This month’s messages:
One positive is that we have had more frosts this year, which has cleared up any mildew we were seeing in winter cereals before Christmas. However, after the recent winter weather snow has thawed and some fields resemble a wetland.
Depending on how long the waterlogging lasts, this could be a concern for winter barley, but less so for wheat. Oilseed rape should be OK, so long as root systems are well developed. Getting some nutrition on all crops will be the priority once it dries up and growers can travel.
Samples sent in for SpotCheck testing from across Scotland have shown some heavy light leaf spot infection and on a couple of farms, 100% of leaves tested positive. Other samples were more variable. In most cases, there were no visible symptoms, but conditions have been cold and wet, so just right for the disease.
Growers need to be fully aware that as soon as they can travel, they need to get a light leaf spot spray on to crops. The last thing they need is disease going up the stem and onto the flowers and pods later in the season, so new growth needs to be protected. If there has been no autumn fungicide applied or you have a susceptible variety, don’t wait for stem extension.
Sprays should be prothioconazole-based, with a product such as Proline the way to go. A rate of 0.32l/ha is a typical rate for light leaf spot, but if you are seeing disease, upping the rate to 0.46l/ha might be more appropriate. Be careful with how much prothioconazole you’ve applied so far and if you want to use it at flowering – remember the total maximum dose is 1.26l/ha per crop for the season.
I very much doubt any OSR crops here will need a PGR included at stem extension, as the cold weather and pigeons have done a job for us. Don’t forget the importance of micronutrients and top up boron, molybdenum and sulphur.
Winter barley is starting to look a bit hungry and will need some nitrogen soon, although it has turned yellow later this season than previous years. There has been a wee bit of Rhynchosporium reported, but it isn’t widespread. Mildew was lingering around in both barley and wheat, but the spell of prolonged weather has nipped that in the bud. Keep an eye on it though, as it could soon raise its head again. In wheats, septoria is the main concerns and if there was any yellow rust the cold would have seen to that too.
In winter barley, a T0 wouldn’t go amiss, and something to get on top of Rhynchosporium such as Kayak (cyprodinil) is a good option. Also, be prepared to apply a T0 fungicide to wheat, but don’t rush in too early. Growers can sometimes apply a T0 thinking the T1 timing is 10 days away, but it takes four weeks, so make sure you follow the advice of your agronomist. Sprays should be based around chlorothalonil, plus or minus tebuconazole where rust is a concern.
Where herbicides were not applied in the back end, growers will be looking to use a product such as Othello in the spring for controlling grass and broad-leaved weeds. Keep an eye on weeds and apply when they are actively growing. Also, watch the weather forecast and don’t apply if a frost is predicted or if it turns mild and there is rapid lush new growth. In both cases, the crop can take a hit.
Contact herbicides are also best applied on their own, but if you are tank mixing, check the list of compatible partners on the Bayer website or download the Agronomy tool app, which is automatically updated with the latest information.
Well you can for free thanks to SpotCheck, a collaboration between Bayer and ADAS with extensive support from the Association of Independent Crop Consultants (AICC). ADAS will be undertaking leaf assessments sent in by growers to make a conclusive diagnosis on what is a very difficult disease to identify.