CIPC and 2,6-DIPN sprout suppression of stored potatoes

A five-year storage season study using small-scale bins was undertaken to determine the effectiveness of 2,6-diisopropylnaphthlene (2,6-DIPN) in combination with isopropyl-N-(3-chlorophenyl)carbamate (CIPC) for sprout suppression of stored potatoes (Solanum tuberosum L.). The study environment simulated a commercial operation and the storage bins held up to 4,500 kg of tubers. Russet Burbank potatoes were tested for four storage seasons, and for one season the bin space was split between Ranger Russet and Snowden potatoes. Sprout suppression was measured as percent acceptable for fresh pack (%AFP), defined as sprouts ≤3 mm in length. When 2,6-DIPN was used alone at 8.3 mg kg^-1 fw, it only provided short-term sprout suppression. Sprout suppression responses for the two chemicals were similar for Russet Burbank, Snowden and Ranger Russet. When 2,6-DIPN was used in combination with CIPC, a significant increase in sprout suppression was observed. In addition, when the two chemicals were used in combination, the amount of CIPC could be reduced by as much as 50% while still maintaining equal or better sprout suppression as compared to CIPC alone. For overall long-term sprout suppression, the best treatment was a combination of CIPC and 2,6-DIPN, each at 16.6 mg kg^-1.