SMALL weeds are easier and cheaper to kill, so get them while they are young.
This logical and straight-forward advice was served up by Syngenta senior solutions lead, Scott Mathew, to citrus growers attending the NSW DPI Citrus R&D Roadshow in Mildura, Victoria last month.
The roadshow was undertaken to highlight the latest research and management updates in the citrus industry.
The session on weeds concentrated on fleabane, feathertop and ryegrass which pose problems for growers.
Mr Mathew spoke on getting the most out of chemical use and spray applications, delivering snapshot do and don'ts when it comes to controlling rogue plants.
He said one area of major concern was chemical resistance build-up in weeds.
He encouraged growers to take the time to deal with an emerging problem before it became a widespread one.
"If you see a survivor, get it out of the orchard or the vineyard or whatever the situation might be," he said.
A list presented showed that as of September this year, 678 populations of annual ryegrass are now classified as resistant to glyphosate.
"Resistance comes about by misusing a product or over-using a particular product," Mr Mathew said.
"Continually using glyphosate is not a good thing from a resistance point of view. Rotate your knock-down herbicides."
He also provided common-sense strategies for crop control.
"Target small weeds. Small weeds are easier to kill and cheaper to kill," he said.
"Keep herbicide application rates robust. Don't do what Western Australia did and cut rates, then they cut them again and they cut them again until the product didn't work and then they started going up again."
Matching water rates to the weeds being sprayed, following label directions and spraying at suitable times of day were other key areas to take note of.
He emphasised the need for stringent recordkeeping as well with some legislation requiring growers report temperature, wind speed and wind directions at the time and place of spraying.
"Now if you get a visit from our friends that check chemical uses and you haven't got that information of all that stuff at the time of spraying, just be aware you could be prosecuted," he said.
Sumitomo representative, Frank Galluchio, followed Mr Mathew by presenting information on a relatively new herbicide called Chateau.
He said it was a molecule which had only been in Australian for the past two years but used on a wide range of products in the United States for a decade.
As a group G chemical, it had strong effect on broadleaf weeds and some grasses.