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ground material. The finished dust should contain 0.5 percent of rotenone, 
that is, 12^ pounds of 4-percent derris or cube and 87^- pounds of carrier or 
diluent. Finely ground sulphur is of value against the common red spider, the 
potato leafhopper on bean, powdery mildew, and the Mexican bean beetle and is 
to be preferred when any of these are present in injurious numbers. It is 
likely to flow too freely from many dusting machines, and care should be taken 
not to apply unnecessarily heavy dosages with consequent higher costs. Twenty 
to 25 pounds to the acre per application is the recommended dosage. The use of 
hoods or trailers, constructed from bamboo poles and barrel hoops and covered 
with muslin, 10 feet long, used one to the row behind power or traction dusters, 
makes possible a considerable saving, in the dosage. 
Commercial rotenone-bearing dusts usually contain 0.5 percent to 0.75 
percent of rotenone and are prepared to be used as dusts. These mixtures should 
not be used for spraying, unless the label on the package indicates that a di- 
luent has been used which will mix readily with water. 
Except in semi-arid regions, plant injury often results from the use of 
calcium arsenate mixtures on beans. Lead a rsenate shoul d never be used on 
bean fol i age because serious injury and reductions in yields often result from 
its use, even when combined with bordeaux mixture. 
The beans should be sprayed or dusted when adults are found in the field 
or when egg masses become numerous on the underside of the leaves. One to 
three, sometimes four, applications are required, depending on the abundance 
of the insect. The beans must be treated on the underside of the leaves, and 
care should be taken that the spraying or dusting is done thoroughly. 
Cul tural control. — The destruction of crop remnants after harvest is 
as important as thorough spraying or dusting. Plow under all plant remnants 
at least 6 inches deep. 
STRAWBERRY WEEVIL 
The hibernation habits of the strawberry weevil in North Carolina 
are such that the destruction of the weevil by burning over its hibernating 
areas is a most effective means of reducing losses from attacks of this pest. 
This burning is necessary only over areas within 100 feet of the strawberry 
field, as observations have shown that 97 percent of the weevils hibernate 
within 100 feet of the cultivated areas. The burning shoul d be carri ed on in 
the wi nte r and not in the spri ng, and every precauti on should be taken to pre - 
vent such fire from getting out of control . 
When the burning method can not be applied, satisfactory control of the 
strawberry weevil may be obtained by dusting with a mixture consisting of 1 
pound of calcium arsenate and 5 pounds of finely ground dusting sulphur. The 
first application should be made as soon as the weevil appears in the field. 
The rate of application will range from 10 to 30 pounds per acre per applica- 
tion, depending upon the density of the strawberry planting. Ordinarily two 
applications are sufficient to protect the early fruit. All applications of 
poison dusts should be discontinued at least 3 weeks prior to the ripening of 
