Controlling Flea Beetles in the Garden

I have noticed a huge increase in flea beetles in my garden over the past 2 years. Flea beetles have become a problem in gardens and canola crops across the prairies. Completely getting rid of flea beetles in the garden is unlikely, but thankfully there are ways to control flea beetles so they don't destroy your vegetable garden.

​What Are Flea Beetles

What Do Flea Beetles Do?

​What Plants Do Flea Beetles Attack?

​The Life Cycle of Flea Beetles

Controlling Flea Beetles in the Garden

Plants that Deter Flea Beetles

Flea beetle on a spinach leaf

What Are Flea Beetles

Flea beetles are small black bugs, about the size of an ant, with a hard shell. When disturbed they jump. There are two types of flea beetles commonly found in backyard gardens, the crucifer flea beetle (pure black), and the striped flea beetle (black with two yellow stripes down the back).

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What Do Flea Beetles Do?

Flea beetles feed on many different vegetables and weeds. Young flea beetles chew holes through the underside of plant leaves, preferring young cotyledon leaves, but eating mature leaves as well. Young plants are more susceptible to demise from flea beetle than older, more mature plants.

A cabbage ravaged by flea beetle

What Plants Do Flea Beetles Attack?

Flea beetles love anything in the mustard or brassica family. Flea beetles attack the following plants:

• alyssum

• arugula

• beets

• broccoli

• Brussels sprouts

• cabbage

• canola

• cauliflower

• eggplant

• hoseradish

• kale

• kohrabi

• mustard

• nasturtiums

• pak choi

• radish

• shepherd's purse (weed)

• stinkweed

• spinach

• turnips

Radishes being eaten by flea beetles

The Life Cycle of Flea Beetles

Adult flea beetles overwinter in soil, leaves, grass and other organic material. They begin to emerge in the spring when temperature consistently reach above 14⁰C (57⁰F). These adult flea beetles feed on young plants, mate and lay eggs in the soil near plant roots. This second wave of adult flea beetles emerge from late July to early September.

Controlling Flea Beetles in the Garden

Flea beetles thrive in sunny, hot, dry locations. Keeping your garden well watered and providing shade during hot afternoon sun can decrease flea beetle activity.

Yellow sticky trap covered with flea beetles

1. Some suggest using trap crops, (alyssum works well for this) by planting them as soon as the flea beetles emerge. I'm not convinced that is the rout to take, as it seems it possibly attracts more flea beetles.

2. A vacuum can be used to vacuum flea beetles off plants.

3. Spray with neem oil.

4. Yellow sticky traps can be used trap adult flea beetles. Check to make sure bees and other beneficial insects are not falling prey to the sticky traps. Discontinue use if you find any.

5. Dematiaceous earth (DE) can be sprinkled on infected plants. Note: be careful not to inhale DE as it can cause lung damage. DE will also kill beneficial bugs. DE only works when it is dry.

6. Waiting until 3 weeks after flea beetles emerge to plant plants they are attracted to can help minimize damage to those plants.

7. Start susceptible plants indoors, so that they are stronger and can withstand flea beetle attack before they are planted outdoors.

8. Cleaning all dead material and tilling garden soil helps destroy and get rid of flea beetles and flea beetle eggs for next year.

9. Use row covers on susceptible plants. The row cover needs to be fine enough the beetles cannot crawl through and you must make sure there are no spaces between the row cover and the soil where the beetles can get through. This only works if you do not already have flea beetle eggs in the soil.

A raised bed covered with row cover to keep bugs out

Row cover options include this amazing netting from Canadian company GRD Netting (this is what I use, you can use discount code Zone3Veg for a 5% discount), floating row cover or this pre made row cover from Amazon. To make hoops for your row cover, check out this row cover DIY tutorial.

Plants that Deter Flea Beetles

Flea beetles do not like catnip, sage or mint. Note: some varieties of peppermint are invasive. Use caution when using peppermint as a companion plant to deter flea beetles.

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