CODLING MOTH—PORTER 349 
With the advent of spraying, the control measures just outlined— 
banding, the scraping of loose bark from the trees, destruction of 
debris, and similar practices—became supplementary or were dis- 
continued entirely. About 15 years ago, Siegler and associates (1927) 
devised a chemically treated band which automatically kills the worms 
that enter it. Such bands are now used by many growers. A revival 
of the various sanitary measures took place from 1926 to 1935, when 
difficulties with spray residues were the most acute. The use of such 
measures was, however, still looked on as secondary and supplementary 
to spraying. 
The predominant development in the codling moth problem has 
been the adoption and evolution of spraying. 
EVOLUTION OF CONTROL BY SPRAYING 
In 1878 the control of the codling moth was completely changed 
by the discovery made by two New York State growers that the 
recently developed use of Paris green against canker worms was also 
giving control of the codling moth. This was reported the following 
winter (Woodward, 1879), and in 1880 there were conducted in Michi- 
gan the first official experiments with an arsenical, known as London 
purple, for codling moth control (Cook, 1880). The favorable results 
obtained stimulated extensive experiments elsewhere with both Paris 
green and London purple. Early in the twentieth century these ma- 
terials gave way to lead arsenate, which in a short time became the 
standard material for codling moth control. Lead arsenate was first 
available as a paste, often prepared by the grower himself from sodium 
_ arsenate and lead acetate or lead nitrate. Soon, however, lead arsenate 
became commercially available in a powdered form, which rapidly 
displaced the paste material, because of greater convenience of han- 
dling. The effectiveness of lead arsenate has been further increased by 
the use of various accessory materials, such as fish oil or mineral oil 
emulsion. With certain accessory materials the lead arsenate con- 
tinues to build up on the fruit and foliage with prolonged spraying, 
instead of leaving the tree with the run-off. 
The spray programs followed by growers have also undergone a 
marked evolution. At first many growers obtained satisfactory con- 
trol with a single spray, applied just after the petals fell. After a 
few years, however, the need for more spray applications during the 
season became evident, and now many growers put on 8 to 10 or even 
more applications of spray for codling moth control. Many of the 
State colleges or experiment stations regularly furnish the growers 
with current information on codling moth development during the 
season, to aid them in the timing of spray applications. The use of 
traps containing baits of fermenting solutions of low-grade sugars or 
