Aussie pistachio industry to 'spray and pray' against disease
The Pistachio Growers’ Association of Australia Incorporated (PGAI) will soon release an interim report advising farmers how to handle an anthracnose outbreak that has cut crop values by 75% this season.
PGAI research committee chair Chris Joyce, says he has received messages from around the globe offering support, as the industry searches for a solution to a disease that has never affected pistachios before.
"The magnitude of this has put us back a long way, we just lost 75% of our value. Pistachios are largely alternate bearing, typically with five to six (metric) tons per hectare in an on-crop and one or two (metric) tons per hectare for an off-crop," Joyce told www.freshfruitportal.com.
"We were going into an on-crop and we were expecting good results, but when you lose 75% of your value you’re struggling to stay alive.
"I’ve received emails from friends all over the world offering to assist, particularly from Californian researchers like Themis Michailides. They had a rather ferocious problem in the late 90's, which was botrytis cinerea."
He says the outbreak is a result of unusual weather conditions in what are normally very dry zones, especially after Cyclone Yasi.
"Typically, when you get rain in the summer it's in bursts, but this year we had four or five events; the last of these being the tail end of Cyclone Yasi, when we had five days of perfect fungus weather. And this is in the arid Murray Valley.
"Now that the orchards are infested with anthracnose spores, they’re not going to need the same deluge to re-create those conditions.
"No one’s ever used fungicides for their orchards before, they’ve never needed to. We’re not sure exactly which one to use as anthracnose is not known to pistachios. We only know the literature on what’s been effective with other crops and applying that to pistachios. We’re spraying and praying."
"In spring (Southern Hemisphere), we’ll send the full report to growers with strategies about various fungicides. I'd say that will be by October," says Joyce.
Joyce admits the Australian industry is 'almost irrelevant' by international standards with a value of around AUD$15 million (US$16 milion), but how the recent anthracnose outbreak pans out could have further-reaching implications.
"Californians and other pistachio growers from around the world are obviously concerned and would like to learn from our experience.
"We were planning to double our harvest area over the next decade, and I think that’s still on but the majority of investing was going to be always from individual existing players, including myself, and all of us having been given a good bashing this year."
Dr Prue McMichael from Scholefield Robinson Horticultural Services is heading up the research project.