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

 

Biocontrol Aid For Avocado And Citrus Growers


A parasitoid wasp, so tiny that 55 pupae fit into a half centimetre circle, and the adult size is only 0.6 of a millimetre, is being released in Kerikeri this Friday (9 March). Further releases will be made in other selected Kerikeri and Bay of Plenty orchards.

This new parasitoid Thripobius semiluteus, is targeted at greenhouse thrips which damage citrus and avocados. Both citrus and avocados are commercially important crops. Citrus earned more than $9.2 million in exports in the year to June 2000, and avocados brought in more than $25.2 million. Growers estimate that greenhouse thrips cost about $6.25 million a year in fruit rejected for export and control costs using insecticides.

The New Zealand Citrus Growers and the Avocado Industry Council, supported by HortResearch lodged an application to release the parasite to the Environmental Risk Management Authority (ERMA). ERMA gave the go-ahead for the release last June but it took several more months to track down a suitable source for breeding in quarantine. Originally from South American they are established in Australia but in the end scientist Karyn Froud said it was easier to get some from a research colony in Italy.

The minute wasp lays its eggs inside greenhouse thrips, eventually killing them. Ms Froud and her team went through an extensive and careful evaluation of Thripobius semiluteus, as required by ERMA, to ensure that it would attack only the greenhouse thrips.

The little wasp arrived here in December 2000 and in the first three generations it had a 250-fold increase in its population providing plenty to release into citrus and avocado orchards in Northland, and the Bay of Plenty.

Ms Froud said only about two thirds of the laboratory population will be released. The remaining third will be kept to build up numbers for further releases.

The introduction of the new parasitoid could well have flow on benefits for home gardeners for although the greenhouse thrips is a serious pest on citrus and avocados they also attack some deciduous trees and such plants as rhododendrons and camellias. In fact it has been found in over 40 host plants in New Zealand.

Greenhouse thrips first arrived in New Zealand in the 1930s, unfortunately the parasitoid did not make it here at the same time, as it did in Australia.

This parasitoid has been successfully introduced into California, Hawaii, Israel, South Africa and Italy.

For further information contact
Karyn Froud, HortResearch Mt Albert, Tel: 09 815 420, or 025 293 1080.
Email: kfroud@hortresearch.co.nz

© 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>>

Elsewhere:


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>>

ALSO:


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>>

ALSO:

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>>