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Flea beetle

Symptoms

The upper leaves of brassicas and various ornamentals are riddled with holes. Seedlings may be wiped out. Swarms of tiny beetles, often shiny and black, hop away when disturbed.

Find it on: brassica seedlings, nasturtiums, alyssum, anemone, stocks, cleome, godetia
Time to act: spring, summer

Overview

The culprit is the flea beetle, which, like its namesake, jumps away when disturbed. The small, shiny, black, brown or blue beetles emerge in April and May, after winter hibernation, ready to start feeding. Eggs laid near host plants hatch in late-summer. The beetles feed for a few weeks before overwintering.


Solution

The upper leaves of brassicas and various ornamentals are riddled with holes. Seedlings may be wiped out. Swarms of tiny beetles, often shiny and black, hop away when disturbed.

Organic

Seedlings are especially vulnerable to attack, so protect them by waiting until they're a good size before planting out. Exploit the beetles' habit of jumping and catch them with a sticky trap. Coat a piece of card with grease, such as insect barrier glue, leaving a clean strip along one edge. Brush the clean edge of the card over the top of your plants - when the beetles hop into the air they'll stick to the grease. Repeat as necessary.

Chemical

Use pyrethrum chemical controls, taking care not to disturb the beetles before an application, or they'll jump out of harm's way.




Discuss this problem

Talkback: Flea beetle
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valerie1 24/11/2011 at 15:29

On my allotment i find that flea beetles are not as selective as your article suggests. They love a wide range of plants from radishes to turnips. I had never heard of them before working on the allotment.

What would interupt their life cycle - apart from killing the adults when they have already attacked the crops?

Valerie

ILOVEBEES 24/11/2011 at 15:29

Before using thiacloprid, imidacloprid, acetamocloprid or any other neonicotinoid pesticide, I recommed visiting the Buglife website, to read their report summarising independent research on neonicotinoids. They kill bees & other non-target insects - eg. butterflies etc. Miniscule amounts impair the ability of insect to function resulting inevitably in death. Also, seek out the fact sheets from the US environment agency -you may get a shock! We used to manage without them & can now.

lacharriere 24/11/2011 at 15:29

thought the sticky solution was an excellent organic idea - have just tried it using a piece of tree band (for protecting against insects).
Seems to have collected quite a lot of the little beasties - will continue daily and see how it goes.
Have protected my newly planted brassicas with small tunnels - hope this will keep them protected

bellamax 24/11/2011 at 15:29

valerie1's comment above is understandable because turnips, radishes and swedes are all part of the brassica family and so are subject to flea beetle attack.

Jaynie 10/07/2014 at 07:31

The flea or pollen beetle has devastated my rambling rose about 3 years running by sucking the buds/blooms dry. I haven't noticed it jumping rather it burrows deep into the centre of the flower and scurries there quickly if it senses movement on the flower. It seems only 'drugged' by the use of pyrethrum control ie it doesn't kill it. So far the way I have found to help is to spray the bush every night with soapy water which brings them out. Then knock them off into a jar containing soapy water to drown them. Cut off damaged blooms (they are still being attacked early July). Sadly though this has resulted in my removing practically all flowers so far.
Hope this helps others as i found it difficult to identify and to get advise regarding control.
- jayne