Watch out for this one
Pesky weed growing resistance
.THE weather is still not very kind to us, offering cooler days and nights, along with some very dry weather.
The one stand-out issue is how the soil dried out so quickly after the October rain.
This quick drying out phenomenon has happened before in past years, after similar prolonged dry spells like we have just experienced since November last year.
With only some relief from Cyclone Debbie at end of March 2017, it is no wonder that our first mid-spring rain of 75 to 125mm has not been able to sufficiently wet the large depth of very dry soil we had present in all our paddocks.
So, with recent follow-up rain of low to medium usefulness, we find many of our summer crops are in trouble.
One plant that has emerged and growing well is windmill grass.
I spoke about urochloa some weeks back as a bad year for it’s large seedling numbers of that introduced species in our cropping land.
Now it is windmill grass’ turn to emerge in large numbers in the recent cool spring conditions.
It is a first cousin of feather top rhodes in the same chloris species, but not as painful to control.
Like a lot of our troublesome weeds, it thrives on zero till systems with surface seed remaining viable over a 12 month period.
Burying the windmill grass [WMG] seed reduces it viability by some months in a wet season.
Dry seasons may lengthen this viability time out further
from research done by GRDC and Uni of Adelaide.
A critical point that my years of paddock walks provided knowledge of is, how quick they can grow from a WMG seed bank germination to physiological maturity in much less than three months.
With other common names
like blow-away grass, umbrella grass, star grass plus others in southern states, its prolific seeding technique (20,000 per plant) has ensured that we have plenty of this particular chloris species to control in the spring, summer and autumn time.
No one should be surprised
that we have glyphosate resistant populations of WMG in southern parts of Australia.
We just do not want it here in the northern region with seed heads blowing all over the area being its prime method of distribution.
So while it is not high on the radar yet, it is another difficult
plant to control totally when it develops glyphosate resistance status.
So keep an eye on your populations of this unwanted grass weed and remember diversity on weed control is always the best way to proceed with all our pesky weeds.