Winter Oil Seed Rape – Diseases & Pests

Some light leaf spot sprays have gone on but the persistently wet conditions and the return of heavy rain means that the ability to travel on fields has become an issue.

If you historically have issues with light leaf spot and would normally apply an autumn fungicide and can still travel then it should be applied as quickly as possible.  If you would have applied an autumn spray but can’t now because of ground conditions then you will just need to accept that the incidence of disease will be higher in the spring and try and manage accordingly then.  There is a handy tool on the AHDB website to let you look at different scenarios on your farm.   This lets you factor in the variety, region and sow date and whether or not you applied an autumn spray to judge what infection levels will be like in the spring.

With most crops well established, the risk from pigeons is reduced as they like a ‘gap’ (traditionally caused by slug damage) to land in and nibble away at the crop.  Keep an eye on crops and take measures to keep pigeons off where slug damage has led to ‘gappy’ crops.

We are now starting to find rape winter stem weevils in a few of our monitored crops.  If you had problems with plants in last seasons’ crop that produced extra lateral shoots or were stunted when you were expecting stem extension, then that could be a sign of rape winter stem weevil infestation on your farm.

Growers are running out of time to apply an insecticide to control rape winter stem weevil – the end of this week is probably the last chance to get an insecticide on before eggs have hatched and the grubs have burrowed into safety within the stem.  Delaying treatment into mid-November will allow egg-laying and hatch to happen, and the grubs will be protected within the rape stem.