Potato growers must get sprouting control programmes under way as soon as possible, the British Potato Council (BPC) has advised.
Crops going into store will be at risk of sprouting, warns Adrian Briddon from BPC's Sutton Bridge Experimental Unit (SBEU). "If you are going to use chlorpropham (CIPC) you must get it on before you see any active sprout growth and applications to sprouted tubers need to be at a higher approved rate. While more expensive, this cuts down the urgency for repeat applications and helps prevent later problems with residues."
CIPC is now subject to a Maximum Residue Limit (MRL) of ten parts per million and samples are tested as part of residue analysis undertaken on behalf of the Pesticides Safety Directorate. "Although CIPC now has an MRL, it is still under review. All growers must be careful not to exceed the MRL. That makes it more important than ever to anticipate any problems."
If the use of CIPC is certain, apply it early, Mr Briddon advises. "If your crop is destined for processing, its use is certain." Growers should also check crop condition carefully – tubers must be dry and skins cured before application. High soil levels on tubers will also reduce product efficacy. During temperature pull-down crops should be monitored on a daily basis, and condition checked regularly throughout the season.