What to do about grubs, the common lawn pest, is a key part of the discussion in Falmouth’s quest to pass a more stringent pesticide and fertilizer ordinance.
In the spring, the Falmouth Town Council discussed updating its pesticide and fertilizer ordinance to be stricter, but the council hit pause on the process in May to take time to synthesize community feedback and do more public education.
The town circulated a community survey earlier this year to solicit opinions on the draft proposal that generated hundreds of responses, with a slight majority coming down against the proposed changes, but some 42% in favor, according to Town Council Vice Chairman Bryce Hach at a meeting earlier this year.
Falmouth’s proposal would prohibit the use and sale of common non-organic weed, grub, and crabgrass control pesticides, according to education materials released by town officials.
It would also bar all pesticides (organic or synthetic) within 75 feet of a water body or watercourse and would prohibit the sale or use of any pesticides that are listed as banned on the U.S. Department of Agriculture’s National List of Allowed and Prohibited Substances.
Allowed organic pesticides would include horticultural and insecticidal soaps, vinegar-based herbicides, essential oil-based pesticides, diatomaceous earth and biological-based pesticides, according to the town.
When it comes to fertilizers, none would be allowed within 75 feet of a water body or watercourse, application would be prohibited from Dec. 1 to March 31, and synthetic fertilizers containing phosphorus would not be allowed on lawns and natural turf. It would also bar outdoor application of sludge or biosolids.
The town’s proposal would allow some exemptions to these restrictions, including pesticide use to control plants like poison ivy and allowing pesticides and fertilizers to be used on golf courses.
The pesticide and fertilizer rules currently on the books, which were adopted in March 2020, require licensed commercial pesticide and fertilizer applications to annually register with the town and report the applications they made during a given year to the town. It also bars the application of fertilizer between Dec. 1 and March 31.
“The main concern raised through the public comment regarding the proposed ordinance is the impact of grubs on lawns,” said Dennis Brown during a recent community workshop to learn more about the planned changes. The word “grub” appears 21 times in the survey responses the town collected, largely in the context of objecting to the proposed ordinance.
Brown, who is chairman of the Highland Lake Leadership Team, was the moderator of the session, which featured a panel of people who had been invited to give their expertise on pesticide and fertilizer regulation.
The panel included Chip Osborne, the president of Osborne Organics, which offers organic turf management; Andrew Baxter, a branch manager for Mainely Grass, a lawn care company; Heather Kenyon, the science and advocacy associate at Friends of Casco Bay, a group that advocates for the environmental protection of Casco Bay; and Fred Dillon, the stormwater program coordinator for the city of South Portland.
In response to a question about whether grubs can be managed with organic treatment options, Osborne said that in his work, he doesn’t advise completely swapping out synthetic for organic grub control. He uses what he called organic integrated pest management (the Environmental Protection Agency defines IPM as using environmentally sensitive solutions to manage pest damage by the most economical means, and with the least environmental hazard or hazard to people).
He said he has successfully used organic pesticides to manage a grub problem – including bacillus thuringiensis (a soil-dwelling bacterium used as a pesticide) – and that in general the aim should not be to completely eradicate grubs.
“There’s nothing that says I have to take eight or nine grubs per square foot and go to zero. That’s not (integrated pest management).”
“We have tested many, many organic products for grub prevention and grub curative. I want it to work. I would love to have it work. (But) we haven’t found any success with that,” Baxter said.
Dillon said the most frequent waiver application the city receives for its pesticide ordinance concerns grub damage. South Portland’s ordinance bans synthetic pesticide use on both private and public property.
Town documents for the latest joint meeting of the Ordinance and Conservation committees on Sept. 4 noted that there was no consensus from the panel on whether organic treatments work on grubs.
During the discussion of fertilizers, Kenyon explained that phosphorus is a limiting nutrient in freshwater and nitrogen is a limiting nutrient in saltwater. The presence of phosphorus in fertilizer can cause an algal bloom in freshwater and the presence of nitrogen in fertilizer can have the same effect in marine environments. Algal blooms can sometimes be toxic and also block sunlight that other plants in the water environment need, she said.
Falmouth’s draft ordinance restricts phosphorus-containing fertilizers, but “only a small part of Falmouth drains to lake systems. The rest drains to Casco Bay, and so I would encourage the Town Council and the conservation commission to consider adding (a restriction on) nitrogen in the future,” Kenyon said.
She said South Portland prohibits synthetic nitrogen and puts numeric limits on organic nitrogen applications. The city allows organic fertilizer containing phosphorus in some select cases. Both organic and non-organic fertilizers can contain nitrogen and phosphorus.
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