612 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



jurious eflfects on ve«Tetation. T^iblication of these data is anticipated 

 as soon as results from tests now under way are available. In sev- 

 eral instances the testinj^ of ofiicial samples has developed to the pro- 

 portions of extensive investigations. This is made necessary in cases 

 involving \veak fungicides recommended for the control of diseases 

 which are so erratic in their nature that very extensive and repeated 

 experiments nuist be made in oi-der to obtain conclusive results. 

 Fungicides which are not wholly inefficient, but which are so weak 

 that the}' are not satisfactorily effective, require extensive testing 

 to demonstrate their relative value, since material loss results in many 

 cases when such i)reparations are depended u])on as substitutes for the 

 standard fungicides generally recommended for the diseases involved. 



The investigation of proprietary insecticides recommended for use 

 against chicken lice and the dog flea, and the effects of the various 

 ingredients of such preparations on these insects has been continued 

 by the entomologists of the board. A large series of the common in- 

 secticides and many miscellaneous substances have been tested and 

 the effective dilutions of these materials determined. These tests 

 have been summarized and brought together in a bulletin entitled, 

 " The Results of Experiments wdth Miscellaneous Substances Against 

 Chicken Lice and the Dog Flea." 



Extensive field tests with commercial calcium arsenate containing 

 other calcium compounds have been made by the entomologists of 

 the board for the purpose of determining the proper dilution when 

 used as a spray or a dust and its effect on the foliage of fruit trees, 

 shade trees, shrubbery, and truck crops. A study is also being made 

 of the relation between foliage injury and the water-soluble arsenic 

 content, as well as the possibility of reducing such injury by combina- 

 tion with hydrated lime or water-slacked lime. Working in collabo- 

 ration with the Bureau of Entomology, many data have been ob- 

 tained on the effect of the soluble arsenic content when such calcium 

 arsenate is used as a dust on cotton plants. 



Special work is now being carried on to determine the value of 

 the various proprietary remedies and of many of the common in- 

 secticides against the chicken mite, and it is planned to publish a 

 paper on this subject during the coming year. 



The experiments to determine the value of the dry substitutes for 

 liquid lime sulphur have been continued and many valuable data 

 have been obtained. 



The scientists of the Bureau of Animal Industry branch of the 

 board, worldng in cooperation with the zoological division of that 

 bureau, have continued investigations relative to the effect of carbon 

 disulphide as a remedy for bots and worms infecting horses, and 

 have extended this investigation to include the effects of carbon tetra- 

 chloride and of arsenic for this purpose. 



It is further proposed to enter this field more extensively during 

 the next fiscal year in order that more definite knowledge may be 

 obtained regarding the inert or active nature of some of the more 

 commonly used ingredients which enter into the composition of 

 articles recommended by manufacturers as remedies for larval forms 

 of certain flies which infest domestic animals. 



