Plan OSR desiccation carefully

Plan OSR desiccation carefully in order to avoid crop damage and yield losses at this final stage warns Hutchinsons Dick Neale.

“The first thing to consider is timing he says, don’t feel pressure to go on too early.”

“Early application timing can damage the seed filling procedure and impact yields. It will also increase the chance of red seeds due to uneven ripening- any more than 5% and the crop will face rejection.”

“The best guide for when the crop is ready is the overall crop appearance and seed colour-  the crop canopy should resemble the colour of a hare’s back. Remember that any samples should be taken from the main raceme as this will ripen first. Take a good sample of pods, out of 20 if 2/3 have changed from green to brown this is the early timing and from this stage, glyphosate can be applied for the next 4-7 days.”

As far as tools for desiccation go, glyphosate is now the only chemical option with the removal of diquat, says Mr Neale.

“However, remember that glyphosate cannot be used on seed crops. Its best to aim for application 14-20 days before harvest. Seed moisture should be at 30% or below for glyphosate application.”

“Rates of glyphosate need to be robust – at least 1440gms of active, and if using generic products then its important to add in the required adjuvant. Glyphosate is very susceptible to cations in the water and this can cause lock up of the active and reduction in the ability for the herbicide to work effectively. Adjuvants have a growth stage cut off for use with 100% dose of pesticide.”

“If preferring a non chemical route then swathing is an option  – but really only tends to suit crops that are thick and are leaning. Its important when swathing to keep the swathed crop off the ground to allow for air flow.”

“Of course, if a crop is weed free and very even, there is the option to do nothing, and leave it to ripen naturally. This is useful if there are large areas of OSR to harvest and you are trying to spread out the harvest window. However the crop will take longer to ripen which means this is not really an option the further north you go due to the lower temperatures and higher moisture levels.”

Pod sticker

Pod sealants can be used to help with pod shatter and delayed harvesting due to weather. If a pod sticker is going on at this timing, then this can be added to the glyphosate, suggests Mr Neale.

“Modern pod sealants act in providing a mesh like structure around the developing pod. Generally, the optimum timing is an advance of glyphosate timing, although more generally applied as part of a tank mix, the main benefit of pod sealants is protection against the potential of pod shatter.”

• Top tips for OSR desiccation
• Timing – don’t go too early; use crop colour for guide- beige is ‘a go!’
• Take seed samples if green then the crop is not ready but brown indicates it is ready
• Chemical options – rates of glyphosate need to be robust – at least 1440gms of active.
• If preferring a non chemical route then swathing is an option  – but really only tends to suit crops that are thick and are leaning
• If crop is weed free and very even, then there is the option to do nothing, and leave it to ripen naturally. Be aware crop will take longer to ripen and not suitable for crops further north.
• Pod stick can be applied with glyphosate toprevent pod shatter in exposed locations
• Good to hold pods longer if you have variable maturity within the field, especially if delayed harvest due to weather conditions.