37i6 Repokt of the Department of Entomology of the 



It is the common belief that the species during normal years is 

 limited to a single brood with a partial second brood. By the 

 time the leaves of the grape fall most nymphs have transformed 

 to adults. The question of the number of broods can be settled 

 only by a series of breedings extending through normal and ab- 

 normal seasons. 



Adults. — As has been mentioned before, the winter is passed 

 in the adult stage. These adults, after returning to the vines 

 in the spring, copulate and the females begin oviposition during 

 June. The over-wintering adults live until August and perhaps 

 longer. Thus one can find this stage of the insect on the vines 

 or among the fallen leaves in the vineyard during the entire 

 year. 



EXPEEIMEA^TS FOR THE CONTROL OF GRAPE LEAF- 

 HOPPER. 



During the seasons of 1910 and 1911 experiments to find the 

 best method of control for the " hopper " were conducted in the 

 vineyards of Mr. Charles C. Horton, Mr. Mark J. Sackett and 

 Mr. Charles Secord of Silver Creek and during 1911 in the vine- 

 yard of Mr. F. A. Morehouse of Ripley. The experiments dur- 

 ing 1910 have been discussed in Bulletin 331, and it will be noted 

 that the most satisfactory spraying mixture contained nicotine. 

 The weakest dilution used was one part of '^ Black Leaf Tobacco 

 Extract" to 100 parts of water. The experiments during 1911 

 were planned to corroborate the results of 1910 and also to test 

 out various brands of nicotine products and other contact insecti- 

 cides. About thirty acres of vineyard were used in the experi- 

 ments. 



From the standpoint of effectiveness in the control of the in- 

 sect, ease of application and safety to the grape foliage, the nico- 

 tine sprays have proven the best of the materials tried. The 

 most economical dilution of a nicotine product was found to be 

 that in which the spray material contained 2/100 of one per ct. 

 nicotine, Tt was demonstrated that with very thorough appli- 



