We first reported on this issue last spring – and it has only gotten worse! Many lawns in Blueridge have been affected. What is happening? The European Chafer Beetle (not native to North America) lays its eggs in your lawn. The eggs hatch into grubs. The grubs eat the roots of your grass, killing it. Racoons, crows and skunks dig up your lawn in search of the tasty grubs. This cycle perpetuates from Fall to Late Spring when the grubs mature into adult beetle. Then they fly off and plant their eggs in another lawn. OK – enough on the life cycle of the Chafer Beetle (or Rhizotrogus majalis), the big question people have is “is there some chemical insecticide I can just spray the daylights out of my lawn to kill all those grubs?”
Answer: Yes and No. You can buy pesticide at your local hardware store BUT its use is banned in the DNV. (which begs the question, why is it available for purchase? That is another story).
Are people buying and using pesticide on their lawns? (specifically a product called Merit, or imidacloprid). Yes – they most likely are. Which is a bit sad, as there are organic options (see below) AND Merit will not only kill the beetle larvae, but all other beneficial insects in your lawn (like earthworms) AND it falls under a class of insecticides that are responsible for the decline in bee populations AND people are applying it now, but it is ONLY effective in July/August (so any application you or your lawn care provider makes now is not only wasted, it will leach into the environment).
- The larvae are only susceptible to treatment when they are babies. So just after the adult beetles lay eggs in June/July. ANY treatment you add at other times of the year will be ineffective.
Gee, insecticide sounds nasty. What else can I do?
- replace your lawn (a somewhat drastic measure). I’ve seen this done in a lot of front yards in Blueridge. It cuts down on maintenance, and is a more environmentally friendly option.
- use nematodes (a type of cut worm that feeds on the Chafer Beetle grubs – killing them). For more info on nematodes – here is some info on nematode use, courtesy of the City of Vancouver. (note: you must order nematodes from your local garden centre ahead of time. Usually they take orders in May. In addition, your lawn must be moist for at least 7 days surrounding application of nematodes. Given our hot dry summers, you will need to get a free watering permit from the DNV for that time).During the third week of July, complete these steps to treat the infestation:
- Buy nematodes (Heterorhabditis bacteriophora) from your local lawn and garden store.
- In the evening or on a cloudy day, moisten your lawn well (to the consistency of a wrung-out sponge).
- Apply nematodes on your lawn at a rate of 70,000 per square foot, or 750,000 per square metre. (Approximately 100 million nematodes should cover a 33 × 45 foot lawn.)
- Keep the soil moist for four to seven days after applying the nematodes to ensure best results.