on the Development of Bitter Pit in the York Imperial Apple." Although the 
title included the term bitter pit, they were working with York spot or cork 
spot. They reported a marked reduction in occurrence of external and internal 
symptoms of the disorder as a result of timely sprays with boron. Sprays made 
of 1 to 8 pounds of solubor to 100 gallons of water were applied at full bloom 
and in some plots at various intervals thereafter. Apparently, nothing was 
gained by using more than 1 pound of solubor. They found that the spray must 
be applied at blossomtime to be effective. Although timely spraying gave 
effective control, they emphasized that the disorder was not completely elim- 
inated. 
Hewitt (65) found that the application of boron at or shortly after full 
bloom, did not affect the translocation or distribution of endogenous carbohy- 
drates, Neither was there any effect on carbohydrate movement induced by dif- 
ferent leaf: fruit ratios, by the boron content of the tree, or by limb gir- 
dling. High temperatures in 1959 increased the translocation of labeled sucrose 
to the shoot tips. It is concluded that the effect of boron sprays in reducing 
the incidence of bitter pit (York spot) cannot be due to their effect on sugar 
translocation. 
In 1961, Thompson and Rogers (164) summarized four season's tests with 
solubor applied as three sprays starting about the time of bloom. When un- 
sprayed trees had 53 to 83 percent cork spot in experimental work, boron sprays 
reduced the incidence to a range of 17 to 26 percent. In orchards where cork 
spot on unsprayed trees involved only 30 to 35 percent of the fruits, no effect 
was achieved with boron sprays. 
Williams (179) found that foliar sprays of boron applied at full bloom 
and one week later consistently reduced the incidence of York spot (Cork spot), 
but the reduction was not always significant. Calcium chloride sprays were 
tested in one season and gave consistent, but not significant, control when 
applied several times from early season to midseason, The addition of calcium 
nitrate to boron sprays did not improve the control of York spot (Cork spot) by 
boron. Early to midseason sprays of calcium chloride combined with boron were 
more promising than early-season sprays of boron alone. 
He reported that York spot became serious when the trees were ringed, 
and that it was reduced when the trees were partially defoliated. He also 
stated that treatments which affected the tree-soil moisture balance generally 
did not affect the incidence of York spot. The latter statement is in dis- 
agreement with the current opinion held by others. The statement appears also 
to contradict the results reported where some trees were partially defoliated 
if the assumption is made that partial defoliation reduces the competition be- 
tween leaves and fruits for water. 
In comparing cork spot and bitter pit, Mattus (103) stated that some 
researchers believe that cork spot results from water-stress conditions early 
in the growing season while late-season water stresses cause injury that 
finally shows up as bitter pit after harvest. 
Bramlage and Thompson (26) applied boron sprays to Jonathan, Stayman, 
and Golden Delicious to study the effect on fruit set, color finish, and stor- 
age life of the apples. Although these varieties are subject to cork spot they 
apparently did not show this disorder during the tests. 
In 1962, Simmons (147) reported on studies on the anatomy of the bitter 
pit areas of apples. The illustrations and text indicate that the author did 
not distinguish between bitter pit and cork spot in making his study. The text 
of this paper states that the anatomical studies were made on Golden Delicious 
and Starking apples sampled in September and October. It is further stated that 
174 
