About 50.7mm of rain over the last 10 days and I think it’s fair to say that it’s quite damp here in Lincolnshire now. Some cereals – winter barley crops in particular – are exhibiting high levels of stress thanks to wet feet, nitrogen deficiency due to leeching as a consequence of the rain, residual herbicide uptake – again as a result of the wet conditions and, latterly, from increasing levels of powdery mildew.
Appearances can be deceptive though and, when you walk into these yellowing winter barley crops, it’s clear that their awful appearance is largely due to the fact that thanks to the mild autumn, the older leaves which should be flat to the floor and yellow, are still sticking straight up in the air. If you peel these old necrotic leaves away, the new growth is perfectly clean and green so nothing to worry about other than having your leg pulled by your neighbours.
Powdery mildew is easy to find in winter barley and is rarely worth treating in winter cereals – unless you’re in a coastal area and it’s swamping the crop – but with prices where they are, you’re probably far better advised to save your money and let the impending winter deal with it. As soon as we get some frosts, that will kill it. The mildew not the barley!
On that note, if your crops are showing the effects of nutrient deficiency and you’re in a position where you can travel, with stress levels as high as they are on these non-frost-hardened lush crops, it is advisable that any trace element or nutrient deficiencies are corrected prior to the application of herbicide mixtures. The mild conditions will come to an abrupt halt at some point in the next few weeks, and the nutrient stressed crops will suffer the most if it suddenly turns frosty – particularly if they’ve just had a cocktail of herbicides thrown at them. On fields without these nutrient deficiency problems, those fields with blackgrass should take priority – along with any fields with no barley yellow dwarf virus (BYDV) protection from seed dressings.
Opportunities to spray blackgrass should be taken whenever they arise once the average weed size is around GS12. Over the last few years we have learned that even as conditions come colder, if the right spraying day presents itself you should take it – hit a dry and drying blackgrass leaf, 12kph max, fine/medium quality spray, a minimum of 2 hours dry including dew fall following application – in fact in cold/poor growing conditions that would be better as 4 hours . . . you know the drill.
As far as BYDV goes, aphid levels – along with 0pomyza (yellow cereal fly), frit fly and bean seed fly – remain high, so any fields without insecticide seed treatments should be placed at the top of the list of “things to make ruts with” – this application can be combined with applications of manganese, magnesium, copper, zinc etc to correct any nutrient deficiencies. If there is a frost forecast you would be best advised to stop spraying by around 2pm preceding it.
Oilseed rape is looking far too well advanced in many fields – I’ve heard reports of buds being present in some of the most forward – but as far as disease control goes, a well-timed robust single fungicide application this autumn seems to have done the trick and, despite mother nature’s best efforts of keeping things mild and damp, we are holding phoma, light leaf spot and alternaria at bay and well below levels which warrant further treatment.
Staying with the mild conditions, on 22 November at midday the soil temperature at 10 cm was 8.4°C – this is still far too warm to the application of propyzamide in my opinion. I’ve been very proactive about blackgrass in OSR once again this year, so in most cases I am not faced with huge populations of large and deep rooted plants. I will be applying my propyzamide when soil temperatures at 10cm are down to 7C and are clearly falling – if that means waiting until January then so be it, there is no point wasting my last line of defence just to get a job out of the way – there’s nothing worse than propyzamide failing and then being told that it must have “been too warm when you applied it”.
Why do people continue to grow winter beans? Rhetorical! If it is too warm for propyzamide applications in OSR, it is too warm to propyzamide applications to winter beans and, judging by the amount of blackgrass that is emerging alongside those winter beans, despite several stale seed-beds and pre-emergence herbicides, I’ve got my work cut out once again this year to control it. I’ve always had better yields and better quality from spring beans without all the hassle and expense of trying to control the blackgrass – glyphosate is an awful lot cheaper than propyzamide, carbetamide, pendimethalin etc, so on blackgrass land, seriously, why do people continue to grow winter beans?
Slugs remain a colossal pain in my…daily routine, so I’m thinking of approaching Heston Blumenthal to find out if we can saute them and sell them to the French as “molluscular gastronomy”. Dragon’s Den here I come.