Concentration 



Twenty five ppm in a dilute spray is the 

 minimum concentration to get any thinning 

 response. If the tree row volume of a block 

 requires 200 gallons per acre in a dilute spray, 

 the label would allow only a concentration of 26 

 ppm (at 35.6 fluid oxinces of Accel or 20 g ai/acre) 

 to be used. Furthermore, in situations where 

 aggressive thinning is necessary and the tree 

 row volume is only 100 gal/acre, the desired 

 level of thinning may not be reached with the 

 use of BA alone, since the label will allow only a 

 concentration of 53 ppm (at 35.6 flxiid ounces of 

 Accel or 20 g ai/acre). In these situations, 

 additional thinning strategies may be neces- 

 sary. 



Accel should be apphed in 50 to 200 gallons 

 of water per acre. Applications in volumes less 

 than 50 gallons per acre may result in poor 

 coverage. 



Cultivars 



Use Accel on responsive cultivars first until 

 you feel comfortable and until you see how it 

 performs in your orchard. Responsive cultivars 

 include Empire, Rome, Mcintosh, and Idared. 



Time of Application 



If using a single application of Accel, apply 

 at the 8 to 10 mm stage (3/8 in), firom 12 to 18 

 days after full bloom. 



The label allows up to two applications of 

 Accel per season. The research has not yet been 

 done to determine the specific effects of multiple 

 applications, so proceed with caution. If two 

 applications are made, do not exceed a total of 

 71.2 fluid ounces of Accel (40 g ai) per acre for 

 the season. With two applications, the first 

 should be applied at the 5-mm fruit stage, and 

 the second should be applied at no later than the 

 10-mm stage. 



Combinations with other Thinners 



BA has been used effectively in combination 



with NAA on Mcintosh. The response was 

 additive; however, Accel interacts with NAA on 

 Dehcious to produce small and pygmy fruit. 

 Therefore, the label specifically states that NAA 

 should not be used in any Accel thinning pro- 

 gram. Where aggressive thinning is required, 

 carbaryl should be included in the thinning 

 program. We have tank mixed BA with car- 

 baryl successfully. The thinning response was 

 additive. The label does not prohibit tank mix- 

 ing with carbaryl but the practice is discour- 

 aged. 



Weather 



Attention to temperature is critical for effec- 

 tive thinning with Accel. It should be applied 

 only when the temperature is 65°F or higher. 

 Ideally, the temperature should rise into the 

 80's within three days following application. If 

 warm temperatures do not follow the applica- 

 tion, thinning results are hkely to be disappoint- 

 ing. Cloudy weather following application, Uke 

 warm temperature, may increase the thinning 

 response. 



Label Change Pending 



There is a label change pending for Accel as 

 this issue goes to press. There are two signifi- 

 cant changes that may occtu*. The rate of Accel 

 per apphcation may be increased to 53.5 fluid 

 ounces (30 g ai) per acre, and the total per 

 season may be increased to 107 fluid ounces (60 

 g ai) per acre. This change must be noted, 

 because overthinning may occur of Mcintosh, 

 Idared, Rome, and Empire if the new maximum 

 rate is used and tree row volume reqires less 

 than 100 gallons per acre for a dilute spray. 



Conclusions 



In this first season of commercial use, use 

 Accel cautiously and follow label directions. Use 

 it first on a responsive cultivar, and do not apply 

 it unless temperature conditions are appropri- 

 ate. 



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20 



Fruit Notes, Spring, 1994 



