Organic Control Measures for Striped Cucumber Beetles

It’s that time of year and cucumber beetles are once again wreaking havoc on tender cucurbit seedlings. In all stages of life, these beetles do damage to cucumbers, winter and summer squash, melons, pumpkins, and gourds. In addition to inflicting significant damage by feeding, these beetles add insult to injury by transmitting bacterial wilt along the way. While there is no easy solution to this problem, preventative measures and specific cultural practices can limit damage and bring an otherwise unruly pest under control.

Know Thy Enemy

There are six species of cucumber beetle in the United States. Perhaps the most prevalent of these is the striped cucumber beetle, a member of the Acalymma genus. Measuring just one fifth of an inch long, this beetle is yellowish green with a black head and yellow thorax, and can be easily identified by three parallel black stripes running lengthwise on the wings of adults.

Cucumber beetles over-winter as adults in bordering vegetation, plant debris, and nearby forest. As springtime temperatures climb, cucumber beetles are actively feeding on the petals and leaves of flowering plant hosts outside of the garden. When cucurbits are planted out into vegetable fields, migration of the striped cucumber beetle is swift. After feeding on seedlings, these adults mate, with females laying up to 1500 eggs each over the course of several weeks.

The Beetle and the Damage Done

In the southern regions, up to three generations of striped cucumber beetles can be produced in one growing season, while the north generally sees only two. Cucumber beetles cause feeding damage three times during their life cycle. Over-wintered adults feed on the cotyledons and stems of emerging cucurbit seedlings. As the eggs develop, larvae tunnel into the soil and feed on plant roots. As second- and third-generation adults emerge, they feed on foliage, flowers, and stems, and can even damage mature fruit.

Fortunately, fully developed, healthy cucurbit plants can withstand 25-50% defoliation before yields are dramatically affected. Far and away the greater threat posed by cucumber beetle infestation is the potential for transmission of bacterial wilt. Bacterial wilt is caused by the bacterium Erwinia tracheiphila, which is stored in the intestinal tract of adult cucumber beetles. Once a plant is infected, the Erwinia bacterium spreads rapidly through the vascular system of the plant, creating resins which restrict the movement of water and nutrients. This causes the plant to wilt and die, sometimes in as few as seven days. Additionally, research has shown that cucumber beetles can be vectors for squash mosaic virus, as well as lead to an increased incidence of powdery mildew and black rot, and a predisposition to fusarium wilt.

Control Measures

Delayed Planting – Growers can avoid the most significant damage by simply delaying the planting of summer cucurbits by a few weeks. If you’re not set on getting the first cucumbers or summer squash to market, let a neighbor’s crop take the brunt of the spring cucumber beetle migration. This tactic can also allow seedlings extra time to grow into vigorous, mature plants capable of withstanding beetle pressure. Some growers in regions with longer growing seasons opt to skip summer cucurbits altogether, planting cucurbits in time for a fall harvest when beetles are much less of an issue.

Cultivation and Residue Removal – As cucumber beetles can over-winter in crop residues both above and below ground, it is important to practice clean and thorough cultivation after fall harvests. Cornell University suggests deep tillage, compost application, and cover-cropping in the fall to encourage decomposition of residue which may harbor beetles through the winter months. Any diseased plant matter should be burned or otherwise discarded rather than composted for future use.

Mulching – Using straw, hay, plastic, or fabric as mulch can deter cucumber beetles from laying eggs in the ground near the plants. While mulching will not halt egg-laying or feeding, it will limit direct access to the stem, as well as significantly slow larval migration through the soil.

Row Cover – Floating row covers can be a big help by excluding cucumber beetles during the seedling stage of life. This allows plants to mature and develop substantive leaf mass and a strong root system, enabling the plant to withstand a moderate pest attack. Remove row covers at the onset of flowering to allow for adequate pollination. Since row covers foster weed growth too, many producers use weed suppressing mulches in combination with floating row cover.

HMS Farm crew planting cucurbits covered with kaolin Clay to help thwart cucumber beetles.

Kaolin Clay – Here at our production farm in Wolcott, VT, we start our cucurbit season off with a bit of defensive strategy. We’ve seen a growing number of producers using Surround, a type of kaolin clay, as a protective film to ward off early damage from striped cucumber beetles. Surround comes in a powdered form, which is then mixed with water and sprayed on the seedlings. Some growers choose to dip entire flats of seedlings into the mix, which coats the underside better than does a backpack sprayer. When the seedlings are planted out in the field, the clay acts as a sticky barrier to hungry cucumber beetles, causing what some call “excessive grooming”. This keeps the beetles busy when they would otherwise be eating your prized seedlings and searching for mates.

Trap Crops - Striped cucumber beetles have food preferences just like we do. There is a long list of cucurbit varieties that are favored by cucumber beetles, and are thus excellent trap crops. By luring cucumber beetles into a concentrated area, control measures can be focused, localizing the damage and limiting the spread of disease. We recommend using Baby Blue Hubbard Squash as a trap crop, as it is highly attractive to cucumber beetles, has particularly vigorous seedlings, and is less susceptible to bacterial wilt than many other squash varieties. Trap crops should be planted on the perimeter of the field in multiple rows if beetle pressure is particularly severe. We recommend planting trap crops a week or two earlier than your primary cucurbit planting to proactively direct migration.

Sticky Traps – When it’s time to take prisoners, many growers employ yellow sticky lines of tape to trap cucumber beetles en masse. Use these ribbons in tandem with trap crops for the most effective control. Homemade yellow sticky traps can be made by coating a yellow plastic cup with glue available specifically for this use. For added effect, attach a cotton swab soaked in the oil of clove, cinnamon, cassia, allspice or bay leaf, all of which act as a powerful floral attractant.

And finally, there’s always hand-picking, but you’ll have to be stealthy because they’ll fly away when they see you coming! Let us know if you’ve had success with other strategies and best of luck to you with your summer cucurbits.



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45 Responses to Organic Control Measures for Striped Cucumber Beetles

  1. Pingback: WHAT TO DO IN THE JULY VEGGIE GARDEN | Fairfield County (CT) Demonstration Garden

  2. Frank Reuter says:

    We planted our first round of cucumbers and found excessive damage by the next morning. So we used a technique we used before: putting out yellow plastic bowls, filled with water and a tiny bit of dish soap, swished around (but not left as suds.) We put out three of these for five plants, and found about forty dead stripped cucumber beetles in a matter of hours. (We had used this technique before but never caught as many.) The yellow color of the bowl mimics flowers. Encouraged, we put out a total of six such bowls. The next morning when I went to do morning picking (strawberries, peas, etc.), the bowls had from 30 to 60 cuke beetles per bowl. Never seen anything like it. Of course, we killed one lady bug too, and a few other bugs, but 99% of the critters in the bowl were stripped cucumber beetles.
    Incidentally, a few years ago, an amazing critter, a Blue Dasher dragonfly showed up in my garden, and spent most of the day flying in and out of my cantaloupe plants; I’m assuming since we had lots of cuke beetles, harder for us to catch when the plants were big, that this voracious predator was giving us a big hand in suppressing cuke beetles, stripped and spotted. Anybody else ever noticed a Blue Dasher doing the same thing?

  3. Pingback: Pest Management on the Small Farm | The Seed Hopper Blog from High Mowing Organic Seeds

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  5. e-holder says:

    Oi !!! First year doing a decent sized garden and we have a major infestation of striped cucumber beetles. They are all over our pole beans, bush beans, and purple hull peas and doing lots of damage. They are also hanging out around the stems of our emerging squash, but haven’t done much damage to them yet. Our pumpkin plants don’t seem to be a major target yet and are doing okay. We planted in late July in North Alabama, so maybe late planting hasn’t helped us. Not sure we can plant these crops much later and miss the frost. So several defense methods listed here. Now to research and see which we have time, patience, and money for…

  6. topes says:

    Hello… muy question is not specifically insect related, but also about deseases with cucumbers… specifically the mosaic viruis, which apparently is transmitted by touching an infected plant and then mechanically spreading the desease to the rest of the plants. Apparently the way to reduce this problem is by using some sort of vegetable support netting hortomallas istead of twine. Can somebody share his/her experience? thanks

    PS this is where i read about the transmission by hand

  7. CaptPuddles says:

    Any one know if cuc beetles eat cheese wheel mallows? I had wonderful pumpkins and yellow squash last year with no beetles. This year my new location for the pumpkins is swarmed. The only thing that has grown out there before was the mallow weeds..
    Just curious.
    My cucumbers and butternut squash are doing wonderful, no beetles..yet..and are further from the pumpkins. It must be from something else unique to that area.

  8. lemonfair says:

    I garden in a community garden, so I will never be able to get rid of the cucumber beetles – just make my own plants more resistant than some others. Bacterial wilt is a persistent problem, and I’m very interested in spraying this coming year with some juices from plants the beetles theoretically don’t like – nasturtium, broccoli, radish, mint.

    One of the Rodale books says that Marketmore 76 is more resistant to bacterial wilt, and I’ve found this to be true. HMS sells this cultivar. I’ve also noticed that neighboring gardeners who grow Burpee burpless cukes have less damage, which makes sense. I think they are burpless because they have less of the cucurbitacin that attracts beetles.

    I’ve used surround, and found it effective for a few days. The problem is that as soon as the growing tip expands just a little it is free of surround and attacts the beetles. I think the surround also slows the growth a little – in effect it shades the leaves from the sun. It’s difficult to keep up spraying the surround on all the new growth.

    But I mostly wanted to let you all know that tomatillos are the most effective trap crop I’ve found. The beetles prefer them to cukes, and the beetles don’t seem to damage the tomatillos. Since the tomatillos self-sow in my garden I just wait until the hundreds of seedlings show some larval damage and then pull and destroy them. This reduces the numbers. But the ones I let grow will continue to attract the beetles all summer long.

    • Sara says:

      I second the part about the tomatillos! We grow tomatillos for picking, as we love tomatillo salsa. Our cucumber rows this year are right beside our tomatillos, and have absolutely no damage from cucumber beetles so far… while the tomatillos have been all but obliterated over the last three days. I’m a little bummed about the tomatillos, but really glad about protecting the cucumbers. The tomatillos grow like weeds, and we’ve already harvested a ton of fruit off of them. Maybe I’ll just let them keep working to defend the cukes.

      We put up the yellow solo cup/tanglefoot traps two days ago, baited with clove oil, and have trapped a bunch of the pesky little beetles, but hand-picking as the sun sets is actually a lot more effective (for us.) They’ve been really easy to grab while they’re mating. This is our first year at a new house, and I’ve never had to battle these guys before, so this is all new to me.

  9. Neem cake says:

    The growing accumulation of our experience demonstrate that Neem work by intervening at several stages of an insect’s life. At first, once Neem cake is consumed by an insect, Neem cake then alters the shape and structure of hormones present in the insect and that are vital to the lives of insect (not to mention, including many invertebrates and even some microbes).

  10. Pingback: Meet The Beetles - And A Bug Or Two | Randy's Perennials & Water Gardens | Lawrenceville, GA | 770.822.0676

  11. Mavis says:

    I am leery of anything that kills all the bugs…I want to keep the good guys. I have subscribed to Organic Gardening for more than 30 years and remember reading more than once, but not recently, about a method of bug control that involves collecting a bunch of the bugs, running them through a blender – with some water, I guess – then using the filtered liquid as a spray on the infected plants. I don’t have the stomach to do this; however, I have discovered that simply squishing some aphids right on the plant causes them to all disappear within a day or two…something about their scent bringing in the bugs that eat them. In a panic the first time I found cucumber beetles on my veggies, I reacted by frantically squashing a number of blossoms to kill the beetles. Funny thing, they were all gone a couple days later. I can’t promise it will always work – I have a few beetles now even though I squashed a couple several weeks ago, but I sacrificed a blossom or two this evening and hope to give the ton of baby cucumbers hanging on the vines a better chance to keep growing.

  12. Kelly Beatty says:

    I have only a few squash and cucumber plants, so I vowed to be vigilant this year after watching them get chewed up, wither, and die last year. my implement of choice is a pair of long, thin, needle-nose pliers. I find that early morning is best, when the blossoms open and the beetles go inside to feed. easy pickins! they also seem to like to mate in the blossoms, and their couplings make them less inclined to fly away. so far, so good: the count is dropping, and plant damage has been minimal!

  13. Pest Control says:

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  14. Hola! I’ve been reading your website for a llong time now and finally got the bravery to go ahead
    and ive you a sshout out from Porter Tx! Just wanted
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  15. Elisa Cannino Soto says:

    First timer and new to any kind of gardening, or growing anything. Its been a long time since I’ve even tried. I killed many a poor house plant with my lack of green thumb. I have googled & looked up lots just for my lettuce & cucumbers. My mother in law, who is old school and plants seem to love her, lol.. Had me spraying my cucumber leaves with coffee. We also used a little dishwashing liquid & water. It did seem to slow down the consumption of the leaves. But a week of rain & there isn’t much to save. Still trying though, out there alot using Tim King yellow tip painted paint stirrer w/ tanglefoot & keeping them going. So many great suggestions out there. Lucky for me, we have a few bats local. Definately thinking of building them a home. Like Tara said. Also the Pryganic that Robert Charland has tried I’m looking into myself. So much help & ingenuity, like Gabe Halberg’s dustbuster idea. Sounded cool & easy but he must be using something alot less powerful, because I damaged a few leaves myself trying it. Oh well, I’m learning growing my own foods isn’t so easy, but with people like you all, I’m finding what works for me. Just want to say “Thank you, to everyone of you who put it out there. God bless.”

  16. Pingback: Cucumbers | OptimysticGardener

  17. tara says:

    a colony of 150 (that’s not many) big brown bats can consume 38,000 cucumber beetles in a summer. put up a bat house near your property and reap the benefits!

  18. Sara says:

    I have been battling these lil pest since the beginning of planting my cucs. This is my first year planting. They have terrorized my melons as well. I was wondering how to get rid of the eggs on the underside of the leaves. If I picked all the leaves that had eggs on them, I would have no plants at all!!! I have gotten good at catching the adults but they seem to be laying faster than I can kill them. Another question is before I plant my winter squash and pumpkins should I rip up my cucs and melon plants to ensure that no bugs are around? I till every time I remove a veggie plant as well. Getting a bit frustrated. I’ve used a bunch of the organic ideas, traps, sprays, ect…many thanks in advance!

    • lemonfair says:

      The easiest way to get rid of the eggs under the leaves is to brush them off with your fingers. They are very soft, and easy to remove. No need to remove the whole leaf. Of course, this is impractical if you have large tracts of cucumbers, but for the home garden it should work well.

      You can crush the eggs with your fingers, but I don’t worry about it. Once they fall to the ground they will dry up, or – if they hatch – there will be nothing there for them to eat on hatching.

      • sandy says:

        Another great way to get rid of eggs is to use duct tape! Just cut a few inches of it, wrap around your fingers with sticky side out, and touch the eggs. They stick to it and then just throw the tape away.

  19. gwen kilchherr says:

    anyone know how effective Spinosad is in controlling cucumber beetles??? thanks!

  20. Angie says:

    This is my first time growing much of anything this year. I live in an apartment, so all of my pants are in containers. I have self-diagnosed that my cucumber plant is being eaten by the cucumber beetle. However, I have not seen anything! Is that normal? I will applying some sticky traps around it in order to catch it. I guess I’m just confused because I’ve never seen one of these beetles and I have been intensely looking at the plant for days.

  21. Laurie says:

    After battling cucumber beetles in previous years, last year I applied beneficial nematodes at the start of the season, and found very few cuc beetles. I still had problems with squash bugs, so the nematodes didn’t help with those. This year I did not spray the beneficial nematodes, but still have not seen any cuc beetles or squash bugs so far (it is still early). This year I am proactively spraying alternately with neem, homemade cayenne/garlic sprays, and sprays made with the juice of boiled rhubarb leaves. I also have mulched this year with 3-4″ of woodchip mulch. I also was able to locate some Surround WP online (it is not sold in CO), and applied it for the first time yesterday. I’ve also read that they don’t like mint or lemon balm, so I’m growing these elsewhere (they can be invasive) and using the leaves as mulch around my cucurbits. I’ve also planted trailing nasturtiums among the cucurbits. With so many variables, I know I won’t know what’s working, but I’m throwing everything at them this year and so far am successful. Perhaps in a month I’ll remember to leave a comment about my results.

  22. Robert Charland says:

    I found my first ever striped cucumber beetle on a squash flower this morning. First thing is I will do is keep a lookout to see if I find more. I think I’m OK unless I notice a heavy, or the start of a heavy infestation. If you have really good soil I believe that nature will balance things out. My Rodale book on Garden insects disease & weed identification guide says that cucumber beetle are preyed on by various soldier beetles. I know that because I use sheet mulching almost exclusively that I have large populations of a variety of beetles. I will not let my cucumbers and squash be decimated at any rate and I am prepared to go to extreme measures just as long as it is approved organic. I recently purchased some Pyganic crop protection EC 1.4 which contains pyrethrins. I was thrilled when I found that this product is OMRI approved and can be used up to day of harvest. It kills over 100 different pests. I thought I was dreaming when I stumbled upon this product because up until then my strongest weapon has been Neem oil which was practically useless against a nightmarish infestation of aphids last year. Still I only use it when I really have to but I will if I find a lot more of the striped cucumber beetle. this year luckily aphid pressure is low. Here is a link to the on-line company where I bought the Pyganic Good luck to you all. Robert

  23. Haig says:

    Cucumber beetles have always been a fact of life in my gardens. In addition to all your recommendations I have resorted to hand picking at night using a head lamp. Feeding activity is very pronounced at night with cucumber beetles as well as a surprising number of other pests. They do not fly away as easily because of the light a can be hand picked. On some evenings a few plants have yielded as many as 100 beetles. I’ve noticed that on squash plants used as trap crops that a high percentage congregate inside the flowers so it is easy just to pick and discard the flower.

    • Andrew S says:

      yes, I can find many congregating in the flowers. It seems they can just hideout in the flowers during the heat of the day.

  24. Kat says:

    This is the second year that the cucumber beetles have waged war against my squash, pumpkin, and cucumber seedlings. Last year I tried organic powder and then dusting with lime, neither did any good. This year I bought the traps and lures, but they don’t seem to do much either. I’ve gone out for the past 3 days and picked them off by hand and squished the bugs- ripping off the heads is good revenge. Our neighbor a mile away plants tons of pumpkins for sale, he never seems to have this problem- but he tills in a lot of manure every year, maybe the healthier seedlings are less susceptible.

  25. Joel says:

    Argh…just discovered these are what are hitting my plants. Like the comment above: looks like a shotgun was taken to some of the foliage.

    I haven’t found any actually on my plants, but they’re flying away when I get to the garden.

    Maybe a treatment of Sevin to kill the initial batch and then monitor them is what’s in order. I was going to make the garlic & red pepper spray, but I want these guys gone today!

  26. Sheryl says:

    I usually head out early in the morning with a cup of coffee and nab a hundred or so beetles by hand. It seems to work in the evening as well (something other than coffee), and the coolness seems to slow the bugs down. In the heat of the sun, they are very challenging because they fly away.

    If I keep the numbers down, the plants seem to have a chance . . . I plant many more than I will need, just in case.

    Datura seems to attract them as well. The purple datura can be planted around the perimeter of the garden, and the seeds are abundant to collect for next year.

  27. Tim King says:

    I have had great success with a “sticky wand,” something I made when I was making some home made sticky traps (which I’m not using any more because they also trap beneficial insects). I took a paint stirrer, painted the end yellow and coated the end with Tanglefoot. I manually trap the beetles by tapping them with the wand and they get stuck on it. Probably not a good solution for someone with a lot of plants, but I’ve been getting up to 20 beetles from one cucumber plant each time I go out. I’m not sure if the yellow color is important, but they don’t seem to get spooked and fly away as the wand gets close. I’ve also found it useful to approach the beetles from underneath if possible as they roll off the plant onto the ground when spooked.

    • Elisa Cannino Soto says:

      Are you Tim King of Freedom Farms? Tried your yellow tip wand technique coated with Tanglefoot. It worked pretty good. Coming at the beetles from underneath not working to good for me although I have managed to get a few after they’ve rolled for other reasons. “Thanks.”

  28. Kathy Fober says:

    I’m trying a product called Tanglefoot. I ordered it from Amazon. I’m going to paint it on yellow solo cups and place them throughout the garden. I did not plant my beloved Zinnias this year because they seem to be a favorite of the spotted cucumber beetles. I also bought a yellow sticky trap from Gardens Alive. It’s up and has gotten some bugs but not any cuc beetles yet. I have only seem two flying so far. Keeping my fingers crossed.

  29. Gabe Halberg says:

    We’ve got a bad infestation this year on our squash, and I’ve been sucking them up in a portable dust-buster type vacuum (read that suggestion somewhere online). They seem a bit more sluggish in the late afternoon/early evening, so that’s a better time to go hunting as they don’t fly away quite so readily. I’ve found that when I jiggle the plants some cuc beetles crawl up out of the soil at the base of the stem as well. The process is tedious, and I’m not sure how effective it is yet, though I did see markedly less beetles today than yesterday. Hopefully it’s helping, though there’s the eggs they’ve already laid to look forward to… :-(

  30. nancy turner says:

    This year, we had our cukes and squashes fully covered w/ row covers… and the cucumber beetles started to lay on our potato plants! (We don’t have much of a potato beetle problem here). I was surprised that they transferred over to the potatoes.

  31. Jerry Wynne says:

    ,, I have used Diatomacous earth around the base of my cucumbers to deter the larva stage from damageing the root system and have pretty good success. My question is ,, when do the beetles arrive. I have pumpkins with four or five leaves and totally looking like a shotgun was used on them ,, and my cucumbers seem to be hole free. How soon do they show up and start their problems,,,, jerry ,,,, ps i have NOT seen any of them on the plants,,, no bugs no eggs??

    • lemonfair says:

      I do not use diatomaceous earth in the garden because it will also damage earthworms. The diatoms are tiny creatures with spiked skeletons (google for a picture), and it’s these spikes that kill the larva. They will not dissipate over time, as they are hard, mineralized skeletons, even though they are tiny.

  32. Rita Jacinto says:

    There is a product on the market that combines a yellow sticky trap with a pheromone lure. These work really well but can be expensive. The lure is an essential oil that is found naturally in bay and allspice essential oils. You can make your won by soaking a cotton ball in the oil and stapling it to the center of a yellow sticky card, hang these just above the leaf canopy and watch the suckers die!

  33. Grace says:

    You mention some different options to help control the cucumber beetles. Could you also give information/links on where one can buy these type of products. Love to read about possible solutions but also would like sources where to purchase too.

    • Roser says:

      Just saw some of these little buggers on my plants. Decided to graze over the ones I could see with a propane torch before heating up the ground around the plant. Just a quick pass killed them instantly without damaging the plant (I hope) and I feel heating up the ground around the plant will kill the larve. Don’t no if its gonna work, but I don’t have anything to loose.

  34. Pingback: Grow So Easy Organic: Organic Control Measures for Striped Cucumber Beetles | Grow So Easy Organic

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