New move to boost prunes

Prune growers aim to boost production as they bolster their integrated pest management (IPM) program with a biological control for fruit tree borer.

Hundreds of thousands of native parasitic wasps have been distributed in Young prune orchards by the NSW Department of Primary Industries as it enters the second phase of a three year trial to develop a biological control strategy.

NSW DPI horticulturist, Sue Marte, said the native wasp promises to be a feasible option for the prune industry.

"A pecan orchard in Moree had similar problems with the same pest and they successfully used native Trichogramma wasps to solve the fruit tree borer issue without resorting to chemicals,” said Ms Marte.

According to Ms Marte the native wasps are likely to work well in prune orchards because most prune growers use little or no insecticide.

“The wasp is susceptible to some insecticides and the predominately pesticide-free environment in prune orchards gives them a good opportunity to search out the pest eggs without the risk of chemical harm,” she said.

It’s the wasp larvae which control the pest. Adult wasps lay their eggs in the eggs of other insects and once the wasp larvae hatch they feed on the host.

The fruit tree borer, also an indigenous insect, lays eggs in trees and its larvae burrow into the wood which reduces productivity and weakens the tree structure.

The trial has captured the interest of Young prune growers, Cheryl and Doug Heley, who are working with the NSW DPI to find a biological solution to the fruit tree borer problem on their farm.

They have developed a new line of breakfast and gourmet prunes to entice consumers back to the humble dried fruit and with a growing product range on the drawing board they want to keep production clean and green.

“We haven’t used any pesticides at ‘Budgi Werri’ since we came here in 2001 and we’re very keen on maintaining sustainable agriculture within a healthy environment,” said Mrs Heley.

“A biological control would be a great help to encourage the long-term productivity of our prune operation.”

Reducing production by up to five percent in healthy, mature prune trees, the fruit tree borer can kill young and drought stressed trees outright.

Mechanical harvesting, a standard practice in the prune industry, requires healthy, strong trees and according to Ms Marte a reduction in borer damage will boost production.

“Their trees will be healthier, their production will be better and income will increase if we can reduce borer damage,” she said.

Funded by the NSW DPI and Horticulture Australia Ltd through grower levies from members of the Australian Prune Industry Association, the project is due for completion next growing season.

Trichogramma wasps were distributed this season and scientists will evaluate their success in controlling fruit tree borers during the 2005/2006 season.

Results from this trial in the Young district will be relevant to prune growers in the Murray Irrigation Areas and Renmark, South Australia.

Borers are a pest of many trees, natives and exotics alike, and benefits generated by the prune project are expected to flow on to the cherry and stone fruit industries.

Media contact: Sue Marte, Young District Horticulturist, (02) 6382 1077 or 0427 800 379.

Issued by:
Bernadette York,
NSW Department of Primary Industries,
Head Office, Orange
(02) 6391 3533
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