Aphids were found in crops almost to the day the Rothamsted model predicted – Arable Farming – Darryl Shailes
I heard my first cuckoo in the Waveney Valley on May 10, much earlier than last year and then again in our garden over the next couple of days ...
I even saw him sitting in a tree about 5am in the morning calling for his mate; Dad was duly invited over.
My daughter was visiting and she then heard him loud and clear the next day and thought she saw him sitting on the telegraph pole near the house. We also saw a hobby, another visitor signifying the summer migration was in full swing. So, with great anticipation Dad came on the Sunday. Unfortunately, we didn’t hear anything close, just the hint of something in the distance, one of those sounds you think, or like to think you hear, but not really sure, maybe a rather wishful auditory hallucination.
However, one migration that is in full swing, but this time very easily found, is aphids into sugar beet. The Rothamsted model used by the British Beet Research Organisation (BBRO) predicted the migration of myzus persicae would start around April 19 and it was amazingly accurate as aphids were found in crops almost to the day. The threshold of one wingless green aphid per four plants was met soon after then and recommendations to treat duly despatched.
At the time of writing the second applications are going on to the non-Cruiser (thiamethoxam) treated crops and we will soon need an emergency approval (EA) for a third treatment, with news just out that BBRO has been successful in its application for an EA for Movento (spirotetramat) as a third insecticide spray after Tepekki/Afinto and Insyst have been applied to crops.
With the need for more justification and recording of thresholds, especially around emergency approvals, I’ve been using our Omnia Scout app for the first time this spring. It’s simple to use, even for me, and can be accessed by the grower so it keeps them informed as to what’s going on.
Late flush of weeds
Weed control has been good in beet with herbicides working well and the same can be said for potatoes so far. With the dry weather we’ve been experiencing there can always be a later flush of weeds but hopefully with crops growing well and not appearing to be suffering too much at present from the lack of significant rain they will outcompete the weeds that do come.
The next big thing to consider in potatoes is blight control. The first applications are going on and we need to be very, vigilant especially with the capability of the dominant strain EU 36 A2.
It was in 2007 that I experienced my first big blight epidemic. Of course, we’d seen blight before, indeed it came into the UK around 1845 and caused the great famines in Ireland and Scotland a few years later. However, it came when we expected it, wet and warm and pretty much followed the old Smith periods that were established in the 1970s.Phenylamide resistance had been identified in 1981 but still it was relatively easy to control if a good resistance management strategy was followed.
In 2007 blight came in very early right across Europe, much earlier than normal and I remember that we were very challenged both by the epidemic itself and getting product applied due to the weather. In that year it was the newly identified Blue 13 genotype that was phenylamide resistant, very aggressive and could infect in a wider range of environmental conditions than we had previously expected.
EU36 A2 is much more aggressive than Blue 13 and able to sporulate much more in cooler weather.
As I’m writing this the risk for blight is very low. However, in all the trials we look at, the plots that break down are generally the ones with the weakest start. So, we mustn’t drop our guard and the programme should start early and be strong enough to cope with these new aggressive strains right from the word go. And the cuckoo, of course I heard him loud and clear after Dad had gone.
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