Flea Beetles, scientifically known as Alticini, are tiny invasive little pests that love to munch on the leaves, roots, and tubers of plants in the Brassicaceae and Solanaceae families.
The Brassicaceae family aka Cruciferae, mustards, and cabbage, contain broad-leafed plants like that of cabbage, spinach, broccoli, kale, and root vegetables such as turnips, radish, and horseradish.
The Solanaceae family aka nightshade and potato contains flowering plants with tubers such as potatoes, and tasty crops like tomato, tomatillos, peppers (including pimiento), and Cape gooseberry. They choose their host plants by smell as well as by sight.
Flea Beetles go through four stages in their lives: egg, larvae, pupa, and adult. They are equally damaging in both larvae and adult stages.
Adults range in size from 1/16 to 1/4 of an inch, and in color from dark brown to bronze to black with several species metallic green, striped-looking, or even blue.
Alticini lays eggs in early spring around the roots of the host plant. The eggs hatch 10 days later, and the larvae go underground to eat and grow.
After hatching in 21 to 35 days, the larvae make cocoons and pupate for about 7-10 days before turning into mature beetles. The adults are capable of both jumping and flying.
So, how to get rid of flea beetles? The following are 15 natural ways to repel them from the garden. These methods are natural and environmentally friendly so there’s no need to worry about accidentally making yourself ill or killing plants.
1. Neem Oil
This natural insecticide is one of the best ways to get rid of Flea Beetles organically.
Neem oil repels and deters these insects by disrupting the feeding abilities of the adults and the eating ability and growth of the larvae when it is absorbed by them.
The oil also masks the scent of the plant, repelling the adult bugs on it. Neem oil helps to prevent diseases these beetles spread as well.
2. Insecticidal Soap
Made from water, vegetable oil (olive oil or canola), and pure organic liquid soap or Castile soap, this potent soapy water solution takes care of flea beetles and most pest problems.
Spray directly onto the beetle in its adult or larvae form, and it will kill it on contact.
Applying it on the plant itself like some of the other deterrents will give the plant a nasty taste that will cause the beetle to go elsewhere. It will eventually kill them if they meddle too much in it.
3. Companion Planting
Using other plants to help disguise your prized crops will disrupt their reasoning ability and prevent them from finding them.
Just among the many plants that repel flea beetles, you can use plants such as dill and marigolds to mask both scent and sight of the target plants.
The right companions can also increase the yield of their partners, improve their flavors, and assist in their growth.
4. Beauveria bassiana
This is naturally occurring fungus extracted from the soil that causes white muscardine disease in Flea Beetles, among other harmful pests.
It doesn’t need to be consumed by the Beetle either. Just being touched by the spores will sick the beetles so badly, they will die eventually.
After the beetles die, the fungus will cover their bodies in a layer of mold creating more spores — a perfect pest deterrent.
If you get Beauveria bassiana from a store to put on your garden yourself, be sure to wear protective clothing and follow the instructions carefully.
5. Till Soil
Keeping the soil tilled at wintertime will keep the adult flea beetles dormant for the season. They won’t have the freedom to overwinter in the soil.
They will freeze when exposed to the cold. Doing this right after harvest but before fall will kill any larvae and pupa.
6. Trap Crops
These are sacrificial plants planted in rows between your crops or those you wish to keep plus on the edges of the garden.
If there is an infestation, you can treat your garden with other flea beetle control methods mentioned in this article to either kill them or prevent the gang from spreading.
7. Sticky Traps
These are mainly utilized to help with identifying an infestation than to prevent one. While man-made, sticky traps are considered to be basically, environmentally friendly.
Keep in mind however that due to the way they work, these traps can also catch other useful insects and bugs including bees and butterflies.
Clover, as well as other living mulch, can help disguise your main crops, making it harder for the Flea Beetle to identify, however, they do compete for resources.
Non-living such as barley straw interferes with the egg-laying process because the eggs need the soil to incubate and hatch properly.
It’s imperative these be removed at the end of the growing season to keep the adults from overwintering in them.
9. Coffee Grounds
Using coffee grounds for flea beetles is a popular remedy among gardeners, but you should be careful which plants you put them around.
While they’re a great natural fertilizer, they have certain chemicals that will adversely affect some plants.
These same chemicals are toxic to Flea Beetles in the larvae stage. Having the grounds spread out over soil under the host plants also messes with the adult egg-laying.
10. Diatomaceous Earth
This is a white powder mainly made from fossilized sea creatures. DE contains, on the microscopic level, shards of silica and shell.
It tears apart soft-bodied insects like larvae killing them. Spread it liberally around the base of plants about two to three times a week and after there’s rainfall.
11. Row Covers
This is actually a man-made deterrent but it is environmentally friendly so it makes the list.
Row covers should be installed over the rows in early spring and before it gets warm enough for the adults to emerge.
Caution: make sure you remove them when the plants start to flower, or your pollinators will have less to feed on.
12. Predators and Parasitic Wasps
Certain bug predators, like the rough stink bug (not to be confused with its pest relatives the green and brown marmorated), feed on beetles both in the adult and larvae stages.
The braconid is another specie of wasps that enjoy laying eggs on adult beetles.
With some research, you can find out which predatory bugs and parasitic wasps are native to your area as well as how to attract them.
13. Beneficial Nematodes
These fantastic microscopic little roundworms go after Flea Beetles in both forms — larvae, and adults.
Beneficial nematodes enter the bodies of the beetles and use them as hosts for themselves and their young. They will remain in the beetle until it dies and then, it will search out another one.
14. Control Weeds
Removing weeds and clearing them out when crop season is over will prevent adult Flea Beetles from overwintering in the garden and surrounding landscape.
This means not just pulling them but also throwing them away far from your garden.
15. Kaolin Clay
Used in its powder form, this versatile white clay will help mask the scent of the plants Flea Beetles love.
Kaolin clay can be used with water to form a spray or it can be sprinkled on the plants.
In addition to deterring the Flea Beetle, this natural clay can assist the growth and development of plants.
Flea Beetle Larvae Identification
Flea Beetle Larvae are vociferous eaters and just as destructive as the adults. They hatch from eggs having a white appearance with brown heads and tiny legs.
They range in size from ⅛ to ⅓ of an inch in size. The larvae hide under host plants as soon as it is hatched, and it will eat until it’s time for them to pupate.
If they devour the host plant, they will move on to another plant, and they find it more by scent than by sight.
Flea Beetle Damage
Flea Beetles are extremely dangerous in both larvae and adult stages, attacking both ends of the host plant. Adults feed on leaves while the larvae go after tubers and roots.
Adults cause shot holing damage: holes made in a shotgun pattern or a loose “lace” pattern on the leaves. If they are bothered while eating, they will jump away and return later to continue.
Larvae mine into tubers and roots making holes and grooves in the flesh. They are so minute they can’t be removed once they’re dug in.
Young plants, as well as those newly transplanted, are so fragile they tend to die from the damage. Mature plants are better able to withstand it and can grow back.
On top of the physical damage imposed, flea beetles also help spread wilt and blight bacterial diseases while denuding your crops.
Flea Beetles are among the worst insect pests a gardener can face. They’re definitely in the top five. The best way to get rid of them is to avoid getting them in the first place.
However, if you do get an infestation, try the above natural remedies before moving to harsher chemicals and insecticides. They are more environmentally friendly, and your plants will thank you.