4 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE 



spur is like a hinge, picking should be an unhinging process. Inexperi- 

 enced or careless pickers, however, often pull the fruit from its attach- 

 ment. This usually results in breaking the spurs, which cuts down the 

 bearing surface and reduces succeeding crops, or in pulling out the stem 

 of the apple and tearing the flesh, thus opening the way to decay. 



Ease of separation is not a reliable index of maturity (10). Under 

 some conditions apples start to drop before they are properly mature. 

 Then they may be harvested before becoming sufficiently mature to 

 develop the best quality after ripening. Harvest sprays, such as naph- 

 thaleneacetic acid, which have come into rather general use to prevent 

 fruit drop in some sections (1), invalidate the ease of separation from 

 the spur as a criterion of maturity. Although these sprays make the 

 fruit stay on the tree longer, they do not interrupt the advance of ma- 

 turity; and as a result of their use picking may be delayed until the 

 fruit is overmature. 



FRUIT COLOR AND APPEARANCE 



The blush, or red color, of an apple is not a reliable index of maturity. 

 The ground color (underlying green or yellow), however, can be used as 

 an index. The quality of a red apple can be judged ordinarily by the 

 proportion of red to green; the more red, the better the eating quality. 

 As most varieties of apples become mature the ground color changes 

 from a green very much like that of the leaves to a lighter shade and 

 eventually to yellowish. The time to pick most varieties is when the 

 first signs of yellowing appear (9). This is not always true with some 

 varieties — Grimes Golden, Jonathan, and Yellow Newtown, for example 

 — when grown under certain conditions. The red sports of some varieties 

 usually become fully red before they are mature, with no underlying 

 ground color left for observation. As a result, they have frequently 

 been picked too soon and have suffered in popular esteem because they 

 were judged to have poorer quality than the parent variety. Although 

 ground color cannot be used as an index of maturity for red bud sports, 

 the ground color of the parent varieties growing in the same vicinity 

 can be so used, as their seasons of maturity are ordinarily about the 

 same. 



As fruit matures on the tree it develops a waxy coating and the lenti- 

 cels, or pores in the skin, become sealed with cork. These changes, 

 however, are not sufficiently discernible with most varieties to make 

 them of muchc-value in determining when the fruit should be picked. 



PERIOD FROM FULL BLOOM TO MATURITY 



The number of days from full bloom to picking maturity has been 

 found to be rather constant over a wide range of climatic and cultural 

 conditions, hence very helpful in determining when the crop should be 

 picked (10). The method requires the keeping of records showing the 

 dates of full bloom of varieties in a given orchard. This is the date when 

 the first petals fall without the influence of strong wind, or when most 

 of the tiasal blossoms in a cluster have opened. When warm weather 

 that brings the center, or king, blossom into full bloom is followed by 

 cool weather that retards the opening and pollinating of the other blos- 

 soms for a week or more, establishing the date of full bloom for most 



