MAY can be a volatile time for international grain prices, particularly in the US.

With the US focus on planting, farmers there are not generally concerned with selling grain.

So traders say that US growers often consider forward selling grain around May as price spikes occur.

However, traders estimate that prices would have to be 25 per cent above what they currently are for that to happen.

Soy bean farmers in Brazil and Argentina are harvesting crops that are expected to be substantial, while US grain producers are planting spring wheat and corn crops.

Weather has been kind to US plantings and most of their crops are now in the ground.

Analysts say they are surprised the price for wheat in the US has remained high, as they have had their best start to the season in 10 years.

There is speculation the current wheat price accounts for the risk of any poor weather in the crop development phase.

And, like their North American counterparts, grain growers in the Mallee and Wimmera have had a great start to crop sowing, with many crops going in early to take advantage of good subsoil moisture.

However, locusts have damaged some crops at Hopetoun, attacking the crops when they were between the one and two-leaf stage.

Faba bean crops around Lake Bolac were sown as early as mid April.

Many grain growers report they have been sowing into adequate soil moisture and further rain this week should provide moisture on the soil surface as well.

Feed barley prices have been supported in the western areas of Victoria with exporters wanting some for a shipment from Adelaide.

Although those with stocks in the South Australian grain-handling system benefited, the impact on markets in Victoria and southern NSW has been minimal.

F1 feed barley remains unchanged this week at $150 a tonne delivered to Melbourne, $145 a tonne delivered to the Goulburn Valley or $150 a tonne delivered to southwest Victoria.

Those farmers storing F1 barley on farms in the Horsham, Dimboola, and Birchip area are able to secure $115 a tonne ex-farm.

Wheat prices are unchanged this week. With new crop wheat prices now at $213 a tonne delivered to Victorian port, they remain at a good $25 a tonne premium to old crop values.

International values changed little last week.

Saudi Arabia has adjusted import wheat specifications to allow for easier imports of Australian wheat.

The country imports 2.5 million tonnes since it stopped irrigating wheat with ground water in 2008.