High Septoria After Rain

May 2002 - Colin Myram's CROP TALK

Former technical director of Crop Care, Colin Myram is an East Anglian-based consultant to the agricultural industry, including farmers and suppliers.

Set-aside

Where set aside is regenerated do not spray black-grass with glyphosate until heads are just fully emerged as that will give best control. Spraying before this time, which is usually end of May/early June, will result in recovery of plants and spraying later could mean that seeds have set.

Monsanto have just launched yet another new glyphosate formulation as Roundup Gold, which has a new wetting system known a TranSorb Technology to give improved results, and on black-grass and couch is rainfast within one hour. This is an advance on previous formulations or wetting systems. On couch it is reported to move more effectively into the rhizomes for a greater long term effect.

Winter Barley

Winter barley, under drought stress towards the end of April, raced through to flag leaf and awns emerged. Many crops will have already received flag leaf fungicide, however in my experience it is better to wait until ear emerged on varieties with a rating of 7 or less for brown rust, which is everything except Angela or Haka!

On the subject of varieties it is good to see more candidates being included in the Recommended List Trials. This is a positive innovation from the new regime of Crop Evaluation Ltd (CEL). I also note that the NIAB members' day is returning to a more technical event rather than demonstration and trade stands. This is to be applauded and perhaps the RASE and the 'Cereals' event will take note.

Winter Wheat

With the dry weather prior to 25th April in East Anglia, some cost savings have been made on fungicides, which will be a welcome relief in view of projected wheat prices for this year's crop. However, with the heavy inoculums present in the base of the crop, there will be high Septoria infection following rain. The early drilling and mild winter could mean infection already with brown rust, although symptoms will only show later. In addition delayed nitrogen uptake, coupled with rapid growth, make crops more susceptible to both trace element deficiency and disease. Yellow rust can be found around the Wash area but weather and variety mix mean that this disease is unlikely to be a major problem.

Cleavers seem to be very prolific this season and if not controlled already will require a reduced dose Starane or Tomahawk with the flag leaf spray. Similarly if thistles are a problem add Ally at full dose.

Generally black-grass control seems to be more acceptable this year except where populations got out of hand due to last season's difficulties and subsequent crops were drilled early.

Crystal/Ice/Trooper has performed well in its first commercial year with one or two expected hiccups in crop safety. It is just as well that this primarily pre-emergence product has been successful as I understand that the other exceptional pre-emergence material, JV485, has finally died and will not see a British field.

With another new post-emergence product in trial giving extremely encouraging results, one can only hope that it passes through the regulatory system without a hitch. Being sulphonyl urea-based, it is a matter of using it in such a way to avoid resistance occuring. We cannot rely on 'fops' and 'dims' or residuals because of the variables of resistance, weather and soil condition.