ERADICATING THE COMMON BARBERRY 21 
Table 3 shows that out of 550 marked bushes, treated with dry 
crushed salt, 536, or 97.5 per cent, were killed. No sprouts or por- 
tions of the bushes designated " killed " were living on the date of 
final observation, which was from 8% to 21 months after treatment. 
The bushes reported living were partially killed. The only bushes 
living were among those which received only 5 pounds of salt piled 
in the base, or to which the salt was applied in a circle 1 foot away 
from the base. In the latter case, portions of the bush within the 
circle were not killed, and new sprouts developed from these live 
parts. No sprouts developed from the lateral roots outside of the 
circle of salt. 
It was apparent that applying the salt to the base of the plant 
(pi. 11, A) was more effective than applying it in a circle remote 
from the base ; also that 5 pounds of salt applied to the base was not 
always sufficient to kill the bushes of the size treated. It further 
appeared that there was little or no difference in the effectiveness of 
the treatment when applied either to cut or standing bushes (pi. 
10, B). 
AREA TREATMENTS 
In view of the satisfactory results of these tests, salt was applied 
to large numbers of bushes growing wild in widely separated areas. 
Barberries were growing as escapes from cultivation on the bluffs 
along the Mississippi River, about 1 mile west of McGregor, Iowa. 
They occurred on land unsuitable for tillage because of its steepness 
and numerous limestone outcrops. It was chiefly pasture land, with 
here and there a few trees, but the barberries constituted the prin- 
cipal shrubby growth. The shrubs were mostly large sprouts from 
wild bushes that had been cut down and ineffectively dug about two 
years before the date of treatment. They ranged in size from small 
individuals of one or two shoots to large clumps 4 or 5 feet in diame- 
ter, the average being about 8 inches in diameter at the base. 
Approximately 500 bushes were treated with 5,700 pounds of 
crushed rock salt on October 21, 1922. The salt was hauled to the 
field in a wagon and distributed to the plants in 10-quart pails. It 
was heaped in piles about the bases of all stalks, the quantity applied 
to each bush depending upon its size. The following statement sum- 
marizes costs : 
Salt, 57 hundredweight at 70 cents $39. 90 
Labor, 14 man-hours at 50 cents 7. 00 
Team aad wagon, 3% hours at 50 cents 1. 75 
Total cost 48.65 
Number of bushes treated 500 
Salt per bush pounds 11. 4 
Cost per bush $0,097 
The results of this treatment at McGregor were very satisfactory. 
The field was inspected in June, 1923, and again later in the summer. 
The treatment was about 99.5 per cent effective. Several bushes were 
found alive, but there were indications that they had not been treated. 
The grass and weeds for a few inches around treated plants were 
killed and served as an index as to whether or not treatment had been 
applied. The missed bushes indicated the necessity of using great 
care to avoid overlooking any plants. The results also indicated that 
