538 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
of sulfur. They also offer a very promising field as a fungicide especially 
for the resistant forms of fungi such as rose and grape mildew. The 
duration of the activity of colloidal sulfur solutions was not carefully 
tested. Should it be that the very fine particles such as are found in 
hydrophilic colloidal solutions oxidize so rapidly as to be of a temporary 
nature, then it is possible that the addition of finely ground sulfur to the 
spray might prolong its effectiveness. 
THE EFFECT OF WEEVILY SEED BEANS UPON THE BEAN CROP 
AND UPON THE DISSEMINATION OF WEEVILS, BRUCH US 
OBTECTUS SAY AND B. QUADRIMACULATUS FAB. 
By A. O. Larson, Associate Entomologist, U. S. Bureau of Entomology 
Abstract 
The experimental work herein reported has been carried on for several years with 
the object of determining the influence of the weevily beans and cowpeas on the pro¬ 
duction of the crop as well as the probability of the infestation of.the crop by weevils, 
Bruchus obtectus Say or B. quadrimaculatus Fab., which were contained within the 
planted seeds. While the planting of weevily beans reduces the yield it does not 
appear to have any bearing on the infestation of the succeeding crop. 
That the planting of weevily beans may have an injurious effect on the 
succeeding crop has been emphasized very strongly by many who have 
written on the control of weevils. Usually the exact nature of the in¬ 
jury is not given. 
Bremner 1 in 1910 gives the inference that the dissemination of weevils 
to infest the growing crop is the main, if not the only injury resulting 
from the planting of weevily seeds (l). 
Back and Ducket 2 in 1918 said, “If seeds are planted that contain 
weevils, the adult weevils emerge from the seed after it has been planted 
and live in the field until the pods are sufficiently developed to receive the 
weevil eggs. They add their numbers to those in the field that have 
migrated from the place of seed storage. To plant peas, beans and 
cowpeas containing living weevils only invites a ‘buggy crop’.” In 
1922 Back 3 said “the germination of beans, peas and cowpeas is likely to 
be seriously affected by the development of weevil larvae. If the 
embryo is destroyed by the larva, or if too much of the bean substance is 
eaten, the seeds can not grow.” 
Popenoe experimented in Kansas 4 with weevily beans as well as peas 
with the following results. “Fifty percent started: of these, three- 
fifths might have grown into plants, as the injury was restricted to the 
1 Figures not in parenthesis refer to literature cited. 
