Squeeze on chemical supplies

Growers are spraying out chemicals as fast as companies can produce them, as the State's farmers wage war on summer weeds.

As a harvest plagued by rain and storms finally winds up, many growers got straight off the harvester and straight onto the boomspray, prompting fears supplies of key chemicals could run short.

Nufarm WA regional manager Steven Lacy said few distributors had extra stock sitting around, with supplies of 2,4D the tightest.

"There were already supply issues before it rained, but many other products used for summer such as metsulfuron, adjuvants and Roundup are quite tight as well," he said.

"We make it here in WA and we don't have a heap - as soon as we make it has left here within the week.

"We've probably delivered three or four times the amount of 2,4D than we did last year at this time."

While Mr Lacy said farmers weren't waiting for chemicals yet, that time may not be far off and he suggested growers get their chemical orders to agents as soon as possible.

The State's biggest grain grower, John Nicoletti, said he had pre-empted fears of a glyphosate shortage by buying two road trains of the chemical earlier in the season.

But as the rain clouds continue to roll in, dumping up to 200mm on some of his paddocks since November, Mr Nicoletti now thinks he will need another road train just to get him to seeding.

He's already sprayed half of his 100,000-hectare program once and last week sprayed another 3000ha for the second time.

"We're spraying Westonia, Bullfinch, Marvel Loch, Southern Cross and Esperance," Mr Nicoletti said.

"This is the worst I've seen it in 33 years.

"I've bought a bit over 100,000 litres of glyphosate and Roundup and about 6000L of Garlon a couple of months ago and half of it has gone already.

"It's the most (chemical) I've ever bought in one hit and the big concern I have if (rain) continues, I can see the companies running out of glyphosate."

Extra staff were employed during harvest to follow the harvester with the boomspray and Mr Nicoletti said the cost of the chemical comes on top of 50,000 tonnes of wheat downgraded to feed this harvest at a cost of more than $4 million.

But Mr Nicoletti isn't alone in feeling the financial burden of a wet harvest.

Narrogin-based farm consultant David McCarthy said most cropping programs for the coming year would have a summer spray applied.

"In many cases they started spraying before they finished harvest," he said.

"We've had two in the last four years where we've had to do a summer spray and there's probably patches around that have had three in the last four, but nothing as significant as this year.

"The summer spray programs are probably a $10 a hectare added cost and whether that affects the profitability greatly probably depends a fair bit on this coming season.

"The only concern is probably how widespread fleabane is becoming."

The weed, which has glyphosate-resistant populations in parts of both New South Wales and Queensland, has continued to spread across WA.

It's now across most of the cropping area, from Esperance to Merredin and Geraldton.

Department of Agriculture and Food senior research officer Sally Peltzer said this season's wet summer had set up near perfect conditions for the weed's emergence.

"They produce 110,000 seeds per plant and… they actually spread reasonably rapidly," she said.

"If you've got a paddock with a lot of it, it's going to suck a fair bit of nitrogen and moisture out of the soil."

Dr Peltzer said research conducted in 2009 indicated that the best control of large fleabane in stubble used a 'double-knock' approach with a range of primary herbicides followed by Paraquat seven to 10 days later.