Inadvertently introduced to North America almost a century ago, Japanese beetles are some of gardeners’ most despised backyard troublemakers. In their larval stage, Japanese beetle grubs live in the soil and feed on tender plant roots. The air-borne adults munch on the fruit and leaves of countless edible and ornamental species including annuals, perennials, trees and shrubs. Without taking any action, either scenario can result in damages and even cause total crop loss. The good news? Spring is good time to make an impact on hungry Japanese beetle populations before they emerge in full force.

To combat these little buggers when they’re most vulnerable, dig down and determine that you, in fact, have Japanese beetle larvae in your yard. They’re approximately one-inch in length, white in color and typically found in a curled position burrowed just a few inches below the surface of the soil. Because moles love to eat grubs, their presence may also indicate an infestation as can random patches of dead turf.

Got grubs? With the all-natural ingredient Bacillus popilliae, Milky Spore is one of the best applications available: it’s effective, easy to use and will not harm beneficial insects, birds, people or pets. Once Milky Spore is applied (anytime the ground is not frozen), grubs ingest the naturally-occurring bacterium and die within a month’s time. Additionally, as these grubs decompose, they release billions of new spores which remain active in soil for up to 20 years and give you a substantial return on your initial investment.

You can also opt to establish live beneficial nematodes which can manage over 250 different insect pests in the soil, including grubs. Like Milky Spore, this is a safe method of biological control and requires warmer 50-55° Fahrenheit ground temperatures.

Come late spring and early summer, Japanese beetles will reach their adult life stage and consequently be a bit harder to eradicate. Oval in shape and less than a half an inch in length with an unmistakable iridescent green coloration, Japanese beetles are easy to identify and large enough to be handpicked and destroyed by placing them in a dish of soapy water. If you don’t have time to frequently monitor and handpick invasive populations, a lightweight crop cover can also be implemented to protect your favorite plantings. Up to your elbows in beetles? Try a natural and powerful spot treatment like Bonide® Rotenone-Pyrethrin Spray before throwing in the towel and turning to a chemical insecticide.

Finally, some gardeners choose traps to capture the adult pests. This is particularly advantageous if everyone in the neighborhood participates, although these traps should be used with caution. Because they do indeed attract Japanese beetles, traps are best located away from any susceptible plants, and prompt disposal is important as the odor of stale lure and bugs in the summer heat is anything but pleasant.

If you’re still not making a dent in the number of Japanese beetles visiting your yard, consider swapping out rose bushes for a more resistant and just as lovely lilac, or choose a magnolia, dogwood or pine in lieu of future plantings of Japanese maples and apple trees. GG

Emphasizing environmentally-friendly gardening practices indoors and out, Kari Bayne is the Senior Staff Writer for The Worm’s Way Group, member of the Garden Writers Association and life-long gardening enthusiast. Get inspired about organics, hydroponics and more at www.wormsway.com or call 1-800-274-9676 to request a catalog.