A rosemary beetle

Rosemary beetle

BBC Gardeners' World Magazine

Published: Tuesday, 5 March 2019 at 3:00 pm

Prevent damage to your herbs by adult and juvenile rosemary beetles.

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Purple-striped green beetles, 8mm long, congregate among the leaves, which they feed on. The beetles lay elongated eggs beneath rosemary leaves from September and continue to do so on warm days right through winter. These hatch after a couple of weeks and the larvae feed on the plants for about three weeks before entering the soil to pupate. Two weeks later the adults emerge and continue munching through the leaves and laying their eggs.

Symptoms

Holes in leaves and tiny elongated eggs left by 8mm-long green beetles with purple stripes.

Find it on

rosemary, lavender, sage, Russian sage, thyme

Organic

Pick off the adult beetles and larvae by hand and destroy.

Chemical

Spray with an insecticide, thiocloprid, between late summer and spring. Avoid using insecticide when the plants are in flower as bees may also be killed.

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