308 REPORT OP STATE BOARD OF HORTICULTURE. 



The first careful experiments by an entomologist with the poison spray 

 were made in Michigan in 1880 by Cook, who bad learned through Mr. 

 Woodward of its successful use in Western New York. Cook sprayed twice 

 with london purple and reported the following results in December of the 

 same year : "The trees were loaded with fruit, but careful examination, 

 made August 19, discovered not a single injured apple. Other apple trees, 

 only a few rods distant, which were not treated with the poisonous liquid, 

 are bearing fruit one-fourth to one-half of which is wormy.'' Notices of 

 the successful use of the poison spray appeared in most of the leading- 

 agricultural papers, yet comparatively few adopted the method for the 

 destruction of the codling moth during the next few years. Entomologists 

 were somewhat afraid to recommend it, and orchardists seemed to hesitate 

 in applying poison for this pest, although it was quite freely used for canker 

 worms.' A very few of the most progressive men adopted the method, and 

 with apparently successful results. 



In ISSf) and 1886 Forbes and Goff made careful and extensive experiments 

 with poison sprays, and the results indicated that at least seventy per cent. 

 of the loss commonly suffered by the fruitgrower from the ravages of the 

 codling moth could be prevented by thoroughly apjilying paris green once 

 or twice in the spring. Similar results were obtained in California by 

 Wickson in 1887. After the establishment of the State Experiment Stations 

 in 1888, a new impetus was given to the adoption of the arsenical sprays, 

 for nearly every station, sooner or later, reported the results of careful and 

 successful spraying experiments against the codling moth. Not only has 

 the practicability and effectiveness of the poison spray been demonsti'ated 

 during the past ten years by the most carefully conducted experiments at 

 nearly every experiment station in the United States, but the thousands of 

 practical fruitgrowers who have thoroughly tried it are unanimous in their 

 testimony that from fifty to even ninety per cent., in some cases, of the 

 fruit that would otherwise be ruined by the insect can be saved at a com- 

 paratively slight expense. To insure success it is necessary to understand 

 some of the essential facts in regard to the "whys and wherefores" of the 

 operation which have been brought out at one time and another by the 

 various experimenters during the past ten years. 



What poison to use — Many comparative experiments have been made 

 with the different arsenical poisons ( paris green, london purple, white 

 arsenic, arsenite of lead, etc.) to determine which is the most effective 

 against the codling moth. In nearly every case the recorded results show a 

 decided advantage in favor of paris green over all other poisons. At the 

 present time hundreds of tons of it are used in the United States in combat- 

 ing the codling moth alone. It is less variable in its composition than 

 london purple, and the latter is more liable to injure the foliage, but its 

 cheapness and lightness cause many to use it in prefei'ence to paris green. * 



Paris green should be used at the rate of one pound in from one hundred 

 and sixty to two hundred gallons of water, or it can be used even a little 

 stronger when mixed with the fungicide, bordeaux mixture. Careful ex- 



*A "Zoektein Poison" was tested by Goff in 1888 and 1889, and "Climax Insect 

 Poison" in Kansas in 1888, Init neither these nor other poisons which have been tested 

 have proved eiiual to paris green in effectiveness. 



