Favourable weather conditions have enabled the disease to carry over from the previous season, allowing stripe rust to occur earlier than usual this season.

"Following the hardships caused by several years of drought many growers chose to rely on post emergent management of the disease," NSW Department of Primary Industries Temora district agronomist Peter Matthews said.

"Correctly timed post sowing fungicide application can be both cost effective and provide good protection for the crop.

"Now that stripe rust is showing up this is the time to begin monitoring."

Mr Matthews said some previously resistant varieties were now known to be susceptible to stripe rust.

"So first step is to find out the status of your variety by checking the latest NSW DPI Winter Crop Variety Sowing Guide," he said.

"The next step in deciding if and when to apply fungicide, is to determine if the disease is present in your crop. This involves monitoring the crop on a regular basis.

"Monitoring needs to be done repeatedly so that the level of disease and its rate of development in the crop can be determined.

"At the same time an assessment of the growth stage of the crop needs to be made, as this affects when you should apply the fungicide to gain the maximum benefit."

Mr Matthews said varying rainfall across the region means crop growth can be anywhere between two leaf and early flag leaf emergence.

"Only once the variety's disease resistance rating, level of stripe rust in the crop and the correct growth stage are known, can growers make the best decision to protect their crops from stripe rust," he said.