Claims by the Green Party that kiwifruit growers should stick to copper sprays in their fight against PSA because it has proven to be successful overseas have been slammed by an industry scientist.
This week Green food spokesperson Sue Kedgley urged the kiwifruit industry to abandon its plans to spray the antibiotic, streptomycin, on their orchards and instead use copper based sprays which she claimed were successfully controlling PSA in Europe.
"Copper based sprays are being used successfully overseas to manage the infection and our orchardists should follow their example."
However, Otago University biochemist, Professor Russell Poulter, says Sue Kedgley simply does not know what she is talking about.
"The latest data from Italy indicates that far from copper controlling it, it is destroying the Italian kiwifruit industry. Not damaging it, destroying it: and it’s going to do the same to the French, the Spanish and the Portuguese. Copper just doesn’t work."
Despite what he says about copper’s effectiveness, or complete lack thereof, Professor Poulter says the chemical element is already being used extensively in the Bay of Plenty.
"They are using copper by the truck load. They’ve got ships coming into New Zealand loaded with copper, I mean huge amounts are being used. If you know the area, it’s getting an overall blue tinge. Despite that, the thing (disease) is still spreading."
Professor Poulter says it appears PSA has a natural resistance to copper, and this is shown by the continuing rapid spread of the disease through the Bay of Plenty.
And while he argues injecting streptomycin may be a better option for kiwifruit growers than spraying it, Russell Poulter says the industry is fast running out of time to act, as PSA spreads even more rapidly in the Spring.
Informed of Professor Poulter’s opinion on the effectiveness of copper in battling PSA, Sue Kedgley told Country99TV.
"The thing is that I understand that this is a crippling disease. It is very serious'
"But I just think there is a temptation to resort to things like spraying an antibiotic and, inevitably, there are going to be significant downstream effects, and really you have to take these into account."
