Rapeseed crops look surprisingly good, with cabbage stalk flea beetle attacks less severe than last year.
However, concerns are growing that farmers will be tempted to sow wheat early, given the rainy season and memories of last year.
Subsequent drilling not only has benefits for black grass control, but also helps reduce the risk of barley yellow dwarf virus and leaf disease.
This is critical with the loss of chemistry, especially since early growers this season are faced with no chlorathalonil.
See also: How to control the speedwell of problematic weeds on calcareous soils
North: David Martindale
Arable Alliance (Yorkshire)
After a prolonged harvest, it’s nice to see the fields cleared and the evidence of what has been one of the toughest growing years removed.
The focus quickly shifted to sowing autumn cereals, with the rush to sow wheat and barley early. Making decisions about how to cultivate based on what happened last year is both puzzling and understandable.
Attempts have been made to negotiate delayed drilling for better black grass control – a task, in some cases, as difficult as negotiating a Brexit deal.
For early-sown cereals, the subsequent weather unfortunately remained hot and dry, which was not ideal for the all-important pre-emergence herbicides to work well for weed control.
In some cases, the relief of having good looking grain early harvests can turn into disappointment, as high levels of black grass may be difficult to control.
Good seedbed quality with humidity and cooler conditions will help to get the best performance from residual herbicides.
For early-sown grains, watch out for aphids and gout eggs. Both parasites can cause damage that will not be seen for some time.
With aphids increasingly resistant to pyrethroid insecticides, their use must be well targeted. There are some good tools available that can help you make decisions about the timing of insecticides for aphid control.
The rye area is slowly increasing in the area. In recent years it has been grown as fodder for anaerobic digestion plants, but now more hectares are being grown for the grain harvested to feed to pigs.
Rye is a good alternative for the second or third position of cereals in the rotation and is particularly competitive against black grass in spring.
The rapeseed plant has been excellent so far. Crops sown before mid-August typically have eight or more leaves and are especially beautiful in appearance, having had little to no ailment from cabbage stem flea beetles.
Crops sown in early September saw the majority of flea beetles, with crops sown in mid-September so far unchanged. Low levels of flea beetles and snail pressure, along with good seedbed humidity, have made planting a much more relaxed and enjoyable experience so far.
High levels of voluntary barley emerged with rapeseed, which required timely herbicide control to prevent crop competition. Clethodim is applied to previously sown crops to control black grass, which is becoming well established.
Delaying this herbicide for too long will impair its effectiveness as OSR plants protect black grass. Phoma is beginning to appear in crops, although it has not yet reached the threshold for applying a fungicide.
West: Neil Potts
Matford Arable (Devon)
Well, here we go again: the start of another season. The cultivation year 2019-20 proved to be the most difficult in most people’s memory, with extreme weather conditions from the beginning to the end.
In the Southwest, crop performance depends on two main factors: whether the crops were planted before the weather broke last fall and whether they were grown on soil that retains moisture.
If one or both of these factors were missing, crop performance was generally poor, resulting in the most disappointing crop result in 30 or 40 years. The big exception of note is the maize crop, which is performing at above average levels overall.
Most of the winter OSR crops were drilled in time from mid to late August and emerged quickly. We have experienced cabbage stalk flea beetle attacks again, but generally not quite as severe as last year.
The acreage of this crop is again smaller this year than last, reflecting growers’ lack of confidence in a crop so difficult to establish and protect against pests that can severely damage yield and quality.
As of this writing, drilling is about to begin in earnest, but there are some crops that have been planted a little earlier and have now emerged or emerging. In the deep southwest, these early drilling crops pose a number of challenges, not least the threat of the barley yellow dwarf virus.
Crops that have already emerged will require at least two applications of aficide, and perhaps even more, depending on how soon or late winter decides to arrive.
Personally, I am still struggling to come to terms with the withdrawal of the Deter Seed Treatment. This product was aimed only at the target pest, with minimal risk to beneficial insects compared to the carpet spraying approach now adopted to control the virus.
Winter barley crops should be given a pre-emergence herbicide, as post-emergence options in this crop are now quite limited, particularly if the weeds have sprouted alongside the crop and established early in the life of the crop.
Hopefully, by the time I write the next article, the drilling will be largely completed and there will be more to report. We hope that time is more on our side for the 2020-21 growth year and good luck to all involved.
South: Tod Hunnisett
Given the absence of insecticide seed treatments and the increased incidence of pyrethroid resistance in virus-carrying aphids, a reasonable strategy to reduce the risk of yellow dwarf virus in cereals is to delay sowing, if possible, until beginning of October.
With the reduction of our arsenal of active weed ingredients and greater resistance of weeds to post-emergence herbicides in a single site, we are more dependent on cultural control to tackle difficult weeds. This involves creating stale seed beds, getting a good weed flow, spraying with glyphosate, and following up with a robust residual herbicide.
These must be applied on fine, firm and moist soil. An easy way to prevent this from happening is to delay drilling, if possible, until early October.
With the loss of chlorothalonil earlier this year and the abolition of key azoles in the near future, disease control in cereals will prove to be a bigger challenge than ever before.
One way to reduce this risk is to not have lush, super advanced crops during the winter. This can also be helped by delaying drilling until October.
By the time you read this article, probably 80% of the cereal area I deal with will have been drilled, with forecasts predicting a positive and stable period for the second half of October. Hmmmm.
Conversely, early sown winter rapeseed looks great. The area I deal with is probably about half the area I have had in previous years. It had surprisingly low flea beetle activity, and crops that took advantage of the August rain fled.
I haven’t seen crops drilled very late, because I don’t have any, so I don’t know how well they’ve been grown.
Forward crops did not like the scorching temperatures in early September, but now that it has cooled down a bit, they have recovered well and look suitable for a cold winter. We can only hope.
East: Ben Pledger
Pharmacy (Bedfordshire / Hertfordshire)
In August, I discussed with rapeseed growers what strategy we would use to gain control of the flea beetle.
I have suggested that with the pest’s resistance to pyrethroid insecticides, we should move away from what would effectively be “recreational insecticide applications”, which would also be harmful to the beneficial insect population.
Instead, we’ll focus on extra foliar nutrition to keep the crop as healthy as possible, so it is able to overcome the attack and grow away from damage. At the moment, this appears to have paid off, without the harvest being canceled due to the damage from the flea beetle.
Sure, the soil moisture and temperature were favorable, but the smaller plants in the odd sprays are missing, and the abundance of cobwebs in most fields shows this approach has been beneficial. The foliar nutrition used was based on phosphites with potash, manganese and zinc.
With last fall’s weather and planting conditions still fresh in mind, the temptation to get drilled early is probably greater than ever for many growers.
However, keep in mind that most black grass will continue watering until mid-October and that the sooner the grains are sown, the more prone they become to barley yellow dwarf virus.
If you prioritize drilling so that fields with a lower black grass pressure are established at the beginning of the drilling campaign, this will allow the dirtier fields to continue flowing. In these situations, glyphosate prior to drilling is a must, as growing from the drill will not kill the black grass.
Some winter grains are now in the ground, and many are starting to emerge. Pre-emergence herbicides have been based on flufenacet + diflufenican in most places, with the addition of tri-alate where the pressure of black grass dictates that more chemistry is needed.
Although they get colder, oats and grain aphids are caught in suction traps. They both carry the barley yellow dwarf virus.
Insecticide applications to control these aphids will facilitate a post-emergence flufenacet-based refill without the need for an additional sprayer step. As with canola, I’m going to add the same foliar nutrition to grains to increase rooting and overall plant health.