Potato growers are appealing to neighbouring cereal farmers to take extra care when spraying glyphosate this summer.
Undetectable levels of drift can cause serious damage to potato crops, especially those grown for seed.
The appeal was launched at Cereals 2008 by Potato Council, supported by HGCA and Assured Combinable Crops (ACCS).
“Seed potatoes are very sensitive to low levels of glyphosate contamination,” says Potato Council’s Rob Clayton.
“It can result in severe crop loss or damage from planting contaminated seed. This can occur from contamination levels below the limit of detection (0.05 parts per million), so extra precautions must be taken when spraying near a potato crop this summer.”
A voluntary 12-point code of practice suggests:
- Spray contractors should provide evidence of PA certification. If possible they should have dedicated sprayers for potatoes.
- Spray operators planning to spray seed potato crops should follow good wash out procedures at all times.
- Leave a suitable headland of an unsprayed crop.
- When spraying glyphosate within 100m of potatoes, take note of wind direction.
- Avoid spraying herbicides when the air speed at boom height exceeds 4 mph (6.5 kmh).
- Avoid very hot and calm days to reduce air movement carrying spray droplets.
- Where possible, use low drift nozzles which have a LERAP 3 star rating.
- Consider using an anti-drift agent based on polyacrylamide with glyphosate (e.g. Companion Gold).
- Check forward speed to avoid spray bounce which may increase spray drift.
- Check weather– avoid spraying near sensitive seed crops in high air temperature, low relative humidity or where temperature inversion is likely, such as following clear nights.
- Look out for the hedges, trees and other boundary obstacles – these can cause eddies.
- Record keeping is a legal requirement and should not be underestimated if the result of glyphosate drift onto a potato seed crop goes undetected until the daughter tubers are replanted.