Green shoots of recovery at iOSR Focus Site
OSR plants’ natural shedding of a greater number of lower leaves as a result of the high populations of CSFB, will put even greater onus on the remaining green leaf area to deliver good yields, believes Syngenta Technical Manager, Georgina Wood.
“Growers may need to further reassess the GAI and leaf area during the spring, if plants continue to drop leaves,” she advised.
“That could have implications for fertiliser rates and timing to ensure plants have the capability to quickly generate new growth."
“It will be especially important if growers have flailed or cut back the crop to remove larvae infested petioles.”
Georgina pointed out trials have shown OSR has a remarkable ability to recover and compensate for lost leaves, but that does mean new growth must be protected. AHDB research has shown OSR requires 60 to 70 days post flowering for seed to reach its optimum size and oil content.
“Extending the growing season by retaining new green leaf area for longer is likely to be crucial for these crops to recover lost potential.
"Crops could benefit particularly from Amistar applications through flowering, to aid green leaf retention and photosynthetic activity.”
The good news is that some of the Light Leaf Spot and Phoma pressure could be alleviated when plants shedding infected leaves.
Trials of companion cropping at the iOSR Focus Site in Cambridgeshire have shown good crop establishment, particularly from rows sown alternating with OSR drilled at 50 cm spacing, compared to where the companion crop is grown in the row with OSR.
However, whilst mustard is being touted as the best option for companion cropping OSR, Georgina Wood reported it was still growing extremely strongly in early February – with implications for competition until frost would take effect.
The results for OSR plant numbers and CSFB larvae populations would be assessed over the spring.