Three wet years, a wet summer and an early season green bridge has seen a widespread epidemic of stripe rust in wheat crops throughout NSW.
However, experts say there is no need to panic.
Dr Steven Simpfendorfer, senior plant pathologist at NSW Department of Primary Industries, Tamworth, said that while the rust is prevalent throughout the state, growers should not 'panic spray'.
"There is a lot of stripe rust about and very early in the season," he said.
"We have collected or been sent 210 samples and 35 per cent of those have been for stripe rust, making it the dominant disease this season.
"It is not unexpected. The three wet years in a row, a wet harvest and a wet summer have greatly increased the rust pressure.
"Along with the GRDC, we predicted this would be a one in 50 year for stripe rust. It is the earliest epidemic we have had.
"Normally the rust wouldn't show up until later and the plant genetics would fight it. But because it has shown much earlier this season, the plant hasn't developed enough genetically to fight it.
"It hasn't helped that many growers couldn't get on paddocks to complete their summer spraying program. That has just added to the pressure."
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Dr Simpfendorfer said growers should be smart with their fungicide spraying.
"I encourage growers not to panic spray, and seek our advice," he said.
"Stripe rust resistant varieties like Lancer may be showing signs of rust now, but will likely clean themselves up as they get older.
"Some varieties are going to need two sprays this season but it is unlikely any will need three."
Senior agronomist at B&W Rural Moree, Brad Donald, said that stripe rust was in most wheat crops in the area.
"It is easily identifiable in most of the wheat crops in the surrounding area," he said.
"I think many growers will go to a two-spray strategy. Some years you can get away with one, but not this year. We are seeing it in varieties you don't usually see it in.
"It's important growers get advice, monitor their crops and be proactive.
"If you are unsure, contact your local agronomist or the NSW DPI and get the best advice you can."
Pursehouse Rural Coonabarabran agronomist, James Fleming, said many of the wheat crops in the area weren't mature enough yet to see stripe rust, but expected it to be a concern.
"At this stage, due to late sowing, the wheat crops in the area aren't established enough for stripe rust, but I expect it to be here," he said.
"We are seeing some rust in oats in the area as well as grazing crops.
"The key is to get on top of it early.
"Growers should be monitoring their crop and keeping an eye out for it.
"It is important they make sure of the variety and treat it accordingly.
"Send samples in to be tested to find out the strain, as it is ever evolving."
John Monk of PY Agronomy, Parkes, said conditions were similar to last year where there was a common occurrence of stripe rust.
"Last year we saw stripe rust in most wheat crops," he said.
"Some varieties can fight it off as it matures.
"Grazing crops in the area have been showing rust. When grazing is done, a first spray at growing stage 32 and a follow up at growing stage 39 will be needed.
"Any susceptible variety will need two passes this season."
