Farmers are working frantically to limit damage to summer fruit crops from this week's heatwave.

Dairy farmers are being urged to change milking times to avoid the heat of the day and avoid stressing out their herds.

Total fire bans tipped for later in the week may slow the grain harvest, now in its final days.

Fruit pickers are starting and finishing work early to avoid the extreme heat and full irrigation allocations are being used liberally.

Five consecutive days of 40C-plus in many areas will climax with fire conditions tipped to approach those of the 2009 Black Saturday fires.

Victorian Fire Service Commissioner Craig Lapsley said the heatwave would bake Victoria's bush and grassland, creating perfect bushfire conditions.

He said the heatwave marked the turning point of the Victorian summer.

"This is the time for people to revisit their (fire safety) plans," he said.

The valuable table grape harvest has started in Sunraysia, but hand-picking stops when temperatures climb past 32C because of softness of berries.

"It is about time we got some hot weather. We need it to finish the crops," Irymple grower Greg Milner said.

Warm and hot weather brings out the sugars in Australian fruit, Victorian Farmers Federation horticulture group president Sue Finger said.

"This is what our fruit is known for, why it is in such demand," Ms Finger said.

"No one likes working in the hot weather, but you have to pick the fruit when it is ready."

The heat has accelerated the wine-grape harvest, with mechanical harvesting of chardonnay grapes starting last week at night in the Mildura region.

United Dairyfarmers of Victoria president Kerry Callow said many farmers now had sprays and fans in their dairies.

"It is not very pleasant in the heat, but we have to milk so all we can do is care for the herd and perhaps milk a little later in the day," Ms Callow said.

The dried-fruit harvest is three weeks to a month away with some sunburn damage suffered by early maturing varieties after an unseasonal hot spell before Christmas.

Source - http://www.weeklytimesnow.com.au/