MANGANESE CHLOROSIS OF PINEAPPLE. 
29 
sulphate with acids, and of ferric chlorid (chlorid of iron) is the 
most practical field treatment for pineapple plants growing on 
manganese soils, these treatments were compared in a more extensive 
investigation and the effects of 1, 2, 3, and 4 applications, and of 5 
different strengths of the three solutions were observed. 
A search in 1918 by C. W. Carpenter (10), then station pathologist, 
having shown the presence of stomata on the underside of the pine- 
apple leaves at the bottom of the grooves of the slightly ridged sur- 
face, it was thought that spraying the under surface of the leaves 
with iron solutions might be more effective than spraying the upper 
surface of the leaves. Accordingly, an experiment was made in a 
large field of uniformly yellow plants which were sprayed once a 
week with iron solutions. The general results of this experiment 
were judged two months after the first application had been made 
and were confirmed by observations at other times. 
Table 15. — Results of various sprayings of pineapple plants on highly manganifer- 
ous soils with solutions of various strengths of iron sulphate, iron sulphate with 
acids, and ferric chlorid. 
Strength 
of 
solution. 
Method of appli- 
tion. 
Number 
of appli- 
cations. 
Improvement made by plants treated with— 
Ferric chlorid. 
Iron sulphate. 
Iron sulphate + 1 
per cent sulphu- 
ric acid. 
Per cent. 
0.5 
Upper 
1 
2 
3 
4 
1 
2 
3 
4 
1 
2 
3 
4 
1 
2 
3 
4 
1 
2 
3 
4 
Slight . 
Slight..- 
do 
do 
Slight. 
.5 
.5 
do 
do 
do 
Under 
do 
.. do.. 
Do. 
Do. 
.5 
do 
do 
do 
do 
Do. 
Do. 
.5 
do 
do 
do 
Upper 
do 
do 
Do. 
.5 
.5 
1.0 
do 
Fair 
Slight 
do 
do 
...do.. 
Do. 
Do. 
Do. 
1.0 
1.0 
1.0 
do 
do 
do 
Under ... 
do 
do 
Fair. .... 
do 
do 
Fair . 
Do. 
Do. 
Fair. 
1.0 
Slight . 
Slight 
Slight. 
1.0 
do 
do 
do 
Upper.. 
do... 
do 
Do. 
1.0 
1.0 
Fair 
do 
Slight 
Fair 
do 
Fair 
Do. 
Fair. 
2.0 
Slight 
do . 
Slight. 
2.0 
do 
Do. 
2.0 
2.0 
do 
do 
Under. 
do 
Green. .. . ... 
do 
Fair 
Fair. 
Green. 
2.0 
1 
2 
3 
4 
1 
2 
3 
4 
1 
2 
3 
4 
1 
: 
4 
I 
Slight 
Slight - 
Slight. 
2.0 
do 
do 
Fair 
Fair.-. 
Do. 
2.0 
do 
do 
Fair. 
2.0 
4.0 
do. 
Upper. 
do 
Slight 
do 
Slight 
Green. 
Fair. 
4.0 
do 
do 
do 
Under ... 
Fair 
Fair 
Do. 
4.0 
do 
do 
Green. 
4.0 
do 
Green 
Do. 
4.0 
Slight 
Fair 
Fair. 
4.0 
do 
do 
......do 
Fair 
.do. 
Green. 
4.0 
4.0 
do 
do 
Do. 
Do. 
8.0 
Upper 
Slight . 
Fair 
Fair. 
8.0 
do 
do 
do 
Under. . 
Faii- 
.--.do.-- -. 
Green. 
8.0 
8.0 
Green 
do 
Dark green. 
Do. 
8.0 
Slight 
Fair .. 
Fair. 
8.0 
do.... 
Green. 
8.0 
do 
do 
do 
do 
Dark green. 
8.0 
16.0 
4 j Dark green 
1 do 
do .-. 
Fair 
Do. 
Fair. 
16.0 
do 
do.... 
do.... 
Under 
2 
3 
4 
1 
L 2 
3 
4 
do... 
do 
do 
do... 
...do 
16.0 
16.0 
16.0 
do 
do 
Fair 
Dark green. 
Do. 
Fair. 
16.0 
do. 
16.0 
do... 
do 
do 
16.0 
do 
... .do.. 
Do. 
