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


Parasites doing well in apple orchards

3 July, 2002

Helpful Parasite Alive And Well In Hawke’s Bay Orchards

A tiny parasite wasp released into Hawke’s Bay apple orchards in February 2001 appears to be thriving.

The new biocontrol agent for the obscure mealybug was released in New Zealand after 6 years work and following approval from ERMA.

This was the culmination of co-ordinated research and support from HortResearch, ENZA, the IFP20 Group of apple growers, NZ Pipfruit, FRST and, finally, approval from ERMA in August 2000. The wasp, with the scientific name Pseudaphycus maculipennis, is called Pmac (‘peemac’) for short.

About 60,000 Pmac were released into six apple orchards around Hastings in February 2001, and have been left to their own devices since then. A trapping programme in April this year showed that they have already established in at least two of the orchards.

“This is good news” said John Charles, the HortResearch scientist leading the programme, “as it shows that they can survive the winter and the normal orchard management programme, and also are able to find sufficient numbers of mealybugs in the orchards to live on and then disperse”.

An additional 140,000 or so Pmac were released to a total of 13 Hawke’s Bay orchards last summer. They have already been recovered from one of these orchards.

“It is too early to tell what impact they are having on mealybug populations in these orchards” Mr Charles said, “but we hope to be able to measure Pmac’s success in controlling mealybugs over the next couple of years. We also plan to release more Pmac into Hawke’s Bay, and to expand the release programme to Nelson apple orchards – and, indeed, any other places and crops where obscure mealybug is a problem.”

The economically damaging obscure mealybug was first found in New Zealand in 1922, and until now it has had no significant natural enemies here. It lives in cracks and crevices in trees or fruit, as well as on leaves and roots of host plants. In apple trees they move into the apple calyx when the fruit is quite small. They feed and grow inside the apple and excrete honeydew. Sooty mould fungi grow on the honeydew and appear as a black deposit around the calyx. Although the fruit is unharmed, and the sooty mould is purely cosmetic, those apples are rejected for export and downgraded to domestic or other uses.

The mealybugs also infest other fruit crops such as peaches and grapes, where they transmit grapevine leafroll disease.

Mr Charles said that with the fruit industries’ rapid move into organics and integrated fruit production (IFP) methods there were increased opportunities for successful biological control. These parasites will be extremely important in further reducing the dependence on insecticides for mealybug control.


© Scoop Media

Business Headlines | Sci-Tech Headlines


Media Mega Merger: StuffMe Hearing Argues Over Moveable Feast

New Zealand's two largest news publishers are appealing against the Commerce Commission's rejection of the proposal to merge their operations. More>>


Approval: Northern Corridor Decision Released

The approval gives the green light to construction of the last link of Auckland’s Western Ring Route, providing an alternative route from South Auckland to the North Shore. More>>


Crown Accounts: $4.1 Billion Surplus

The New Zealand Government has achieved its third fiscal surplus in a row with the Crown accounts for the year ended 30 June 2017 showing an OBEGAL surplus of $4.1 billion, $2.2 billion stronger than last year, Finance Minister Steven Joyce says. More>>


Mycoplasma Bovis: One New Property Tests Positive

The newly identified property... was already under a Restricted Place notice under the Biosecurity Act. More>>

Accounting Scandal: Suspension Of Fuji Xerox From All-Of-Government Contract

General Manager of New Zealand Government Procurement John Ivil says, “FXNZ has been formally suspended from the Print Technology and Associated Services (PTAS) contract and terminated from the Office Supplies contract.” More>>