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INTRODUCTION 
This is a revision of multigraphed circular E-376, as issued by the 
Bureau in April 1936. The developments of the 1936 season at the various 
oratories of this Bureau have made desirable certain changes in the recom- 
mendations issued last year. 
LOCATION OF WORK 
This Bureau's researches on methods of control of certain insects, having 
for their o . the elimination of harmful insecticidal residues from the 
vegetable products, are being conducted at the following field laboratories: 
Alhambra, Calif.. Baton Rouge, La.. Biloxi, Miss., Chadbourn, N. C, Charleston, 
S. C, Columbus, Ohio, Sanford, Fla., and Phoenix, Ariz. The work on tobacco 
insects is being conducted at the following locations: Clarksville, Tenn . , 
Quincy, Fla., Oxford, N. C, Florence, S. C, and Windsor, Conn. 
MATERIALS TESTED 
The recommendations included in this circular are based principally upon 
tests with the following insecticides: D ust s : Commercially prepared or home- 
mixed derris or cube root powder, pyrethrum powder, and cryolite (natural and 
synthetic), used with various diluents, paris green diluted with hydrated lime, 
and commercial calcium arsenate in the undiluted form and diluted with sulphur. 
Sprays : Derris or cube root powder in water, commercially prepared extracts of 
derris and of pyrethrum and combinations of these materials, and cryolite 
(natural and synthetic) . 
PRINCIPAL INSECTS INVOLVED 
The principal pests involved in these experiments are several kinds of 
lepidopterous larvae attacking cabbage and including the imported cabbage worm, 
the cabbage looper, the diamond-back moth, the cabbage v/ebworm, the corn ear- 
worm, and cutworms. Also the celery leaf tier, the Mexican bean beetle, the 
pepper weevil, the vegetable weevil, the melon worm, the pickle worm, the 
strawberry weevil, tobacco hornworms, and flea beetles. 
RECOMMENDATIONS FOR CONTROL 
The following recommendations are applicable only to certain crops on 
which harmful insecticidal residues may occur on the marketed product and are 
the best methods available that can be utilized and at the same time insure 
against harmful residues remaining on the product consumed by man. 
It will be noted that lead arsenate is not recommended for the control 
of insects attacking any vegetable crop considered in this circular. 
The use of other arsenicals and cryolite is, however, suggested as a 
control for certain insects on several of the crops under consideration. This 
suggestion is made with the provision that the poison should not be used after 
the appearance on the plant of fruit or foliage which will be sent to market or 
consumed . except in cases where it is definit ely know n + h a t washing or stripping 
will remove all spray residues . 
