# Striped cucumber beetle (Acalymma vittatum) > Small yellow-orange beetle with three bold black stripes; a major pest of cucurbits and vector of bacterial wilt. Source: https://insectscanner.com/species/striped-cucumber-beetle/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Striped cucumber beetles do not pose a bite or sting risk to people and are not venomous. They can be a nuisance in large numbers but pose no direct health threat. Handle with care if needed; wash hands after contact. **Pets:** Not toxic to pets. Small beetles may be eaten by pets but generally cause no harm. If pets consume large numbers and show digestive upset, consult a veterinarian. ## Quick facts - Scientific name: Acalymma vittatum - Also called: Cucumber beetle - Order: Coleoptera (Beetles) - Family: Chrysomelidae (Leaf beetles) - Size: 4.5-7 mm long - Colours: Yellow-orange, Black, Cream (larva) - Habitat: Vegetable gardens, farms and wild areas where cucurbits grow; adults on leaves, flowers and fruit; larvae in soil on roots - Range: Eastern and central North America (native and widespread where cucurbits are grown) - Active: Spring to fall in temperate zones; most abundant in warm months and during cucurbit flowering and fruiting - Lifespan: Adults live several weeks to a few months depending on season; overwinter as adults in plant debris or soil - Effect on plants: Garden pest - Pest: yes ## Overview Acalymma vittatum is a small leaf beetle strongly associated with plants in the squash, cucumber and melon family (Cucurbitaceae). Adults feed on leaves, flowers and fruit of cucurbits, and their larvae feed on roots and crowns. In addition to direct feeding damage, striped cucumber beetles are the primary insect vectors of Erwinia tracheiphila, the bacterium that causes bacterial wilt in cucurbits. They are common across eastern and central North America and appear in gardens and farms during warm months. ## How to identify it Adults are elongated, about 4.5-7 mm long, with a yellow to orange background and three distinct longitudinal black stripes running the length of the elytra. The head is black and the pronotum (area behind the head) is yellow; the underside is black and the legs are mostly yellow with dark markings. Larvae are slender, worm-like, white grubs with a brown head, and live in soil where they feed on roots. Pupae develop in the soil. - Three distinct black longitudinal stripes on a yellow-orange elytra (wing covers). - Small size: roughly 4.5-7 mm long with a black head and a yellow pronotum. - Found on cucurbit leaves, flowers or young fruit during warm months. ## Lookalikes - **Spotted cucumber beetle** (Diabrotica undecimpunctata): Spotted cucumber beetle has yellow elytra with black spots (usually 11) rather than continuous stripes; pronotum is yellow or with a dark central spot. - **Western striped cucumber beetle** (Acalymma trivittatum): Very similar striped pattern; ranges and subtle morphological differences separate them (A. vittatum is the common eastern species, check local range to distinguish). ## Life cycle - **Egg:** Females lay clusters of small yellow eggs in soil near host plants; eggs hatch in about 1-2 weeks depending on temperature. - **Larva (grub):** Larvae are slender, white, worm-like grubs with a brown head that feed on roots and crowns in soil for several weeks, reducing plant vigor. - **Pupa:** Larvae pupate in the soil; pupal development lasts several days to weeks before adults emerge. - **Adult:** Adults emerge in spring, feed on foliage and flowers, mate, and may produce one or more generations per season depending on climate; many adults overwinter in plant debris or soil. ## Diet and predators - Young eat: Roots and crowns of cucurbit plants - Adults eat: Leaves, flowers, stems and developing fruit of cucurbits; will also feed on pollen and nectar - Predators of the young: Soil-dwelling predators such as some beetles, ants and parasitic nematodes (limited impact) - Predators of adults: Birds, spiders, predatory insects and parasitoids; however, natural control is often insufficient in crops ## Effect on plants and gardens Adults skeletonize leaves and feed on flowers and young fruit of cucurbits (squash, pumpkin, cucumber, melon). Larvae feed on roots and crowns, weakening plants. They are important vectors of bacterial wilt (Erwinia tracheiphila), which can kill cucurbit plants. ### How to get rid of it Use integrated methods: cover young plants with floating row cover until flowering to prevent adult feeding and transmission of bacterial wilt; rotate cucurbit crops and remove crop debris to reduce overwintering sites; hand-pick adults early in the morning and drop into soapy water; place yellow sticky traps to monitor and reduce numbers; use trap crops (e.g., early-planted squash) to concentrate beetles and then treat those plants; if necessary, use registered insecticides targeted to cucumber beetles following label directions and local regulations. Encourage natural enemies and maintain field sanitation. Bacterial wilt cannot be treated; preventing beetle feeding and transmission is the best protection. ## Where and when to find it Adults on leaves, flowers and fruit of cucurbits; larvae in soil feeding on roots and crowns near host plants. - Best time: Warm months (spring through fall); early morning is a good time to find adults when they are less active and easier to hand-pick. - Tips: Inspect undersides of leaves and flowers on cucurbit plants. Use a yellow sticky card to monitor early-season arrival. Photograph dorsal view to capture the characteristic three stripes. ## Fun facts - Striped cucumber beetles are important because they spread bacterial wilt, which often causes more crop loss than their feeding damage alone. - They are attracted to yellow and flowers as adults feed on pollen and nectar, which is why yellow traps work well for monitoring. - Some growers use early-planted 'trap crops' to concentrate beetles on sacrificial plants that can be treated or removed. ## Frequently asked questions ### Do striped cucumber beetles bite? No, they do not bite people. They will chew plant tissue but are not harmful to humans. ### Can striped cucumber beetles ruin my cucumber plants? Yes. Heavy feeding can stunt seedlings and damage fruit, and more importantly the beetles spread bacterial wilt which can kill plants. ### Why are cucumber beetles in my garden? They are attracted to your cucurbit crops (cucumber, squash, melon, pumpkin) for food and breeding. Adults feed on foliage, flowers and fruit and lay eggs in nearby soil. ### How do I get rid of them organically? Use floating row covers until plants flower, hand-pick beetles into soapy water, use yellow sticky traps for monitoring, employ trap crops, remove crop debris to reduce overwintering, and consider organic insecticides (pyrethrin, spinosad) following label directions. ### Do insecticides stop bacterial wilt? Insecticides can reduce beetle numbers and lower the chance of bacterial wilt transmission but cannot cure infected plants. Preventing beetle feeding is the best strategy. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/154287), [Wikipedia](https://en.wikipedia.org/wiki/Striped_cucumber_beetle). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.