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Drenching for Scald Control and Storage Requirements by Cultivar

Braeburn--This variety has a low risk of scald development. Diphenylamine (DPA) at 2,000 ppm should alleviate this risk. DPA has also been reported to reduce internal problem in Braeburn. Precondition fruit for 14 to 17 days at 40 degrees F prior to applying CA regimes. Oxygen concentration should be kept at 2 to 3 percent and carbon dioxide below 0.5 percent to help avoid Braeburn browning disorder.

Cortland--Treat with DPA at 2,000 ppm and and store at 2 to 3 percent oxygen and 5 percent or 2 to 3 percent carbon dioxide at 36 degrees F or 32 degrees F, respectively.

Delicious--Scald can be a problem if fruit is picked too early; therefore, treat fruit with DPA at 2,000 ppm. Store at 1.2 percent oxygen and 2.0 percent carbon dioxide. If carbon dioxide exceeds 3 percent, premature mealiness and cavities can occur.

Empire--Treat with DPA at 1,000 ppm. The storage regime for Empire is 2.0 to 2.5 percent oxygen and 1.5 to 2.0 percent carbon dioxide.

Fuji--Treat with DPA at 1,000 ppm and store at 4 percent oxygen and 0.5 percent carbon dioxide. Maintain this relatively high level of oxygen as long as significant watercore is present.

Gala--No scald treatment is required. The storage regime recommendation is 1.2 percent oxygen and 2 percent carbon dioxide.

Golden Delicious--Skin shriveling can be a problem with CA storage. Polyethylene bin liners, sometimes used to raise humidity around apples, may slow the rate of cooling. Polyethylene hoods, if used, should be placed over the bins after field heat has been removed from apples. To help reduce skin shrivel, do not store bins of Golden Delicious on the top tiers. Golden Delicious does not require anti-scald treatment. Storage conditions are 1.1 percent oxygen and 2 percent carbon dioxide.

Granny Smith--Granny Smith is very prone to scald and requires 2,220 ppm DPA. Storage conditions are 1 percent oxygen and 1 percent carbon dioxide.

Idared--Normally this variety keeps well in regular storage, but because Jonathan is one of Idared's parents, Idared can develop Jonathan spot in regular storage. In CA storage, Jonathan spot usually does not occur. DPA is recommended at 1,500 ppm and storage at 2 to 3 percent oxygen and 2 to 3 percent carbon dioxide.

McIntosh--More is probably known about this cultivar, based on work done in New York State, than any other. DPA is recommended at 1,500 ppm and storage at 2 to 3 percent oxygen and 2 to 3 percent carbon dioxide. Continuous use of 5 percent carbon dioxide may cause injury on skins of less mature fruit. Thus, the carbon dioxide level should be varied, beginning at 2 to 3 percent the first month and being raised to 5 percent thereafter. Fruit will be firmer if stored at temperatures below 36 degrees F, but various disorders may appear at lower temperatures.

Northern Spy--No scald control is recommended. Storage regimes include oxygen at 2 to 3 percent and carbon dioxide at 8 percent and 2 to 3 percent when stored at 38 degrees F or 31 degrees F, respectively. Although two possible CA combinations are listed (Table 6-2), a temperature of 32 degrees F maintains fruit firmness better.

Rome Beauty--This cultivar has moderate risk of scald and should be treated with 2,000 ppm DPA. A storage regime of 2 to 3 percent oxygen and 2 to 3 percent carbon dioxide should be employed.

Stayman--Scald control for this variety is 2,000 ppm DPA This variety is stored at 2 to 3 percent oxygen and can withstand up to 5 percent carbon dioxide, but because it is frequently stored with other varieties, 2 to 3 percent is generally used.

York Imperial--Scald control for this variety is of less concern, given its emphasis in the processing market. A storage regime of 1 to 2 percent oxygen and 0.5 percent carbon dioxide at 32oF is recommended.

Other varieties--Experiments in New York State with Jonamac, Mutsu, Jonagold, and Spigold indicate that 31 degrees to 32 degrees F with 2 to 3 percent carbon dioxide and oxygen is satisfactory.