Astrantia leaf miner

The appearance of astrantia plants can be spoiled by the larvae of a fly that feeds within the leaves.

Astrantia leaf miner damage

Quick facts

Common name Astrantia leaf miner
Scientific name Phytomyza astrantiae
Plants affected Astrantia
Main cause Larvae of a leaf-mining fly tunnelling in the foliage
Timing April-May and July-August

What is astrantia leaf miner?

Astrantia leaf miner is a small fly which develops as larvae that feed within the foliage of astrantia plants.

Symptoms

The adult flies are 2mm long and greyish brown in colour. They feed by rasping the leaf surface, causing many small pale spots on the upper leaf surface.

More significant damage is caused by the creamy white larvae. They eat the internal tissues of the leaves and cause whitish brown discoloured blotches. The mines typically have a pale edge around the darker brownish centre.

There are two generations during the summer and by August leaves can be affected by several mines.

Control

Astrantia plants will survive and produce flowers, even when there is extensive leaf mining, so control measures are not essential.

Non-chemical control

Other than removing infested leaves or squashing the larvae within the mines there are no non-chemical control options.

Chemical control

  • It is very difficult to achieve control of leaf miners with insecticides
  • If plants become extensively infested a systemic insecticide that may kill the larvae inside the leaves can be used. One systemic insecticide is available to home gardeners the neonicotinoid acetamiprid (e.g. Bug Clear Ultra)
  • A close watch should be kept on the foliage in April-May and July-August so the insecticide can be applied when damage is beginning
  • Plants in flower should not be sprayed due to the danger to pollinating insects
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener

Download

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

Biology

Astrantia leaf miner has two generations during the summer. The females deposit their eggs on the foliage during April and July. The eggs hatch into legless larvae that tunnel into the foliage where they eat the internal tissues. The mines are initially linear but later broaden to form a whitish brown blotch mine. When fully fed, the larvae pupate within the mines.

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