PICKING MATURITY OF APPLES D 



of the colors. The four colors, numbered from 1 to 4, have been 

 found satisfactory for general use on apples. When the color of an 

 apple falls between two of the standard shades given it can be noted, 

 for example, as ''between 3 and 4" or as 3y 2 . A greater number of 

 colors would make the comparison more difficult and would add 

 little to the accuracy of matching the fruit color. 



The firmness of the flesh of the fruit can be most accurately meas- 

 ured by the use of a pressure-test apparatus. Such an apparatus 

 with methods for its use has been described previously 5 and is now 

 available on the market. This apparatus measures in pounds the 

 pressure required to force a plunger seven-sixteenths of an inch in 

 diameter into the apple to a depth of five-sixteenths cf an inch, the 

 skin being removed prior to making the test. Figure 1, reproduced 

 from Department Circular 350, illustrates the method of making the 

 test. The fruit to be tested is placed against any convenient solid 

 surface, such as a wall, or the trunk of a tree if the test is being made 

 in an orchard. The plunger tip is placed in contact with the cut 

 surface and pressure is applied. When the plunger tip has pene- 



Fig. 1. — Fruit pressure tester, showing method of its use in testing an apple 



trated to a depth of five-sixteenths of an inch an electric contact is 

 made which lights the small flashlight attached to the instrument. 

 The amount of pressure in pounds required to force the plunger into 

 the fruit to this depth is then read directly on the scale. In order to 

 obtain a satisfactory indication of the condition of any variety at 

 least 10 to 20 apples selected from different trees and different parts 

 of the trees should be used. Two or more tests may be made on each 

 apple and the results averaged. Tests should be made within a few 

 hours following picking. 



The tenacity with which the fruit adheres to the tree can be esti- 

 mated only in a general way. If the stem of sound fruit separates 

 from the spur when the fruit is lifted or is given a slight twist, it 

 would be considered that the fruit is loosening on the tree and sepa- 

 rates easily. Under this condition it is probable that a small amount 

 even of sound fruit may be dropping. If no fruit is dropping and if 

 the fruit can be picked only with considerable effort, it is considered 

 that the fruit is still firmly attached to the tree. The dropping of 



3 Magxess, J. R., and Taylor, G. F. ax improved type of prbssuke tester for the 

 determixatiox of fruit maturity. U. S. Dept. Agr. Circ. 350, S pp., illus. 1925. 



