Crows!! Why Are You Destroying My Lawn?!?! March 01, 2016 11:37

Crows Eating Grubs

In recent time, maybe you've noticed the strange phenomenon of devastated lawns in Vancouver. Maybe you've thought, wow, Vancouver is filled with amazing gardeners and terrible lawn stewards. Maybe you've thought, "new business venture opportunity! Tending lawns, and supplying non-hack-job mowers!" Maybe you've thought this is your opportunity to be Vancouver's real-life superhero - the friendly, neighbourhood Lawn Man/Woman/Girl/Human! What is actually happening is the consequence of a delicious European grub called the Chafer Beetle, which appeared for the very first time in New Westminster in 2001 and has since made themselves at home all over Metro Van. Who brought those buggers over?! 

Before the Chafer Beetle looks like a beetle, it exists as a small, plump, beigey white grub. It has six legs, a brown bowl shaped head, and you will probably find it curled into a ball under your grass. Their bodies are pretty hard, which keeps them protected from bugs who want to eat them alive with their vicious jaws. Since they are blind, they have thin white hairs that act as sensors. Their creepy beige color is a result of a lack of pigment, which creatures above ground carry to protect ourselves from the sun. Since these wrinkly grubs live underground and will hopefully never see the sun, it would be useless for them to waste precious energy on this pigment.

Chafer Grub
Chafer grub found right beneath some East Van grass in late February. Nom nom.

After hibernating deep into soil, away from the cold surface frost, around February, these larvae munch as much as they can from shallow roots of plants like grass. In mid-May, they will have enough energy to make their transition into their pupae form, which resembles a hybrid character that is half Skeletor, half Ridley Scott's Alien. It stays in pupa form for only two weeks. In June, they metamorph into their final adult self - the flying, buzzing, Chafer Beetle. In this form, they live for only 7-14 days, and spend the entire time swarming around trees and shrubs.

Chafer Lifecycle
From egg, to larva, to pupa, to adult Chafer Beetle form. Photo cred: entomology.osu.edu

You may have seen these buzzing swarms and thought what a miraculous recovery in population the bees have made this year, and what a good job they are doing pollinating that tree... Wait a minute, these trees have no flowers, there's no pollen! Upon closer look, you may realize these are not cute bumblebees, which are actually solitary individuals. These are disgusting Chafer Beetles! But what are they doing up there in large swarms, buzzing around like bumblebees? Well, in short: they are having a great bit orgy party. They spend their entire time as adults mating. They mate, lay eggs, go back to mate some more. And then, spent from all the action, they die shamelessly leaving their carcasses all over your streets, lawns, even at your door steps. 

In July, the eggs they have laid begin to hatch into the first instars, a first of many exoskeletons which, starting in September, will be shed a few times as they grow into bigger instars. And so, the process repeats. 

Chafer Grass
Excellent tilling job by our friends the crows. Honorable mentions to the racoons and skunks!

So what can we do about these ultra rapidly invasive buggers? Well, lucky for us, these protein-rich grubs make a delicious snack for the many crows and trash pandas living in Vancouver. My recommendation is to let the animals eat their grubby lunches, and subsequently, do the dirty work of tilling your land. Then plant an awesome garden filled with deep rooted plants the chafer grubs won't care for. 

New Garden!Let the crows do the hard work of tilling your grass so you can put in a beautiful new garden with deep setting roots.

Other recommendations by the City of Vancouver include inoculating your garden with a nematode called Heterorhabditis bacteriophora in July when the instars are at their most physically vulnerable. You have to water the nematodes in so they can swim their way to the larvae. This is not great in the summer months of July, as this is usually when drought season starts, but if you can manage to get a watering  exception from the city, the nematodes will swim into the larvae and eat them alive from the inside out! Sounds harsh. My human sensitivity prefers they be offed quickly with a satisfied chomp of a crow's beak.

Murders hanging around the trees, ready to feast
Murder of crows hang around in food coma after a good chafer feast.

There is one more thing we can do to help reduce the Chafer Beetle population, which is to eat them ourselves! Insect cook Dominique Goulet says his preference is to "...roast [grubs] with salt and other spices." He suggests to "enjoy [them] with crackers and hummus, or in your salad. If you want less crunch, stir fry [them]. Make sure to boil for 60 seconds before cooking."

Mmm... Rub-a-dub-dub. Thanks for the grub.

 

by Kelsey Cham Corbett
March 1st, 2016