Grains Research and Development

Date: 01.02.2003

Night spraying: how's that?

WITH THE hotter and drier summer months many graingrowers will divert their attention away from cricket to the more pressing issue of summer weeds and perhaps night spraying.

Graingrowers elsewhere should note the success of their northern counterparts with night spraying of summer weeds and consider its merits, according to NSW farmer, consultant and GRDC Southern Panel member, Alan Umbers.

"Problems arising from moisture stress and high temperatures often make spraying at the optimal time difficult, "

Mr Umbers said. "However, it is now well accepted that nighttime application of herbicides for weed control in summer is successful. "

According to Mr Umbers, some of the benefits from spraying at night rather than in the heat of the day include:

  • Weeds are less stressed and more likely to absorb herbicide, move it around and bring about their undoing.
  • There is usually less chance it will be windy during the night and so the risk of herbicide being dispersed beyond the target weeds is lower.
  • The relative humidity is higher at night and spray droplets last longer and stay on the leaf surface longer.

Farmers spraying summer weeds at night report that they use the same water volumes with the herbicide, they use the same spray nozzles, spray pressure and speed, Mr Umbers said.

"They give the weeds some time to get over the heat of the day, starting spraying at about midnight and going till about midday. "This means that the weeds are less stressed and the farmers can get to watch the cricket. "

Contact: Mr Alan Umbers 02 6892 1112

Region North, South, West