1919.] PUBLIC DOCUMENT — No. 31. 41a 



connection. These experiments will be continued and elabo- 

 rated. 



Observations to determine the existence and, if present, the 

 importance of a second brood of the codling moth in Massa- 

 chusetts have been made for a number of years. The con- 

 clusion had about been reached that no second brood is present 

 in more than a few scattered individuals. Last summer, 

 however, a brood of considerable size was noted, and it has 

 been decided to carry these observations further. 



For ten years the dates of appearance of the young of 

 several of the common scale insects have been recorded in 

 the hope that the range in this time, even in the most widely 

 different seasons, would not be so great as to prevent the 

 fixation of a date for treatment to be given them. A study 

 of the results has now finally destroyed this hope, but has 

 unexpectedly pointed out a new aspect of the subject which 

 may lead to equally desirable results though in a totally 

 different way. This subject, therefore, is being continued, 

 to obtain more data for use with the new basis of research. 



At the request of the Food Administration, tests of a material 

 known as Nature's Plant Food were made to ascertain its 

 value, if any, as an insecticide and also as an insect repellent. 

 About 20 tests were made with this substance on 7 different 

 kinds of insects, both under laboratory and field conditions, 

 with check tests in all cases. The evidence obtained from 

 these experiments was that the material is not an insecticide. 

 As a repellent, it was compared with ground limestone and 

 sifted road dust. The tests indicated that its value as a 

 repellent is no greater and no less than that of any other 

 inert substance of equal fineness and adhesiveness and applied 

 in the same amounts. Where these factors are equal, the 

 selection of the material to use should be entirely on the basis 

 of cost. 



Several ''proprietary insecticides" of unknown value have 

 been tested during the year. Kling Kill Insecticide, put out 

 by the Commercial Chemical Company, St. Paul, Minn., and 

 claimed by its manufacturers to incorporate several new and 

 radical ideas in insecticide manufacture, was given some atten- 

 tion. The absence of copper and lead from its composition 



