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Cucumber Beetles

Cucumber Beetles

Acalymma vittatum and Diabrotica undecimpunctata

Insectalso: Striped cucumber beetle, Spotted cucumber beetle

Small yellow beetles, either striped or spotted, that swarm cucurbit seedlings and flowers. Beyond the chewing, they are the main carrier of bacterial wilt, a disease that can kill a vine outright, which makes protecting young plants critical.

🔎 How to spot it

About 1/4 inch and yellow to greenish-yellow: the striped cucumber beetle has three black stripes down its back and a dark head, while the spotted cucumber beetle wears twelve black spots. The creamy-white larvae feed underground on roots. Look for the beetles on leaves, inside blossoms, and on stems, along with chewed leaves and scarred fruit.

🥀 Damage it causes

Adults chew leaves, flowers, and the rind of fruit, and the larvae feed on roots. The greater threat is disease: the beetles carry the bacterium that causes bacterial wilt and spread it as they feed, so even light feeding can be deadly. Seedlings and young plants up to the five-leaf stage are the most vulnerable to infection.

🛡️ Prevent it

Protect cucurbits with row cover from planting until they flower, then remove it so bees can pollinate. Keep beetle numbers very low on young plants, since that is when bacterial wilt takes hold. A perimeter trap crop of an attractive squash around the main planting, plus crop rotation and fall cleanup, all reduce pressure.

🧯 If it is already here

Handpick beetles in the cool morning when they are slow, checking inside flowers where they hide. Yellow sticky traps help catch them. If you must spray, treat at dusk after the bees have left to protect pollinators, and concentrate on keeping seedlings clean through the vulnerable early weeks.

💡 Good to know

Managing the beetles is really how you manage bacterial wilt, because there is no cure once a plant is infected. A vine that wilts despite moist soil, with cut stems oozing a sticky thread, has most likely been killed by the wilt the beetles delivered.

🌱 Plants it attacks

82 plants in the library can be attacked by this pest

Acorn SquashAdirondack Blue PotatoAdzuki Bean🥔All Blue PotatoAmbrosia CornArmenian CucumberAtlantic Giant PumpkinBeauregard Sweet PotatoBitter MelonBlack BeanBlack Beauty Zucchini🍉Black Diamond WatermelonBlue Lake Green Bean🥒Boston Pickling CucumberBottle GourdBroad Windsor Fava BeanButtercup SquashButternut SquashCafe au Lait DahliaCannellini BeanCantaloupeCasaba MelonCharleston Gray WatermelonCinderella PumpkinCostata Romanesco ZucchiniCranberry BeanCrenshaw MelonCrimson Sweet WatermelonDelicata Squash🥒Diva Cucumber🥒English CucumberFingerling PotatoFordhook 242 Lima BeanGalia MelonGerman Butterball PotatoGolden Bantam CornHoneydew MelonHubbard SquashJack-O-Lantern Pumpkin🍉Jubilee WatermelonKabocha SquashKarma Choc DahliaKennebec PotatoKentucky Wonder Pole BeanKidney BeanKirby CucumberLemon CucumberLuffaMammoth SunflowerMarketmore Cucumber🍉Mini Love Watermelon🍉Moon and Stars WatermelonMung BeanNavy BeanNorland Potato🍉Orangeglo WatermelonPattypan SquashPersian CucumberPickling CucumberPinto BeanProCut Sunflower🌱Provider Bush BeanPurple Dome New England Aster🥔Purple Majesty PotatoRed Noodle Yardlong BeanRed Pontiac PotatoRomano BeanRusset PotatoScarlet Runner BeanSilver Queen CornSnake GourdSpaghetti SquashSugar Baby Watermelon🎃Sugar Pie PumpkinSuyo Long CucumberTorch Mexican SunflowerTromboncino SquashWinter MelonYellow Crookneck Squash🍉Yellow Doll WatermelonYellow Summer SquashYukon Gold Potato

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.