3 - 



Table 3. Influence of ethephon on red color development on 



'Niagara.' Sprayed with 1/2 pint of ethephon on August 

 25; harvested August 28, 1973^. 



?. 



Red color, % 



Treatment 8/23 8/28 Increase in^color, 



Ethephon 49 7l Ua^ 



Check 48 51 3b 



^Applied with a Hardie sprayer 



^Means, within a column, followed by a different letter are signifi- 

 cantly different at the S% level. 



Ethephon was used extensively on Early Mcintosh, Puritan and 

 Milton varieties by Massachusetts growers in 1974 with generally 

 good results. Several growers observed that color developed more 

 slowly following the ethephon spray in 1974 than in 1973, particu- 

 larly with the earliest-sprayed trees which did not develop satis- 

 factory color for 7-8 days. The color benefit from later sprays 

 on the same variety in the same block was apparent within 3 days 

 and the fruit were picked on the fourth day. This shows that color 

 develops more quickly in some instances than others and that there 

 is no substitute for a careful daily check of trees. Early vari- 

 eties are notorious for uneven ripening. Therefore, it may be advis- 

 able, for some varieties, to make one picking to remove the riper 

 fruit and then apply ethephon. This should help minimize the prob- 

 lem of over-ripe fruit at harvest. Some growers may wonder about 

 the possibility of spraying the ethephon, then picking the ripe 

 fruit that day, or 1 or 2 days later. Although the ethephon-apple 

 label is not definite with regard to pre-harvest interval, AmChem, 

 the manufacturer of ethephon, prefers to discourage the spraying 

 of this chemical and harvesting the same day or 1 or 2 days later. 

 Harvesting the mature fruit and then applying the ethephon is the 

 preferred practice. Ethephon applied alone accelerates fruit drop. 

 Therefore, naphthaleneacetic acid (NAA) should be used with the 

 ethephon to counteract this abscission effect. 



Use on 'Mcintosh. ' Our suggestions are based on 3 time periods for 

 sale of ethephon-treated 'Mcintosh' fruits prior to normal har- 

 vest time (Labor Day or shortly after), during normal harvest, and 

 after several months of storage (Table 4) . The volume of fruits 

 sprayed with ethephon should be based upon anticipated sales during 

 one or more of these sale periods. The harvest of ethephon-treated 

 fruits must not interfere with the timely harvest of fruits for CA 

 since the placement of ethephon-treated fruits in this type of stor- 

 age is not recommended. Our data and those from a regional exper- 

 iment involving New, York, Maine and Massachusetts, show that ethe- 

 phon-treated fruit which still are in good condition will store 

 satisfactorily in CA, but we are concerned that apples not in good 

 condition will be stored. However, if labor difficulties worsen, 

 it may be necessary to extend the harvest season by advancing it 

 through the judicious use of ethephon on CA 'Mcintosh, * 



