7- 



This indicates that a Promalin application increases the ^/D ratio 

 of all fruits on the tree equally. Therefore, a grower can expect 

 to find some rather flat-looking Delicious on Promalin- treated 

 trees at harvest time although there should be fewer than on check 

 trees . 



Delicious is not the only cultivar that can be elongated with 

 Promalin. If pollenizers are located within the rows of Delicious 

 being sprayed you can expect elongation of these fruit also. In- 

 creased length of such cultivars as Mcintosh and Cortland in most 

 cases would not be desirable. Therefore, when applying Promalin 

 attempts should be made to avoid spraying pollenizer trees where 

 increased calyx-end length is not wanted. 



We observed that the typiness of Delicious was improved re- 

 markably by Promalin throughout Massachusetts in 1978. A response 

 of this magnitude has not occurred every year. It was noted this 

 year that Promalin induced other responses in addition to elongating 

 fruit. Promalin caused thinning on 20-year-old Royal Red Delicious 

 when adjuvenants and a buffering agent were included with the Pro- 

 malin (Table 2) . It is estimated that the crop was reduced slightly 

 below the load considered to be ideal. Promalin does thin young 

 Delicious trees much 'more severely than mature trees. Seed number 

 and fruit diameter were reduced by Promalin in some experiments 

 but these parameters were unaffected in others. No fruit weight 

 increases have been observed in our tests even though they have been 

 shown to occur in other parts of the country. Increased bitter 

 pit and cork spot were observed this year for the first time when 

 excessive rates of Promalin were used. We do not feel that this is 

 a problem that will be encountered under normal circumstances. 

 However, since Promalin did increase bitter pit and cork spot, in 

 situations where low fruit Ca levels may occur, the use of this plant 

 growth regulator may aggravate the problem. 



Comments on Trial Use in 1979 



We do not discourage the use of Promalin. However, we do 

 encourage growers to proceed cautiously and apply Promalin to only 

 a portion of their Delicious trees. As a grower gains more exper- 

 ience with Promalin applied at his location, on his trees, and in 

 his sprayer, and is convinced the response is good and the side 

 affects minimal, then, is the time to move ahead and apply it on 

 a larger portion of his Delicious trees. 



It is not possible to effectively evaluate the Promalin response 

 (or the response of any other growth regulator) at your orchard 

 without leaving some trees unsprayed. We suggest that 3 or 4 re- 

 presentative trees should be clearly tagged and left unsprayed at 

 2 or 3 different locations in your orchard. This should provide 

 a valid and unbiased basis for evaluating the effect of Promalin 

 in your orchard. 



