Generally, annual applications of nitrogen (N) are made. 

 Growers are steadily changing from the use of ammonium nitrate 

 to urea. In many instances, N applications are split, with half 

 being applied in November and the remainder being spread in the 

 spring. Calcium, zinc and magnesium may also be deficient and re- 

 quire application in British Coltombia orchards. 



Both pesticides and plant growth regulators are applied with 

 sprayers delivering about 50 gal/acre. Most growers do not have 

 spray equipment to make dilute applications. 



Chemical thinning of apples, including Mcintosh, is often done 

 with dinitro materials (Elgetol*). This is applied during the full 

 bloom period. Elgetol* acts by burning the stigmas of unpollinated 

 flowers and thus reducing the number of fruit that set. If the 

 weather turns excessively moist or cool during the first 4 days af- 

 ter the spray application, serious overthinning and leaf burning 

 may occur. Sevin* is not used as a thinner because of its detri- 

 mental effects on the predator mite population. Consequently, the 

 thinning results I saw in British Columbia on Mcintosh were much 

 poorer than we would expect to have in Massachusetts. Often there 

 was overthinning of the bottom limbs and clustered fruit at the 

 top of the tree. Clusters of fruit were generally broken up by 

 hand- thinning after June drop. 



The major stop-drop compound used on Mcintosh is 2,4,5-TP. 

 Very serious carryover effects of 2,4,5-TP showed up in the spring 

 of 1977 from applications made late in the summer of 1976. Delayed 

 foliation at shoot tips, small leaf size, and reduced fruit set 

 and fruit size were all symptoms of the carryover effects. This 

 problem was serious enough to reduce the Mcintosh crop in British 

 Columbia in 1977. The problem may have been particularly severe 

 in 1977 because the application of 2,4,5-TP in 1976 was made prior 

 to and during a period of very hot weather, and also because the 

 2,4,5-TP was applied as a concentrate spray. Alar-85* is normally 

 not used as a stop-drop material and NAA apparently is not effec- 

 tive enough. 



Approximately 300,000 boxes of Mcintosh each year are treated 

 with ethephon to advance ripening for sale of these fruit soon af- 

 ter harvest. It is recommended that both NAA and 2,4,5-TP be inclu- 

 ded with the ethephon and that these chemicals be preceded by an ap- 

 plication of Alar-85* in mid-summer. 



Growers are experiencing increasing problems in establishing 

 trees on old sites. It now is recognized that the poor growth is 

 due to soil acidity where trees previously grew. Lime has not been 

 added routinely in the past because the fruit-growing area is arid 

 and thus the soil has had a pH of 7.0 or greater. In existing 



*Trade name 



