Australia
December 17, 2015
Double knocking northern weeds (fa la la la)
Deck the halls with the double knock,
Fa la la la la, la la la la.
Tis the season to conserve moisture,
Fa la la la la, la la la la.
Don the weeds with two modes of action,
Fa la la, la la la, la la la.
Or glyphosate resistance will cause problems,
Fa la la la la, la la la la.
OK, it doesn’t rhyme, but you get the picture!
Earlier in the year, we reported on glyphosate resistant awnless barnyard grass and how it is less glyphosate resistant in cool weather. We incorrectly recommended to “double knock when it’s hot”.
Really, we should have recommended to always double knock because the risk of glyphosate resistance in this weed (and others) is very high. And let’s face it; it’s always hot at this time of year.
So what is a good double knock in Northern Australia?
The Queensland Department of Agriculture and Fisheries (DAF) weed research team (based in Toowoomba) has researched the double knock for a number of the northern grass weeds.
There are differences between species in how they react to the double knock, but there are some common threads.
A good double knock for northern grass weeds is a robust rate of glyphosate applied to pre-tillering plants followed by plenty of paraquat or Spray.Seed® about 4 to 7 days later. Some weeds favour 2 to 4 days between knocks where others favour 7 to 14 days, so 4 to 7 days is a good compromise.
Glyphosate resistance is a big threat to the northern farming system, but it can be managed.
Topics
Species
