When a 25 microliter droplet of Promalin was placed either in the 

 calyx end of the flower or on the receptacle, fruits with large ^/D 

 ratios were harvested (Table 1). The same amount of Promalin applied 

 on the petals of a flower produced no response. However, when the 

 amount of Promalin applied to the petals was increased 6-fold, fruit 

 elongation occurred. Nevertheless, 150 microliters of Promalin appl- 

 ied on the petals was not as effective for increasing the E,/D ratios 

 of the fruits as 25 microliters of Promalin placed on its receptacle, 

 Therefore, it appears that Promalin must come in contact with the 

 flower parts that are incorporated into the final structure of the 

 apple to be most effective. 



Surfactants and Adjusting pH of Spray Solution 



In general, we do not recommend the use of surfactants with 

 growth regulators. Many formulated growth regulators (e.g. Alar-85, 

 Fruitone N, etc.) already contain a surfactant. It doubtful that the 

 addition of another surfactant to the spray mixture would be of sub- 

 stantial benefit. In contrast, the Promalin formulation contains no 

 surfactant. Last year we reported that glyodin and Triton B-1956 

 (both products that increase wetting) enhanced the response of 'Del- 

 icious' fruits to Promalin 



Table 2. The effects of surfactants and pH modification on the per- 

 formance of Promalin applied to 'Royal Red Delicious,' Shelburne, 

 MA. , 1978. 



Treatment' 



Check 



Promalin 



Promalin + Sorba (Mg) + 

 Glyodin 



Promalin + Sorba (Mg) + 

 Biof ilm 



Promalin + Buffer-X 



4 

 4 



8bc 

 Ic 



1.03a 

 1.02ab 



156ab 

 161a 



1 pt of each chemical was used per 100 gal. of water. Treatments 

 applied at a rate of 125 gal/acre at petal fall of the king blossom. 



^Numbers in a column, followed by different letters are significantly 

 different at odds of 19 to 1. 



In 1978 trials we made the Promalin solution more acid (to pH 4.0) 

 with Sorba-Mg2, and added glyodin or Biof ilm (a surfactant). These 

 spray mixtures, with the pH adjusted were more effective in increasing 

 the L/D ratio of the fruits than Promalin applied alone (Table 2) . 

 The mixture containing Promalin and Buffer-X (contains a surfactant 

 and lowers spray pH) produced fruit elongation comparable to Promalin 



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