66 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



grape root-worm and from severe pruning in the spring. For this 

 reason it might be urged by some that this experiment was not a fair 

 test of the efficacy of a poison spray, because, it is said, beetles desert 

 vineyards in this condition for those having a dense foliage. That 

 there were a large number of beetles present, however, is shown by 

 the heavy deposition of eggs in the untreated check, even though the 

 foliage was light. 



SPRAYING EXPERIMENT IN A NEWLY INFESTED VINEYARD. 



Since a part of the campaign against this pest is to determine if 

 thorough and timely spraying, conducted for a series of years, will 

 prevent the deterioration of thrifty vineyards but recently infested, 

 an experiment w^as planned in another vineyard. This vineyard is 

 20 years old, on gravel soil, making a good growth of canes and luxu- 

 riant foliage. It is infested wdth the grape root-worm, but is not yet 

 showing evidence of deterioration. The block contains about G acres ; 

 1 acre was left unsprayed for check and the method of examination 

 to determine results was the same as in the preceding experiment. 



The following table gives the record of egg deposition in this block, 

 as a result of the spray applications : 



Table III. — Slioioing egg deposition on siinii/ed nnd cheek pints. 



CHECK (UNSPRAYED) PLAT. 



SPRAYED PLATS. 



Formula: "> pounds blue vitriol (copper sulphate), 5 pounds lime, 3 pounds arsenate of lead, 



- 50 gallons water. 



METHODS OF RECORDING RESULTS. 



The figures on egg dejiosition given in the tables above were ob- 

 tained by carefully removing all of the loose bark from the bearing 

 canes and the trunks of 25 consecutive vines, and recording the num- 

 ber of egg clusters found. Since the Qgg clusters varied in size, they 

 were classified — after the eggs in a large number of clusters had been 

 counted to ascertain the actual number — as /(t/f/c, when containing 50 



