How to control flea beetles
Flea beetles can be a real nuisance, especially when your plants are just getting started in the spring. This is a time that they need to get off to a good healthy start, and these flea beetles eat them to death, one tiny bite at a time.
This spring I have had some pretty serious issues with flea beetles on my eggplant, beans, and to a lesser extent my peppers. Flea beetles attack a wide variety of plant types, but most flea beetles only like one type of plant. They achieve this broad spectrum attack on plants, because there are many types of flea beetles.
There are actually (5) flea beetles on this poor eggplant
What do they look like?
They are usually small, shiny, black or brown, and jumpy like a flea.
What plants do they typically attack?
They typically feed on the leaves of beans, solanaceous plants such as eggplant and peppers, and brassicas. I have found that they are brutal on my beans and eggplants.
How do I know that I have flea beetles on my plants?
Flea beetles create a shotgun hole effect on the leaves of the plant as if they were blasting your poor plant with a sawed off shotgun. You will typically be able to see the flea beetles on the plants. If you shake the plant they will jump, just like fleas.
“Shotgun hole” damage on my beans that is characteristic of the flea beetle
Cultural and physical control methods
1. Rotate your crops: If you grow the same thing in the same spot year after year, you are making it too easy for them. My beans are probably too close to where I had them last year, and they have just been destroyed this spring.
2. Trap crops: Radish can be used as a trap crop. I did plant my radish next to my beans this year, but it had little effect, so I will not try this again.
3. Vacuuming: Some people will vacuum the fleas off the plants every day or so. This can be effective, but it must be done often. I don’t think it is very practical.
4. Mulching can diminish the flea beetles by interfering with the soil stage of the beetle.
5. Floating row covers: These can be put out in the early spring when the beetles come out. It is important to seal them well, as the beetles are small.
Chemical control methods
1. Your garden variety insecticides can be effective for a week or so, but you do have to reapply. I would not spray these if you can avoid it. If you have a bad infestation, there are better alternatives.
Alternatives to chemical control
1. Neem oil can be effective as a repellant.
2. Diatomaceous earth applied as a powder to the leaves is also a good repellant.
I normally just let the flea beetles have at my plants. Typically, the plants are strong enough to grow out of the beetle damage, but this year they really caught my eggplant transplants before they had a chance to root, so I ended up spraying neem oil on my eggplants. This should give my poor eggplants an opportunity to grow without being harassed for a little while. My beans are in worse shape, but I have 4 additional sowings, so I am not so worried about it.