SPRAYING PEACHES WITH ABSEHTICAL6. 207 
None of these, however, gave sufficient promise to warrant field 
tests. 
From the foregoing it will be noted that severe injury has resulted 
from the use on peach of green arsenoid, Paris green, zinc sulphid, 
red sulphid of arsenic, tersulphid of arsenic, and sulpho-arsenate of 
soda. Injury from arsenate of lead has been variable, according to 
season, and especially depending upon the number of applications 
made. Two early treatments of the poison at the rate of not over 
2 pounds to 50 gallons of water, with an equal or greater quantity of 
lime added, have on the whole caused comparatively little injury, 
although in some years injury has been fairly well marked. Three 
applications of lead arsenate in limewater, however, have rather 
uniformly been injurious. No important difference in the burning 
effect of the different brands of arsenate of lead has been detected: 
and according to the tests made in 1910 in the comparison of rain 
water and w 7 ell water no difference between them was discernible. 
The time between the applications of the poison and the appear- 
ance of injury to the foliage varies, depending upon the arsenical 
in question. Thus Paris green, green arsenoid, and sulphid of 
arsenic promptly show a shot-holing and yellowing of the leaves. 
which later drop more or less completely. (See PL XVII, figs. 1-6.) 
The injury resulting from lead arsenate is about the same, only it is 
slower to appear. In the case of tw T o applications dropping of the 
leaves may be so gradual as not to attract attention and may be 
largely compensated for by the production of new foliage. A third 
application, however, is generally followed by a decided and prompt 
dropping of the foliage, usually within 10' days or 2 weeks, leaving 
the branches more or less bare and the fruit exposed to the sun. 
Arsenate of lead also produces a notable reddening of the fruit, 
though this reddening is due in part to an increased amount of sun- 
shine following the thinning of the leaves. This increased coloring 
is the subject of common remark by growers, and if but one or two 
applications of the poison have been made is not so pronounced as to 
detract from the appearance of the fruit. A third application, how- 
ever, very generally results in an intense dark-red coloring and the 
associated changes brought about very often result in brown depressed 
areas of variable extent and a. cracking on the sunny side o( the 
peach. Fruit so injured is worthless and mostly drops before ripen- 
ing time. (See PI. XVIII, fig. 1.) 
For the proper control of the curculio on peach three or four applica- 
tions of the poison would be desirable. However, in view o( the injury 
resulting from more than two treatments, recommendations have been 
limited to two timely applications of the poison, and always with the 
addition of limewater. This treatment gave a considerable degree oi 
protection and has recently come into a rather extended use by 
peach growers. 
