Evaluation of CIPC application and behaviour and its influence on the variability of CIPC residues

Control stores (c.1,700 tonnes), without modification and where CIPC fog was allowed to rise directly into the store headspace resulted in variable CIPC residue levels. Application of fog via a simple plenum (a covered walkway through the main block of boxes) improved residue distribution considerably in some stores, but not consistently. The use of fans, to create a positive pressure or negative pressure plenums, to increase recirculation of fog, also did not lead to consistent improvements in CIPC residue distribution or sprout control efficacy.

In contrast to the standard ‘overhead throw’ and modified ‘overhead throw’ stores, the positively ventilated ‘suction wall’ store resulted in the most even CIPC residue distributions and good sprout control efficacy. Results comparable with those in bulk stores, using inverter controlled fans, were obtained. The ‘suction wall’ store type is dependent on the correct box type being used though, and when this was not the case store performance deteriorated. In addressing CIPC efficacy in box stores, it is considered doubtful that simple modifications to ‘overhead throw’ stores can be totally effective, although some are certainly likely to enhance their performance significantly.