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UNITED STATES
DEPARTMENT OF AGRICULTURE
LIBRARY

Book number

1
Sn823

no. 35

series

'" 3 5 -5 5.4-0

//

U. S. DEPARTMENT OF AGRICULTURE,

DIVISION OF ENTOMOLOGY— BULLETIN NO. 35, NEW SERIES.

L. O. HOWARD, Entomologist.

^shC^nt nf

"Zion, Di l^icult^

REPORT OF CODLING-MOTH INVESTIGATIONS
IN THE NORTHWEST DURING 1901.

C . B . SIMPSON

Investigator.

: *>

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1902.

LETTER OF TRANSMITTAL.

IT. S. Department of Agriculture.

Division of Entomology.
Washington., D. 0., May 19, 1902.
Sir: I have the honor to transmit herewith the manuscript of a
report on the codling-moth investigation in the Northwest during
1901. conducted by Mr. C. B. Simpson, a special agent of this Division,
and prepared by him for publication. Fruit growers in the North-
west, and especially in the States of Idaho. Washington, and Oregon,
have complained that conditions in that part of the country must be
very different from those which hold in the Eastern apple-growing
sections, inasmuch as the remedial treatment which is found satisfac-
tory in the East does not give equally good results in the Northwest.
Therefore, under a special appropriation from Congress, some work
was begun by this office in the late summer of 1900, Mr. Simpson
being appointed to carry out the investigation and experiments. A
report upon the work which he did in the season of 1900 was published
in Bulletin 30 (new series) of this Office (pp. 51-63). In 1901 he was
able to make a somewhat earlier start, and the results were therefore
more satisfactory. This work is described in the accompanying bul-
letin. The present summer (1902) Mr. Simpson started for the field
early in May. and it is hoped that at the close of the season the investi-
gation will have arrived at such a point as to enable the publication of
a full and satisfactory bulletin covering the whole problem. 1 recom«
mend this bulletin to be published as Xo. 35 (new series).
Respectfully.

L. O. Howard.
'Hon. James Wilson. Entomologist.

St <■/; tary of Agricultui\ .
2

3522

CONTENTS

Page.

Itinerary 5

Work done from Ithaca, N. Y 6

Teachers' institutes 6

Status of the fruit crop for 1901 , 6

Injury due to codling moth in 1901 7

Fruits infested by the codling moth 7

Introduction and spread of the codling moth in the Northwest .. 8

Life zones and present distribution 9

Life history of the codling moth 10

The egg 10

The larva 10

The pupa 13

The moth 13

Generations of the insect 15

Overlapping of generations 18

Causes and conditions which affect the numbers of this insect 18

Preventive measures employed against the codling moth 19

Remedial measures employed against the codling moth 20

Measures against the larvae 20

Spraying 21

Early sprayings 21

Later sprayings 22

Material for the spray 24

Expense of spraying 25

Picking and destroying wormy fruits 25

Banding 26

Measures against the adult 27

_ Trap lanterns 27

Baiting the moth 27

Resume and conclusion 27

3

ILLUSTRATIONS

PLATES.

Page.

Plate I. Entrance holes of larvae 12

II. Fig. 1. — Banded tree and near-by fence. Fig. 2. — Post of fence shown

above, with splinters removed 12

III. Fig. 1. — Portion of fence post, showing old pupa skins. Fig.

2. — Cocoons in cracks in bark 12

IV. Fig. 1. — Piece of bark, showing moth just emerged, and old pupa

skins. Fig. 2. — Band on which the remains of 330 cocoons were

counted 16

V. YiewTs in orchard of Hon. Edgar Wilson, showing location of apple

house in relation to orchard 20

TEXT FIGURE.

Fig. 1. Map of Pacific Northwest, showing life zones 9

4

REPORT ON CODLING-MOTH INVESTIGATIONS IN THE
NORTHWEST DURING 1901.

ITINERARY.

In accordance with the authorization of the Secretary of Agricul-
ture and the instructions of the Entomologist, the following report is
submitted upon the investigations of the codling moth in the Pacific
Northwest for 1901.

I left Ithaca, N. Y., June 15, for Idaho, arriving at Salt Lake City,
Utah, June 19. The Utah Agricultural College was visited and con-
ferences were held with the authorities in regard to the codling moth.
From Logan I went to Pocatello, Idaho, and thence to Market Lake,
Idaho, to look over a grasshopper outbreak. At that place I found
Professor Aldrich and with him looked over the infested section.
A report of the results of this work has already been submitted.
June 24 I left Market Lake and was accompanied by Professor Aldrich
to Shoshone, Idaho, from which place I went to Shoshone Falls and
Blue Lakes. Mr. Perrine's orchard at Blue Lakes was examined
closely and remedial measures were advised. The 28th and 29th I
spent in observing conditions about Mountainhome, arriving at Boise
the 29th, where I spent a few days in looking over the orchards in
that vicinity. A trip was then made to Nampa, Caldwell, Payette, and
Weiser, Idaho, with return to Boise the 13th of July. Many trips
were made to orchards about Boise. August 14 another trip was
made, which included Nampa, Caldwell, Payette, Weiser and Emmett.
Returning to Boise August 25, I remained there two days and then
was in Mountainhome from the 27th to the 30th. In September sev-
eral trips were made to Beatty, Nampa, and Meridian, and one to
Payette.

October 4 I went to Portland, Oreg., for the purpose of attending
the fruit fair and conferring with the Oregon people. I had a long
talk with Professor Cordley and others of the Oregon Agricultural Col-
lege and from there went to southern Oregon. From southern Oregon
I returned to Portland and from there went to Moscow, Idaho. In com-
pany with the Entomologist and Professor Aldrich, I left Moscow
October 18. After spending several days at Boise, I started for Wash-
ington, D. C, October 22 and arrived there on the 26th.

5

WORK DONE FROM ITHACA, N. Y.

Not being able to begin work in the field early enough to make
observations during the blossoming period, circular letters were sent
to prominent growers in Idaho asking them to conduct observations
and begin experiments.

Letter No. 1 asked for observations in regard to the times of bloom-
ing, etc., and on life of the insect during that period. Several ren-
dered valuable aid by making excellent observations.

Letter No. 2 asked several growers to begin cooperative experiments,
which the writer would complete when he arrived upon the field. In
every case the freeze of June 5 left no apples upon the trees which
were selected for the experiments. Much work had been done by
some growers in starting these tests.

Letter No. 3 was sent to 60 growers in different parts of the State
asking that band records be kept. The fruit growers responded well
to this request, and over 40 replies were received. Many valuable
records were obtained.

TEACHERS' INSTITUTES.

During the summer the writer addressed four teachers' institutes
upon the subject of the codling moth, the aggregate number of teachers
present being about 180.

In each of these talks the damage caused by the insect and the impor-
tance of the subject were dwelt upon. A brief but fundamental
sketch of the life history was given, fully illustrated by photographs
and specimens of the insect's work. The most approved methods of
control were explained and the results obtained by the same were
given. The teachers were told how they might introduce the subject
into their school work as a nature-study topic. Directions were given
as to the method of presenting the work and collection of specimens.
In these talks the writer took great pains to interest the teachers and
has been rewarded by knowing that, in a great number of instances,
the teachers put the suggestions into practice.

On account of the small fruit crop no summer meeting of the State hor-
ticultural society was held. Two farmers' meetings were addressed —
one at Caldwell and another at Mountainhome. The attendance was
poor, but the interest shown amply repaid the efforts exerted.

STATUS OF THE FRUIT CROP FOR 1901.

Early in the spring the fruit crop of 1901 promised to be large. A
sudden freeze June 5, at which time apples were about the size of
marbles, practically ruined all prospect for a good crop. About Boise
prunes and peaches were all killed, and in some orchards no apples
were left, while in others considerably over half a crop remained. In
other sections conditions were about the same. Mr. McPherson esti-

mates that there was only about 10 per cent of an apple crop in Idaho
in 1901, and his estimate is probably not far from correct.

On account of this short crop the price of apples was high and those
who could save a large part of what crop the}^ had made good profits.

INJURY DUE TO CODLING MOTH IN 1901.

On account of the small crop it is impossible to give an estimate that
is of any value in regard to the damage by the insect in 1901. It was
certainly much greater than in%1900.

In orchards with but little fruit the apples were all wormy, many
of them containing from 5 to 10 holes. The writer counted the
remains of 23 eggs on one apple and 17 on another.

The number of the insects was decreased but little by the freeze,
while the number of fruits the}r had to work upon was greatly les-
sened. Consequently, in the orchards that were well cared for a large
percentage of the fruits was wormy in spite of spraying and banding.
The following are estimates of injury b}^ the codling moth in individ-
ual orchards and in localities:

M. A. Kurtz, at Nampa, had over half a crop of apples. Many of them were under-
sized. SprayiDg and banding were well done. The loss for the whole orchard was
about 20 per cent.

Mr. C. Hinze, Payette, had about half a crop of Jonathans. About 50 per cent
was saved from this insect. Spraying alone was used.

Hon. Edgar Wilson had a small crop of Ben Davis and Jonathans. Early spray-
ings were made and bands were used. Less than 40 per cent of these were saved.

Mr. John McGlinchey had nearly a full crop at Payette. Early sprays were made
but banding was neglected. Not over 20 per cent was saved.

Mr. Seth Heath, 9 miles from Mountainhome, thinks he saved 80 per cent of his
apples and pears. Spraying and banding and other measures were used.

Mr. W. S. Whitehead, of Boise, saved only about 20 per cent by spraying and no
banding.

Many orchards were noted in various localities where all the fruit was wormy.

Professor Aldrich has found that the damage in and about Moscow was about 5
per cent.

It was reported that about Walla Walla, Wash., and in the valley of the upper
Columbia River the conditions were about as they were in the Boise Valley.

In the Willamette Valley the writer has been told that the injuries where no meas-
ures were used varied from 30 to 80 per cent.

In southern Oregon the writer found orchards near Central Point in which the
injury did not exceed 5 per cent. In an untreated orchard 20 per cent of the apples
were estimated to be damaged. Growers said that this orchard showed much less
injury than many others in that locality.

FRUITS INFESTED BY THE CODLING MOTH.

The apple is by far the most subject to the attacks of this pest, and
practically all of the work has been directed against the insect in this
fruit.

In 1900 it was noted that some varieties of apples were more subject

to the attacks of this moth than others, and a list was prepared in order
of injury. In 1901 but little revision of the list was necessary.
The following is the revised list:

Pewaukee (always badly infested) .

Red Astrakan.

Bellflower varieties.

Spitzenberg.

Grimes Golden, Northern Spy, Gravenstein.

Wealthy.

Baldwin.

Ben Davis ( very variable) .

Rome Beauty (variable).

Jonathan.

Winesap (always least infested).

This list was made from observations in many orchards and is a
composite of the conditions in these orchards. Local conditions are
to a great extent the cause of the variability.

Pears are but little infested when compared with apples. In the
very worst localities the injury sustained rarely if ever reaches 20
per cent, and, when remedial measures are used, injury varies from 5
to 15 per cent.

Man}^ quinces were examined, but not a single case of infestation
was noted.

Having in mind Professor Bruner's observations when he found
larva? which he took to be those of the codling moth feeding in seed
pods of roses, the writer examined hundreds of these pods without
finding any larvae or eggs.

It has often been reported that the codling moth larva? were attack-
ing peaches, prunes, and plums. Upon investigation it was found in
eveiy case that the attack was made by the larva of the peach-twig
borer.

INTRODUCTION AND SPREAD OF THE CODLING MOTH IN THE

NORTHWEST.

Dr. C. V. Riley, in his Sixth Missouri Report (187-1), mentions this
insect as working in Utah, where it had evidently been introduced a
year or two previous.

The Scientific American of November 11, 1882, mentions that the
codling moth made its appearance in California in 1871.

Prof. J. M. Aldrich states that this insect has been known in the
Clearwater Valley since 1887, and in southern Idaho nearly as long.
By many orchardists in southern Idaho the writer was told that the
above date is approximate^ correct. Many stories are told of how
the insect reached Idaho, one being to the effect that the insect was
introduced in dried prunes. Without doubt the insect was introduced
in apples shipped either from Utah, Oregon, or Washington. When

9

once introduced it can be readily understood how the insect spread
over the apple-growing area by the shipping of fruit from one section
to another. The spread is found to be along the lines of transporta-
tion. It was retarded in a great measure by the fact that many
orchards were isolated. A well-marked case of immunity resulting
from isolation is shown in the case of Mr. Perrine's orchard at Blue
Lakes. This orchard was free from the insect until two or three years
ago, and is now but little infested. Mr. Perrine thinks the moth was
introduced into his orchard in old boxes. The spread from orchard to
orchard by the flight of the moths has been comparatively slow, and
usually follows a river valley.

LIFE ZONES AND PRESENT DISTRIBUTION.

The status of the insect has been studied as far as the data at hand
would permit. The life zones found in Idaho (fig. 1.) may be de-
scribed as follows:

The Boreal zone comprises that part of the State known as the Panhandle, a strip
along the northeastern side of the State and a large area in the central part of the
State which is connected with the eastern strip.

BOREAL.,
TRANSITION.
UPPER SONORAN-

Fig. 1.— Map of the Pacific Northwest, showing life zones— locaities infested by codling moth indi-
cated by dots,

The Transition zone is limited to an irregular area in the north and a fringe around
the Boreal in the south. The southwestern and southeastern parts of the State are
also in this zone. The Transition area in the northern part of the State is somewhat
different from that of the southern part, on account of the larger amount of rainfall.

10

The Upper Sonoran comprises the area about the Snake River Valley. This area
is continuous with the same zone in Oregon on the west and Utah on the south. An
arm extends down the Snake River Valley on the western border. A small area of
this zone is present in the valleys of the Snake and Clearwater rivers at Lewiston.
At this point several of the Lower Sonoran fruits are grown.

The relations of the codling moth to these zones are as follows:

Boreal. — As no apples can be grown in this zone, this insect does not occur.

Transition. — The insect occurs in this zone, but is never greatly injurious. At Mos-
cow the injuries for the past three years have been 21, 10, and 5 percent, respectively.
Many fruit growers have told the writer that the insect has its ups and downs, vary-
ing from practically no injury to 25 per cent. Correspondents at Almo, Cassia
County; Lakeview, Laclede, and Rathdrum, Kootenai County; and Paris, Bear Lake
County, state that they can find no indications of the insect at those places. The
observations of those in the best position to know indicate that these locations are
not well fitted for the growing of apples. The northern part of this zone, however,
is evidently more suitable for apples than the southern part.

The Upper Sonoran. — From 80 to 90 per cent of the fruit raised in Idaho is grown in
this zone. Some varieties of apples reach perfection. The codling moth reaches its
maximum of numbers and destructiveness in this zone, and here the greater part of
the investigation has been made.

LIFE HISTORY OF THE CODLING MOTH.

Many important variations in the life history of this insect were
noted in 1901.

THE EGG.

As in 1900, many eggs were observed. In orchards where there
were hut few apples eggs were found in enormous numbers. On one
apple the number of eggs or remains of eggs was found to be 23
(PL I. I))\ on another 17. It was difficult to ascertain the time of
hatching of the eggs, hut the times of hatching of eight were found
with reasonable accuracy. These hatched in from three to eight days,
with an average of about live days.

THE LARVA.

In a day or so after the egg is laid, a horseshoe-shaped band, which
is the embryonic larva, may be seen. Later the form of the larva
may be easily distinguished. In about live days the fully formed
larva breaks its way through the shell and immediately seeks to enter
an apple. The writer has many times attempted to observe the hatch-
ing of an egg and the entering of the apple, but has failed, although a
few times the attempt was almost successful. The young larva of the
first generation has been observed to spend some time upon the fruit
and then to enter the calyx by squeezing its way in between the calyx
lobes.

In 1900 the earlier countings showed that about 60 per cent entered
the calyx end. Without doubt this low percentage was caused by

11

including' the early individuals of the second generation. In 1901, by
numerous countings, the average was found to be 83 per cent, with a
minimum of 79 per cent. In one counting of 130 apples, 106 had
entered the calyx and 21 the side. About half of those that
entered by the side entered where the apples touched. In 12 apples
there were two worms each. Three larva? were killed by fungi or
bacteria. Of those which had left the apples, 13 had left by the calyx
and IT by the side.

By far the larger number of the larva? of the later generation enter
the apple at other places than the calyx — in some cases, from 90 to 100
per cent. They enter at the sides (PI. I), at the stem, and particu-
larly where the apples touch. In badly infested orchards it is a rare
exception to find apples which touch without finding also the entrance
place of a codling-moth larva.

A few larva? of the second generation were taken out of their bur-
rows a few hours after they had entered and were placed upon apples in
order to see what they would do. All immediately commenced search-
ing for a place to enter. They would try to bite through the smooth
skin, but their jaws would make but little impression. One of them
entered at the stem, another found a broken place in the skin, and
another succeeded in piercing the smooth skin. As has been noted by
other observers, 1 found that the larva? while entering eat but little, if
an}r, of the skin or flesh of the fruit, but push the particles out behind
them. They seem intent upon getting away from the light. Professor
Cordley states that he has seen them spin silk over the mouths of the
holes as soon as they have fully entered.

A few authors have advanced the opinion that those larva? which
hatch on the leaves eat sparingly of the leaves before they find the
apples. In spite of many attempts to throw light upon this point, the
writer can offer no evidence; but he believes that man}^ perish on
account of this habit, as they get any poison that may be on the leaves.
In the field a large majority of newly hatched larva? never reach an
apple, but perish. This was especially true in 1901 on account of the
scarcit}^ of apples. The apples which had 23 and 17 eggs had only 5
and 1 worm holes, respectively.

When entering by way of the calyx, the larva eats its first few meals
at the surface before commencing its burrow into the fruit. On enter-
ing at the side, the larva eats out a circular mine immediately under
the skin, which can be easily distinguished by its lighter color. In
about three to five days the larva, after making its burrow funnel-
shaped, starts toward the central portion of the fruit. When the calyx
is entered a large amount of castings is thrown out (PL I, D), but
when the side is entered but a small amount is thrown out (PI. I,
A, B, C). When the central portion of the fruit is reached the larva
eats out an irregular cavity which is found filled with pellets of excre-

12

ment bound together with silk. Data as to how long it takes the larva
to become full grown were secured. However, the number of experi-
ments and the number of larvae were small and more work must be
done before a good average can be given. The shortest time was
fourteen days and the longest twenty-five, with twenty-one days as an
average. When the larva is full grown it eats its way to the outside
of the apple, but remains within, plugging the hole with frass. In
a day or so this obstruction is pushed out, and the larva crawls out
and immediately seeks a place in which to spin its cocoon and complete
its transformation.

The effect of this insect on the apples and pears is such that the}T
ripen prematurely and fall from the tree, being worthless for com-
mercial purposes.

The larva makes its way from the apple to the place of spinning its
cocoon in one of three ways. Most commonly it simply crawls from
the apple to a twig, thence to branch, and thence to the trunk of a
tree. Experiments conducted b}T Professor Aldrich upon trees with 5
bands show that twice as many larvae spin their cocoons under the top
band as under any intermediate band, and the next highest number
was found under the bottom band. In case of windfalls, the larvae
leave the apple and crawl to a suitable place along the ground. In a
few cases the larvae drop from the tree to the ground by a silken
thread. Many of these threads have been noted by the writer.

The larva? spin their cocoons in a variety of places. Those noted are
as follows: Under loose pieces of bark (PI. Ill, fig. 2) on rough trees;
in the cracks in the crotches of trees; in cracks or holes in the tree
trunks; under splinters on fence posts (PI. II, and fig. 1 of PI. Ill);
in the rough bark of adjacent trees- (PI. Ill, fig. 2); in any kind of
rubbish about the trees; under anything lying against or upon the
trees; in cracks in the dry earth about the trees; and, in some few
cases, in dried fallen apples. The place of first choice under normal
conditions is under the loose bark, in the crotches, or in the holes or
cracks in the tree. When the tree is smooth and the earth is dry we
sometimes find a considerable number of cocoons in the cracks in the
earth.

In general the larva selects a dry, tight place, and it may gnaw out
a hole in the bark and incorporate the pieces in the cocoon. Many
times a silk tube 2 or 3 inches in length is found with a cocoon at one
end. Evidently the larva did not find a place tight enough and con
tinued spinning until such a place was made. In these cases a cap of
silk is found. Cloth bands furnish a place for spinning cocoons most
acceptable to the larvae.

The larva spins its cocoon in about two days. The cocoon is com
posed of a single thread of silk, a product of the silk glands common

Jul. 35, New Series, Div. of Entomology, U. S. Dept. of Agriculture

Plate i.

Entrance Holes of Larv/e.

Bui. 35, New Senes, Div. of Entomology, U. S. Dept. of Agriculture.

Plate II.

Fig. 1.— Banded Tree and near-by Fence.

Fig. 2.— Post of Fence shown above, with Splinters removed.

Bui. 35. New Seres, Div. of fc.nto.ino ogy. U. S Dept o* Agncuiturj

Plate 111.

Fig. 1.— Portion of Fence Post, showing old Pupa Skins.

Fig. 2.— Cocoons in Cracks in Bark.

13

to the larvae of this order of insects. The cocoons of the early gener-
ation are fragile and not so heavy or well made as those of the later
generation, in which the larva passes the winter.

THE PUPA.

The larva when spinning its cocoon is bent upon itself, but when
the spinning is completed it straightens and becomes shorter and
thicker. In about five days it sheds its last larval skin and becomes a
pupa. One can always find this skin in a pellet at the caudal end of
the pupa. The pupa is about half an inch long and at first is a pale
yellow color, later becoming brown. The last day before the moth
emerges it assumes a bronze color. The antennae, mouth-parts, legs,
and wings of the moth may be clearly seen, all soldered together in an
immovable mass. The segments of the abdomen are movable and are
armed on their caudal edge with spines which point backward.

Some time after the beginning of warm weather in the spring, or
twenty-one or twenty-two days after commencing the spinning of the
cocoon, in the summer, the moth emerges. The pupa pushes itself
through the wall of the cocoon and out free from any obstruction.
This is accomplished by rapid movement of the abdomen, aided by
the spines which point backward. Pupa? were observed to have
moved themselves fully an inch before a suitable place for emergence
was found. They sometimes thrust themselves through muslin or
burlap when such is used for bands and neglected. Soon after the
pupa is free from the cocoon the pupa skin splits down the back and
the moth slowly crawls out. Many experiments were carried out to
determine the time elapsing between the spinning of the cocoon and
the emergence of the moth. The shortest time was twelve days, and
the longest during the summer was twenty-eight days, with an
average of twenty-two. Only a very small percentage emerge the
twelfth day.

THE MOTH.

Upon emerging the wings of the moth are small, the legs weak, and
the body soft. The moth clings to the bark head up (PL IV, fig. 1),
the wings gradually expand, and the legs and body harden and get
stronger. Later the moth holds its wings for a few minutes above its
back, like a butterfly. The wings are then replaced and the moth is
ready for flight. During all these proceedings the moth carefully
avoids the sunlight. After the wings are fully expanded and dry the
moth frequently changes its position b}^ running rapidty up the tree.
In from ten to thirty minutes after emerging the moth usually flies to
the lower branches of the tree and is lost as far as further observation
is concerned. Quick, somewhat erratic flight is characteristic, the
flight being so rapid that the eye can not follow it.

14

It is generally stated by writers on this insect that the adult is but
rarely seen in orchards. During the summer of 1900 the writer saw
only about half a dozen moths in the field. During the summer of 1901
from one to three were seen every day spent in orchards. These were
usually on the fruit or on the upper surfaces of the leaves. On being
disturbed they would flit away and be lost to sight.

But few fruit growers are familiar with the adult form of this
insect. On this account many mistakes are made as to its identity.
Anyone can easily confine larva? or pupae and in a short time settle the
question of identity. The moth is quite variable in size, but never
expands more than an inch. The wings at a glance have the appear-
ance of watered silk, but upon closer examination one finds them
crossed by numerous rows of gray and brown scales, which give the
appearance of the plumage of a bird. Behind the tip of the forewing
there is a large dark-brown spot which bears rows of bronze and gold-
colored scales. The hind wings are of a light grayish color, darker
toward the margin.

The sexes may be readily distinguished by the fact that the males
bear a black pencil of hairs on the upper surface of the hind wing
and a black spot on the under surface of the forewing.

Mr. Hitt, of Weiser, found in 1896 that of 50 moths but 7 were
males. The writer found the females exceeding the males in number,
but can give no figures.

During the summer of 1900 the writer found a moth on the trunk
of a tree that had all the appearance of a codling moth except the
color, which was buff' and gold throughout, the bronze spot being
much the same as in the codling moth. During the summer of 1901,
4 well preserved and S badly worn specimens having the same color
were secured, and 2 others were observed in the field. Mr. Hitt, of
Weiser, found 7 of these moths among 50 moths bred in 1896. Mr.
McPherson has also noted this buff-colored moth. Whether this is a
variety of Oarpocapsa pomonella or another species has not yet been
determined.

According to many observers the codling moth has been seen to feed
upon the juice of ripe apples. Many fruit growers tell me that they
have seen many moths about cider mills and have seen them feed on
cider.

The conclusion arrived at by all investigators of this insect is that
it is but little attracted to lights such as are used in trap lanterns.
The Avriter finds, however, that moths will seek a window when they
have emerged in a dark room or cellar.

In cages the egg laying begins the second day after emergence and
has been observed to continue until the fourth day. In the field some
egg^ were observed to have been laid in the late afternoon and early
evening.

15

The moths lay practically all of the eggs of the first generation
upon the fruit, while those of the later generation are laid both upon
the fruit and leaves. From many observations the writer is led to
believe that there is no general rule as regards the eggs of the second
generation. In some orchards the majority were found upon the fruit,
and in others upon the leaves.

In cages the moths rarely live over a week.

GENERATIONS OF THE INSECT.

From the economic standpoint the number of generations is an
important feature, as that is the chief factor in determining the amount
of damage. In the Eastern States the generations vary from one and
a partial second to two and a partial third. In California, Oregon,
New Mexico, and Alabama, various investigators have published the
statement that three generations occur. Professor Gillette has recently
come to the conclusion that there are only two generations in Colorado.
Professor Cordley says that there are only two at Corvallis, Oreg.
In south Idaho, both Mr. McPherson and Mr. Hitt have advanced the
idea that there are three full generations, and sometimes a partial
fourth.

The writer has regarded this as one of the most essential points to
be determined in the investigation of this insect. In 1900 an attempt
was made to solve the problem. At the end of the season, though but
little data had been secured, the conclusion was reached that there are
three generations. The writer was not at all satisfied with this con-
clusion, and in 1901 considerable time was spent in studying this point.

Examination of the records of worms caught under bands showed
that at certain periods greater numbers of worms went under bands
than during the intervals between these times. By collecting and
studying all available records it was found that these periods were
quite constant, and this appears to be the best and most accurate way
of determining the limits and number of generations.

In June, 1901, circular letters were sent to 60 fruit growers in dif-
ferent parts of the State of Idaho asking that records be kept of the
larvae killed under bands. But very few growers failed to answer.
Among those who responded, a few stated that apples were not grown
in their sections; others banded and found no larva? or wormy apples;
and still others could send no record on account of crop failure; but
a large number sent in valuable records. These records were tabulated
and curves have been drawn on cross -section paper. a

«It was the author's intention to include in the present report a number of charts
showing these curves; but owing to incompleteness of preparation, and other circum-
stances, these charts have been reserved for publication in a later report.

L. O. H.

16

A summary of the more important records is here given :

Records of capture of codling-moth larvse under bands.

Year.

Locality.

Observer or ,
source of rec-
ord.

Num-
ber of
trees.

First
maxi-
mum.

Second
maxi-
mum.

Days
be-
tween
maxi-
ma.

Total
num-
ber of
worms.

Time be-
tween re-
moval of
bands.

Aver-
age,
per

tree.

1897

Mr. Ayers

do..

Prof. J. M. Aid-
rich.

H. G. Gibson . .

J. Shearer

do

140
140
40

4

3

80

128

23

26
34
27
4
10

July 17
July 10
July 20

July 26
July 18
July 1
July 5
....do...

July 13
July 5
July 12
....do...
June 25

Sept. 1
Sept. 10
Sept. 24

Aug. 11
Aug. 17
Aug. 30
....do...

Sept. 2

Aug. 27
Sept. 2
Sept. 4
Sept. 10
Aug. 13

46

62
66

46
' 60
61
56
59

45
50
54
60
49

12, 247

20, 909
8, 620

467

215

3,554

1,690

4,141

2, 829

2,880

194

666

640

Weekly. . .

do....

do....

Daily .....

Weeklv...

do....

do....

do....

do....

do....

do....

6 per mo..

2-5 days ..

87.48

1898
1899

1901

1901
1901

do

Juliaetta

Nampa

Payette

149.35
215. 50

116.75
71.66
44.42

1901
1901

1901
1901

do

Provo, Utah..

do

do

do

Utah Agricul-
tural College.

do

do

13.2

180

108.2
84.7

1901
1901
1901

Hagerman ...

Lewiston

Caldwell

R. E. Conner . .
S. G. Iasman . .
Win. C.George.

8.2
166.6
64

659

55

All of the records here given show plainly that there are but two
maxima of larvse entering bands. There are many sources of error
in obtaining the figures. A maximum lasts from six to eight da}Ts.
Weekly records are much more liable to error on account of the length
of the intervals. The average length of time between maxima, fifty-
five days, is undoubtedly too high, as the records of Mr. Gibson
and Mr. George show the time to be fort}T-six and forty-nine days,
respectively.

The writer has secured many other records, but they can not be
relied upon for determining the number of generations, as some of
them were taken on too few trees, and others commenced too late or
stopped too early in the season.

The intervals between the maxima ma}T be approximated in another
way. From one maximum of larvae entering bands to another should
be the length of the life cycle of the insect. The length of the stages
in the life of this insect vary greatly, and averages can be accurately
determined only b}r a great number of experiments. The observa-
tions of the writer upon the length of the different stages are not
so complete as could be wished, but w7ill serve to show the averages
approximately. The egg stage was found to vary from three to eight
days, with an average of about five days. The life of the larva outside
of the cocoon is from fourteen da}^s to twenty-five days, averaging
about twenty-one days. The time spent in the cocoon was found to be
from twelve to twent}r-eight days, averaging about twenty-two da}Ts.
The egg-laying period was observed to begin the second day after the
emergence of the moth and continue till the fourth day. Three da}rs
would probably be a good average. The total of these averages is
fifty-one da}^s, which time compares favorably with the interval
between the maxima of larvse entering1 bands.

Bui. 35, New Series, Div. of Entomology, U. S. Dept. of Agriculture.

Plate IV.

y ' j"y<' fi'i^

Fig. 1.— Piece of Bark, showing Moth just emerged, and old
Pupa Skins.

Fig. 2.— Band on which the Remains of 330 Cocoons were
counted.

17

By adding fifty-five days to August 27 (the average time in 1901 of
the maxima for the second generation), we should expect the maximum
of the third generation entering bands. At that date (October 19) no
such maximum appears upon the various records. It was noted in
1901 that none of the larvae which spun cocoons after September 1
transformed, but all wintered as larvae. In 1900 the corresponding
date was September 7.

Mr. McPherson observed the period of the greatest number of eggs
of the •first generation to be from May 10 to May 25. The writer
observed the same period of the second generation to be from about
July 13 to August 1. But when the time came for the Qgg period of
the third generation very few eggs were seen.

Observations were made daily in the orchards and the courses of
these generations were watched as carefully as possible. On account
of the variability of location of orchards and the overlapping of gener-
ations, observation is very liable to lead to error and can not be taken
as proof except in so far as corroborated by other evidence.

It has been often noted that many }^oung larvae enter the apples in
September. Whether these are the last of the second or the first of
the third generation is a question which has puzzled the writer. .But
few of these new entrance holes were observed at Boise last Septem-
ber and October, and the writer is inclined to believe that the larvae
were the last of the second generation. If there was ever a full third
generation, or a partial one, it should have occurred in 1901 by reason
of the earliness of the season.

Professor Gillette's article on the generations of this insect has been
carefully read. In general the writer's conclusions are the same, but
the3T are based on data of a very different kind. The writer can
not agree with Professor Gillette when he says that it is impossible
for a partial third generation to be produced. A study of the life
zones will show that we should expect some differences between the
life history of the insect in Colorado and the same in Idaho.

The writer confesses that on many points there is a lack of data,
and on this account does not wish to make the sweeping assertion
that there are only two generations of the codling moth in southern
Idaho. Whether or not there may be a partial third generation is
still an open question and one which can be solved only b}^ careful and
accurate work. This much, however, is reasonably certain: The third
generation is of little or no importance, whereas in the past it has been
regarded as a full brood.

All future work will be based upon the assumption that there are
two generations. It is hoped that next season's work will throw more
light upon these doubtful points and fully establish the facts.

With the knowledge that there is no fourth brood and no full third
£7341— No. 35—02 2

18

brood, the question of the control becomes easier for the Idaho fruit
growers.

OVERLAPPING OF GENERATIONS.

The overlapping of the generations is one of the conditions which
makes the control of the insect most difficult. In 1900, from July 7
to about September 7, the writer could find all stages of the insect.
In 1901 about the same conditions were noted.

According to Mr. Hitt's experiments, the moths in the spring of
1896 emerged during twenty-three days.

The overlapping renders the spraying less effective than it would be
if all the insects were in the same stage at the same time.

This overlapping is accounted for by the fact that some of the
insects, being in favorable situations, grow more rapidly, and others,
in unfavorable places, lag behind.

CAUSES AND CONDITIONS WHICH AFFECT THE NUMBERS OF

THIS INSECT.

There are many natural conditions which tend to decrease the num-
bers of this insect in the Pacific northwest. Comparatively few of
the eggs hatch. Infertility, excessive dryness, and the heat of the sun
seem to be the causes of this. In 1901 thousands of the young larvae
must have starved on account of not having apples to feed upon.

No insect parasites were noted in 1901. A bird belonging to the
creepers was noted at Payette. This bird was very active in hunting
food on the apple trees, and without doubt destroyed many codling-moth
larvae. Growers in this locality say that the bird is increasing in
numbers. Many pupa? were found to be dried and shrunken, evidently
killed by excessive dryness. In more humid sections bacterial and
fungus diseases kill many. But if these unfavorable conditions and
natural enemies alone are relied upon, almost every apple in an
orchard in badly infested localities will be wormy.

There are many reasons which may be assigned for the large num-
ber and the great destructiveness of the codling moth in Idaho. The
first and probably the most important fact in this connection is that
the second generation is more numerous than the first, and does a
larger part of the injury. This is doubtless due to the climate. It is
also more difficult to combat this second generation with sprays than
it is the first. The overlapping of the generation is another fact that
makes the spraying more difficult.

One reason for the great destructiveness of the codling moth in Idaho
may be found in the life history of the insect. .V great many of the
fruit growers have used remedies which are absurd. When the proper
remedies were used they were not used in the proper manner, and
hence failure resulted.

Bui. 35, New Series, Div. of Entomology, U. S. Dept. of Agriculture.

Plate V.

Fig. 1.

W

#M

&»*&&£*!

Fig. 2.

!

,"*"' '*''"' j *» uyyut.: -nfej*J*L

'>'•'

'^Jm£JE ' -^at -

.' \,

§?« -:■"

fr^g|

Hd^^^BE^HnEr^

otBH^B^H

L^V^^H^^Q

Fig. 3.

Views in Orchard of Hon. Edgar Wilson, showing Location of Apple House
in Relation to Orchard.

19

The absence of remedial measures, use of improper ones, and
improper use of suitable remedies have resulted in the abundance of
the insect, and have caused many to be discouraged and to have the
firm belief that the insect can not be controlled.

The presence of old, neglected orchards is a source of constant sup-
ply of the insect, and these orchards render control more difficult.

PREVENTATIVE MEASURES EMPLOYED AGAINST THE CODLING

MOTH.

There has been in the past an idea prevalent among the fruit
growers of the Pacific northwest that the codling moth can be exter-
minated. That idea is at present held by only a few. The writer
has always said that he believed it impracticable to entirely eradicate
this insect from a large area. In an isolated orchard there are strong
hopes that it can be done. Next season an attempt will be made to
exterminate the insect in I. B. Perrine's orchard at Blue Lakes.
This orchard is practically isolated and ail methods will be used.

The very best general result that can be expected in Idaho is to
control the insect so that its ravages will not exceed 10 per cent.

There are some localities in Idaho where the moth has not yet
appeared. By keeping all infested fruit and old apple boxes away
from these localities, immunity may be secured. In other localities
at high altitudes sudden freezes will sometimes reduce the numbers
of the insect to such an extent that it takes two or three years for it
to again become injurious. Fruit growers in these localities should
use the utmost vigilance, and, at the first appearance of the insect,
remedies should be applied and the insect exterminated if possible.

When the wormy fruit is picked in the fall, it always contains
larvae in different stages. This fruit is stored and the insects com-
plete their growth and spin their cocoons in the angles of the boxes
and in cracks in the building. In the spring, immediately after
emerging, the moths seek the nearest orchard. Where apples are
stored in great quantity the fruit on the nearest trees is all damaged.
Two well-marked cases of the results of storing apples were noted in
Idaho in 1900. In both cases the apples growing nearest the apple
house (PI. V) were all wormy. In one case they were evidently
infested in this way for about 5 rows toward the center and about 15
rows along the side of the orchard. In 1901 this place was still the
place of worst infestation in one orchard. These conditions may
easily be prevented by shipping the apples immediately after picking,
and destroying the culls. If the fruit must be stored, the windows
and holes of the storehouse should be screened. The moths will
collect at these screens and may easily be crushed, or, if the house is
so tight that they can not escape, they may be left to die.

Many fruit growers have committed a grave error in regard to the

20

crops of young orchards. The first crop is always small, and many
do not think it worth while to use means against the moth for that
season. The next season's crop is usually larger and always has a
large percentage of wormy apples. If, however, the grower had
destroyed most of the worms the previous season, the second crop
would have suffered bat little loss.

It has often been observed in Idaho that the apples in orchards in
which the trees were irrigated by flooding were less wormy than
those in orchards which are irrigated by ditches. Single trees or
blocks of trees in ground that is continually moist bear less wormy
fruit than those which are irrigated only occasionally. The only expla-
nation offered for these facts is that the larva will not spin its cocoon
in a moist place, and that moisture favors the diseases of the insect.

Whenever possible, the writer advises that the ground immediately
around the trees' be kept moist, especially when the larva? are spin-
ning their cocoons in greatest numbers. Care must be taken in doing
this, as too much water will eventually either serionsh' injure or kill
the trees.

The writer has noted many old, neglected orchards in various locali-
ties where no attempt was made to keep the insect in check. It needs
no explanation that these orchards furnish a constant supply of moths
to adjoining orchards, and in that way the loss in the orchard which
is well cared for is greater than it would be if both received good care.

In towns and cities many people have in their lawns apple trees
which also furnish a constant supply of the insects. These people
wish the trees for shade only and have no desire to raise fruit. The
writer has approached these people many times when the opportunity
presented itself, and showed them what they could do' to lessen the
difficulty. The people who desire apple trees for shade only could
easily destroy all the apples early in the season, and thus no damage
would be done.

REMEDIAL MEASURES EMPLOYED AGAINST THE CODLING MOTH.

To intelligently apply remedial measures necessitates as a first essen-
tial an accurate knowledge of the life history of the insect. With this
as a basis, any fruit grower may- adapt the measures employed to his
circumstances. It will readil}r be seen that there are certain periods
in the life of this insect when it is vulnerable, and others when it is
comparatively safe.

The few experiments which have been made against the insect show
that it is impracticable to undertake the destruction of the eggs.

MEASURES AGAINST THE LARV.^E.

A large majority of all the remedial measures that have been used
are against the insect in this stage.

21

Spraying.

Against the young larvae entering the fruit, spraying with arsenical
poisons is most generally used. The object is to place the poison in
such places that when the young larvae enter the apple they will get
some of the poison with the first few meals.

EARLY SPRAYINGS.

The best time to spray is immediately after the blossoms fall and
before the lobes of the calyx are closed. By spraying at this time the
open calyx forms an excellent place to catch the poison, and by the
closing of the lobes it is retained for some time. As before stated,
from 80 to 85 per cent of the larvae of the first generation enter by
the calyx. Many cases might be cited showing the efficiency of this
first spraying. One example will suffice: In the spring of 1901 the
writer examined two orchards, separated only by a road. One had
been sprayed thoroughly and other measures had been used ; the other
had not been sprayed, and no other measures had been used. From
the first generation about 10 per cent of the apples in the sprayed
orchard were wormy ; in the unsprayed orchard 25 to 30 per cent were
wormy. By connt it was determined that in the unsprayed orchard
83 per cent of the wormy apples had been entered through the calyx,
while in the sprayed orchard only about 10 per cent of the larvae
which entered by the calyx had escaped the poison.

On account of not being able to commence this work in the earl}T
spring, the writer was unable to make observations upon the hatching
of the eggs of the first generation. Mr. Hitt furnishes the following
data: In 1896 the first moths appeared May 5, and they continued to
emerge until May 25. He also noted that the apple trees were in full
bloom May 1. In 1901 the moths developed in advance of the
blooming period.

Mr. McPherson noted the appearance of the first moths April 23,
in 1901, and the first eggs May 10, which was about the time that the
blossoms fell from the Winesap, Jonathan, Golden and Ben Davis
varieties.

Investigators in different parts of the country have found that the
poison stays in the calyx and is effective for at least a week; hence,
the lateness of the moth offers no difficulty. Exactly what the moths
do between the time of emerging and egg laying still remains to be
studied in this locality. Professor Cordley has noted the same state
of affairs in Oregon, and thinks that the cool nights prevent the moths
from ovipositing.

The second spraying should be done about a week or ten days after
the first. This spraying is intended for late larvae of the first
generation.

22

In cases of very bad infestation, or if extermination is aimed at,
the writer would recommend a third spraying in this connection.

The writer has neglected no opportunity to impress upon the fruit
growers of the Pacific Northwest that the first spraying is by far the
most important remedial measure against this insect, and has gone
so far as to state as his belief that one good spraying when the calyx
is open saves more apples than all of the other remedial measures
together.

LATER SPRAYINGS.

The question of late sprayings is one of the points now under dis-
cussion among entomologists and horticulturists. The facts gleaned
from publications, letters, and conversations with those in the best
position to know are as follows :

Professor Gillette, of Colorado, writes that in Colorado there are
some fruit growers who advocate 9 or 10 sprayings, while others
say that they obtain just as good results with 2 or 3. Professor Gil-
lette says he has two cases in mind where as good results as one could
wish were obtained with only 2 sprayings. He says he can hardly see
how more than a slight benefit can be obtained by any spraying after
the second.

Professor Card, in his Nebraska bulletin, rather discourages later
sprayings.

Prof. M. V. Slingerland, in his bulletin upon this subject, states
that he can not see how the larvae get any of the poison from the side
of the fruit.

Professor Washburn, of the Oregon station, concludes that 2 or 3
sprayings will save from 70 to 80 per cent of the early apples, and
that 6 sprayings will save from 65 to 70 per cent of the winter apples.

Professor Cordley says that now he can obtain a much higher
efficiency.

The writer visited the orchard of Olwell Bros., Centralpoint, Oreg.,
and estimated their loss in 1001 to be 5 per cent from the codling
moth, and Mr. James Olwell told him that the loss was greater than
in 1900. Many other apple growers in southern Oregon are obtaining
similar results every year.

Mr. Gas Goeldaer, of Boise, Idaho, writes that by spraying he saved
98 per cent of Ids apples, and Mr. C. Hinze, of Payette, Idaho, reported
to the writer in 1900 that by spraying he had saved 95 per cent of his
apples. Instances of such results, however, must be regarded as
exceptional and may be deceptive, as account is probabl}T not taken
of the amount of fallen, wormy apples. It still remains to be proved
exactl}r what percentage of apples can be Scived by spraying alone
in badly infested localities.

This question of later spraying has become one of the most impor-

23

tant features of the control of this insect. The writer has made many
observations as to the efficiency of the spray. It is a common thing
in sprayed orchards to find places on the apples where larvae had
entered and, a day or two after entering, had died. This condition
was found to be much more frequent in sprayed orchards than in those
which were unsprayed. Without doubt these larvae were killed by
the spraying. Exactly how and when the larvae get the poison is a
question. As has been stated before, the larvae eat but little of the
skin or flesh of the apple while entering. The cavities in which they
are found dead are usually of such size that it would take the larvae a
day or two to make them. Particles of lime are sometimes found in
these cavities. While seeking a place of entrance the larva may get
some of the poison, and it may live a day or so after getting the fatal
dose. Some of the spray may get into the entrance hole and be eaten.

Soon after dying, the larvae become dry and shrunken and can be
distinguished only by the presence of the head.

The writer once noted a case where 70 cent of the larvae entering
in the course of two or three days were found dead. It is extremely
probable that a considerable part of them died naturally. Many
other observations were made, but never was such efficiency noted
again.

In many orchards that had been well sprayed, hundreds of these
spots were noted which had been caused by the larvae and upon exam-
ination no larvae were found.

In 1901 the writer found a larva which had begun an entrance hole
and had just died.

On account of these observations and the general results obtained
by spraying and banding, the writer has no hesitancy in recommend-
ing these later sprayings. Without doubt the efficiency is much less
than in case of the first spraying, but the writer believes them well
worth the expense.

The writer has found that many growers spray when they have
time and do not take into consideration the stage the insects are in.
Some spray every three weeks and others spray when they see the
number of entrance holes increasing. As already shown, the larvae
are entering more or less all summer; but at two certain periods of
the season there are many more entering than at other times. One
can easily see that the theoretically perfect time for spraying would
be when the larvae are entering the fruit in greatest numbers. It is
therefore essential to recommend simple, practical methods for deter-
mining this period of greatest entrance. The writer advises every
one who wishes to spray for the codling moth to keep a daily band
record on about 1 trees. By a study of this record the maximum can
be easily found. In the summer this maximum will be found some-
times between June 25 and July 15. By experiment we have found

u

that the maximum of egg hatching should occur twenty -nine days
after the time when the greatest number of the preceding generation
entered the bands. In the record made b}^ Mr. Gibson it will be
noted that the first maximum occurred June 26, and that by adding
twenty-nine days we get the date of Jul}" 26. As the maximum of
egg hatching extends oyer some time, spraying must be done before
this date in order to get those which are early. In this instance the
spraying should have been done between July 15 and August 1.
Observation in the orchard in which the record was taken showed
the period of greatest number of eggs to be between July 13 and
August 4.

The writer has never had an opportunity to test this recommenda-
tion thoroughly. Many practical tests were made, and the results of
these show that it is absolutely essential for highest efficiency to do
the sprajdng when the largest number of larvae are entering. The
writer would advise two thorough sprayings during this period.
Another rnay be made if infestation is bad.

MATERIAL FOR THE SPRAY.

It is recommended in every case that arsenical sprays be used for
this work. Paris green is most used in the proportions of 4 pound to
160 gallons of water with 2 pounds of lime. By the use of this solu-
tion excellent results are secured, but on account of its cost and liability
to settle man}T are abandoning it for the white arsenic compounds.

London purple is rarely used alone. Mr. Tiner, of Boise, and Olwell
Brothers, of Centralpoint, Oreg., are using a combination of Paris
green and London purple. Olwell Brothers use the following propor-
tion: Water, 120 gallons; Paris green and London purple, 9 ounces
each; and lime, 2 pounds. Mr. Tiner believes that in this way the
poisons are kept in suspension better. Such good results are obtained
that these growers are loth to adopt other compounds. White arsenic
compounds are being used more and more with results just as good as
those obtained with other arsenicals. Dr. H. P. Ustick, of Boise, and
Mr. C. Hinze, of Payette, have used them successfully. Information
as to the methods of making these spra}Ts have been published in Idaho
and the fruit growers are familiar with them.

As far as the writer can learn, lead arsenate has never been used as a
spra}T against this insect in the Pacific northwest. The writer believes
that it will be found excellent, and will use it in experiments next
season. There are a few fruit growers who use whale-oil soap with
the sodium arsenite. Many observations were made in connection
with the use of this mixture to ascertain if it caused the poison to
remain on the fruit longer. Without doubt this is the case, but the
soapy solution collects on the under sides of the apples and damages

25

them materially. In one block of Jonathans fully 50 per cent of the
clean apples had spots caused by the soap.

It is intended that future work will show exactly which one of these
arsenites is the most effective.

EXPENSE OF SPRAYING.

From the data given by the fruit growers it is found that spraying
is comparatively inexpensive. The material to spray 2,000 trees costs
about $5. Orchardists always have teams and men already employed,
so that the extra expense on account of spraying is very small com-
pared with the benefit. By the use of a gasoline-power outfit the work
can be done much more quickly, and, in a large orchard, with less
expense in the end. When quickly done the cost should be less than
1 cent per tree per spraying. If inferior appliances are used, or the
trees are larger than the average, the cost will be greater. Labor is
the most expensive factor in spraying.

Picking and Destroying Wormy Fruit.

While the larvae are feeding in the apples, these may be picked and
destroyed. This is especially recommended as an effective remedy for
use early in the season. As has often been shown, thinning the apples
to 4 inches apart produces a finer quality of fruit and causes the tree
to bear well each year. It is strongly recommended that in Idaho,
between June 1 and 15, the fruit be thinned, and that in thinning all
wormy apples be removed and destroyed. The writer believes it well
worth while to thin apples in order to kill the codling-moth larvae,
without considering the other advantages. Picking and destroying the
wormy apples during July and August is too expensive to be of any
great value in a large commercial orchard.

In order to get best results, orchards should be cleared of all wind-
falls as promptly as possible, so that the worms contained may be
destroyed. In some small orchards it is the practice to allow hogs to
run in the orchard and pick up the windfalls. It would be an almost
endless and expensive undertaking to pick up and destroy the wind-
falls in a large orchard ever}^ day or two. The writer does not think
it worth the expense if the proper precautions are taken in the use of
the bands.

The cheapest and most effective way to get rid of culls, windfalls,
and the apples picked in thinning is to buiy them. Water should be
allowed to run into the holes, and not less than 10 inches or a foot of
earth should cover the fruit. If the earth is in clods, it will be well
to pack it. Many observations were made during the season of 1901
to ascertain the effect of burying in this way. In many cases the larvae
succumbed to diseases induced by the moisture. Most of them spun

26

cocoons at the surface of the apples, but the moths were unable to
escape. Larvae put in the earth remain a longer time in the cocoon
than they otherwise would.

Banding.

When the larvae leave the apples and seek a place in which to spin
their cocoons another point of attack may be taken advantage of by
furnishing a suitable place for the spinning of the cocoons and by kill-
ing the worms after they have entered the place. This object is accom-
plished by placing cloth bands from 8 to 10 inches wide around the
trunks of the trees. If the trees are large, each of the larger branches
may also be banded. The bands may be made of any heavy fabric,
such as burlap, old clothes, old carpet, etc. The band should be folded
once lengthwise and placed around the trees about 1^ to 2 feet from
the ground. After placing the band around the tree, a small nail
should be driven through the ends firmly into the tree. The head of
the nail should be nipped off. Subsequent removal and replacing of the
bands may be done more quickly by this method of fastening.

The number of worms caught under these bands is sometimes aston-
ishing. (PL IV, fig. 2.) It is quite common to find, during a maximum
period, from 50 to 100 each week for two or three weeks under the
band on a single large tree. The highest number Professor Aldrich
records as caught on one tree from July 7 to October 15 is 191. Under
neglected bands as inairy as 200 have been found at one time. It is
found in orchards that have been sprayed and banded that, in Septem-
ber or the first part of October, the worms are very scarce, thus in a
way showing the efficiency of the methods.

Apparently banding is one of the most effective methods, and there
are two highly essential features that can not be emphasized too
strongl}T: (1) All places suitable for spinning cocoons other than bands
must be removed or rendered unsuitable. The loose bark should be
scraped from the tree, all holes and cracks in the trees should be filled
with mud or cement, and the earth around the trees should be kept
moist during the periods when the worms are most numerous. (2) At
regular intervals the bands must be examined and all the larvae and
pupae killed. The interval between examinations of the bands recom-
mended heretofore has been six or seven days. During the summer
of 1901 the writer, by numerous experiments and observations, found
that every ten or eleven days is often enough to kill the worms. This
extension of time between the changing of the bands reduces the cost
of banding considerably, as instead of 11 or 15 changes of bands there
is need of only 10 or 11.

Many methods have been devised for killing the larvae, but the most
rapid and effective is either to crush them or cut them in two with a
knife.

27

At the suggestion of Hon. Edgar Wilson the writer again experi-
mented with Paris green in and under the bands to find whether or not
the worms would get any of the poison and be killed. Five bands
were thoroughly soaked in a strong solution of Paris green and a
large quantity of the dry poison was dusted on 10 others. These
were placed upon trees and examined every day or two. Mot a single
larva was found dead. Many were found to have spun their cocoons
in the poison which was laying in the crotches of the trees.

Bands should be placed upon the trees not later than the middle of
June and should not be finally removed until about a week after the
crop has been harvested. By a close watch on a few bands one can
tell when the worms begin to descend in the spring. After the first
week in September it is found that very few, if any, larvae change to
pupae and emerge. It is not advisable to let any bands stay on the
trees all winter, as they rot, and the cost of bands is a considerable
item in a large orchard.

Many fruit growers believe that under favorable circumstances they
can save almost half their crop by banding alone.

It is strongly urged that, late in the fall, during the winter, or early
in the spring, the orchard be examined, and all the larvae found in
crevices and under the bark of the trees killed.

MEASURES AGAINST THE ADULT.

TRAP LANTERNS.

Considerable effort has been made to put the facts about trap lan-
terns before the Idaho apple growers. The agent for a patented trap
sold 240 in Boise and vicinity. He claimed that he caught 6 codling
moths in one night. A majority of the growers who bought these
traps found out for themselves that this method is useless. A very
few still advocate its use. The writer did not think the method worthy
of experiment.

BAITING THE MOTH.

One fruit grower at Mountainhome uses buckets of cider or vinegar,
with which he says he catches large numbers of codling moths. Dr.
Riley's experiences show that these catchings must have been acci-
dental. The writer set out some of these cider buckets and in two
weeks while the moths were flying caught but few. The notes on the
experiment were misplaced, but the writer remembers that about 10
codling moths were caught and many Noctuids. At best the results
of the method would in no way be commensurate with the expense.

iu£stjm:e and conclusion.

As has been before stated, the codling moth can not be exterminated
throughout the Pacific northwest. Reduction of the damage with

28

least expense has been the object in view. The writer believes that
by the intelligent use of the methods herein given the moth can be so
well controlled that the injuries will be between 2 and 10 per cent.
With the insect under control, it will not be necessary to use all of
these measures every year.

The writer has never had the opportunity of putting all of these
recommendations into practice in one orchard. This would have been
done had it not been for the freeze of 1901. Advice was given many
times as to the treatment of orchards and the results were noted as far
as possible. Some of the successes are here given:

M. A. Kurtz, Nam pa, Idaho, has an orchard of about 2,500 trees,
many of which are stunted partly on account of lack of care. In 1898
there was less than a full crop, about 50 per cent being damaged; in
1899 there was a full crop, but only 100 boxes of clean apples were
harvested. In 1900 there was about one-fourth of a crop, and all were
wormy. In 1901 Mr. Gibson, in charge, began good cultivation, spray-
ing, and banding. There was probablj- over a half crop. The trees
were all sprayed with Paris green four times, and a majority of them
a fifth time. Bands were well attended to. The writer visited the
orchard frequently during the season, the last visit being made the
latter part of September, when the fruit was estimated to be damaged
as follows: Ben Davis, 5 per cent; Steele's Winter Red, 10 per cent,
and Blue Pearmain, 25 per cent. A few Ben Davis trees showed 10
per cent of damage. A large amount of the fruit was undersized.
The writer could not get figures after the crop was harvested, but he
believes the work done against the codling moth was quite successful.
The only cause of uncertainty was the fact that the crop was small
the year before, and the insect might possibly have been reduced
on this account.

Hon. Edgar Wilson has an orchard (PI. V) near Boise, containing
about 1,000 trees, about 2,000 of which were bearing. There was a
light crop of Jonathans and about one-half crop of Ben Davis. Only
the earty sprayings were made, and they were well done. Bands
were well attended to. The later sprayings were not made, and the
bulk of the injury was done by the second generation. Not over 10
per cent of the apples in this orchard were free from worms. In 1900
from 85 to 90 per cent were saved.

Mr. Tiner, of Boise, has about 100 trees, in a badly infested locality.
Spraying and banding were well done, but only about 30 per cent of
the fruit was saved. In 1900, 80 per cent was the amount saved.

The losses in many other well-treated orchards with small crops
varied from 20 to 80 per cent. In those orchards where the loss was
higher only partial measures were used. In untreated orchards in
badly infested localities the loss was always about 100 per cent. The

29

reason of these excessive losses, even when the best measures were
used, may be accounted for by the fact that the freeze killed a large
percentage of the fruit, while the moths survived.

01 well Brothers, of Oregon, spray every three weeks during the sea-
son, and the writer examined the orchard in October and estimated
only 5 per cent loss from the codling moth.

The writer feels grateful to the Idaho growers for the way they
have adopted his recommendations. Plans have been partially made
for next season's work. In general, the plans are to select one or two
typical badly infested orchards and there apply remedial and pre-
ventive measures to demonstrate exactly what can be done against the
insect. The writer has no fears that the results will not substantiate
all that is claimed for the remedial measures.

O

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(J

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of Entomology and Plant C