We need to be very careful to manage the remaining blight actives we have left – Arable Farming – Darryl Shailes
We had sharp frosts just before Christmas and the pond froze over. The swans had fun, walking around on the ice ...
After the frost came the rain, and we’ve had a mini flood, with just a bit of water in the garden but it soon went, so no opportunity to get the canoe out and paddle across the meadows that run up to the Waveney.
However, the rain was very welcome, and speaking to many growers, the pumps have been able to run and the reservoirs are filling up well.
That’s the first part of the puzzle hopefully sorted, as over in the East where I am based, no water for irrigation means no potato crops.
The area planted will still be down, with some growers pulling out of potatoes all together. The cost of growing potatoes is so high now that good returns are challenging and yields must be high even to stand still.
Last season was a very low season for blight and I’ve not heard of any in stores, although there are plenty of other problems.
As always blight pressure next season will depend very much on the weather but hopefully background inoculum will be pretty low from volunteers due the lack of blight in 2022.
One thing we need to keep an eye on is the announcement that Danish growers have got astrain of blight that is resistant to the CAA group of chemistries that include benthiavalicarb, dimethomorph and mandipropamid.
EU_41_Al has been around for a while in Denmark, Holland and Belgium but has not yet been found in the UK. However, it has only just been confirmed that some strains of the genotype are resistant to CAA chemistries.
Danish growers have not been using multi-site chemistry such a mancozeb for a number of years now, initially due to the high taxation based on the amount of active ingredient being applied and now the EU ban, so this puts pressure on the single site actives left.
Also, another factor could be that in many European countries the blight strategy has been to run with sequences of blight products unlike the UK where generally the strategy is to alternate actives and mix actives when the risk is high.
This combination of the ability of Phytophthora to generate new genotypes and the way it is controlled means it’s probably inevitable that this should happen, as we have seen changing genotypes in the EU with some showing resistance to different chemical groups for some time now.
Initially it was with Blue 13 to phenylamide such as metalaxyl, then fluazinam and Dark Green 37. Now with EU_41 to CAAs, we need to be very careful to manage the remaining active we have left with strong anti-resistance blight programmes.
This highlights the importance of multisite chemistry such as mancozeb, and we have to hope HSE feels the same, but also the need for the industry to support the genotyping in the UK that was part of the ‘Fight against Blight’ campaign under the old AHDB Potatoes.
There has been some frost damage reported in the beet crop left in the ground after the pre-Christmas frosts, and as I’m writing in mid-January this won’t help any fields that are still to be lifted.
The lack of leaf canopy to help protect the crowns due to the combination of beet moth damage and cercospora coming in late again has not helped.
It’s important that we recognise the value of canopy cover in late-lifted crops and maybe we need to come up with some different strategies to ensure as little damage from unpredictable frosts and these new ‘continental’ problems in the future.
If we had a more normal English summer, for example, cooler and wetter, it would probably be different, but will we ever have one of those again?
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