100 





nj 

 u 

 (/) 



< c 



^1 



5 



3 to 



U. 



c 



0) 



u 



a> 

 a. 



DNo DP A DSOO ppm DP A 11000 ppm DP A 12000 ppm DP A 



Figure 2. Effects of DPA when more than 60% of fruit were predicted to scald. Percent of fruit showing any 

 scald-like symptoms. 



highly scald susceptible fruit from the Warren MA site 

 responded to 500 or 1000 ppm DPA to a much greater 

 degree than did the corresponding fruit from other 

 sites. (The only statistical comparison which could be 

 made was with HRC and there the difference was 

 significant at odds of 1:100). Yet overall, 2000 ppm 

 DPA would have to be recommended for confidence 

 that scald would be controlled in these highly scald 

 susceptible fruit. Note that all the fruit samples 

 represented in Figure 2 were harvested before 24 

 September, and Delicious are not normally harvested 

 that early in New England. Results for samples 

 harvested during the commercial harvest period will 

 be represented below in Figure 3 and Tables 1 and 2. 



Intermediately Scald-susceptible Fruit 



When we moved on to consideration of the next 

 category of fniit, those of intermediate scald- 



susceptibility, we began looking closely at scald 

 severity, as well as whether any scald-like symptoms 

 were evident. Most of the samples of "very scald- 

 susceptible" and "intermediately scald-susceptible" 

 included fruit displaying scald of varying degrees of 

 severity. Scald would clearly render some of the fruit 

 unsaleable in the fresh market. Other fruit, however, 

 displayed scald, or scald-like symptoms, which would 

 not be noticeable to the casual observer, and would not 

 likely downgrade the fruit. The "very scald- 

 susceptible" fruit tended to have enough severe scald 

 that there was no question but that 2000 ppm DPA was 

 needed if the fruit were to be stored for 25 weeks. In 

 the fruit of intermediate scald susceptibility (or less), 

 there often were few fruit with severe scald. In some 

 cases we had difficulty determining if a given apple 

 did or did not have scald. Therefore, we used a rating 

 system which separated fruit showing any discolora- 

 tion that might possibly be scald, from fruit with more 



Fruit Notes, Volume 63 (Number 3), Summer, 1998 



