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Rosemary beetle

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
Time to act: late-summer, autumn

Overview

Purple-striped green beetles, 8mm long, congregate among the leaves, which they feed on. The beetles lay elongated eggs beneath the 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.


Solution

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

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.




Discuss this problem

Talkback: Rosemary beetle
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kaycurtis 24/11/2011 at 15:27

never ending battle all these bugs, need more of the good guys

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.

susan gilbert 14/06/2014 at 16:29

I have just found these beetles on my lavender bush. I have never seen them before. are they new to this area (East Yorkshire) and what should I do about them?