For the first time in two years we’re getting a winter! As I write this, I’m looking at a couple of inches of snow, the outside air temperature is 0.1C, soil temperature at 10 cm is 1.8C and January delivered 28.8mm of rain.
I know I’m teaching my grandmother to suck eggs, but a prolonged cold and frosty spell is exactly what we need to start bringing things back into balance in the field – this run of frosts (we have had 15 in the last 17 nights) is ably drying out the fields as well as the yellow rust and barley mildew, which were easy to find before Christmas.
For an agronomist, a dusting of snow is a double edged sword, because on the one hand it puts paid to any thoughts some growers may have of going out and applying nitrogen to cereals and oilseed rape too early – an annual battle with some – but on the other it makes it very difficult to see things when you’re walking fields!
The general synopsis of my wheat fields up here in Antarctic Lincolnshire then is that blackgrass seems to be pretty much under control where drilling was delayed and robust stacks of residuals were applied within the seven days following drilling. That’s not to say I’m complacent and, at the very earliest opportunity and signs of movement, I will be urging my growers to get their Atlantis on – dry leaf, 12kph, a minimum of two hours clear of rain, blah blah blah…..if you don’t know by now, there is no point banging on about it.
Many winter wheat fields show moderate levels of Septoria on the older leaves, so the T0 protective spray timing will be critical once again this season – but that’s several weeks away yet. With this in mind, chlorothalonil-based products look likely to be in high demand and will once again feature regularly throughout my fungicide programme.
Wheat bulb fly (WBF) egg hatch has yet to start in this part of the world, although once this current run of frosts abates, I’m sure it will be triggered. Knowing the history of this pest of your fields is far more important than being told “egg counts are low and therefore it’s not going to be a bad year” by the experts. If you know that certain fields have a history of WBF and you have late drilled wheat after sugar beet, vining peas, potatoes etc then you should be prepared to deal with it. The only control we have is a seed treatment or an egg hatch spray of chlorpyrifos (kills the larvae between the egg and the plant).
Chlorpyrifos is one of the few sprays which can be applied on a frost as long as you can get it out of the sprayer – but you need to leave a 20m headland unsprayed next to any watercourse and make a note of the spraying date – because you have to leave four weeks between chlorpyrifos and Atlantis. Failure to do so not only compromises the blackgrass control, it compromises crop safety. I have a nagging feeling that WBF could be significant this spring if the numbers of adult flies I saw in the field last June and July are anything to go by.
Oilseed rape disease control has been outstanding, the propyzamide is beginning to work well now after the six or seven weeks since application, but as temperatures pick up over the next few weeks, keep an eye out for light leaf spot and, as soon as you see it – spray it! All we have are protectant fungicides against LLS – and all we get is about three weeks protection – so the earlier you see it, the better your yield will be.
Meetings and paper work dominate at the moment – NMax, nitrogen and other nutrient plans – but with February now upon us, thoughts turn to seed for spring drilling. If you are considering growing spring beans and you are using home saved seed, it is absolutely critical that you get that seed tested for stem nematode. I don’t think I’ve ever heard of so many samples showing up high levels of this pest and, as there is no chemical control, it would be very unwise to drill an infested seed lot – you’ll not only compromise yield, you’ll also contaminate the soil and, if beans are regular feature in your rotation, that’s not the best decision you will ever make. If, in last years seed crop, you saw reddish brown blisters on the stems of the bean plants – this can be indicative of stem nematode. So when you get your seed tested for germination and ascochyta, specify stem nematode too – it’s best to know what you’re dealing with before it’s too late to do anything about it. Mind you, you’ll probably need to get a mortgage or sell a kidney if you need to go out and buy new bean seed!
It may only just be February, but they are already talking about shortages of herbicides, fungicides, growth regulators . . . . . why didn’t I work harder at school?