Spud Special: Unprecedented levels of aphids being found
At last, night time temperatures have got in to double figures and crops have responded. Most ware crops have now got to full canopy or not far off, so the sunshine amounts in July and August will pretty much dictate yields. Seed inspections are on-going and so far I am not anticipating too many issues, however, the number of aphids, particularly peach potato aphids, being caught in yellow water traps is unprecedented.
As a result, seed crops are receiving regular mixtures of both pyrethroid and anti-resistant insecticides such as Plenum (pymetrazone), Biscaya (thiacloprid) and Teppeki (flonicamid). I have also seen some ware crops with high numbers of aphids in them which have required controlling, it is worth remembering that colonising aphids can cause major problems if left untreated and in some instances the viruses they transmit can cause tuber quality issues.
The next few weeks can be quite worrying for seed growers, particularly those who have fields adjacent to oilseed rape crops as glyphosate applications are made to desiccate them. If you have rape crops next to seed crops or if you are a sprayer operator spraying rape off with glyphosate, please be aware that it can cause major issues, not just from direct drift, but also if applying in very warm conditions with the fine drift moving in convection currents. Glyphosate insurance claims can cost a lot of money, even the minutest amount of contamination can cause major problems.
Blight still seems to be non-existent, at the time of writing I have yet to receive a Smith period or even a half Smith period warning. Some growers are on ten day spray programmes, while others are on seven. The products I am recommending differ according to this, with cheaper products being used more frequently and more expensive chemistry with the addition of cymoxanil for kick-back activity being used where extended intervals exist.