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Asparagus beetle

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last updated Mar 26, 2013
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Asparagus beetle larvae. Credit: RHS/Science.

Asparagus beetle is the most widespread and damaging pest of asparagus during the summer months. Heavy infestations weaken the plants and cause a poor crop in the following spring.

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What is asparagus beetle? Back to top

Asparagus beetle is a pest both in its adult and larval stages. They eat the foliage, and also gnaw bark from the stems, causing growth above the point of damage to dry up.

Symptoms Back to top

  • The adult beetles are 6-8mm long (about 1/4in), black in colour with six yellow blotches on their wing cases and a reddish thorax
  • Both the adult beetles and their grubs feed on asparagus foliage and bark
  • If the bark around the stem circumference has been completely removed, the stem and foliage above dries out and turns yellow brown

Control Back to top

Non-chemical control

Burn old stems at the end of the year to destroy overwintering beetles. Hand pick the beetles and larvae from plants when seen from late spring onwards.

Chemical control

Large plantings, where hand removal is not feasible, can be sprayed with pyrethrum (Py Spray Garden Insect Killer, Doff All in One Bug Spray or Scotts Bug Clear Gun for Fruit & Veg). If the plants are in flower, spray at dusk to avoid harming bees.

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Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

Biology Back to top

  • The beetles emerge from the soil in May and June and lay elongate black eggs that are attached by one end to the asparagus spears and foliage
  • The creamy greyish-black larvae are up to10mm long (3/8in) when fully grown, after which they go into the soil to pupate
  • There are two generations between May and September
  • In the autumn, adult beetles seek sheltered places where they overwinter

Quick facts

Common name Asparagus beetle
Scientific name Crioceris asparagi
Plants affected Vegetable asparagus, but not ornamental Asparagus species
Main symptoms Presence of beetles or their grubs on the plant. The foliage is eaten and may dry up and turn brown
Most active May-September
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