ERADICATING TEE COMMOX BARBERRY 
27 
little or none of the material is absorbed by the plant. In this case 
its action might well be compared to burning the plant, which in 
the case of barberries is very ineffective. The difficulty and danger 
connected with handling a strong acid, however, were the principal 
reasons for discarding this chemical. 
PHENOL 
Pure phenol or carbolic acid (C G H 5 OH) is a white, crystalline sub- 
stance. It is used extensively in solution as a disinfectant, but has 
not been generally used as a herbicide. Jones and Orton (8) experi- 
mented with it for this purpose in 1899, and others have since used 
it to a limited extent. United States Pharmacopoeia phenol was 
quoted at 14 cents a pound in 950-pound drums, while crude phenol 
(15 per cent grade) was quoted at 35 cents a gallon in wooden bar- 
rels. The crude phenol contains some cresols and other impurities. 
In the greenhouse, 3 grams of chemically pure phenol applied to 
the surface of the soil in 8-inch pots containing small barberries 
caused the death of the plants in 14 days. The results of field 
experiments are shown in Table 6. 
Table 
-Summary of treatments of individual, marked barberry hushes with 
phenol 
Date of 
treat- 
ment 
Date of 
final ob- 
servation 
Quantity of chemi- 
cal per bush 
Method 
of appli- 
cation 
Bushes cut 
off or left 
standing 
Location of area 
Bushes 
treated 
Bushes 
killed 
Per- 
centage 
killed 
1922 
Apr. 23 
Do— 
Do—. 
1923 
June 27 
—do 
—do 
1 pound chemi- 
cally pure. 
1 gallon of crude 
15 per cent acid. 
do 
Drench . 
.-do 
—do 
Standing.. 
— do 
Cut off— 
Marshall, Wis. 
do 
do 
15 
20 
20 
9 
20 
20 
60 
100 
100 
Total . 
55 
49 
89 
1 
1 
It is evident from an examination of Table 6 that sufficient experi- 
mentation was not done with phenol to warrant any definite con- 
clusions. One gallon of the crude acid produced 100 per cent 
fatality, but at 35 cents a gallon at the shipping point the cost would 
be prohibitive. Probably a smaller quantity would have given 
equally satisfactory results. The principal reasons for discontinuing 
the experiments were (1) the favorable results which* were being 
obtained with other chemicals and (2) the difficulties of handling 
carbolic acid in large quantities. The danger to the clothes as well 
as to the persons of those handling it is considerable and must be 
taken into account. 
PICRIC ACID 
Picric acid (trinitrophenol, C 6 H 2 (N0 2 ) 3 OH) is poisonous to ani- 
mals and also is an explosive. As large quantities were available at 
the end of the war, the. possibilities of its value as a herbicide were 
worth investigating. Experiments in the greenhouse, however, re- 
sulted unsatisfactorily, and field tests were not made. In the green- 
house 200 cubic centimeters of a saturated solution applied to the 
soil in an 8-inch pot of small barberries failed to kill the plants. 
