Magness Pressure Tester Model 30A equipped with a 7/16 inch plunger. Fruit weight and
firmness were determined on the concentration x application date experiment on Maygold
peach. The size of the Maygold experiment prohibited harvesting the entire tree so
approximately 1 bushel was harvested randomly from each tree. Limbs were selected at
random around the tree and all of the fruit on the limbs harvested. From each 1 bushel
tree sample, 30 fruit were randomly selected, weighed collectively, and firmness determined
on 15 of these at random.

 All treatments were hand thinned at the proper stage of fruit development. Fruit in
all experiments was harvested at shipping maturity. A standard insect and disease spray
program was followed throughout the season consisting primarily of parathion and sulfur
and sulfur alone near harvest.

 RESULTS AND DISCUSSION

 The data in Table 1 indicate that Alar exerted little influence on the fruit weight of
Armgold and June Gold peaches. However, the 500 and 1000 ppm rates tended to increase
fruit weight above the control while the higher rates reduced fruit weight in comparison
with control. A considerable amount of leaf drop was noticed about 2 weeks after appli-
cation of the 4000 ppm indicating that this rate was probably phytotoxic to the Armgold
variety. The time of application appears to have been too late on these 2 varieties based
on pattern of fruit development.

 All concentrations of Alar except 1000 ppm significantly decreased firmness on Suwannee
 peach in comparison to the control (Table 2). Economically the 2000 ppm rate was as good as
 4000 ppm and would require only half the amount of chemical.

 The data in Table 3 indicate that several concentration x application date combi-
 nations could be used to obtain the same end result. The lowest firmness value of 5.69
 pounds was obtained with 1000 ppm applied 25 days after full bloom. The largest fruit by
 weight was 1000 ppm applied 20 days after full bloom. The 1000 ppm rate applied 15 or 25
 days after full bloom would probably be the best treatments to use commercially followed
 by 500 ppm applied 15 days after full bloom.

 Several of the 2000 and 4000 ppm treatments had low firmness values but the fruit
 weight in most cases was lower than the control though not significantly lower. A firmness
 value of 7.25 pounds and fruit weight of 107.80 grams was obtained by applying 4000 ppm 30
 days after full bloom. Not all of the combinations have been listed but from an economical
 standpoint it seems that either 500 ppm applied 15 days or 1000 ppm applied 15-25 days after
 full bloom would be the most promising.

 SUMMARY

 The data reported in this paper are based on 1 year of research on the influence of
 Alar on fruit development of peaches. The rates used on Armgold and June Gold were
 ineffective at the time they were applied. The use of 2000 ppm Alar on Suwannee peach
 appears to be slightly better than 500 ppm. Application of 500 ppm 15 days after full
 bloom or 1000 ppm 15-25 days after full bloom on Maygold peaches gave the greatest decrease
 in fruit firmness with an accompanied increase in fruit weight. This study will be
 continued another year on each of the varieties.



 JBA
 9/11/69
 100 CC