11 



The orchards are grown under sod culture with a strip along 

 the tree row kept free of weeds with herbicides. The Swiss divide 

 the year into 3 seasons in regard to weed control. The first sea- 

 son is post-harvest when an herbicide is applied to control weeds 

 as protection against mouse damage. The second season starts at 

 end of winter when a weed-free area is desired under the trees to 

 facilitate growth and an herbicide is applied if needed. Lastly, 

 the third period commences in late-June when regrowth of annual 

 weeds are desired to compete with the tree for moisture and nitrogen. 



NAA and NAAm (Amid-Thin*) are used for chemical thinning but 

 not carbaryl (Sevin*) . Carbaryl is not used because it is toxic to 

 bees and it tends to enhance build-up of mites. 'Boskoop' and 

 ' Gravenstein' are chemically thinned only if weather has been very 

 favorable for pollination and fruit set, whereas 'Golden Delicious' 

 almost always requires chemical thinning and follow-up thinning by 

 hand. 'Spartan' are thinned with NAAm applied at 751 petal fall 

 to 1 day past petal fall, and again 10 to 14 days later if neces- 

 sary . 



The apple growers in the main fruit regions of Switzerland 

 apply, on the average, 15 fungicide and pesticide sprays per season. 

 However, it may be possible to reduce the insecticide sprays in 

 half by monitoring insect populations, especially those of codling 

 moths and summer fruit tortrix moths ( Adoxophyes reticulana ) . The 

 primary pests are powdery mildew, scab"j and codling moth. ^However, 

 codling moths are not particularly injurious in well-sprayed orch- 

 ards as is the case in Massachusetts. Rosy apple aphids, green 

 apple aphids, and red mites are considered secondary pests although 

 the author observed rosy apple aphids to be much more abundant than 

 in Massachusetts. Much time and money is being spent on experiments 

 with intergrated pest control. 



Like Massachusetts growers, the Swiss are primarily concerned 

 with nitrogen and Ca levels. Four applications of calcium chloride, 

 as separate applications, 9,7,5 and 3 weeks before harvest, is the 

 general recommendation for reduction of bitter pit. Late Ca sprays 

 are more effective than earlier sprays but applications closer than 



3 weeks before harvest are not made because of public concern 



it is easy for the public to keep a watchful eye on spray practices 

 on small farms interspersed with villages. 



Ethephon has been researched but its use is not permitted. 

 Alar-85* is used on apple trees to increase fruit set and enhance 

 flower bud initiation, suppress vegetative growth and control pre- 

 harvest drop. Fruit set is increased with 1500 to 2000 ppm of this 

 growth retardant applied at full bloom. Shoot growth is suppressed 

 and flower bud initiation enhanced by 1500 to 2500 ppm Alar-85*, 

 the concentration depending on the variety, applied when the cur- 

 rent season's growth is 8 to 10 inches long. Preharvest drop is 

 problem with only 'Gravenstein' and to minimize drop, Alar-85* is 

 applied 60-70 days prior to harvest. 



*Trade name 



a 



