EXPERIMENTS WITH INSECTICIDES UPON POTATOES. 191 



SUMMARY. 



It is claimed for Bug" Death that k acts as an insecticide, 

 fungicide and fertilizer. 



Bug Death is chiefly zinc oxide. It contains no nitrogen, a 

 mere trace of phosphoric acid and a small amount of potash. 



As an insecticide. 



At the rate 100 pounds per acre it freed potato vines from 

 bugs. 



At the rate of 40 pounds per acre it had no appreciable effect. 



Bug Death drives the bugs and makes them leave the vines. 



Bug Death kills comparatively few of the bugs. 



As a fungicide. 



Blight did not appear as soon nor as badly on plants to which 

 Bug Death was applied at the rate (in 3 applications) of 180 

 pounds per acre as on untreated vines. 



Effect on foliage. 



At the rate of 40 pounds per acre no appreciable effect. 



At the rate of 100 pounds per acre some of the leaves curled 

 on the edges and finally died. 



As a fertiliser. 



As its only fertilizing constituent is a little potash it was not 

 tested as a source of plant food. 



Its economy. 



Because of its high cost and slow application, no one growing 

 any considerable amount of potatoes can afford to use Bug Death. 

 The price of the labor required to apply Bug Death to one acre 

 will buy the materials and spray two acres with Bordeaux and 

 Paris green. 



BLACK DEATH AND ENGLISH BUG COMPOUND. 



These two compounds have been quite extensively advertised 

 and presumably more or less used in the State. Black Death is 

 apparently Paris green diluted with gypsum to make weight and 

 colored with charcoal. English Bug Compound depends upon 

 white arsenic for whatever value it may have as an insecticide. 

 Gypsum is employed to dilute the white arsenic and to give 

 weight. As both of these goods depend upon arsenic as the 



