Results from the 2003 Commercial SmartFresh^TM (1-MCP) Trial on Apples in Canada

A research permit (66-RP-03) was granted by the Pest Management Regulatory Agency (PMRA) to allow SmartFresh treatment at five commercial apple storages in Canada for the 2003 harvest season. Treatment was limited to a maximum of 20 rooms for all sites, and a maximum total of 6500 tonnes of apples could be treated under the permit. All treated apples had to be exported. The overall purpose of this research was to demonstrate the efficacy of commercial applications of SmartFresh (1-MCP) on apples in Canada, while the research permit was specifically granted to establish a Maximum Residue Limit (MRL) for the use of 1-MCP in Canada. This summary is on the efficacy.

Selected commercial storage rooms (18 Empire, 1 McIntosh) were treated with SmartFresh (1 ppm) for 24 hours according to the AgroFresh directions for use. Corresponding control (non-treated) apple samples were held for the 24-hour period in a nearby storage room at approximately the same temperature. Following SmartFresh treatment, control samples were returned to the treated storage room and controlled atmosphere (CA) conditions were established immediately thereafter.

Overall, apples harvested at optimum maturity for long-term storage responded well to the SmartFresh treatment, whereas apples harvested after optimum maturity responded poorly. After 14-days at room temperature, ‘Empire’ apples treated successfully with SmartFresh exhibited 5-6 lb greater firmness than the control non-treated fruit. Similarly, treated apples had <0.1 ppm of internal ethylene compared to more than 200-300 ppm in the control fruit. These benefits from SmartFresh treatment were still evident after mid- to long-term storage, plus 1 week at room temperature. Some fruit developed internal browning after 7-9 months of storage, but there was no significant effect of SmartFresh on the incidence. CO₂ injury was also apparent in a few fruit samples, which were mostly not treated with DPA to reduce high CO₂ sensitivity.

It important to note that most of the data collected from this commercial trial has been on Empire apples. Different cultivars respond differently to SmartFresh. Therefore, cultivars other than Empire should not be expected to necessarily respond the same to SmartFresh treatment. There will no doubt be many learning curves as this product becomes increasingly adopted by the Canadian apple industry.