Japanese beetles causing problems in Maritime gardens

Gardeners are being warned of a species of invasive Japanese beetles that are rampant in the Maritimes.

Another year calls for another generation of Japanese beetles and experts say the higher numbers in recent years could be due to the warm temperatures.

“Insects are cold blooded, the warmer it is, the faster they metabolize, the faster they grow, the more they reproduce,” says Andrew Hebda, Nova Scotia Museum retired curator of zoology.

These insects are easy to spot. They are around one centimetre in length, have a metallic green head and bronze-coloured wings. Some experts like Hebda say they are actually quite attractive, but that doesn’t take away from how destructive they actually are.

“Japanese beetles actually start as grubs in your lawn so they have been investigating your lawn and creating lawn damage, and they will emerge and find plants they like to nibble on,” explains Emily Tregunno, with Halifax Seed.

They tend to seek out healthy lawns and plants.

“If they find a garden that has a lot of delicate leaves, good leaves they will stay there until something better comes along,” adds Hebda.

They won’t be leaving anytime soon, experts say now is the peak season and they won’t be leaving until fall.

“The more you are able to get them under control of them now at the adult stage which is what we are seeing now on the plants right now, that’s the adult Japanese beetle. You want to control those now with traps, picking and squishing, however you can control them is great,” says Tregunno.

Gardeners at a community garden in Dartmouth said last year was their worst year yet. Although they acknowledge the peak for this season is just starting and they could see a lot more.

“Last year we were picking beetles at the same rate we were picking beans. I’d have four volunteers picking beans and four volunteers picking beetles. It was a good bean harvest but a lot of beetles,” says Katherine Carey, North Grove Community Farm and Market coordinator.

So far, they are picking between 30 to 100 of these beetles every day. Carey states every day she seems to find more and more.

“I’m out there usually twice a day when they get to their worst and I am picking them and putting them into a bucket of soapy water and removing that and any of the damaged leaves from where my garden is so that I am not attracting more,” says Carey.

There are ways to get ahead of them, but it starts early in the spring when the beetles are just grubs.

“You also need to think about controlling them at the grub season as well, so early in the spring season and over that spring season while they are in your lawn, you want to control them then, and you also want to control them in the fall as a grub as well,” says Tregunno.

This can be done through biological sprays, nematodes and digging them up as well. As for when they hit adulthood, there are plants that deter them but also traps that work as well.

“It’s really, really critical that you put them in the right spot of your property, so they will attract beetles in, you will see an influx coming in, so you want to put these traps about 30 feet away,” says Tregunno.

When it comes to those that eat them, not much does. Some birds, insects and raccoons, but their main predators according to retired curator of zoology, Andrew Hebda, do not exist here in North America.

“Bit by bit our fauna may adjust to that, but this may be a great new source of food for somebody. But at the moment though, we don’t, and that’s the problem with bringing some things from one place to another,” says Hebda.

Experts remind those gardening this summer that the Japanese beetle’s season here in North America is fairly short and as long as gardeners keep on top of picking them off their plants, their crops should have a good shot at surviving.

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