ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 115 



This single treatment, as above described, made just after the 

 falling of the petals, in the experience of Professor Melander has been 

 sufficient to keep the codling moth under complete control. Doctor 

 Ball, however, inclines to two early treatments, the second being 

 given before the calyx lobes entirely close, as within ten days after 

 the falling of the petals. At the time of this latter treatment the 

 stamen bars have become more or less shriveled and more readily 

 permit the entrance of the spray into the inner calyx cup. The two 

 practices as recommended by Professors Ball and Melander do not 

 differ in principle, however, and Doctor Ball's second treatment is in 

 the nature of a supplementary one. In summing up his experiments, 

 covering several years in Utah, Doctor Ball states his conclusions as 

 follows : a 



The first early spray is the best, the second is nearly as good, and the third is of 

 little value. 



Two early driving sprays will kill an average of 90 per cent of the first brood of 

 worms. 



Sufficient poison is retained [in calyx cup] from the early sprayings to kill an average 

 of 74 per cent of the second brood of worms. 



Two early sprayings correctly applied are worth from 6 to 16 times as much as three 

 late ones. 



Professor Melander says : 6 



A single thorough spraying has afforded practically 100 per cent returns over hun- 

 dreds and hundreds of acres of Washington orchards. The same benefit from the 

 single spraying has also been abundantly attained in Colorado and Utah. 



Aside from the particular question involved as to whether the one- 

 spray method will sufficiently control the codling moth under eastern 

 conditions, several other considerations must be taken into account. 



In the arid valleys of the West, as in Utah, Washington, and Colo- 

 rado, practically the only important insect enemy of the fruit of the 

 apple is the codling moth, and fungous diseases are, on the whole, 

 of but little importance. The use of fungicides is therefore not ordi- 

 narily necessary and there is thus to be controlled only the codling 

 moth. 



In the Mississippi Valley and Eastern States, however, and in 

 central and eastern Canada, there are, in addition to the codling moth, 

 the apple and plum curculios and the lesser apple worm, which in 

 many sections are exceedingly injurious, the plum curculio in some 

 parts being scarcely less in importance than the codling moth itself. 

 Furthermore, the general prevalence of fungous diseases, such as the 

 apple scab, apple fruit blotch, bitter rot, and leaf-spot affections, 

 requires several fungicidal treatments during the season. Entomolo- 



oBul. 67, Bur. Ent., U. S. Dept. Agr., p. 75, 1907. 

 & Journal of Economic Entomology, vol. 2, p. 67, 1909. 



