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Common Stalk Borer

Common Stalk Borer

Papaipema nebris

Insectalso: Stalk borer, Stalk borers

The caterpillar of a native moth that bores into the stems of corn and a very wide range of thick-stemmed herbaceous plants, tunneling inside and causing the top to wilt. It often moves from grassy weeds and field edges into a garden, where a single borer can ruin a prized stem.

🔎 How to spot it

The larva is three quarters to two inches long and is easy to recognize when young, brownish to purple with white lines running the length of the body and a dark saddle band about one fourth of the way down that makes that area solid brown or purple. As it matures the white lines fade and the body becomes brownish gray. The adult is a small gray-brown moth with white spots and a wingspan of about one to one and a half inches.

🥀 Damage it causes

The larva chews leaves and then bores into the stem, and the tunneling makes the plant wilt, with the central leaves dying while visible holes and frass mark the entry. Because the young borers migrate from grassy weeds into nearby plants early in the season, the first damage often appears along the edges of a planting. A single stem can be killed, which is significant on flowers and vegetables grown one to a stalk.

🛡️ Prevent it

Mow and control grassy weeds in and around the garden in late summer and fall, since the eggs are laid on grasses and weedy borders and the borers move from there into crops the next spring. Clean up weedy field edges before the season to cut off the source. Pull and destroy wilted, infested stems with the borer inside before it matures.

🧯 If it is already here

Once the larva is inside the stem, sprays cannot reach it, so the practical response is to remove and destroy infested stems and to manage the weedy hosts that supply the borers. If a borer is found, it can sometimes be dug out of a split stem on a valued plant. Preventive weed management the season before is far more effective than rescue treatment.

💡 Good to know

The common stalk borer has one generation a year, overwinters as eggs laid on grasses and weeds, and pupates in late summer near the soil surface. It feeds on a very broad list of plants, which is why it turns up on everything from corn to garden perennials. The dark banded young larva with white stripes is the surest way to identify it.

🌱 Plants it attacks

364 plants in the library can be attacked by this pest

Adirondack Blue PotatoAfrican Blue BasilAfrican MarigoldAgapanthusAgeratumAgrimonyAji Amarillo PepperAlice du Pont Mandevilla🥔All Blue PotatoAloe VeraAmbrosia CornAmethyst Falls WisteriaAmish Paste TomatoAnaheim PepperAnemoneAngelique TulipAngeloniaAniseAnise HyssopAnnabelle Smooth HydrangeaAnnual VincaApeldoorn TulipApple MintApril Tryst CamelliaArizona Sun Blanket FlowerArp RosemaryAshwagandhaAugust Beauty GardeniaAutumn Joy SedumBachelor's ButtonBanana PepperBarbara Karst BougainvilleaBay LaurelBeauregard Sweet PotatoBecky Shasta DaisyBee Balm🍅Beefmaster TomatoBenarys Giant ZinniaBengal Tiger CannaBetter Boy Tomato🥬Bibb Lettuce🍅Big Beef TomatoBig Boy TomatoBlack Beauty EggplantBlack Cherry TomatoBlack Krim Tomato🥬Black Seeded Simpson LettuceBlack-Eyed PeaBlack-eyed Susan VineBlood OrangeBlue Bird DelphiniumBlue Bird Rose of SharonBlue FescueBocking 14 ComfreyBonesetBorage🍅Box Car Willie TomatoBrandywine TomatoBrunneraBurning BushButtercrunch LettuceButterfly Blue Pincushion FlowerButterfly Marguerite DaisyButterfly WeedCafe au Lait DahliaCaladiumCalendulaCalibrachoaCalifornia Giant ZinniaCalifornia PoppyCampanulaCarawayCardinal FlowerCarolina GeraniumCarolina JessamineCarolina Reaper PepperCatnipCayenne PepperCelebrity TomatoChamomileCherokee Purple TomatoChervilChocolate MintCinnamon BasilClimbing HydrangeaClimbing Prairie RoseCocktail Vodka BegoniaColeusCommon ChivesCommon FlaxCommon MallowCoral Drift Groundcover RoseCosmosCreeping PhloxCrimson Cherry RhubarbCuban OreganoCubanelle PepperCulantroCuminCupani Sweet Pea

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.