To spray or not to spray

Jeff Green | Oct 14, 2020

Cottage Associations, property owners consider Gypsy Moth options

It had a dramatic effect in late June and early July. The ground was bone dry, the mask order was a fresh reminder that the global pandemic was here to stay, and the trees started shedding caterpillar waste and crunchy broken dead leaves that fell everywhere.

The gypsy moth infestation this past summer was the worst in 30 years. The moths that followed, later in the summer, left millions of egg sacs on trees, rocks and wooden fences throughout eastern Ontario, raising fears that 2021 will be an even more dramatic gypsy moth year. While the main target species for gypsy moth larva, deciduous oaks and maples, are not likely to suffer major damage from two consecutive years of infestation because they regenerate leaves quickly, the secondary target of the larva, Pine and Hemlock, are at greater risk.

Most rural landowners are not in a position to pay for gypsy moth spraying using Btk, the only approved treatment for gypsy moths in Ontario. The cost is $357 for one acre and $96 for each subsequent acre, over $1,700 for a 15-acre property. This is pricing supplied by Zimmer Air Services of Blenheim, a company that does most of the spraying in Eastern Ontario. FOCA, the Federation of Cottage Associations of Ontario, has posted information from Zimmer Air on the Gypsy Moth tab on their website, FOCA.ca

FOCA takes a neutral position regarding spraying but they have facilitated communications between their members and Zimmer Air, raising concerns for some waterfront property owners who oppose spraying because they think it is unnecessary or they consider it a potentially harmful practice.

Bacillus thuringiensis - subspecies kurstaki (Btk) the substance that Zimmer air sprays on forest cover “is a naturally occurring substance. It is toxic only to the larvae (caterpillars) of specific insect species,” says a Zimmer Air document. “For Btk toxins to be activated, the alkaline conditions that exist only in certain insects’ digestive systems must be present. The acidic conditions in the stomachs of humans and animals are not present and do not activate Btk toxins, which is why the pesticide is not toxic to humans and animals. Btk has been used in many countries without health impacts to individuals on medications or vulnerable populations.”

One of the factors of the spraying that requires cooperation among neighbours is that Zimmer Air requires that any property owner that hires them provide a waiver from their direct neighbours. The neighbours can either hire Zimmer themselves to spray, refuse or permit Zimmer to spray their neighbour’s property, right to the property line, or refuse and insist that the spray remain well within the boundaries (20 metres) of their neighbour’s property.

Ed Nowiki, a property owner on Kennebec Lake in the Arden area of Central Frontenac received information from the Kennebec Lake Association (KLA) from Zimmer Air.

“I say no to spraying. I was here 31 years and remember many infestations. And spraying attempts!” Nowiki said in an email to KLA Cahir Doc Mairorino, that he copied to the Frontenac News. “You and your organization do not have the legal right to organize this healthcare initiative, nor do you have the funds to do so. The legal costs will hamper all your other stewardship efforts and you will be fighting Mother Nature which I thought you had a better respect of,” he added.

On the KLA website, Mairorino posted a letter that he sent to association members, within a section on the site that contains information and links to academic and official government information sources about gypsy moths and cyclical infestations.

In his letter, Mairorino said “The KLA is neither for nor against a spraying initiative. The KLA believes the decision to become involved must be one that is made by each individual property owner. Accordingly, the KLA is committed to ensuring that information that is provided to members and other property owners, in order that all might make an informed decision about whether or not to have their properties sprayed.”

The same page on the site includes links to material provided by Zimmer Air, including a link to a Frequently Asked Questions (FAQ) page on the Zimmer Air spraying program.

Links to the Zimmer Air order form for spraying and Zimmer Air waiver forms for neighbours are also included.

There is also a link to a Nature Note article by Aileen Merriam that was posted in the 2020 KLA summer newsletter. After describing the life cycle and feeding patterns of gypsy moth larva, which cause all the damage, Merriam pointed out that the larva are also a food source for birds, mice, shrews, squirrels, chipmunks and even raccoons.

Under the section, “So What can we Do? Merriam wrote the following: “The short answer is very little. Some suggestions were discussed in the December 2019 newsletter. To date no control methods have been completely successful and some harm beneficial species. In the early 1990s, for a number of years, the area surrounding Kennebec Lake had one of the worst outbreaks of gypsy moths in Ontario.

Wide areas were defoliated; many trees were killed. Fortunately, after the last outbreak, nature took over the job of repairing the damage to the forest. Dead trees fell and decomposed and other trees and shrubs took their place.

“As devastating as the current outbreak is, we can take comfort in how relatively quickly, and thoroughly, the forest recovered after the last outbreak. By 2019, no one would have believed the extent of defoliation in the 1990s.”