dormant oil in our early season mite-control pro- 

 grams may be advisable compared to the use of 

 Apollo alone. Treatments combining oil plus Apollo 

 provided the greatest degree of ERM suppression 

 in this trial. The most cost effective approach, how- 

 ever, may be to apply oil at 1/4-inch green followed 

 by Apollo alone around tight cluster since no addi- 

 tional benefit was noted from including oil again in 

 the second application. 



Continuing the use of dormant oil would also 

 be consistent with a prudent resistance manage- 

 ment program. Researchers in Canada, where 

 Apollo has been registered since 1989, already sus- 



pect tolerance to the material despite the limita- 

 tion to only one prebloom application per season. 

 Taking pressure off the Apollo treatment by reduc- 

 ing the number of viable eggs present at the tight 

 cluster stage may ultimately extend the effective 

 lifetime of this material. 



More work is necessary to determine the best 

 approach to utilizing this new material in a com- 

 mercial orchard setting. We intend to continue this 

 study in 1996 in order to broaden this database and 

 to look more closely at the potential interaction be- 

 tween dormant oil and this new class of ovicidal 

 miticides. 



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16 



Fruit Notes, Spring, 1996 



