Flea Beetle

Flea Beetle

Flea Beetle Facts

Common Name: Flea Beetle

Scientific name: Psylliodes/Phyllotreta/Alticini

The Flea Beetle feeds on many plants in the brassica family including cabbage, broccoli and sprouts.

Also; turnip, radish, salad rocket, wallflower and alyssum. As well as, nasturtium and cleome.

Flea Beetles are active in the spring and summer.

Symptoms include:

  • Small rounded holes in the foliage, particularly on seedlings
  • Brown scar tissue surrounding the holes in the leaves
  • They also feed on the root system, causing the plant to wilt, so check on the ground too

Flea Beetles will jump off the plant when it's disturbed. Birds and frogs will eat Flea Beetles.

Non-Chemical Treatment of Flea Beetle may include:

  • Water and mist regularly; Flea Beetles do not like the wetness
  • Encourage predators for outdoor plants
  • Cover with insect netting/mesh

Main types of Flea Beetle are:

Black flea beetle (Phyllotreta Atra). Its colour makes it difficult to spot against the soil.

Large striped flea beetle (Phyllotreta Nemorum). This is black with two slightly irregular yellow stripes down its back. At 3mm it is slightly larger than the small striped flea beetle.

Small striped flea beetle or turnip flea beetle (Phyllotreta undulata). Similar to, but smaller than the large flea beetle, it has a pair of wide yellow stripes down its back.

Mangold flea beetle (Chaetocnema concinna) is a glossy, bronzed black with indented wing cases. It attacks beetroot, spinach and spinach beet.


About Flea Beetles


During the summer the adults become inactive and move to cool shaded places before returning to feed on brassica plants in the autumn. After a few weeks eggs are laid from which larvae emerge, these tunnel into the petioles of brassica plants throughout the winter into spring depending on weather conditions.  From late autumn the larvae migrate to the soil to pupate. The adults hatch from these pupae in summer. Adults can also overwinter in hedges and other sheltered areas, emerging in late spring to feed on leaves and pods. There is one generation per year.

The flea beetle is a small, jumping beetle of the leaf beetle family (Chrysomelidae), that makes up the tribe Alticini which is part of the subfamily Galerucinae. Historically the flea beetles were classified as their own subfamily.

Though most tribes of the Galerucinae are suspect of rampant paraphyly in the present delimitation, the Alticini seem to form a good clade.

Traditionally, the Alticini were separated from other Galerucinae by the presence of a metafemoral spring (i.e., jumping hind legs). Recent phylogenetic studies suggest that jumping hind legs evolved multiple times in the Galerucinae, rather than once, and that several genera should be transferred between Alticini and Galerucinae sensu stricto (or Galerucini in some classifications).

Flea beetles are very small beetles. They are mostly about 2mm long, but big bugs can be 3-4mm. Commonly shiny black, but some have a yellow stripe down each wing case, some even come in a dark metallic blue and the larvae are white with a brown head and 3 pairs of legs and are 2.5 mm long. The adults have well developed hind legs which allow them to jump many times their own height when disturbed. 

In hot dry conditions large numbers of invading adults can put at risk the establishment of crops of spring sown oilseed rape and other cultivated brassica crops unless appropriate control measures are taken.

Flea beetles usually do not cause fatal damage to established plants because the leaves are already large enough to survive a few holes. The real danger is that the beetles can spread bacterial diseases, such as wilt and blight, from plant to plant. Additionally, in leafy crops like lettuce or spinach, the holes can bring down the quality of the leaves. Therefore, it is still important to consider them a pest.


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