Continuing dry conditions in the east are resulting in very uneven oilseed rape establishment.
Where the better seed-beds on lighter soils have caught the odd shower of rain, plant populations are sufficient to make a crop. Thankfully most rape plants have managed to find moisture and have survived.
Nevertheless on heavier soils and in poorer seed-beds rape establishment is down to 10-20% and these situations require a good amount of rain to fully moisten the seedbed and encourage further germination. Even then low plant populations and reduced plant vigour may result in a poor crop going into winter.
There has been quite a lot of leaf miner damage to OSR plants although this is mainly restricted to cotyledons. In some places flea beetle have been active even where the more persistent seed treatments have been applied. Dry conditions may have reduced systemic movement of the insecticide active ingredient within the plant. A foliar insecticide may need to be applied in these situations.
Wheat drilling has started albeit into dust and clods. Seed rates needto be adjusted upwards in these dry conditions to take account oflikely emergence date and cloddy seed-beds. Although slugs are notactive at the moment, resulting seed-beds, when it does rain, will beconducive to slug activity.
Fields destined for pre-emergence herbicides will be sprayed as soon aspossible after drilling rather than waiting for moisture. The herbicideactive ingredients that we are using, other than tri-allate, are notreadily volatilized in dry, bright conditions so will not degraderapidly in dry seed-beds.
Most of them are taken up both by the roots and the shoots ofgerminating weeds. Shoot uptake is more important in dry conditionswhen herbicides may not reach the rooting zone of weeds. Trials resultsand field observation during the dry autumns of 2003 and 2007 showedthat pre-emergence herbicides continue to provide high levels of weedcontrol even in dry seed-beds.