42 
BULLETIN 1451, U. S. DEPARTMENT OF AGRICULTURE 
the latter so that it will reach the fine roots of the plant and be read- 
ily absorbed by them. It is essential, therefore, to know where these 
roots are located. As has been said, the barberry, while having a 
large spreading root system, also produces an abundance of fine 
feeding roots immediately around the base of the shoots. It was 
found that if a chemical was applied so as to reach these roots the 
death of the plant was likely to occur. It also was found that, while 
all the shoots of a bush might be connected by stolons, they were in- 
dependent to the extent that in order to insure the death of all of 
them each must receive a portion of the chemical. 
Table 17. — Comparison of the 10 best chemicals used for hilling barberries 
[Words set in italic indicate a favorable result or condition] 
Chemical 
Quantity 
producing 
results given 
Per-| 
cent- Approximate 
age of j cost of dose 
bushes per bush 
killed | 
Avail- 
ability 
Ease of 
handling 
Safety 1 Remarks 
1 
Sodium chlo- 
ride. 
Kerosene 
Sodium arse- 
nite. 
Sodium di- 
chromate. 
Calcium chlo- 
ride. 
Furfural _ 
Gasoline 
Petroleum- 
gas oil. 
Phenol, 15 per 
cent crude. 
Water-gas 
drip oil. 
10 pounds 
dry. 
1 gallon 
0.4 pint in 
solution. 
1 pound in 
solution. 
15 pounds 
dry. 
1 quart 
1 gallon 
do 
do 
do 
100 
100 
100 
100 
90 
100 
97 
96 
100 
90 
10 cents de- 
livered. 
IS cents de- 
livered. 
8 cents f. o. b. 
8 cents f.o.b. 
24 cents f.o.b. 
9 cents f. o. b. 
23 cents de- 
livered. 
7 cents f. o. b. 
35 cents f.o.b. 
10 cents f.o.b. 
Excellent.. 
—do 
Fair 
...do 
—do 
Poor 
Excellent.. 
Fair 
...do 
Poor 
Satisfactory. . 
do 
—do 
do 
Disagreeable 
do 
Satisfactory.. 
do 
Di s agree- 
able. 
Very dis- 
agreeable. 
Excellent 
— .do 
Very pois- 
onous. 
Excellent 
do 
do - 
Fire hazard. 
Excellent 
Corrosive... 
Excellent 
Action slow. 
Not suffi- 
ciently test- 
ed. 
Do. 
Action slow. 
Do. 
Not suffi- 
ciently test- 
ed. 
On the basis of effectiveness in killing common barberries, a few 
generalizations may be made from the studies of the chemicals here 
reported. 
1. Sufficient chemical or solution must be applied so that the 
fibrous roots around the base of every shoot will receive a lethal dose. 
2. Gas-forming substances generally fail to give uniformly satis- 
factory results, probably because of irregularities in the permea- 
bility of the soil around a bush. 
3. Heavy oils and tarry substances fail to produce general killing, 
probably because of their failure to penetrate the soil to a sufficient 
extent or the failure of the roots to absorb them. 
4. Light oils, on the other hand, are fairly satisfactory. 
5. Inorganic salts are very satisfactory when applied in sufficient 
quantity to reach all the fibrous roots around the base of the shoots. 
Five criteria of a satisfactory chemical for barberry eradication 
were established. In the order of their importance these are : Effec- 
tiveness, cost, availability, ease of handling, and safety. In Table 
IT the 10 best chemicals are compared on this basis. When a chemi- 
cal was satisfactory in any particular, in making up the table that 
item was put in italics. 
