A decent amount of October rain has proved just what the doctor ordered in helping our pre-emergence herbicide pick-up and counter the blackgrass that was beginning to appear in many September wheat drillings. So far we have only had to over-spray a handful of fields – all early drilled on ground that gets so wet that later autumn sowing is too risky to contemplate.
Even though conditions have been so unstable, the past four weeks have provided enough decent breaks to get all but our latest wheats after maize drilled-up in good shape. Being so reliant on strong pre-em activity these days, we have to make sure we have enough of a window to roll and spray as well as drill at an adequate and consistent depth, which puts even more pressure on frayed nerves.
With the dry September it has been more nerve-jangling than ever holding off on large areas to get the wheat drilling conditions we wanted, as well as the best pre-planting glyphosate kill. But, once again, it has been more than worth it. Not only have we managed to spray off two good flushes of blackgrass in many cases, but most of our later seed-beds have been in much better shape than those prepared a month earlier.
This has been valuable for slug as much as weed control. The large numbers of slugs around in August virtually disappeared through September. Below ground, though, it was a different story, with a lot of seed-hollowing where dry seed-bed conditions made it difficult to achieve effective consolidation.
Pre-baiting ahead of wheat drilling wherever early autumn populations were high has been extremely valuable this season. The huge kills we achieved in ex-rape stubbles have really helped keep the lid on problems following the rain as well as earlier out-of-sight damage.
With grain and bird cherry aphid numbers building-up noticeably in the balmy weather, we’re just going in with our first insecticides on the wheat. As it’s too early to know whether any blackgrass we’re seeing is half alive or half dead, we’re not waiting to combine this with any post-em blackgrass herbicides. We must keep barley yellow dwarf virus (BYDV) out and, under current conditions, we can’t afford to rely on much more than six weeks activity from Deter (clothianidin) treatment.
Aphid spraying decisions have been less straight-forward in the rape. Conflicting reports over the extent of damage from turnip yellows virus (TuYV) mean we’ve taken a cautious approach based strictly on Myzus persicae numbers in our traps. So far, we’ve sprayed around a third of our crops – mainly further south.
Phoma levels are staying good and low, so we’ve been able to concentrate our early fungicide applications on regulating the growth of more forward hybrids whose vigour has been so valuable this autumn. All our oilseed rape will be receiving a November spray targeted at light leaf spot and phoma. It doesn’t look like we’ll have enough cold weather to open up the crop for propyzamide anytime soon, so we’re set for separate early winter applications here too.