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Bee-friendly ways to de-grub your lawn

Geste - Pour une pelouse « amie des abeilles »

Chances are that if you've followed the news this summer, you've heard about neonics, AKA bee-killing pesticides.

These pesticides have been banned temporarily for some uses in Europe, but are still widely used in Canada for agricultural purposes, especially on corn.

Did you know that neonics can also be found in products intended for use on your lawn, in particular to treat white grub infestations?

Merit, one commonly used insecticide, contains an active ingredient, imidacloprid, that belongs to the neonic family. Yikes! This product, which is available over the counter throughout Quebec, can be bought by citizens and lawn-care business alike, although some municipalities do require a permit to use it. 

Fortunately, there are other, less obviously harmful ways to prevent or control white grub infestations.

But first, what are white grubs?

White grubs are the larvae of such beetles as the:

  • common June beetle
  • European chafer
  • Japanese beetle

They can harm your lawn by causing:

  • wilting
  • drying 
  • discoloration

In the spring and fall, white grub infestations attract skunks, raccoons and birds – predators that will not hesitate to dig up your yard in pursuit of a tasty treat.

So, what are some bee-friendly alternatives for preventing or stopping a grub infestation?

PreventiNG a GRuB INFESTATION

  • Raise the mowing height for your lawn. It is harder for beetles to lay their eggs in longer grass. 
  • See a bare spot? Seed it right away.
  • Turn off outside lights during egg-laying season (June and July) to avoid attracting beetles to your yard.
  • Water your lawn. A well-watered lawn can tolerate a higher number of grubs before damage occurs. But lawns that are already under stress, due to an an acidic pH or another invader such as leaf bugs, are much more vulnerable.
  • Attract more desirable predators. Ants and certain birds, including starlings and blackbirds, feast on the larvae without causing as much damage to your landscaping as skunks.

Speaking of desirable predators...

There is a type of microscopic worm, called a nematode, that preys on white grubs.

You can buy nematodes in a hardware store or gardening centre.

Nematodes can be applied to your lawn with water using a:

  • watering can
  • hose attachment
  • sprayer
  • mister

Be sure to remove any filters that could harm the nematodes. 

The mixture also needs to be stirred regularly to ensure that the worms are evenly distributed throughout. The more care you take, the greater your chances of success.

Apply the worms to your lawn in the evening – never in the sun.

The soil should be 15 degrees Celsius and moist.

The best time to act is late August or early September.

Before application, water the lawn thoroughly. Water carries the nematodes to the grubs, where they infest them. Once inside, the nematodes multiply and release a bacteria that eventually kills their host.

The effectiveness of the treatment may vary depending on the species of nematode. Heterorhabditis bacteriophora seems most effective against the European chafer and Steinernema carpocapsae against the common June beetle.

Remind me again why we really should ban neonics Already

In June, the Task Force on Systemic Pesticides, an international group of 50 independent scientists, released a review of 800 studies confirming concerns about the harmful effects of neonics on bees and other pollinators, as well as to many other beneficial species, including butterflies, earthworms and birds. "As independent scientists, we can now say conclusively there is clear evidence of harm sufficient to trigger regulatory action," explained one of the authors, Madeleine Chagnon, professor of biology at the Université du Québec à Montréal. 

In addition, neonics:

  • persist a long time in soil
  • leach into our waterways

Exposure to neonicinoid pesticides from contaminated food and water also raises public health concerns. These neurotoxic chemicals may harm the developing human nervous system, according to the European Food Safety Authority, and some are suspected endocrine disrupters.

What else can you do?

Join us in calling on our regulators to side with the science and ban neonics