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.

 

 

This entry was posted in Growing Tips, Plant Pests. Bookmark the permalink.

30 Responses to Organic Control Measures for Striped Cucumber Beetles

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

  2. 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.

  3. 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!

  4. 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??

  5. 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.

  6. 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… :-(

  7. 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.

  8. 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.”

  9. 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.

  10. 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!

  11. 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.

  12. 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.

  13. 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
    http://www.environmentalgreenproducts.com/store/insect-control-c-344.html Good luck to you all. Robert

  14. 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.

  15. 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.

  16. gwen kilchherr says:

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

  17. 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!

  18. 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!

  19. Pingback: Cucumbers | OptimysticGardener

  20. 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.”

  21. 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
    to mntion keep up the good job!

  22. Pest Control says:

    Thiis web site really has all the information I wanted concerning this
    subject and didn’t know who to ask.

  23. 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!

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>