Flea Beetles

(Question)

I am getting ready to plant radishes, arugula and lettuce in raised planters with potting soil. Last year my radishes and arugula were attacked by Flea beetles. Is there anything I can do to prevent and control them? I live inMarkham
Thank you

(Answer)

Flea beetles love vegetables from the cruciferous family such as radishes and arugula, so it’s good to consider some preventative measures as you are planting these early crops.

It’s always useful to understand the life cycle of the pest you are trying to control.  Adult flea beetles over winter in soil and plant debris.  They lay their eggs in the soil in early summer.  The larvae hatch in 1-2 weeks and feed on roots for about 10 days (but cause little damage) before emerging as adults to feed on your plants.  There may be one to three generations of flea beetles per growing season depending on the species.  The bulk of the damage is caused by the adult beetles that emerge in the spring.  Seedlings are most at risk.  Mature plants are generally less susceptible to this pest.

There are a number of steps you can take to prevent flea beetle damage but the most effective one is to plant your cruciferous plants in another part of your garden.  In your case, this can be fresh potting soil or ensuring the soil in your planters is well tilled and all garden debris removed – this will eliminate any overwintering flea beetles.  Once your seeds are planted, cover your planters with summer weight garden fabric to prevent new infestations.  You should be able to remove the fabric by mid summer.

Other preventative approaches include:

  • Grow susceptible plants such as radishes and arugula interspersed with less susceptible plants.
  • Grow a trap crop to attract the bulk of the pests and keep them away from other plants.  Could your radishes be grown in a separate container for this purpose?  Some damage to the radish leaves may not effect the overall development of the radish root.
  • Use sticky traps to trap the beetles.
  • Mulch your raised planter to help retain moisture in the soil, as rain and moisture reduces feeding activity of flea beetles.
  • During the growing season, if flea beetles have been active, cultivate the soil to destroy any larva.
  • Sow the seeds of any susceptible plants as late in the season as possible as flea beetles are most active in the early spring.

I hope one or more of these approaches will work for you and contribute to a great crop of radishes and arugula this year.