4 MASS. EXPERIMENT STATION BULLETIN 381 



reached, by which time an apple has developed "good eating condition." 

 That ultimate eating quality is due in large part to initial ([uah'ty at time 

 of picking is a logical conclusion. This is apparent in the generally ac- 

 cepted notion that Mcintosh apples which have matured fairly well on 

 the tree develop the highest eating quality. "Green" Mcintosh, on the 

 contrary, never do reach this state. The idea that apples improve in cold 

 storage is basically false. Low temperatures simply prolong the interval 

 of ripening. Of course, no increase in red color occurs in storage. Studies 

 at this Station and elsewhere indicate that delated picking of Mclntosli is 

 imperative if the highest quality development is desired. Further, the 

 studies show that early-picked "green" fruit often stores rather poorly. 

 Color ant[ quah'ty in a crop from a given tree are often closely associated. 



Use of Hormones 



The use of hormone sprays to delay dropping of Mcintosh just prior 

 to and during harvest, if sufficiently successful, sliould encourage grower.s 

 to delay picking somewhat in order to take advantage of this critical 

 period in quality and color development. Improvement of an entire 

 crop in these factors would be a significant accomplishment, especially 

 if it were not accompanied by disproportionate losses due to excessive 

 tiropping. Further, it has been shown in a previous publication (6) that 

 Mcintosh apples continue to grow in size into October and that a ver\- 

 significant increase in yield results from this late-season growth. It is 

 the purpose of this bulletin to analyze briefly the results of some drop 

 control experiments at the Massachusetts Experiment Station in 1940 

 and to evaluate the method in the light of the considci'ations just dis- 

 cussed. 



EXPERIMENTAL TESTS 



The work involved several tests Avith four varieties. Each test included 

 two or three to many comparisons. Five commercial proprietary products 

 and the pure naphthalene acetic acid powder were used. When the pure 

 cliemical was used, it was dissolved in a small quantity of alcohol and 

 was then added directly to the water in the spray tank. Its low rate 

 vjf solubility in water made this procedure necessary. The commercial 

 products, being specially prepared to take care of this solubility problem, 

 were used as received. When the manufacturers' directions were followe<U 

 assuming that their statements were correct, spray mixtures contained 10 

 parts of pure hormone to a million parts of water (10 p. p.m.) or 3.8 grams 

 in 100 gallons. This was the "standard" or 0.001 percent concentration 

 for 1940. The most effective chemicals (hormones) for harvest drop con- 

 trol seem to be naphthalene acetic acid and naphthalene acetamide. These 

 two have been about equally effective in many tests. In commercial prep- 

 arations, various hormone carriers, both liquid and dry, were used. A 

 carrier dilutes the pure hormone and the resulting mixture is more readily 

 handled and used by growers. 



While most of the tests were made in the Experiment Station orchards, 

 several cooperative tests with growers were followed rather closely. In 

 practically all of the tests, the sprays were applied very thoroughly with 

 a four- or six-nozzle broom at about 350 pounds of pressure. The attempt 



