Between the lack of rain and a severe frost event this week, South Australian farmers are feeling the pinch from the weather.

Some farmers said they were not bothering to reap what they had sown, as their crops were in such a state that the cost of harvesting outweighed any possible return.

Jamie Evans, a farmer from the Mallee, grows cereal crops and runs livestock, and said he was not holding his breath for things to turn around this season.

"The paddocks are pretty much turning brown — what was possibly coming out got frosted off the other day," he said.

A Loxton fruit farmer has lost large swathes of fruit following Monday's frost event. (Supplied: Loxton fruit grower)

"There's just no moisture to even try to reshoot or do anything."

Struggling to feed his herd, Mr Evans has had to "pull the pin" early and sell off roughly 1,500 ewes.

With approximately 1,000 remaining, Mr Evans is still trying to work out if he can feed them.

"We don't have a lot of hay stocks left after the dry summer we had," he said.

"It just doesn't look like there's anything around to buy [either]."

Crops are withering on the vine following Monday's frost event. (Supplied: Loxton fruit grower)

Monash grape grower Michael Spivahparis said conditions were the worst he had seen in 46 harvests.

"Everywhere you look, you know, [there's] between 80 and 100 per cent damage right through the whole area," he said.

"It's the worst I've ever experienced in expense to income ratio."

What can growers do?

The Australian Wine Research Institute's general manager of industry and support, Mardi Longbottom, said the damage needed to be properly evaluated, which could take about a week.

She said the extent of the damage and the incoming weather conditions would determine the risks a grower may face.

If the damage was light, then the frosted tissue would dry and fall off, according to Ms Longbottom.

However, she said in wet weather farmers needed to be on the lookout for diseases like botrytis, a fungi that damages wine grapes and other plants.

"Some of the pictures I've seen, some growers are going to have partial damage … that's probably the most difficult to manage," she said.

"This is where the shoot at the top might be damaged, but at the bottom, it's okay.

"These vines are likely to develop lateral shoots, which may produce a second crop."

Ms Longbottom said vines would produce fruits of "variable ripeness and lower quality fruit" as well as crowding the canopy.

Farmers are still not out of the woods with Ms Longbottom warning the frost could strike some regions until the end of November.

"Don't jump straight into action, because if there's still a risk of frost in your region, this will affect what you do from here on," she said.

"In most cases, though, the most economic decision is to do nothing.

"If you do decide to do something, though, do it relatively quickly, because all the energy from those vines is going into producing new growth."

Josh Lush's lentil crop has been devastated by frost. (ABC News: Justin Hewitson)

John Lush, who has been farming in Mallala for 56 years, said frost had been the final nail in the coffin.

A record low of roughly 150 millimetres of rain has produced one of the driest seasons Mr Lush has seen.

"We won't know the impact of it for a few more days, and then we won't really know the impact of it until we start harvesting the crops," he said.

Combined with low grain prices Mr Lush said it was "the perfect storm" where "everything's lined up to diminish our income for the year".

However, improvements in technology, technique and grain resilience mean things are not as bleak as they once might have been.

John Lush says frost has been the final nail in the coffin for his farm. (ABC News: Justin Hewitson)

"The last year we had like this was in 1967 when I first came here and I sold one truckload of grain for the year. We'll do way better than that now," he said.

"We're actually a lot better at doing this than we used to be, which is why we've still got a chance of breaking even this year, whereas in the past, we'd have been just devastated right off.

"We'll live to fight another day."

Source - abc.net.au