74 VI. Entomology. 



Bulletin No. 235. Co-operative Spraying Experiments: 



I. Experiments Against the Plum and Quince Curculios. 



II. Final Demonstration of Efficiency of a Poison Spray for the 

 Grape Root-worm. 



III. Making Bordeaux Mixture with " New Process " or Prepared 

 Lime. 



Co-operative experiments. — Co-operative experiments were con- 

 tinued by this Division this year against the plum curculio and the 

 rose-chafer. Twenty pounds of arsenate of lead were sent to each 

 of four prominent fruit-growers with directions for its use against 

 the plum curculio. During the summer I saw most of these experi- 

 ments, and reports at the end of the season were very favorable for 

 this method of controlling this pest of stone fruits. 



An extensive rose grower on Long Island, who co-operated with 

 us last year in an experiment against the rose chafer reports that: 

 " The results of these experiments so far appear to be that the 

 arsenate of lead can be used in perfect safety on roses in the propor- 

 tion of I pound in 5 gallons of water, so far as the foliage is con- 

 cerned, and that the rose bugs will certainly keep away from it when 

 applied at that strength." A vineyardist who used this poison at the 

 same rate on grape vines, making but one application, reports that 

 a sprayed row which for two or three years had been stripped of the 

 fruit by the rose bugs had, he feared, too many grapes this year 

 for the good of the vines. Where he used the poison only half as 

 strong the grapes were not so good or numerous, and the men did 

 not find as many dead rose bugs. I think our work during the past 

 two or three years has demonstrated that the rose-chafer can be con- 

 trolled with the arsenate of lead poison, but it must be used in very, 

 heavy doses. 



The San Jose scale continues to increase its depredations in the 

 fruit-growing sections of the State and is constantly appearing in 

 new localities. While the lime-sulphur spray continues to be the 

 cheapest and one of the most effective insecticides yet discovered for 

 this pest, many fruit-growers, and especially owners of fruit trees or 

 shrubs in yards, desire something easier to make and more agree- 

 able to apply. The new so-called soluble or miscible oil preparations 

 seem to offer the solution of this difficulty, as they are easy to make 

 and not very disagreeable to apply. One of our most prominent 

 fruit-growers discovered the San Jose scale in one of his orchards 

 last fall, and would have cut and burned the trees immediately, but 

 was finally persuaded to let me make a thorough test of one of these 



