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The 1973 tree census data indicated that Delicious should re- 

 place Jonathan as the major apple variety. However, much will de- 

 pend upon the performance of this variety on size-control rootstocks, 

 since 72% of the Delicious non-bearing acreage in 1973 was on these 

 types of rootstocks. Delicious is extremely vulnerable to frost 

 and fruit set is frequently poor. 



Mcintosh has been one of Michigan's leading apple varieties 

 for many years, but non-bearing trees represented a very low per- 

 cent of the total Mcintosh trees in 1973. This fact plus antici- 

 pated tree removals indicate that Mcintosh production in Michigan 

 will decline in the future. The fruit are easily bruised during 

 harvest and many growers experience difficulty obtaining adequate 

 red color on this variety. Recent plantings have been primarily 

 spur-type Mcintosh. 



Northern Spy is not being planted heavily. It is very slow to 

 come into production and is grown primarily for the processing mar- 

 ket. Growers are more interested in dual purpose apple varieties 

 and summer varieties. Idared is becoming very popular, since it 

 bears at an early age, has a semi-spur type growth habit, produces 

 large attractive fruit which have excellent packout, and stores 

 well. It has returned a premium to Michigan growers during late- 

 season marketing periods. 



We anticipate an increased production of summer apple varie- 

 ties because young-bearing trees and non-bearing trees represented 

 a very high percentage of the total for summer varieties in Michi- 

 gan orchards in 1973. Paulared and Jerseymac predominate in re- 

 cent plantings of summer varieties. 



Irrigation 



Young trees have limited root development and are readily 

 stunted by prolonged drought conditions. Thus, many orchardists 

 have found that trickle irrigation is beneficial in young plant- 

 ings. Dr. A.L. Kenworthy, in our Department of Horticulture, has 

 also obtained some interesting results applying nitrogen (N) through 

 the trickle system. He cooperated with 2 commercial orchardists 

 in northern Michigan and applied N in 4 applications at weekly in- 

 tervals during June. The treatments consisted of N applied at 

 the same rate used by the growers when applying a ground applica- 

 tion in late fall or early spring, and at rates equal to 50 or 25% 

 of the grower rate. Ammonium nitrate or urea was used depending 

 on the grower's preference. He found no significant differences 

 in leaf N among the 3 N rates applied through the trickle irriga- 

 tion and the ground application applied by the growers. Half as 

 much nitrogen applied through the trickle irrigation system ap- 

 peared as effective as the grower's soil application. No yield 

 differences have been observed. 



