Teagasc has just issued a comprehensive crop management advisory update.
In many cases farmers have not been able to get back into fields since crops were drilled.
The poor weather has made fields very soft underfoot. Some attempts to spray crops have left big ruts in tramlines, which will have to be endured for the rest of the season.
While there are many jobs to be done, the advice is to try to prioritise them into urgent treatments and those that can potentially wait until spring.
For anyone with winter barley drilled, it is probably the crop for which treatment is most urgent.
Crop management
There have been many questions to Teagasc advisors over the last few weeks about the need to spray an insecticide for aphid control.
Research indicates that when there has been a lot of rain, it actually reduces aphid flight and so should reduce the risk.
However, in areas where there is a history of bad barley yellow dwarf virus (BYDV) infections, farmers should walk crops and try to identify if aphids are present.
They will usually be more visible on headlands so it is a case of starting there. If it is felt that an insecticide is necessary, then one well-timed application will be as effective as multiple applications.
Trials from both Oak Park and Cork over the last number of years clearly show no benefit from multiple applications.
There are two options – either a pyrethroid or Transform, which is in its use-up period. There is very little difference in performance.
Grass weed control will also be a priority now, as annual meadow grass and sterile brome control will be more difficult the longer we have to wait.
Products such as Firebird, Flight, Tower, etc., work best when grass weeds are small at the one- to two-leaf stage, but they will struggle when the grasses begin to tiller.
Growers should consult their Teagasc advisors for which options will suit their situation best.
Winter oilseed rape
The next crop that needs attention right now is winter oilseed rape according to Teagasc. Many growers opted not to apply a herbicide at drilling due to the dry conditions.
According to Teagasc, some have applied a graminicide since, to control volunteer cereals and some grass weeds. But others have not.
Phoma lesions are now apparent on crops and in many cases, the 10% ‘infected leaf’ has been breached. Crops in this category will need treatment.
For weed control, many growers will choose AstroKerb at 1.5-1.7L/ha. This will give control to a wide spectrum of weeds, including blackgrass. However, growers are strongly advised to consult the label or the Teagasc Crop Report for specific details.
Straw from crops treated with AstroKerb must be chopped and cannot be used for bedding.
As a consequence, these fields should be included in the Straw Incorporation Measure (SIM) on the Basic Payment Scheme (BPS) application again next year.
For disease control in rape, growers should include a fungicide – the likes of a prothioconazole based-product at half rate. Proline has been specifically highlighted by Teagasc in this regard.
There may be some advanced crops that could benefit from a growth regulator effect. The inclusion of a tebuconazole (Fezan or Prosaro), or a metconazole (Sirena) will meet this requirement.
According to Teagasc, wheat and oat crops can generally wait for spring applications. They tend not to be at as high a risk from BYDV due to later drilling.
In the case of wheat, there are still plenty of options for grass weed control in the spring, according to Teagasc.