How to Identify Flea Beetles
Given that there are so many species of flea beetles, they vary in appearance quite a bit. Colors range from black to tan, with other, brighter colors mixed in, and the beetles may have a solid, striped, or spotted pattern depending on the species.
To identify flea beetles, it’s easier to look for signs of their damage (described below) than for the beetles themselves. At only 1/16 of an inch in length, flea beetles are very tiny and will quickly spring away—like fleas—if they see you approach!
When Do Flea Beetles Appear?
Adult flea beetles overwinter in brush and wooded areas. Adults pose the biggest threat early in the planting season as they are emerging, typically when outdoor temperatures reach 50ºF (10°C). At this time, seedlings are being planted, too, and they are most susceptible to beetle damage.
Eggs are laid at the base of plant stems in early summer after the spring feeding period, and larvae feed at the roots.
Flea Beetle Damage
Adult beetles feed on foliage, producing “shotholes” in the leaves. Look out for these holes especially on young seedlings, where damage is most rapid and will cause the most harm. The holes they make will be round and can quickly damage leafy greens. New leaves are usually damaged first, and they will have a lacy appearance.
Flea beetles usually don’t cause fatal damage to established plants because the leaves are already large enough to survive with a few holes. The real danger is that the beetles can spread bacterial diseases, such as wilt and blight, from plant to plant. Therefore, they are still important to consider a pest.
Photo Credit: University of California White Mountain Research Center. Flea beetles can cause leaves to appear lacy after they’ve caused a lot of damage.
Reader Comments
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Flea beetles
Do they live indoors
Cucumber Beetles
No, cucumber beetles are not generally a problem indoors, unless they’ve hitchhiked on your clothing or a plant that you brought inside. Even then, they are unlikely to reproduce indoors.
hi, We have some mustard
hi, We have some mustard grown here, unfortunately, flea beetle left so many holes on them. After that, I found that the hole edge get purple, so it looks like there are so many purple holes on mustard. It's different from holes flea beetle left on other vegetables. Do you know the reason for this?
Purple Holes
Some varieties of mustard naturally have a purplish tinge to the leaves, so our guess would be that the tissue immediately surrounding the holes in the leaves starts to die and lose its green chlorophyll, leaving the dark color around the holes. On the other hand, a fungal disease called alternaria leaf spot may cause purplish-black lesions in leaves. Search google for an image of alternaria leaf spot and see if it matches what you’re seeing. If alternaria leaf spot is the culprit, remove heavily affected leaves and avoid planting mustard in the same spot next year.
Any chance of damage to birds that forage in the garden?
I am just wondering whether the dead beetles sprayed with this mixture pose any danger to songbirds foraging in the garden?
Bird Safety
Hi Kathleen,
The amount on the insects should be small enough that there will be no adverse effects to birds.
Flea beetle control
Can I make a spray with 100% alcohol? Maybe only 1shot to 5cups water?? Or would coffee grounds be better on the ground with flour sprinkled on the plants?
Flea beetle spray
How often should you use the spray?
get rid of flea beetles
Hi, Meredith. You can apply as often as once a week. Good luck!
Flea Beetle Indoors
Do you have any suggestions for eradicating flea beetle indoors? I am a florist who uses locally grown flowers and these bugs seem to have setup camp in the drop ceiling of my studio. Not sure what they are surviving on.
flea beetles on tomato leaves
I sprayed one leaf with the alcohol/water/liquid mixture yesterday. The leaf turned brown and curled. Any other ideas? Maybe less alcohol?
Reduce Alcohol
Yes, dilute the mixture with more water. Try doubling the amount of water and testing again.
Alder flea beetles
My alder trees get these guys every year. I tried to wrap fly paper around the trunks this year and it appears to have helped a bit, but do they fly up from the ground into the upper areas of the trees or do they migrate up the trunks into the leaves? If they travel up the trunk, sticky tape would seem to be a possibility for controlling them. Any ideas? I lost an ancient singleton alder years ago from these bugs. If left alone, they can do significant damage.
eliminating flea beetles
We turned to the experts for help with this one, Roderineo, especially because you have them in your trees. Because the fleas seem to overwinter in the leaf and plant residue at the base of the trees (see the following), you might consider cleaning up those areas.
• Here’s a forest management site that describes their life cycle: https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5186816.pdf
• Here’s the Oregon Cooperative Extension: http://oregonstate.edu/dept/nurspest/alder%20flea%20beetle.htm
• Britain’s Royal Horticultural Society has very good information; here’s what they say about this: https://www.rhs.org.uk/advice/profile?PID=850
We hope this helps!
turnips
what is it when I grow turnip the get holes all through them underground in the little turnips ive never seen any bugs could it be cutworms and how do I get rid of them?
turnip holes
Hi, Ken, It could be cabbage maggots, which are the larvae of the cabbage root fly. They love turnips. The most efficient preventative is to use floating row cover (light-weight “cloth”) in such a way that it creates a tunnel and is secued at ground level on all sides (and ends). The cover can touch the plants, but should be loose enough as to not constrict growth of the plant. We hope this helps!
tomato insect
I'm not sure that I have flea beetles because they don't try to jump away (or flee.. yuk) when pulled off my tomato plants. They tend to cling to the leaf. They are dark black, a tad shiny and shaped like a football with a somewhat rounded tail and a bit more pointed head. They are very small, 1/16" or smaller. They do have wings, small antenna and appear to have eight legs. Aside from that, they eat small elongated holes in the leaf and may have been responsible for yellowing of the plant especially on the bottom 1/4 of the plant. However, plant food seems to have helped with the yellowing. I applied Sevin spray this morning and hope that helps. Are these flea beetle and what else can I try if the spray doesn't help?
flea beetles
How large are the "parts" of alcohol and water? You specify 1 Tablespoon liquid soap, but not the amount of alcohol and water to which it is added.
flea beetle spray
You’re right, Linda. It seems we’ve mixed apples and oranges here. We suggest mixing 5 cups water with 2 cups alcohol plus 1 tablespoon of liquid soap.
Alcohol concentration for flea beetle spray
I'm thinking ahead to the next growing season and how best to combat the flea beetles that always destroy my Brassicas. I rent a plot in a community garden, so I don't have as many options as I would on my own land. In looking at your alcohol spray, it seems a little heavy on the alcohol, and I wonder if it might burn young plants. Is there a minimum ratio of alcohol to water that would still be effective against these pests, or is it just trial and error? Also, I have heard that vinegar can help. Do you have any thoughts on this and what might be a good ratio of vinegar to water to deter the beetles but not damage the plants? Thanks.
alcohol and vinegar sprays
I’m not sure if a study has been done as to the minimum ratio of alcohol/water plus soap for effectiveness. However, you are right to be concerned about burning plants. With alcohol sprays, always test a solution on a small area before spraying an entire plant or crop; some plants may be more sensitive than others. You might try a solution with a small percentage of alcohol to water and work up to determine the minimum you can use and still have it be effective. As to vinegar, same precautions. One must be very careful about proportions, or as you have read, the vinegar’s acetic acid can kill plants (at higher concentrations, vinegar is used as an herbicide). Some sources suggest avoiding using it at all, especially on vegetables or flowers. Others suggest 3 parts water to 1 part vinegar, and only spraying leaves. If you try this route, you might try diluting the solution even further, then testing on a small area first. Hope this helps!
blue flea beetles
We have stacks of blue flea beetles on our land and see them as a blessing. They got on top of the dreaded buzzies and congregate in large clusters on dying vegetation. Our little granddaughter treats them as pets. They are most welcome apart from being beautiful.
Blue beetles
We have these little suckers everywhere on our property. Vegetable garden, strawberry patch and the house garden and natives. Any clues how to treat. Not sure about the rubbing alcohol on food we will be eating. And how to treat such a large area.
The Beetle Blues
Hi, Betty: Sorry to hear! It sounds like these might be blue milkweed beetles, which always pose a tricky problem because hosts for them like milkweed and oleander, which you would want to eliminate if nearby, are also beneficial to monarch butterflies and others. The best thing to do is bite the bullet and try to physically remove as many as possible by plucking or even using a handheld battery-operated vac. Another option is an organic insecticide applied very specifically to aggregations of beetles where found. It’s important to try to do this before they lay their eggs, so alacrity is of the essence. Good luck!
Heres another trick to try as well
Take old coffee grounds and about 5 or so drops of hot sauce care not to use much hot sauce as it can burn roots but put that at base of all plants .. For leaves i use flour once a week on all my plants.. The only down side i seen with flour was little dough balls in my yard but they go away in a short period of time after it rains i reapply everything again
Do shining flea beetles bit
Do shining flea beetles bit and we found one in our house but we don't have any plants inside or outside our home
Is there any risk in eating
Is there any risk in eating the plants that were infected with flea beetles? My entire crop of Arugula was infested and now my Brussels sprouts are getting eaten as well. I am also noticing small brown balls where they sprouts are growing. Any advice is appreciated.
WHAT ARE THE CATIPILLARS THAT
WHAT ARE THE CATIPILLARS THAT PUNCH THROUGH THE HUSKS AND INTO THE CORN EAR AND HOW DO YOU PREVENT THIS.
THANKS
The corn earworm is the
The corn earworm is the larvae of a tan night-flying moth. Wait 'til the ears start to fill out and put 1 or 2 drops of mineral or vegetable oil on the silks. You can also treat the corn with Bt (Bacillus thuringiensis).
Mineral oil. A few drops into
Mineral oil. A few drops into the silks at top of ear. Works like a charm
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