As I write this article on Sunday 27th October the mercury is falling and the wind is strengthening ahead of the remnants of the tropical storm which is about to batter us. Tropical is certainly an apt word to describe the unseasonably mild conditions we have been experiencing of late.
Oilseed rape crops that were struggling a month ago have grown away well, thriving in the mild, damp conditions and most, if not all, should survive the winter. Slug activity is extremely low, with very few crops showing any signs of slug activity – a refreshing change from last year!
Some of the more advanced crops are now knee high and have had an application of Caramba (metconazole) to slow them down and protect against Phoma. Remaining crops at a more normal canopy size have yet to be sprayed, levels of Phoma are currently very low or non-existant and I am advising growers to hold off at the moment.
Centurion Max (clethodim) applications to control blackgrass have done a superb job and control levels seem near 100% of what had emerged at the time of application. Remember though, that to protect the product and avoid the build up of resistance you must follow up with propyzamide shortly once soil temperatures have fallen into single figures.
Cereal crops are emerging well, but early pre-emergence applications applied to dry seed-beds have not done a very good job and there are plenty of reports of farmers spraying off early drilled cereal crops with high populations of blackgrass in them. Crops are still very soft and any planned post-emergence herbicide applications need careful thought to avoid scorching the crop badly.
Aphid numbers are high, so is the risk of barley yellow dwarf virus (BYDV) and crops are now receiving an aphicide to hopefully prevent a repeat of autumn 2011! If you are tank mixing with herbicides, avoid cheap EC formulations of insecticide and use Hallmark Zeon (lambda-cyhalothrin) or Mavrik (tau-fluvalinate) instead to reduce the scorch risk.