140 THE GYPSY MOTH. 



It is interesting to note that while many of the gypsy 

 caterpillars were apparently uninjured by the spraying, the 

 canker-worms and tent caterpillars were almost exterminated, 

 and the tussock moths {Orgyia leucostig7na) disappeared. 

 The trees of the infested region were never in better con- 

 dition than at the end of the spraying season of 1891, and 

 the fruit crop was larger than it had been for many years. 

 Though this cannot all be credited to the spraying, the con- 

 trast between sprayed and unsprayed trees was often very 

 marked, the sprayed trees bearing more and finer fruit. 



During the spraying season thirty heavy spraying outfits 

 were worked back and forth between the outer part of the 

 infested region and its centre. Fifteen towns were thus 

 covered. There were also a dozen light fifteen-gallon hand 

 tanks which were sent into the outer towns. They were 

 carried in wagons, two men being assigned to each was^on. 

 The tanks and pumps used were the same as are used with 

 the cyclone burner (Fig. 1, page 120). The men with the 

 light outfits went to the outlying orchards and residences, 

 where a few trees were infested. They filled their tanks at 

 brooks or wells and carried them by hand to such infested 

 spots as were not accessible by a team, sprayed the trees in the 

 vicinity, reloaded the tanks upon the wagons and drove to the 

 next infested place. In this way the isolated colonfes in the 

 outer towns were covered by the sprayers. The large tanks 

 mounted upon wagons and handled by from four to six men 

 were used mainly in towns where water service was available 

 and were filled from hydrants or stand-pipes. The order was 

 given to spray everything green within two hundred feet of an 

 infested plant or tree. An adherence to this regulation caused 

 the spraying of all vegetation in the worst infested towns. 



No extended spraying with Paris green has been done since 

 1891. While spraying with Paris green cannot be considered 

 a successful method of extermination, it destroyed a consid- 

 erable proportion of the number of very young caterpillars 

 wherever it was done efficiently and in season. It thus 

 checked the multiplication and assisted in preventing the 

 spreading of the species. Though it failed to accomplish 

 the end sought, it was certainly the most efiectual method 

 known at that time of disposing of the young caterpillars. 



