New Zealand mealybug threatens meconopsis

Plantsman Ken Cox has questioned the importation of plants from New Zealand after one of Scotland's most characteristic flowers, the meconopsis, came under threat from an imported root eating mealybug.

He said the cold-hardy New Zealand mealybug kills meconopsis and primula roots and could have come in on a tree fern log. Cox added that Australia and New Zealand have "stringent regulations on imports, so why do we import plants from New Zealand?

"I can't understand if we understand if we know all these pests and diseases are in Australia and New Zealand, why don't we apply the same rules to importation, for bare root at the very least, or better still not import from Australia and New Zealand. The mealybug could kill all the meconopsis in Scotland."

He said there had been an outbreak in the last six months in Scotland, which could eat the roots of cordyline, dendrobium, dianthus, erica, eucryphia, gentiana, ozothamus, rhododendron and rhopalostylis, among others. Grasses, tomatoes and heather can also be affected.

Defra's UK Plant Risk Register states: "Polyphagous root-feeding mealybug endemic in New Zealand and now present in Scotland and northern England. Though most hosts suffer minor impacts, large populations can build up on some hosts such as Meconopsis and cause damage. Stakeholder groups may wish to continue monitoring developments, including any spread to the wider environment, i.e. heather."

Symptoms are underperforming plants with 2-3 mm insects covered in a golden yellow wax attached to the roots.

The non-native golden root mealybug, Chryseococcus arecae was first recorded outside Australasia in the UK in Dunblane, Perthshire in September 2012, than at a garden in Ross-shire in 2013. The mealybug is a native of New Zealand that unlike other root mealybug species found in Britain can be found on the roots of outdoor plants all year round.

The RHS said there are no pesticide controls for root mealybugs in open ground and infested plants should be burnt.


Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

Pest & Disease Factsheet - Plane anthracnose

Pest & Disease Factsheet - Plane anthracnose

Take action to avoid this disease causing dieback and rendering plants unsaleable

Pest and disease management - Phytophthora root rots

Pest and disease management - Phytophthora root rots

Treatments to defend against these pathogens should be used alongside good hygiene practice.

Pest & Disease Factsheet - Needle blights

Pest & Disease Factsheet - Needle blights

Prevalent in wet, humid conditions and particularly on susceptible crops grown under overhead irrigation, tip blights can adversely affect a range of conifer species.


Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Latest Plant Health Alerts