornell researchers have linked neonic use to decreased survival rates in monarch larvae feeding on milkweed near treated fields. These caterpillars ingest the pesticide-laden leaves and suffer delayed development, weakened condition, and increased mortality.

Other studies suggest that neonic-contaminated dust from seed planting machines can settle on milkweed and other critical host plants, creating toxic “hotspots” for butterfly larvae and other insects.

The Long Reach into Human Health

Although neonics were designed to be less toxic to humans, recent research raises troubling questions about long-term exposure. Cornell’s Department of Public and Ecosystem Health has examined how these chemicals show up in drinking water and food—particularly in produce treated during growing and even in processed items like baby food.

A 2022 review by Cornell scientists highlighted that neonicotinoids are commonly detected in surface and groundwater in agricultural areas, especially after rainfall. These residues are difficult to remove during standard water treatment processes. Chronic low-level exposure, particularly in infants and pregnant women, may be associated with developmental and neurological effects. Some animal studies have shown that neonics interfere with acetylcholine receptors in mammals—just as they do in insects—which could have implications for the human brain.

Researchers at Cornell stress that while more studies are needed, the current regulatory framework underestimates the risk of cumulative exposure to neonics through food and water. Meanwhile, European regulators have already banned several neonicotinoids for outdoor use, citing overwhelming evidence of ecological harm and potential human health risks.

Some Commonly Available Neonicotinoids

Commonly available insecticides that use neonicotinoids as their active ingredients are widely available for agricultural, commercial, and residential use. Here are the most commonly used neonicotinoid-based insecticides, along with their active ingredients:

1. Imidacloprid

One of the most widely used neonicotinoids worldwide.
Common products:

• Bayer Merit (lawn and turf)
• Admire (agriculture)
• Confidor
• Gaucho (seed treatment)
• Premise (termites)

2. Clothianidin

Often used as a seed coating and in soil treatments.
Common products:

• Poncho (seed treatment, especially corn)
• Arena (turf and ornamental uses)
• Belay (cotton and soybean fields)

3. Thiamethoxam

Frequently found in both agriculture and garden formulations.
Common products:

• Cruiser (seed treatment)
• Actara (fruit and vegetable crops)
• Meridian (turf)
• Tandem (a mix with bifenthrin for pest control)

4. Acetamiprid

Considered less toxic to bees compared to others, but still a neonicotinoid.
Common products:

• Assail (fruits and vegetables)
• Ortho Flower, Fruit & Vegetable Insect Killer

5. Dinotefuran

Used in both agriculture and household pest control.
Common products:

• Safari (ornamentals)
• Venom (vegetables and ornamentals)
• Zylam
• Alpine (for indoor pest control, including bed bugs)

6. Nitenpyram

Often used in veterinary products.
Common products:

• Capstar (oral flea treatment for pets)

Time for a New Approach

The case against neonicotinoids is no longer limited to environmentalists or fringe researchers. Mainstream science—including leading voices from Cornell University—has made it clear that these chemicals pose a complex and urgent threat. Bees, butterflies, and the broader ecosystem depend on our ability to adapt agricultural practices in response to this evidence.

There are already viable alternatives. Integrated pest management (IPM) systems use biological controls, crop rotation, and selective spraying to reduce pest damage without harming beneficial insects. Some farms have returned to older, less persistent pesticides with more targeted effects. In lawn and home gardening settings, you can make pesticide-free choices and support pollinator-friendly plantings.

Ultimately, protecting pollinators means protecting ourselves. The collapse of bee and butterfly populations is not just a biodiversity issue—it’s a food security and public health issue.

By heeding the warnings from Cornell and other research centers, we can begin to shift away from chemical dependency and toward a more balanced, regenerative relationship with the natural world.

Source: https://www.offthegridnews.com/survival-gardening/how-a-popular-pesticide-threatens-bees-butterflies-and-human-health/