Under 

 color, such 

 vigor, or d 

 color may b 

 color up to 

 tion. Furt 

 may not br i 

 factory lev 

 ety) within 

 allowed to 

 becomes gre 

 non- sprayed 

 after the e 

 10-year-old 

 Extra Fancy 

 check trees 

 color. 



conditions that are normally associated with p 



as high temperatures, wet and cloudy weather, 

 ense trees, the ability of the fruits to devel 

 e so low that an ethephon spray still will not 



satisfactory levels within 7 or 8 days after 

 hermore, both on young trees and older trees, 

 ng the fruit in the interior of the tree up to 

 el (501 of surface having red color typical of 



7 days after treatment (Table 2) . When the f 

 remain longer on the tree, however, the color 

 ater between the ethephon-sprayed shaded fruit 



shaded fruit. It is of interest to note that 

 thephon spray in 1974, 661 of the interior fru 



trees had typical red color and would have gr 

 On the other hand, none of the interior fru 



would have graded U.S. Extra Fancy in regard 



oor fruit 

 excessive 



op red 

 bring 



applica- 



ethephon 

 a satis- 

 the vari- 



ruit are 



difference 

 and the 

 11 days 



it on the 



aded U.S. 



it on the 



to red 



Table 2. The influence of 1/2 pint of ethephon applied on Septem- 

 ber 5, on red coloration of shaded 'Mcintosh' apples . 



Treatment' 



Ethephon 

 Control 



Red color 

 973" 



1973 



wn — 



9/17 



Red 

 "973"" 



color < 

 9/12 



1974 (%) 

 9/16 



T5^ 

 4a 



T2a 

 33b 



10-year-old trees on M.7 



3a 

 3a 



58a 

 33b 



76a 

 28b 



^7r9" 



Ethephon 

 Control 



3a 

 3a 



40-year-old standard trees (30 ft spread) 



29a 

 16b 



50a 

 26b 



la 

 la 



16a 

 9b 



28a 

 10b 



52a 

 21b 



^NM, 20 ppm, and 2,4,5-TP, 10 ppm, used for drop control in 1973 

 and 1974, respectively. 



y 



Means for tree type, within a column, followed by a different let 

 ter are significantly different at the 51 level. 



By 

 obtain 

 juice o 

 ing ade 

 correct 

 and doi 

 followe 

 mit bet 

 the app 



the time the ethephon fruits in the interior of most trees 

 adequate color, they will probably be suitable only for 

 r immediate sale because of ripeness. The problem of obtain- 

 quate color on the interior of large dense trees can be 

 ed somewhat by pulling the water sprouts during the summer 

 ng some light summer pruning. These procedures should be 

 d by spot picking which will lighten the crop load and per- 

 ter light penetration into the interior of the tree before 

 lication of an ethephon spray. 



Use on early maturing varieties . Ethephon is a very useful tool 

 on early varieties. In general, a single application applied 7-10 

 days before normal harvest at 1/2 pint per 100 gallons of water 

 will increase red color development within 4-5 days (Table 3). 



