The Japanese Beetles Are Coming! The Japanese Beetles Are Coming!

Correction: They're already here.

For the last three years, I planned to apply milky spore to my lawn, and for the last three years, I did not, and so every summer, the Japanese Beetle Battle ensues.

Japanese beetles (popillia japonica) are voracious feeders--they can cause serious damage to a small, organic garden. The little metallic dudes were accidentally brought to the United States from Asia around 1916. They are said to devour more than 300 types of plants--in my garden, they especially dig basil, carrot tops, and pepper plants. Once they mature into the adult seen below, there is not much hope of eradicating them. The trick is to get them the year before, by treating their young with something called milky spore.

Milky spore is a naturally occurring bacterium that acts as an effective organic pesticide for beetle larvae, which live for most of the year under your lawn as ugly, white grubby guys. Milky spore, which comes in powder form, should be applied after adult beetles lay their eggs and the eggs are hatched. We're currently under beetle attack now in the Midwest, so if your garden is, too, the time to apply milky spore is coming! I plan to treat my yard in the next three to four weeks.

Keep in mind that treatment this year doesn't help with this year's Beetle Battle--it's to head off next year's war. This is how it works: in August, newly hatched grubs begin to feed on tender grass roots, so it's a perfect time to apply milky spore. The grubs digest the stuff, the bacteria begins to reproduce in the gut of the grub, and within a few weeks, no more ugly, white grubby guys. If they are not killed off at this time, they burrow deep below your lawn and emerge many months later as hungry Japanese Beetles.

To fight off the mature beetles that are already at work this year, the best thing to do is begin midnight bug hunts. Get out there with a bowl of soapy water and a flashlight. They are attracted to light, so get the landscape lights off of your plants during this time and onto a plantless area--the back wall of my house works well. The beetles conveniently congregate there, allowing for an effective surprise attack.

These guys are fairly slow-moving, so it's not difficult to locate them and knock them into the soapy bowl. Sometimes I get really crazy, especially after my 11pm glass of red wine, and knock them to the ground, using my cute pink garden clogs to stomp them to oblivion.

The earlier you get to these guys the better, because upon finding a particularly delicious cultivar, they attract additional Jap Beets by leaving a pheromone trail ... a sort of neon, flashing bug billboard that reads "Eat This--It's Super Yummy!" You may have seen the pheromone traps sold at hardware stores and garden centers, but many experts feel that the traps attract more beetles than are caught. I decided to stay away from them.

I have tried to detract them from my yard by spraying a spicy pepper water on my plants: 5-6 diced habaneros, garlic, and cayenne in some water, let sit in the sun for a few hours, then strain it. I tried it for a few days, and it actually seemed to help, but it was right before leaving town, and the remaining potion did nothing but stink up my garage. I do think that it's worth another try. Garlic planted in your prized beds is also said to turn them off. And geraniums are said to attract them, and then kill them off.

Japanese beetles are a huge summer problem in Midwest gardens--what are your experiences with them?

   “O'er folded blooms on swirls of musk,
   The beetle booms adown the glooms
   And bumps along the dusk.”

   -- James Whitcomb Riley

Sources:

Cook, Kelly A. and Grey, Michael E, "Japanese Beetles: Popillia japonica Newman," Integrated Pest Management, http://ipm.illinois.edu/fieldcrops/insects/japanese_beetles/index.html.

Hart, Anna, "Home Organic Gardening Pesticides--Part 2," Organic Springtime, http://www.organicspringtime.com/organic-pests/home-organic-gardening-pesticides-part-2-41/.

"How to Control Japanese Beetles in Your Organic Vegetable Garden," Blue Horizon Farm, http://www.bluehorizonfarm.com/organic-gardening/japanese-beetles.html.

"Japanese Beetle Quarantine," Rutgers Department of Entomology, http://www.mosquito.rutgers.edu/jb.htm.

Liskey, Eric, "Japanese Beetle: Bugs from h-e double hockey sticks," Everyday Gardeners, http://www.bhg.com/blogs/everydaygardeners/2012/07/06/bugs-from-h-e-double-hockey-sticks/.