general use today (Table 5). Based solely upon cost, 2. 

 Accel does not appear to be a competitive chemical thin- 

 ner. However, Accel does have the potential to fruit 

 size in addition to the size effect attributed to thinning. 3 

 The economic value of apples in large size classes must 

 be considered when selecting a chemical thinner. Cost 4 

 of the chemical per se is not the only factor. 



Based upon thinning efficacy and cost, it seems that 

 the most cost-effective way to use Accel may be in com- 

 bination with other thinners. 



6. 



Conclusions 



1. Apply Accel during the most favorable weather 7. 

 when fruit size is between 6 and 12 mm. 



Consider petal-fall thinning if weather is favorable. 

 Chances are that you will have a second chance if 

 needed. 



Warm temperatures are required for Accel to work 

 well. 



Do not apply Accel alone at a concentration of less 

 than 25 ppm. 



Consider increasing the activity of Accel by com- 

 bining it with other thinners. 



Be careful when combining Accel with NAA. 

 Pygmy fruit or small apples may result. Accel and 

 NAA have worked well on Mcintosh. 

 Generally, Accel plus Sevin is a good thinning com- 

 bination. 



Fruit Notes, Spring, 1995 



