West: Keep watch for sawfly larvae

Early drilled rape crops are nowup and away, with two to four leaves, and some may require a growthregulatory fungicide in a few weeks.

These crops tend to be after winterbarley, and while the economics of this crop can be questioned, ithas clear benefits in respect to the following rape crop.

In contrast, very little rain inSeptember and strong winds have meant late planted crops are sat indry soil, yet to germinate. There are also some crops with splitemergence. Spraying these crops is a bit tricky, with plants atdifferent growth stages, and sprays requiring the crop to be atexpanded cotyledon stage.

Many crops have had some autumn nitrogen,but the dry conditions have meant we are yet to really see aresponse. Slug pellets have been required in some cases.


Turnip sawfly larvae have been found inturnip crops and last year’s rape stubbles, so monitoring is takingplace. One consolation of the dry conditions is sub-soiling appearsto have been working well, which will benefit crops in the seasonahead.

Stale seed-beds ahead of drilling cerealsremain stubbornly un-green! I am not convinced this is due toblack-grass dormancy, but more the lack of moisture. Combine thiswith early drilling and you have a good recipe for grass weeds.

In fields with bad problems try and holdyour nerve and let the stale seed-bed green up and drill late.Alternatively, don’t forget the plough, still a useful tool in theongoing battle against grass weeds.

Despite the dry conditions I would stilladvise applying pre-emergence herbicides once fields are drilledand rolled. Just check seed depth and seed-bed quality beforeapplication. Trials last season reinforced the importance ofincluding flufenacet as the key component of pre-emergencemixes.

Although the currentdry conditions have slowed down slugs, a return to damp conditionswould see activity resume in earnest, so be vigilant.

Need a contractor?

Find one now
See more