What makes neonics harmful and how to avoid them in the garden

This month, a reader named Martha Lynne sent The Press Democrat a rather impassioned plea for an article that would alert the people of Sonoma County to the dangers of neonicotinoid pesticides.

“Please consider writing an article about neonicotinoids — the danger they pose to pollinators and how to buy plants that are free of this chemical,” she wrote. “I haven’t figured out how to do this, and I’m sure many other readers are in the same boat.”

What’s so bad about neonics, as this group of chemicals is called?

First, some context. Neonics are systemic, meaning they spread through the whole plant, from the roots to the leaves, flowers, nectar and pollen. Neonics are designed to paralyze the nervous systems of pests that suck sap from food and landscape plants so they die and drop off.

However, that also means beneficial pollinators like bees and other insects that gather nectar or pollen have their central nervous systems damaged. According to a study published earlier this year by the journal Nature, neonics have been shown to disrupt bees’ olfactory associative memory, their memory of odors, which is critical for them and other foraging pollinators. The pesticide makes it impossible for the insects to remember where their food sources are, which means starvation for them and their colonies.

Not only that, but those who do carry nectar or pollen back to the hive or nest poison those who work and feed there.

There’s increasing evidence that neonics stay in the soil and water and return, even years after application, through weeds, wildflowers or crops grown on the land that was sprayed.

Hummingbirds affected

According to the environmental justice group Friends of the Earth, “This summer, new research from Canada indicates that neonicotinoid insecticides, implicated in a global bee decline, are contributing to hummingbird decline.” The study looked at levels of neonics in hummingbirds and found that the birds consume them when they drink nectar from contaminated plants.

“Similar to bees, hummingbirds remember where flowers are located and return to the same places for food. Researchers are concerned neonicotinoids will disrupt the memory of hummingbirds and make it difficult for them to navigate and return to flowers for food,” according to the study.

The American Bird Conservancy reported that studies show neonics are extremely toxic for birds. A single seed coated with the most popular neonic is enough to kill a songbird.

One study found that even one-tenth of a neonic-treated corn seed, ingested daily during egg-laying season, is enough to affect reproduction, according to Friends of the Earth.

That’s how toxic these chemicals are to pollinators, upon which we rely to produce abundant crops of fruits and vegetables. So is anyone doing anything about this problem?

Restrictions

In 2013, the European Union and a few neighboring countries restricted the use of neonics. In 2018, the EU banned the three main neonics for all outdoor uses, although member states may make exceptions in rare cases.

What about here in the U.S.? During former President Barack Obama's administration, the EPA took sulfoxaflor, touted as a “next-generation neonicotinoid” by Monsanto, its manufacturer, off the market. After former President Donald Trump’s administration took over, the EPA put it back on the market. Its status under President Joe Biden’s administration is still undetermined. Five older formulations of neonics are still on the market here.

Neonicotinoids accumulate in plants and the soil over time as applications are repeated annually. Scientists recently have found levels of neonics in honeybee forage plants that are 20 times the concentration level that will kill 50% of bees in a colony.

In California, a bill, AB-567, has been introduced in the state legislature, aiming to chip away at neonic use. It says “On or after Jan. 1, 2024, the use of a neonicotinoid on a seed is prohibited.” Many crop seeds are coated with neonics so as the plant grows, its tissues are suffused with the systemic pesticide, killing insects that might damage the plants. The bill is currently working through the committee process in Sacramento. However, it does not address the use of neonicotinoids as sprays on the surfaces of plants or on the soil.

Alternatives

Lynne, the reader who encouraged this newspaper to cover this story, recounted in an email her experience looking for unsprayed plant material. It wasn’t a simple task.

“I asked a local retail nursery how I could buy a plant that has not been sprayed. I was told I would have to give the staff the names of the wholesale nurseries where the plants came from, and that they would have to call each one. This employee had no idea which nurseries that supplied them used neonics and which didn’t. She seemed to think it would be impossible to know such a thing.”

One way to get a handle on whether landscape or garden seeds or plants have been sprayed with these chemicals is to check with organic nurseries. Environmentally harmful agricultural chemicals like neonics are not allowed in organic growing. The only way to know for sure that a nursery is truly organic is to see whether it has California Certified Organic Farmers certification. These certifiers make on-site inspections and take samples.

One wholesale nursery in Sonoma County with this certification is the Sonoma Valley Wholesale Nursery in Sonoma. Owner Paul Martinez said, “Unless the stock comes from a certified organic nursery, you can assume it’s been sprayed.”

You must make that assumption, he said, because without certification, there’s no way to know with certainty unless you know the grower and are convinced he or she has a reliable source of unsprayed plant material.

“The chief thing is that if buyers want organic plants, they should ask for them — demand them,” Martinez said. “That’s what will drive the market to supply them.”

If you’re growing food plants or ornamentals from seed, he suggested buying organic seed from the many catalogs that list this information. The plants grown from that untreated seed will not harm pollinators.