49 Farmers’ Bulletin 1220. 
soft and helpless, and a stirring of the soil close along the rows by 
cultivation, as with the so-called horse-hoe, is doubtless fatal to many 
of them. Pupation is perhaps at its height just before the grape 
blossoms, though this time may be determined with some exactness 
by examination of the insects in the soil. The grape rootworm has 
several natural enemies, which 
in the aggregate do consider- 
able to keep it reduced. 
CONTROL. 
Since the adults feed freely 
on the foliage for some days be- 
fore egg laying, they can be 
destroyed by thorough spray- 
ing of the vines with an arseni- 
‘al, such as arsenate of lead. 
This should be used at the rate 
of 14 pounds of the powder or 
3 pounds of the paste form to 
each 50 gallons of spray. The 
poison should be applied in 
Bordeaux mixture necessary 
for the control of fungous dis- 
eases. According to ( experi- 
ments by the Geneva, N. Y., 
agricultural experiment station 
the effectiveness of the spray is 
greatly increased by the addi- 
tion of 1 gallon of molasses 
to each 50 gallons of liquid, 
though its adhesiveness is much 
lessened, and care should be 
taken to apply it when weather 
conditions are favorable, and 
repeat after heavy rains. The 
Fig. 44.—Injury by grape rootworm to roots first application should be 
Nuss given shortly after the first 
beetles or their feeding marks are to be seen on the leaves, and the 
second treatment about 10 days later. 
While the time of treatments for best control of the grape root- 
worm and the grape leafhopper do not exactly coincide, yet under 
average conditions of abundance of these two pests they should be 
kept in check by a combination application of arsenate of lead and 
nicotine in Bordeaux mixture (see schedule, pp. 74-75). Where 
