rosemary beetle

Q: How do I Identify and control Rosemary Beetle?

What’s the damage?

So, you’re looking forward to picking some rosemary to go with that roast lamb and from ten metres away you notice that it’s looking a bit ragged round the edges, turning brown and dying back. On closer inspection, some of the stems have been eaten back to stumps and when you get up close many of the other herbs are looking much the same. What’s going on here then?

What’s the cause?

These are the signs of rosemary leaf beetle damage. Looking rather flash in its purple striped, metallic green jacket, this small beetle is easy to spot. Out to dine on the new shoot tips of aromatic, herby type plants such as sage, thyme and mint (and rosemary, of course) causing them to die back, they will sometimes have a dessert of the flowers as well.

Nip them in the bud:

Vigilance starts in spring when you need to be looking out for the larvae. Small, pale grey slug-like critters with a dark stripe down the side – if you spot them, pick off, squish and leave for the birds to eat – it’s all a big food cycle.

If things get out of hand:

But if squishing makes you queasy or there’s just too many, here’s what to do:

  • try the organic pesticide Bug Clear Gun for Fruit & Vegetables; this is a treatment we particularly like because it’s organic, so safe to use on edibles.
  • If you should choose another spray it’s important to check that herbs are listed on the product label and the manufacturer’s instructions must be followed, particularly the harvest interval that needs to be left between treatment and using the leaves.
  • Bug Clear Ultra can be used on ornamentals which are being grown as non-edible.

Hopefully you will not be too bothered by this pest but, if you do find it, plants should not be sprayed if they are in flower to avoid harming bees and other pollinating insects.

 Learn to live with a few non-desirable insects as they do add to the overall ecology of your garden.  

Garden Pests