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White Grubs

White Grubs

Family Scarabaeidae

Insectalso: Grubs, Lawn grubs, June beetle larvae

The fat, C-shaped larvae of scarab beetles, including Japanese beetles, masked chafers, and May and June beetles, that live in the soil and chew on roots. They are best known for browning out patches of lawn, but they also feed on the roots of vegetables, seedlings, and ornamentals, weakening plants from below.

🔎 How to spot it

Grubs are plump, soft, C-curved larvae up to about an inch long, dirty white with a tan to brown head and three pairs of small legs near the front. You find them by digging a few inches into soil or under loosened, browning turf. Above ground the signs are irregular patches of wilting or dead plants and spongy lawn that pulls back like loose carpet, often torn up further by skunks, raccoons, and birds digging for the grubs.

🥀 Damage it causes

White grubs chew off roots and root hairs, so plants wilt, yellow, grow poorly, and pull up easily because the root system is gone. In lawns they create dead patches that look like drought even after rain; in the garden they damage the roots of seedlings, vegetables, strawberries, and potatoes. Healthy turf can tolerate up to about ten grubs per square foot before damage shows.

🛡️ Prevent it

Reduce the beetle egg-laying that starts an infestation by not overwatering lawns in midsummer, since the adults prefer to lay in moist soil. Keep plants and turf vigorous so they outgrow light root feeding, and turn over garden soil in fall to expose grubs to cold and to birds. Manage the adult beetles, such as Japanese beetles, to limit the next generation of grubs.

🧯 If it is already here

Where a few plants are affected, dig and destroy the grubs you find. Beneficial nematodes (Heterorhabditis bacteriophora) and the bacterium milky spore can be watered into moist soil to attack grubs, working best on young grubs in late summer. Time any treatment for late summer when grubs are small and feeding near the surface, not for the large, deep grubs of spring. Water treatments in well.

💡 Good to know

Several different beetles share the white-grub stage, and they can be told apart by the pattern of hairs, called the raster, on the underside of the tail end. Grubs hatch in summer, feed near the surface, then burrow deep to overwinter and return to feed in spring before pupating. Because they spend most of the year underground, late summer is the only practical window to control them.

🌱 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.