The loss of the active ingredient 2.4-DB in herbicides has been well documented and has led to a reduction in the options available for farmers looking to use clover-safe sprays when spraying weeds on new reseeds.
New chemistry has emerged, particularly in the form of Pro-Clova and there is talk of other clover-safe options being developed as well. From an efficacy point of view, 2.4-DB was a good all-rounder in terms of its control over commonly found weeds in reseeds, such as dock, thistles, nettles and chickweed.
A demonstration at the grassland village at the Moorepark open day highlighted the importance of the timing of the post-emergence spray.
Each of the plots were sown 48 days prior to the open day with a grass and clover seed mixture.
The demonstration was to show the difference in weeds within the plots based on the difference in timing of post-emergence spraying. On the plot that was sprayed 30 days after sowing and 18 days before the open day, there were no visual signs of any weeds.
This plot was not sprayed after sowing
However, on the plot that was sprayed 40 days after sowing and eight days before the open day, there were some well-established and younger docks evident in the sward.
Meanwhile, the third plot has not been sprayed at all and there were lots of docks in this plot.
The demonstration highlighted two things: number one, the importance of post emergence weed control and secondly, the importance of the timing of that weed control. It highlighted an issue that many farmers are leaving it too late to go in with the post-emergence spray and this is leading to an increase in docks after reseeding.
This plot was sprayed 40 days post-sowing.
There must be some flexibility around the timing of the spray to take into account growing conditions and the size of both the dock seedlings, but also the clover seedlings. Docks should be the size of a €2 coin and clover should have three leaves.
However, targeting to spray at 30 days post-sowing is a good target. If it needs to be delayed by a week or so based on growing conditions and weather then that is possible, and still be within the appropriate window.
In brief
A demonstration at the Teagasc Moorepark open day highlighted the difference in weeds in reseeded plots based on different spraying dates post-sowing. The plot that was sprayed 30 days post-sowing had a lot less weeds than the one sprayed at 40 days. Targeting 30 days post-sowing for spraying is a good policy, but growing and weather conditions should be taken into account too.
The loss of the active ingredient 2.4-DB in herbicides has been well documented and has led to a reduction in the options available for farmers looking to use clover-safe sprays when spraying weeds on new reseeds.
New chemistry has emerged, particularly in the form of Pro-Clova and there is talk of other clover-safe options being developed as well. From an efficacy point of view, 2.4-DB was a good all-rounder in terms of its control over commonly found weeds in reseeds, such as dock, thistles, nettles and chickweed.
A demonstration at the grassland village at the Moorepark open day highlighted the importance of the timing of the post-emergence spray.
Each of the plots were sown 48 days prior to the open day with a grass and clover seed mixture.
The demonstration was to show the difference in weeds within the plots based on the difference in timing of post-emergence spraying. On the plot that was sprayed 30 days after sowing and 18 days before the open day, there were no visual signs of any weeds.
This plot was not sprayed after sowing
However, on the plot that was sprayed 40 days after sowing and eight days before the open day, there were some well-established and younger docks evident in the sward.
Meanwhile, the third plot has not been sprayed at all and there were lots of docks in this plot.
The demonstration highlighted two things: number one, the importance of post emergence weed control and secondly, the importance of the timing of that weed control. It highlighted an issue that many farmers are leaving it too late to go in with the post-emergence spray and this is leading to an increase in docks after reseeding.
This plot was sprayed 40 days post-sowing.
There must be some flexibility around the timing of the spray to take into account growing conditions and the size of both the dock seedlings, but also the clover seedlings. Docks should be the size of a €2 coin and clover should have three leaves.
However, targeting to spray at 30 days post-sowing is a good target. If it needs to be delayed by a week or so based on growing conditions and weather then that is possible, and still be within the appropriate window.
In brief
A demonstration at the Teagasc Moorepark open day highlighted the difference in weeds in reseeded plots based on different spraying dates post-sowing. The plot that was sprayed 30 days post-sowing had a lot less weeds than the one sprayed at 40 days. Targeting 30 days post-sowing for spraying is a good policy, but growing and weather conditions should be taken into account too. 
SHARING OPTIONS