BUREAU OF ENTOMOLOGY. 235 



* INSECTICIDE INVESTIGATIONS. 



"Work under this project has been continued as in fonner years 

 in cooperation with the Bureaus of Plant Industry and Chemistry, 

 and has included the testing of miscellaneous proprietarj^ insecti- 

 cides, and further testing of insecticides developed by the bureau 

 or others for use alone and in combination with fungicides. Further 

 attention has been given to the determination of the range of useful- 

 ness of calcium arsenate on pome and stone fruits and grapes. Test- 

 ing work is under way in Connecticut, Michigan, Virginia, Arkansas, 

 New Mexico, Colorado, and Oregon. Working under these varied 

 climatic and other conditions, the results, when available, should 

 settle the points under investigation. 



In view of the present high cost of arsenate of lead, orchardists 

 and manufacturers have evidenced decided interest in arsenate of 

 lime. Experiments thus far made indicate that it may be used in 

 all situations where Paris green has been employed, and that for 

 pome fruits it will be a satisfactory substitute for arsenate of lead 

 when used with lime or fungicides containing lime. 



Progress has been made in the investigation of the insecticidal 

 constituents of plants, especially the so-called derris. This insecti- 

 cide of oriental origin acts both as a contact and as a stomach 

 poison. As a stomach poison it is efficient against only a few in- 

 sects, while as a contact insecticide it is efficient against a wide 

 range of insects. A detailed report on the subject is planned at the 

 close of the growing season 1918. 



Further tests have been made with nicotine as an agent for kill- 

 ing the eggs of insects, especially those of the codling moth. Re- 

 sults as a whole indicate an ovicidal action of nicotine, but not suf- 

 ficient to give satisfactory control of the codling moth when used 

 alone. Preparation of a report on the subject will be undertaken 

 as soon as data for the present season's work are in hand. 



Studies of the relative toxicity and physical characteristics of 

 various arsenicals, undertaken in cooperation with the Bureau of 

 Chemistry, are being continued and progress made. An extended 

 report on insecticides, spraying apparatus, etc., has been issued as 

 Farmers' Bulletin 908. 



CRANBERRY INSECT INVESTIGATIONS. 



The work on cranberry insects in New Jersey has been completed, 

 and a Farmers' Bulletin (No. 860) covering the principal insect 

 pests of this crop in that State has been published. Special articles 

 on the more important species have been published or are in the 

 course of preparation, and practical control measures have been de- 

 veloped for the principal pests. 



An investigation of the insects affecting cranberry bogs in the 

 State of Washington has been undertaken in cooperation with the 

 agricultural experiment station of that State, beginning with the 

 spring of 1918. Several of the important eastern cranberry-insect 

 pests have been introduced into the Washington bogs with plants from 

 the East with which the bogs were started, but it will be necessary 

 not only to study these insects under their new far-western condi- 

 tions but also to see whether native western insects will take to the 



