Newspaper article Evening Chronicle (Newcastle, England)

Protect Your Herb Gardens

Newspaper article Evening Chronicle (Newcastle, England)

Protect Your Herb Gardens

Article excerpt

Anyone with a herb bed should watch out for the rosemary leaf beetle (Chrysolina americana), a herb-munching menace which has become one of the UK's most troublesome pests, according to the RHS advisory service.

Andrew Halstead, principal entomologist for the RHS, says: "Unfortunately, it appears that this year's newcomers are going to cause problems for gardeners for a while to come."

Originating from southern Europe, both adults and larvae eat the foliage of rosemary, lavender, thyme and sage.

Gardeners can identify the adult beetles by the metallic green and purple stripes on the wing cases and thorax. The grubs are greyish-white with five darker lines lengthways. Fully-grown larvae can reach 8mm, the same size as the adult beetles.

Halstead adds: "Rosemary beetle can be controlled either with insecticides or hand picking of the adults and larvae.

"Unfortunately, there are no recommended insecticides that can be used on rosemary and other herbs if they are to be used for culinary purposes.

"Where pesticides are used, these are best applied in late summer to early autumn or in the spring, when the beetles and larvae are active on the plants, but avoid spraying while the plants are in flower."

Anyone can access advice and information on garden pests and other horticultural problems by visiting the advisory pages on RHS Online ( visit

The pests which prompted the most enquiries to the RHS advisory line in 2005 were:

1. Slugs and snails: Most active from early spring to autumn when they feed on a wide range of plants, seedlings and emerging shoots and foliage of herbaceous plants.

2. Lily beetle (Lilioceris lilii): Voracious pest of lilies (Lilium species) and fritillaries (Fritillaria species), with both the larvae and adult beetles devouring the foliage during spring and summer.

3. Vine weevil (Otiorhynchus sulcatus): Destroys a wide range of plants, both in its adult and larvae stages. …

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