Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search


Gorse enemy gains strength

5 December 2005

Gorse enemy gains strength

A European insect that devours new growth on gorse has overcome a slow start and is now being found in greatly increased numbers, much to researchers' delight. Gorse is one of New Zealand's worst weeds.

The gorse soft shoot moth (Agonopterix umbellana) was released throughout the country in the early 1990s to attack the plant, but initially struggled to survive. However, more recently the moth has been found to be thriving in some South Island sites.

"At the best site near Blenheim, we didn't even need to get out of the car to be able to see them," says Landcare Research's Biocontrol of Weeds Programme leader, Lynley Hayes.

"We estimated that there were more than 100 caterpillars per square metre of gorse bush. "We can also confirm that as expected the caterpillars are eating nothing but gorse. In other words, they are not attacking any other plants."

The Marlborough District Council liberated the moths at this site in 1996 as part of its programme to develop biological control for serious weeds in the region. Ms Hayes says the moths are also doing well at a site in North Canterbury, and are common now around Lincoln, near Christchurch.

"As well as this, they've established at a couple of sites further south. Their progress at North Island release sites is currently being checked." The gorse soft shoot moth is one of a suite of six insects imported to New Zealand as biological control agents, to attack gorse at different growth stages. Gorse thrips and gorse spider mites suck sap from the foliage during most of the year.

The gorse soft shoot moth feeds on new growth in the spring and early summer and then colonial hard shoot moth takes over and feeds on all parts of the plant from autumn through until spring.

The gorse pod moth and gorse seed weevil eat the seeds. All six agents are now established in New Zealand, but only three of them are common.

"People who are interested in establishing gorse biocontrol agents on their property should contact their regional council, who will help to source them locally," says Ms Hayes.

Landcare Research scientist Hugh Gourlay says because of the weed's seed bank, resilience and ability to regrow, this suite of insects may take some time to decrease the amount of gorse in New Zealand.

"Predictive models suggest it may take as long as 50 years for noticeable change, so biocontrol is not a quick fix for those who need to control the plant right now. Biocontrol offers a long-term solution to the problem".

The Marlborough District Council and Landcare Research will hold a field day near Blenheim on Thursday 8 December to show the caterpillars "in action", and allow people to take some home for their own gorse. Participants should bring thick gloves, secateurs, paper bags and a chilly bin to Misty Heights, Kaituna Valley (about 2 km from the Wairau River bridge), at 11 am or 1 pm. Parking areas and directions will be signposted.


© Scoop Media

Business Headlines | Sci-Tech Headlines


TradeMe: Property Prices In Every Region Hit New High For The Very First Time

Property prices experienced their hottest month on record in December, with record highs in every region, according to the latest Trade Me Property Price Index.\ Trade Me Property spokesperson Logan Mudge said the property market ended the year with ... More>>

Motor Industry Association: 2020 New Vehicle Registrations Suffer From Covid-19

Chief Executive David Crawford says that like some other sectors of the New Zealand economy, the new vehicle sector suffered from a case of Covid-19. Confirmed figures for December 2020 show registrations of 8,383 were 25% ... More>>

CTU 2021 Work Life Survey: COVID And Bullying Hit Workplaces Hard, Huge Support For Increased Sick Leave

New data from the CTU’s annual work life survey shows a snapshot of working people’s experiences and outlook heading out of 2020 and into the new year. Concerningly 42% of respondents cite workplace bullying as an issue in their workplace - a number ... More>>

Smelter: Tiwai Deal Gives Time For Managed Transition

Today’s deal between Meridian and Rio Tinto for the Tiwai smelter to remain open another four years provides time for a managed transition for Southland. “The deal provides welcome certainty to the Southland community by protecting jobs and incomes as the region plans for the future. The Government is committed to working on a managed transition with the local community,” Grant Robertson said. More>>


OECD: Area Employment Rate Rose By 1.9 Percentage Points In The Third Quarter Of 2020

OECD area employment rate rose by 1.9 percentage points in the third quarter of 2020, but remained 2.5 percentage points below its pre-pandemic level The OECD area [1] employment rate – the share of the working-age population with jobs – rose ... More>>

Economy: Strong Job Ad Performance In Quarter Four

SEEK Quarterly Employment Report data shows a positive q/q performance with a 19% national growth in jobs advertised during Q4 2020, which includes October, November and December. Comparing quarter 4, 2020, with the same quarter in 2019 shows that job ad volumes are 7% lower...More>>

NIWA: 2020 - NZ’s 7th-warmest Year On Record

The nationwide average temperature for 2020, calculated using stations in NIWA’s seven-station temperature series which began in 1909, was 13.24°C (0.63°C above the 1981–2010 annual average). New Zealand’s hottest year on record remains 2016, when... More>>

Quotable Value New Zealand: Property Market Set To Cool From Sizzling To Warm In 2021

Nostradamus himself could not have predicted the strange series of events that befell our world in 2020 – nor the wild trajectory of New Zealand’s property market, which has gone from “doom and gloom” to “boom and Zoom” in record time. Even ... More>>