← All pests
Japanese Beetles

Japanese Beetles

Popillia japonica

Insect

Shimmering metallic-green-and-copper beetles that swarm in mid-summer and skeletonize leaves, flowers, and fruit. They feed in groups, and the damage itself draws in more beetles, so a few can quickly become a mob.

🔎 How to spot it

Adults are about 1/2 inch, with a bright metallic green head and thorax and coppery-bronze wing covers, plus a giveaway row of small white tufts of hair along each side of the body. They are active from June through September, peaking in July and August, and feed out in the open in clusters. The larvae are white, C-shaped grubs in the soil.

🥀 Damage it causes

Adults skeletonize leaves, eating the soft tissue between the veins and leaving a lacy network behind, and also chew flowers and fruit. Because feeding releases odors that attract still more beetles, infestations snowball on a favored plant. The grubs feed on grass roots and can brown patches of lawn.

🛡️ Prevent it

Favor plants Japanese beetles tend to avoid, such as boxwood, lilac, conifers, and daylilies, when adding to the garden. Watch from late June so you can remove the first arrivals before their feeding odor recruits a crowd. A healthy lawn tolerates a modest number of root-feeding grubs without any treatment.

🧯 If it is already here

Handpicking is the most practical control: in the cool morning, while the beetles are sluggish, knock or shake them into a bucket of soapy water, and repeat daily through the flight. Do not hang the pheromone lure traps sold for them; research shows the traps attract far more beetles than they catch and increase nearby damage. Protect high-value plants with an approved product if needed.

💡 Good to know

Skip the bag-style pheromone traps unless you are deliberately luring beetles away from a distant garden; in a typical yard they make things worse. Daily handpicking early in the season pays off, because knocking out the first beetles keeps the attractant odor and the crowd from building.

🌱 Plants it attacks

714 plants in the library can be attacked by this pest

Acorn SquashAdirondack Blue PotatoAdzuki BeanAfrican Blue BasilAfrican MarigoldAgapanthusAgeratumAgrimonyAji Amarillo Pepper🍓Albion StrawberryAlice du Pont Mandevilla🥔All Blue PotatoAlmondAloe VeraAmbrosia CornAmerican BasswoodAmerican Beauty Dragon FruitAmerican BeechAmerican PersimmonAmethyst Falls WisteriaAmish Paste TomatoAnaheim PepperAnemoneAngelique TulipAngeloniaAniseAnise HyssopAnjou PearAnnabelle Smooth HydrangeaAnnual VincaApeldoorn TulipApple MintApril Tryst CamelliaArbequina OliveArizona Sun Blanket FlowerArkin CarambolaArmenian CucumberAroniaArp RosemaryArugulaAshwagandhaAsian PearAsian PersimmonAtemoyaAtlantic Giant Pumpkin🥕Atomic Red CarrotAucubaAugust Beauty GardeniaAunt Molly's Ground CherryAutumn Joy SedumAvocadoBachelor's ButtonBalsam FirBalsam PoplarBanana PepperBarbara Karst BougainvilleaBartlett PearBay LaurelBayberryBeach PlumBeauregard Sweet PotatoBecky Shasta DaisyBee Balm🍅Beefmaster TomatoBenarys Giant ZinniaBengal Tiger CannaBetter Boy Tomato🥬Bibb Lettuce🍅Big Beef TomatoBig Boy TomatoBilberryBing CherryBitter MelonBlack BeanBlack Beauty EggplantBlack Beauty ZucchiniBlack Beluga LentilBlack Cherry TomatoBlack CrowberryBlack Currant🍉Black Diamond WatermelonBlack Kabouli ChickpeaBlack Krim TomatoBlack RaspberryBlack Sapote🥬Black Seeded Simpson Lettuce🥕Black Spanish RadishBlack Tartarian CherryBlack WalnutBlack-Eyed PeaBlack-eyed Susan VineBlood OrangeBloomsdale SpinachBlue Bird DelphiniumBlue Bird Rose of SharonBlue FescueBlue Lake Green BeanBluecrop BlueberryBocking 14 ComfreyBok Choy

For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.