104 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
(Carpocapsa pomonella, Linn.). Experiments each year since confirm 
all that was then said. Ht is a matter of surprise that one early ap- 
plication of these arsenites should be* so effective, when we remem- 
er the natural history cf the insect. Butin thiscase, asever, facts 
are too strong for theory, as I have shown for years. One applica- 
tion of the poison made in May, before the apples are larger than 
peas, in fact, almost as soon as the blossoms have well fallen, is often 
all-sufficient. This year 1 have two crab-apple trees adjacent. One 
was treated, the othernot. Frequent and careful investigation has 
failed to find an affected apple in the one case, while in the other a 
large proportion of the fruit is destroyed. 
‘Two points should be urged regarding this remedy: (1) Do not 
delay the application till June, when the larve are far into the fruit, 
out of harm’s way. Neglect of this caution explains why some 
even of our careful investigators have partially failed. The remedy 
should be applied just when it will aiso destroy the destructive leaf- 
rollers and the dreaded canker-worms. (2) We must use a weak 
mixture. One pound of the poison to 100 gallons of water is best ; 
then we can make thorough work without injury to our trees. With 
a pound to even 50 gallons of water we are quite likely to destroy 
some of the foliage if we make a thorough application.” (A. J. Cook, 
Proc. 7th Ann. Meeting Soc. Prom. Agr. Sci., Buffalo, N. Y., 1886.) 
It is but fair to state that in the Hlinois experiments by Forbes, now 
to be treated, the first recommendation urged by Cook, viz, that the 
application be not deferred until June, was not followed and the first 
application was made June 9, although the season was probably a 
late one, as Forbes states that when the spraying with Paris green 
was begun the apples were only as large as currants. It should also 
be stated that Forbes’ Paris green solution was stronger than Cook’s 
London purple solution, the former using 14 ounces to 5 gallons 
water, and the latter 1 pound to 100 gallons,* with the result that in 
Worbes’ experiments considerable damage was done to the foliage. 
Moreover, Forbes’ experiments with London purple were not begun 
until June 13, four days after his first Paris green application, and 
his mixture was only a little more than two-thirds the strength of the 
Paris green solution, which, by the way, made it slightly weaker 
than the solution recommended by Cook. These facts, therefore, 
render his conclusions as to the value of London purple of littl 
weight, while his conclusions concerning Paris green should be 
accepted only with the understanding that he injured the foliage by 
the strength of his mixture. Forbes’ conclusions from his 1885 ex- 
periments are as follows: 
**(2) Owing to the searcity of apples and the abundance of apple 
insects, the season was the most unfavorable possible for the success 
of these remedies. ; 
“*(3) The insecticides were applied suspended in water, the Paris 
green in the ratio of 14 ounces to 5 gallons, the London purple in 
half that weight. 
* * * * * * * 
“‘(4) The spraying with Paris green began when the apples were 
about as large as currants, and four days later with the London 
purple. 
* * * * * * * 
*The London purple used by Forbes contained 22.5 per cent. metatlic arsenic and 
the Paris green 15.4 per cent. 
