Fruit maturity . Maturity is the stage of development at harvest. 

 If too immature at harvest, fruit will never develop top quality 

 flavor and may be more subject to shriveling, scald, bitterpit and 

 browncore after harvest. If overmature, fruit will deteriorate 

 quickly and be more subject to softening, breakdowns and rots. 



How to identify maturity is a difficult question. Pressure 

 test, color (especially undercolor), abscission, and flavor are 

 helpful guides, but experience with your own fruit may be your 

 best measure. Use of growth regulators has made this an even more 

 difficult question. Alar* delays maturity, but not as much as 

 many people think. Its phenomenal drop control capability and its 

 delay of softening can be misleading. Do not delay harvest of 

 Alar*-treated fruit ; a significant amount of the firmness difference 

 between Alar*-treated and untreated fruits will disappear rapidly 

 during storage. Ethrel* hastens maturity, and despite our belief 

 that Ethrel*-treated fruits can be stored if^ harvested at the right 

 time, we think that it's hazardous to try to CA-store Ethrel*- treated 

 apples commercially. The hormone-type Stop-drop sprays also promote 

 maturation, and should be used with this understanding. 



Further complicating the maturity problem is the use of red 

 strains and dwarfing rootstocks. Since for marketing reasons har- 

 vesting is usually gauged by red color, the red strains are prob- 

 ably an advantage to proper storage management since less mature 

 (and longer keeping) fruit may be harvested. However, among the 

 strains of 'Delicious' it is well known that some red strains mature 

 well ahead of others. Therefore, it cannot be assumed that red 

 strains are just like the standard strains except for color; other 

 criteria must also be watched. It is very likely that some root- 

 stocks influence maturity, although this must yet be defined. Again, 

 you cannot assume that fruits from dwarf ing-rootstock trees are 

 the same as those from seedling -rooted trees. You must watch these 

 fruits closely. 



Just when to harvest apples for maximum storage life is perhaps 

 the most frustrating question to face. In Massachusetts, flesh 

 firmness of at least 15 to 17 lbs (if Alar*-treated, 16 to 17 lbs) 

 is considered essential for 'Mcintosh' if they are to be stored in 

 CA. If you are using a pressure- tester to gauge fruit maturity, be 

 sure you are using it properly . (See: "The Use of a Pressure Tester 

 to Measure Firmness of Apples''. Fruit Notes , March/April, 1977). In 

 Michigan, a simple test has been~devised to measure the amount of 

 ethylene gas being produced by apples as a means of determining 

 whether they are suitable for long-term or for short-term storage, 

 and it is being used commercially there, but we as yet have no per- 

 sonal experience with this test in Massachusetts. 



Most of the problems due to harvesting slightly immature apples 

 can be dealt with, and these fruit will have the potential for long 

 storage. Most of the problems due to harvesting overmature apples 



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