22 BULLETIN 1357, U. S. DEPARTMENT OF AGRICULTURE 
collected 8 to 10 inches from the main stem of a plant, and at a depth || 
of 6 to 7 inches from the surface. Usually they are found at a depth | 
of 2 to 3 inches, and as many as 19 specimens have been found | 
among the roots of a single plant. 
FEEDING HABITS 
Although their first attention seems to be given to the smaller 
| feeding rootlets, the larve also gnaw and penetrate the main roots. 
| (Fig. 2.) They have been observed to girdle the crowns just below 
| the soil sur face, resulting in the loss at one establishment of over 
| 100 “ own-root ” plants which had been set about three months pre- 
| viously. Older bushes can withstand more severe feeding before 
showing the effects. Plants in a decidedly poor condition had been 
growing in a bed for five years and showed many furrows in the 
main roots which had evidently been the source of larval nourish. 
ment. Only a few new growths were produced after “ pinching ” 
the shoots, and these were short and weak because the vitality of the 
plants was very low, and the foliage lacked its normal green color. 
These plants were used for experimental work on the soil stages 
: and accurate counts were made of the number of larve and pup 
i found in each. During the examination of 481 of these plants 2,991 
larve and pups were “found, or an average. of 6.22 to a plant, the 
i maximum being 23 specimens. 
Examination made i in August, 1921, of the soot and soil around 
| 58 plants dug up at random in different sections of a greenhouse 
where 3,000 plants were being removed, showed that 130 larve and 
| 150 pupe were present, or an average of 4.8 specimens of the soil 
Hl stages to each plant. If this condition prevailed throughout the 
| house it would mean that there were 14 400 individuals in the soil at 
i that time. Since egg laying is continuous throughout the spring and 
| early summer months, the roots of these plants had probably been — 
subjected for several months to attacks by successive large broods of 
larvee 
A comparative lack of the fresh white feeding rootlets was con- 
spicuously evident in the case of the infested plants mentioned above. 
Even though very few of the older plants die as a direct result of 
the larval attack, they become so we akened that many of them fail 
to withstand the rigorous treatment accorded the bushes when sub- 
jected to artificial “dormant conditions. It is a cultural practice 
among the growers during the drying-off period to withhold water 
from the plants for a period of from two to four weeks or longer, 
after which the greater part of the growth is pruned off until only 
from 12 to 18 inches of the main stems are left. Moisture is again 
made available to the roots, and normal plants will immediately put 
forth new growth from the buds. Extensive injury to the root 
systems (fie. 2) prevents them from functioning normally and re- 
sults in the loss of the more severely injured plants. 
In less than three days 23 newly hatched larve confined in a vial 
with soil containing roseroots chopped in half-inch lengths have 
eaten the equivalent “of 10 inches of roots which were approximately 
one-sixteenth to three thirty-seconds of an inch in diameter. In 
several instances where pups were kept in the same cage they were 
chewed by the larve. That the larve are able to burrow through the 
