Dry T1 may have meant light PGR use - now is the time for a good PGR at T2.
A very dry & cool April has meant many people reduced PGR dose and loading on their winter cereals. This may have compromised the plants ability to build a good anchorage system to provide the needed support later in the year.
Where early PGR applications were light, T2 is now the time to shorten the upper internodes and strengthen the stem to help increase resistance to lodging.
At GS 37-39, crops are still only about 50% of their final height and so rapid growth following the recent rains and late uptake of fertilizer can easily result in lodged crops.
A height reduction of just 5cm is enough to increase the variety lodging resistance score by the equivalent of one point.
Yield potential is still good for many crops, think of the leverage forces that heavy rain and high wind may exert of the crop later in the season, so now is the time to provide insurance against lodging.
Terpal® is an alternative PGR at T2, especially in barley crops where the combination of mepiquat-chloride and 2-chloroethylphosphonic-acid provide the best option against brackling and evening-up the height of the main and side tillers.
| PGR program so far | Timing T2, GS 37/39 | Comments |
| Low to Medium risk situations e.g. crop has had T0 & T1 PGR | Medax® Max 0.3 kg/ha OR *Terpal® 0.75 l/ha | Where yield potential is high, and wanting to keep upper internodes short to reduce stem lodging risk |
| High risk situations e.g. Crop has only had T1 PGR or reduced T0/T1 | Medax® Max 0.4-0.5 kg/ha OR *Terpal® 1.0 l/ha | Consider boosting dose if crop growth is already ‘leggy’ and crop had no T0 PGR. Use the higher rates on rapidly growing, vigorous crops such as Hybrid Barley, Rye and Oats*. |
*Terpal® is not approved for use on winter oats
Effect of brackling trial conducted by ADAS in 2019 highlighted the impact a brackled crop can have on yield.
Each 10% increase in the area brackled reduced yield by 0.11 to 0.14 t/ha.
Both Medax® Max and Terpal® applied at GS 37 were found to be effective at
Independent trials carried out by NIAB have also shown the benefit of T2 applications of Medax® Max and Terpal® to reduce crop height and lodging.
| Crops | Max individual dose(kg product/ha) | Max total dose(kg product/ha) | Latest time ofApplication |
| Winter wheat Winter triticale * | 0.75 kg | 1.0 kg | Up to and including the end of booting (BBCH 49) |
| Winter barley ** | 1.0 kg | 1.5 kg | Up to and including the end of booting (BBCH 49) |
| Winter rye ** | 1.0 kg | 1.0 kg | Up to and including the end of booting (BBCH 49) |
| Spring wheat Durum wheat Spring oat | 0.5 kg | 0.5 kg | Up to and including flag leaf ligule just visible (BBCH 39) |
| Winter oat Spring barley | 0.75 kg | 0.75 kg | Up to and including flag leaf ligule just visible (BBCH 39) |
| Other specific restrictions: * A maximum of 0.5 kg/ha can be applied to winter wheat and winter triticale during booting (BBCH 41 to 49). ** A maximum of 0.75 kg/ha can be applied to winter barley, winter rye during booting (BBCH 41 to 49). | |||
Use plant protection products safely. Always read the label and product information before use. If you have any queries or require further information, please contact your local BASF agronomy manager. Contact details can be found at www.agricentre.basf.co.uk. Or the BASF Technical Services Hotline: 0845 602 2553
Medax® Max contains prohexadione calcium and trinexapac ethyl. Terpal® contains mepiquat chloride and 2-chlorethylphosphonic acid. Medax® Max and Terpal® are registered trademarks of BASF. All other products are those of other manufacturers where proprietary rights may exist.
Always read the label and product information before use. For further product information including warning phrases and symbols refer to www.agricentre.basf.co.uk
