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CROP CRACK - 08.03.08
By WENDY FEARON
Clarendon Agricare - March has come in like a Lion
March certainly has come in like a lion and hopefully will go out like a lamb. Thankfully temperatures have improved throughout this week, but ground has been slow to dry out.
Many autumn sown crops are unusually forward for this time of year after a mild winter. In almost all winter crops sprayed with an autumn herbicide excellent weed control has been achieved. The main problem weed appearing in these crops now are cleavers.Starane XL may be applied as temperatures improve.
Some later sown crops are still quite open and spraying should be delayed until all spring germinating weeds have appeared. Hussar may be used on winter wheat up to 2nd node and will control AMG up to the end of tillering (GS30).
Wild oats are now appearing in both winter barley and winter wheat and problem fields should be treated as soon temperatures become consistent day and night and all the wild oats have germinated.
Many crops are now under stress not least from unusually high levels of mildew present. Unlike previous years it will be essential to apply a T0 fungicide on many winter crops.This treatment should include a good robust rate of fenpropimoph which is both a contact and systemic morpholine fungicide. Opus team which is a co-formulation of epoxiconazle and Fenpropimorph will be used at this time on both barley and wheat and Amistar Opti should be applied to second wheat’s in the mix to help prevent take all.
Fertiliser applications have held off up to now but as temperatures improve and hopefully conditions are dry, winter crops should be carefully assessed for fertiliser application. First nitrogen’s are now going on and some growers are choosing to use Urea as a cheaper alternative but we must remember this is much slower than chalk. When urea is applied and enters the soil it is converted into ammonic nitrogen which is attracted to the soil particles and will preventing leaching.
When winter oilseed rape crops are as open as the one in the photo and with prices for OSR rising as they have been, weed control particularly cleavers, mayweeds, thistles and groundsel will be worthwhile.
Cleavers are the most aggressive BLW competitors impacting yield & oil content. As yield robbers, mayweeds, groundsel and thistles follow close behind. All these weeds impact harvesting flexibility.
Thistles and mayweeds are more sensitive to Galera than cleavers and therefore less dependent on continued good growing conditions for optimal control. At this point in time, where the target is either thistles and/or mayweeds Galera applications can go ahead. Galera has no chickweed activity.Kerb will control chickweed up to 10cm.Both Galera and Kerb may be mixed and would cover a broad range of weeds.
Where soils are relatively warm growth of crops and weeds will occur.
Cleaver control is optimised when there are stable air temperatures of at least 6°C and rising, but preferably 8°C or higher - diurnal variation with very low night temperatures are likely to give very poor results particularly against cleavers.
In backward or open crop canopies hold the application for cleavers & wait until the crop has picked up nitrogen and is clearly growing & cleavers growth is softer.
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