The recommended timing of application is when the weeds are at the two to four true leaf stage, but it can control weeds up to six true leaves depending on species. In most situations this will coincide with an application during crop growth stage 14 to 18, the four to eight true leaf stage.
In practice weeds rarely emerge at the same time or grow at the same rate so application timing should be determined by the growth of the dominant weed species for the field situation. In most instances this will be fat-hen as it, and other tall weeds, have the capacity to inflict serious yield penalties on sugar beet if left uncontrolled. Conviso One should be applied before fat-hen reaches four true leaves.
Optimum Conviso One spray timing
There is a wide range of crops that can be sown following a crop of sugar beet that has received the Conviso One herbicide. In order to minimise the risk of crop damage from the residual effects of thiencarbazone, the active substance with lasting residual effect, there are however, several principles of good crop management that should be observed.
Best practice requires that ahead of all following crops the land should be mouldboard ploughed to a depth of at least 20 cm (8 inches) prior to sowing or planting. Where a beet crop fails or is abandoned, it is advisable to allow a month to elapse before re-sowing with a maize crop, even after ploughing.
It is expected that those intending to establish a crop in the same calendar year as the beet crop was sown will drill winter wheat as there are few alternatives that can be sown late in to the autumn and winter and be expected to deliver a respectable performance.
In the year after application, the following crops may be sown:
- Winter and spring barley
- Winter and spring wheat
Although not on the label as approved for sowing after use of the Conviso One herbicide, trials conducted by Bayer have found the following crops can be grown as part of a balanced rotation:
- Field beans
- Mustard (as a cover crop)
- Winter oilseed rape
If groundkeepers are found in the following crop, treat with a hormone herbicide such as MCPA and 2,4-D as these have been found to be effective against ALS-tolerant sugar beet.