APPLE PEST'S 
The Larvae or Worms 
The larvae do not all hatch at once, 
those in the warmer situations being the 
first to emerge, and those coming from a 
single egg patch usually vary several 
days in their date of emergence. 
The date of hatching is by no means con- 
stant, but is determined by the earliness 
or lateness of the season, exactly as is the 
time for the opening of the buds. The 
earliest of the larvae emerge with the first 
bursting of the buds of the apple trees, 
and when the blossom buds of the apple 
begin to show their pink color the larvae 
of the leaf roller have mostly hatched. 
The active hatching season is usually dis- 
tributed over about one week to ten days, 
the time varying with the temperature. 
If the days and nights are cool, the period 
lasts longer than if hatching takes place 
at a time when the days and nights are 
warm. 
At first the larvae are very small, hard- 
ly one-sixteenth of an inch in length, and 
dull greenish-yellow in color, with black 
heads. As they feed and grow, they be 
come deeper green in color, and the black 
head and first segment of the body above 
become quite conspicuous. 
On hatching, the little larva goes at once 
in search of food, and may eat into an 
unopened bud or find its way into one of 
the folds of the tender unfolding leaves, 
which it soon ties together with delicate 
Silken threads of its own manufacture. 
Thirty days of feeding are sufficient to 
mature the larva, which then ceases to 
feed, and in a few days more changes to 
the third, or chrysalis (pupal), stage, 
usually among the curled leaves which it 
has tied together with the silk threads 
above mentioned. 
The Moth 
The moths measure from _ three- 
eighths to four-eighths of an inch in 
length with the wings closed; the ex- 
panse of the full-spread wings usually 
varies between eleven-sixteenths and one 
inch, the prevailing color is a rusty brown, 
varying in typical specimens from rather 
light to quite dark, and there is always 
present a large pale-yellow to almost 
523 
white diagonal patch on the front margin 
of the wing a little beyond the middle. 
Natural Enemies 
The fruit tree leaf roller has numerous 
bird and insect foes which tend to hold it 
in check. The various bird enemies are 
the blue bird, robin, catbird, red-winged 
blackbird, oriole, kingbird, phoebe and 
English sparrow. 
The fruit tree leaf roller in the larval 
stage has been found difficult of con- 
trol because of the manner in which the 
larvae feed on the foliage and fruit, and 
also on account of the fact that they are 
very resistant to poison sprays. Applica- 
tions of arsenicals alone and in combina- 
tion with 40 per cent nicotine solution 
have greatly reduced the amount of in- 
jury to the fruit and foliage, but these 
Sprays have not been so effective as is de- 
sirable. 
A series of experiments for the destruc- 
tion of the egg masses, conducted dur- 
ing the dormant season, have shown the 
value of mineral oils. Kerosene emul- 
Sion, crude-petroleum emulsion, and mi- 
scible oils have been tested. The last 
mentioned, when used at the strength 
commonly employed against the San Jose 
scale—that is, 1 gallon to 15 gallons of 
water—will prevent most of the eggs 
from hatching. From 93.23 to 96.21 per 
cent of the egg masses were destroyed by 
this material on the experimental plats. 
Good results also were obtained by the 
use of kerosene and crude-petroleum 
emulsions, although these substances 
were, on the whole, not quite equal to 
the miscible oils. The ease with which 
sprays may be prepared from these last 
commend them to many orchardists al- 
though the home made emulsions are 
cheaper. In preparing a kerosene or 
crude-petroleum emulsion care is neces- 
sary to insure a thorough and stable 
emulsion. 
It should be stated that injury to trees 
treated with oils sometimes follows, al- 
though no such injury was noted in con- 
nection with the present experiments. No 
more spray should be used than is neces- 
sary properly to treat the tree, and the 
