THES IS

Life History, Habits, and. Control of the Indian Meal Moth Plodla interpunetella Hbn., Order Lepid.optera, .

Submitted to the OREGON AGRICULTURAL COLLEGE

In Partial Fulfillment of the Requirements

For the Degree of

MASTER OF SCIENCE

by

Guy R. McGinnis

May 10, 1928 APPROVED: Redacted for privacy

7 F __

In Charge o ajor

Redacted for privacy

Dean of Soho cl of ______

Redacted for privacy

Chairman of Committee on Grad.uate Sti.uly. ACKNOWLEDGME1TS

The writer wishes to express his appreciation for the assistance which was given him in the preparation of this thesis by Professor Don C. Mote, Professor E. H.

Wiegand, Professor 'vi. J. Chamberlin, Professor H. A.

Sciillen, B. a. Thompson, Joseph Wilcox, and Oren A.

Hills.

Professor Mote suggested. the subject and supervised all the experimental work. He was always ready to give information and offer suggestions which the writer many times needed.. Professor Wiegand furnished all the in- formation which was used regarding the methods of prooessiri and care of prunes. Professors Chamberlin and Scullen gave much valuable information in the way of suggestions and criticisms which the author used. freely. Thompson, Wilcox, and Hills assisted in the preparation of the pb.otographe and also gave a&anY useful suggestions on the work in general. TABLE OF CONTLNTS.

Page Contents

1-- Introduction Injury and. losses

2-- Reasons for undertaking problem 3-- Prune Processing

4-- Economic history and distribution 5-- Distribution Hosts

6-- Synonymy Parasites Classification

7-,- Description

8-- Life history and habits

lo-- Table I, Time required for egs to hatch

11-- Life history chart Life history discussion

13-- Table II, Emergence and te:uperature records Table III, Emergence records

16-- Description of adult

17-- Description of

18-- Description of pupa 19-- Control measures Heat experiments

20-- Table IV, Results of dry heat tests Hot water tests

21-- Table V, Results of hot water tests

22-- Discussion of hot water tests Page Contents

23-- Penetration of temperature within the prune Table VI, Time required to raise temperature within the prune to 120 degrees F.

24-- Penetration of heat into bunches of prunes Table VII, Time required to raise temperature of bunches of prunes to 120 degrees F.

25-- Heat experiments on larva and pupa Discussion of heating results

26-- Infestation of boxed prunes

27-- Fumigation with carbon bisulí'ide

28-- Table VIII, Results o± carbon bisulfide fumigation. Discussion of fumigation results

29-- Control recommendations 32-- Summary

35-- Photographs

38-- Bibliography Life History, Habits, and Control of the Indian Meal Moth Plodia interpunctella Hbn., Order , Family Pyralidae.

The Indian Meal Moth, Plodia interpunctella, Hbn.,

is the worst which the prune packers have to contend with in Oregon. It is distributed throughout the state and. is a probi m wherever prunes are handled.

Although the actual loss to the prune industry has never been estimated, it would undoubtedly be thousands of dollars. A conservative estimáte of the infestation of boxed prunes is 2% to % early in the season which gradually increases to 10% later in the year. Several times entire carloads of prunes have been sent back to be reprocessed to clean up the infestation which was found in them. The infestation may occur after the prunes are packed and ready for market or it may occur before the prunes are packed and go through the processor into the boxes.

Injury and Losses

This insect is one of the most destructive of the stored product pests. It is found in mills, storage houses, stores, homes, in fact every place where food i kept for any length of time. The larvae eat out the embryo of grains making them useless for seed purposes, and as a destroyer of nuts and dried fruits, it has no equal. The loss is not ue alone to the quantity oÍ food. eaten, but also to the web and. excrement which the larvae leave behind wherever they go, imtil the material

is an unsightly mess and. not fit for human food.

The actual financial loss to all stored. products due to this insect has never been estimated. The only estimate I have seen was by C.H.Popenoe, (103) who claimed that there was a 20% damage to the peanut crop

in 1910, which would be three million dollars. The losses to the prune packers of the state would be hard to estimate, because they occur in several places.

There is a loss due to infestation before packing, another on refunding or replacing infested, boxes, and that of dissatisfied customers who have received infested goods.

Reasons for Undertaking Problem.

The object in undertaking this problem was to determine how and where prunes, that have been processed and packed, become infested with the Indian Meal Moth, and how this infestation can be prevented.

Since the processing of prunes usually req,uires a temperature high enongh to kill all , and the boxes are assumed to be tight enough to prevent their entrance, the problem resolves itself into a study of the life history and habits of the different stages of 3 the insect, and temperature and fumigation experiments

in order to determine the most practical method of preventing the infestations.

Prune Processing

Since the method of processing prunes and the control of this moth are intimately related, a short account of tÌis method will enable one to understand the following work better.

The processing, grading, and packing of prunes is a specialized industry separate and distinct from the growing and drying industry. Although the varieties of prunes differ in districts, the packing methods are the same.

Dried prunes received at the packing houses are first sampled and graded. The grading is done with a vibrating screen which has circular openin's of different sizes. They next go on to a screen which removes dirt, leaves, and stems, and are then ready for the processing.

There are two methods of processing prunes. ith one method, the prunes pass through hot water in per- forated buckets, with the other they pass over a vibrating conveyer while jets of steam are forced upon them. The time required in both cases is from one minute to a minute and a half. Processing cleans the 4 prunes, destroys insect life, and renders the prunes

soft and pliable and gives them a glossy appearance.

The fruit gains in weight about six to eight per cent by the absorption of water.

The prunes are packed directly from the processer without cooling or drying in boxes of different sizes which are lined with paper. The hot fruit is put into

the boxes by weight, pressed flush with the top, and the cover nailed on at once. The boxes retain a high temperature for several hours after packing.

Economic History and Distribution

Plodia interpunctella Hbn. was described by Hubner

(55) in 1827, and from then until 1858, all the articles on the moth were written in Europe.

Guenu established the genera Plodla in 1845 using interpunctella as the type.

In 1858 Asa Fitch (43) described the moth and called it Tinea zeae Fitch, and gave it the common name in use today, Indian Meal Moth. The next time it received attention was a short description by Clemens

(28) in 1860. He called it zeae. Walch (147) was the next American to publish anything on the moth and in an article, The Peach Worm, was undoubtedly referring to dried peaches as the host. Riley published two articles, one in 1870 (111) on Bee Bread Devoured by 5

Worms, and Worms Infesting Meal Sacks, in 1880 (112).

Riley and Howard wrote a number of articles on Plodia

interpiinctella Hbn. which were published in Insect Life

(113-119). There was quite a controversy at that time

with the European writers over the identity, and how to

distinguish Plodia interpunctella Hbn. and phestia

ku.ehniella Zeller. Riley and Howard undoubtedly

convinced the European writers they were wrong for the

name Plodia interpunctella Hbn. is now firmly

established. Since 1890, there has been numerous

articles, circulars, and bulletins on the moth in which

it has been grouped with the other stored product pests.

Distribution.

Distribution of the pest is world wide because it

is carried to all ports of the world in foods. It has been mentioned from every place in the world where

there has been any entomological writings.

Hosts.

The larvae have a wide variety of hosts. They include: all cereals and their milled products, all dried fruits, dried vegetables (59), seeds, (21), candy

(especially marshmallows (65) and chocolate (103), nuts (40), drugs (such as dried vegetables and roots)

(29), honey comb (111), museum specimens such as plants and, insects (29), spices (48), sugar (118), yeast cake

(48), dried, bark and, roots (48), peanuts (103), woolen

cloth (118). The writer has taken it in prunes, and

English walnuts and has reared the insect in prunes,

English walnuts, wheat, and, corn.

Synonymy.

Ephestia interpunctella Ragonot, Ephestia

elutella H'bn, Tinea zeae Fito., and, Tinea granella

Walker. The synonyms have been few and they were all used previous to 1890.

Parasites.

Habrobracon hebector Say (H. juglandes Ashmead), a

Braconidae, is the only parasite that has been mention- ed. De Ong (37) says that it is a very efficient worker and confines its activities to the stored product pests.

Classification.

Plodia interruncte1la Hbn. is a menber of the family Pyralidae, sub-family whose distinguishing characters are: narrow long forewings which are banded or mottled with shades of gray or brown. In this subfamily there is a fringe of long hairs on the part of vein Cu of the hind wings; the radius of the forewings is only four-branched; and 7

the frenulum of the female is simple. The subfamily has more than 300 described, from our fauna.

Description.

Labial palpi and head reddish fuseous; thorax dark fuscous, with a reddish shading; abdomen ochreons; forewings yellow ochreous with a few scattered black scales to basal line; this line is well out from the base, black, broad, with uneven edges, but with generally even rounded course from costa to inner margin; narrowly edged with ochreous outwardly, then wing reddish brown outer margin; middle field costally heavily sprinkled with blackish, which is broken by the somewhat large, oval, yellow, ocher discal spot; outer line black, mixed with gray scales, not very distinct, parallel with, and near the outer margin. Hind wings shining light fuscous. (By Hurlst, Geo. D. 62).

Popular Description

Adult moth when at rest measures 9.5 mm to 12 mm in length, the wing spread is from 12 to 19 mm. In color they appear brownish with the outer two thirds of the forewings reddish brown with irregular bands of' blackish scales, the inner one third a light gray.

The abdomen varies from a dark brown to a dark gray.

The palpi project beak-like, or are porrected, which b

sometimes gives them the name of snout moth.

The larvae when first hatched, measure about one

millimeter in length, and are a dirty white, or a pale

greenish yellow color, with dark head. When mature

the larvae measure from 12 to 14 min., are cylindrical

in form, largest in the middle tapering to both ends.

The head and thoracic shield are dark brown, and the

entire body is sparsely covered with long slender whitish hairs.

The pupa are a brownish color and measure from 6

to 8 mm. In length. The eyes are very prominent, the wing pads extend almost to the sixth abdominal segment.

The eggs are creamy white ïn color, flattened, and ovoid in shape. They measure 0.5 mm. in length by 0.3 to 0.35 mm in width. They are soft and easily crushed.

The surface is slightly ronghened..

Life History and Habits

The following life history information was secured by rearing individual insects in glass vials, groups of from 10 to 20 Insects in glass jars, and large numbers of insects in boxes. Prunes were placed in all the receptacles to give the Insects as nearly as possible, natural conditions. During fall and winter, observa- tions were made daily. The adults used for the records were caught In the different containers and kept in 9

glass jars. High and low temperature records were

recorded, except during sunmer, from three different

places; the laboratory, the store room, and. the green- house. The observations and records of this began

October 1, 1926 and ended April 1, 1928.

Life History.

The winter is passed as larvae always active under laboratory temperatures of 50 to 70 degrees F., and I

think this would also apply to storage conditions in

Oregon where temperatures were equivalent to those in the laboratory. They pupate when the warmer weather begins, usually March and early April. he pupa stage lasts from 10 to 22 days, depending on the temperature.

The emerged moths are not very active the first day, but they usually have laid eggs the following morning, especially if fertilized. Unfertilized females extend the preoviposition period to two and three days.

The egg stage is from 6 to 14 days depending on the temperature. Eighty eggs were used to determine the length of the egg stage. On January 2, 40 eggs were placed near the radiator in the laboratory where the day temperature avereged 90 degrees F., and. 40 were placed in the store room where the day temperature averaged 6 degrees F. The following table shows the results. Table I lo

Time Required. For Es To Hatch In Different Temperatures

Store Room Laboratory

Date No. hatched. Date No. Hatched. 1928 l98

Feb. 3 3 Jan. 31

Feb.4 4 Feb. 1 8

Feb. 5 6 Feb. 2 10

Feb. 6 10 Feb. 3 12

Feb. '1 10 Feb. 4 8

Feb. 8 3

Four failed to hatch Two failed to hatch.

The above table shows the difference in the time required for eggs to hatch with a difference of 24 degrees F. day temperatures. Six days was the shortest and ten days was the longest time required with a temperature of 90 degrees F., while eight days was the shortest arid fourteen days was the longest time required with a temperature of 66 degrees F.

The young larvae emerge from the egg through a circular opening which they make ïn the end of the shell and apparently begin feeding at once. In a few days web is noticed scattered over the food. These larvae apparently are mature in from 60 to 90 days but continue il

feeding until August or early September, pupate, and. the

second generation of moths emerge the last of September.

Life History Chart of Two Generations

a Year with Temperatures

from 50 to 75 degrees F.

:Jan:Feb:Mar:Apr:May:Ji.m:Jul:Aug:Sep:Oct:Iov:Dec;

Adults :

:Eggs :

:Larvae: : : :

Pupa :

ti. st. .1....Larvae ..S

:Pu.. : : : : : : :

First generation ...... Second generation

Life History Discussion

The above life history of two generations a year

applies only to laboratory conditions with pruxies as the host, and temperatures ranging from 50 to 75 degrees F.

A few moths emerged during January and February

1926 from prunes that were placed near a radiator where

the temperature was about 90 degrees F. for eight hours during the day. Others that were in a maximum tempera-

ture of 75 degrees F. began emerging March 10. During

the winter of 1926-27 no moths emerged from September

26 to March 30. This indicates that temperature is a

determining factor in the date of emergence, but whether

it would influence the number of generations a year was not determined because the larvae are still active.

From observations made where different hosts were used, apparently the host has some influence on the number of generations. On January 2, 1928 thirty full grown larvae each were placed in a box of prunes, corn,

English walnuts, and wheat, which were all kept under the seme temperature conditions of 90 degrees maximum and 50 degrees F. minimum. The actual age of the larvae was unknown, but their size indicated full growth. On

February 29th, the following observations were recorded: nuts, 20 adults had emerged, 4 pupa; corn, 6 adults emerged, 3 pupa; wheat, 4 pupa, no adults emerged; prunes, 1 pupa, no adults emerged. Because of the short duration of these tests, and the nearness to the spring emergence, they are not a true indication of what would hapDen over a longer period of time, but they do

Indicate the possibility of a variable life history with different hosts.

The following tables suggest that temperature might 13

regulate the number of generations a year. Most of this

variation takes place in the latent prepupal period..

Table II

Emergence and Temperature Records

From September 25, 1927 to March 15, 1928. Temperature

Laboratory:

MInimum 54 to 64 degrees F. Average 58 degress F.

Maximum 82 to 90 degrees F. Average 86 degrees F. Store Room:

Minimum 51 to 60 degrees F. Average 56 degrees F.

Maximu.m 66 to 7 degrees F. Average 70 degrees F. Greenhouse:

Minimum 55 degrees F., Maximum 76 degrees F.

Average 65 degrees F. Greenhouse temperature

records taken from December 15, 1927 to March 15, 1928.

Table III

Emergence Records. Store Room Emergences.

Da t e Number of moths emerged.

Sept. 30, 1927 1 Last emergence of moth

March 10, 1928 1 First emergence of moth

March 12, 1928 i moth emerged. 14

Store Room Emergences Continued.

Date Number of Moths emerged.

March 16, 1928 2 moths emerged

March 19, 1928 2 moths emerged

March 20, 1928 1 moth emerged

March 23, 1928 4 moths emerged

March 26, 1928 3 moths emerged, many pupa

and larvae f oi.md.

Laboratory Einergences:

Sept. 25, 1927 1 Last emergence of moth

Jan. 4, 1928 1 First emergence of moth

Jan. 8, 1928 1 moth emerged

Jan. 13, 1928 1 moth emerged

Jan. 19, 1928 1 moth emerged

Jan. 23, 1928 2 moths emerged

Jan. 24, 1928 6 moths emerged (Came from

larvae used. in fumigation

tests)

Jan. 25, 1928 2 moths emerged (came from

larvae used in fumigation

tests)

Jan. 26, 1928 1 moth emerged

Jan. 30, 1928 2 moths emerged

Feb. 4, 198 1 moth emerged lb

Laboratory Emergences Continued.

Date Iumber of Moths emerged

Feb. 7, 1928 1 moth emerged

Feb. 11, 1928 2 moths emerged

Feb. 14, 1928 2 moths emerged

Feb. 16, 1928 1 moth emerged

Feb. 20, 1928 1 moth emerged

Feb. 22, 1928 3 moths emerged

Feb. 23, 1928 1 moth emerged

Feb. 26, 1928 2 moths emerged

Feb. 28, 1928 1 moth emerged

Mar. 1, 1928 2 moths emerged

Mar. 3, 1928 3 moths emerged

Mar. 4, 1928 1 moth emerged

Mar. 7, 1928 3 moths emerged.

Mar. 9, 1928 1 moth emerged

Mar. 12, 1928 1 moth emerged

Mar. 14, 1928 2 moths emerged

Mar. 15, 1928 1 moth emerged

Mar. 18, 1928 1 moth emerged

Mar. 20, 1928 3 moths emerged

Mar. 21, 198 2 moths emerged

Mar. 23, 1928 2 moths emerged

Mar. 26, 1928 3 moths emerged, many pupa

and larvae found. l)

Greenhouse Emergences:

Date Number of moths emerged.

March 15, 1928 moths emerged, first

emergence.

Larvae that were used in fumigation and heating

tests all pupated much earlier than did the larvae not

so treated. Apparently the fumigation and heating process caused the larvae to pupate sooner for all

pupated in 8 to 12 days after treatment while the larvae

in the controls were still active two months later.

The Adult.

The adults live from 5 to 10 days and are nocturnal in habits. When conditions are normal, egg laying

Occurs mostly at night or in darkened places. The actual egg laying at night was not observed but on numerous occasions when newly emerged females were placed with males during the day no eggs were found at

5:00 p.m. while eggs were found at 8:00 a.rn. the next morning. The rate of oviposition was difficult to determine, but the moth would. travel over the prunes with the ovipositor bent down stopping regularly to expel an egg. This would continue until 10 to 20 eggs had been laid when it would rest for an hour or two and. then repeat the egg laying. Most of the oviposition occured the first three or four days. They are credited 17 with laying from 300 to 4CC eggs, but my count for 18

females was from 60 to 210 eggs, or an average of 160

each. Copulation takes place but once, and they

apparently take no food.

The Larvae

The larvae require from 60 to 90 days to attain

full growth, Like the adults they are nocturnal in habits, always working between or underneath the prunes away from the light. They were active all winter under

laboratory temperatures of 50 degrees F. minimum at night and 70 degrees F. maximum during the day. They are capable of hibernating for a period of two months,

the longest I kept them, but can undoubtedly exceed that time. All materials are webbed together, and the larvae feed most of the time inside this mass. On prunes the web Is on the outside webbing frass and other loose materials together. They spend most of their time in- side of holes they bore in the prunes. The larvae can extend the prepupal period for several months, or long enough to allow only one generation a year.

Wilson (145) claimed that the larval instars varied greatly even with the same conditions of temperature and food. He found that the entire period ranged from 40 to 80 days with an average of 60 days. In all, the larvae molt six times. The first instar required from 9- to 16 or more days; the second 7 to 10 or more;

the third 4 to 9 or more; the fourth 6 to 14 or more;

the fifth 6 to 12; the sixth 8 to 18 days.

The writer made several attempts to determine the length of the instars but always failed. The failure might be due to the larvae crawling inside the prune to cast their skin or to the similarity in color of the head capsule and prune which made them difficult to see.

The Pupa.

After attaining its growth, and with favorable conditions, the larvae prepares a pupal cell of finely woven web. They lay dormant in the cell for from 1 to

10 days before any change is noticed. The first signs of a change is the swelling of the larvae until the segments, and folds of the skin are aLaost indistinct.

The color then begins to grsduaily change to a brown, and the wing pads begin to show, this change continues until the pupa is an even brown color with prominent eyes and wing pads. his change requires about two days. About thirty six hours before emergence the wing pads, thorasic segmerts, and the head turns black, and a black line appears on the dorsal surface of the abdomen.

This line gradually broadens until the whole pupa is black, and in a few hours the pupal case is split and the adult emerges. CONTROL MEASURES

Heat Experiments

Since hot water is used, in the processing of prunes one of the most logical methods of control of the Indian

Meal Moth would be to make the temperature of the water high enough at this time to kill all stages of the insect. Then, if infestation caine later it must be from other sources.

Experiments were run with both moist and dry heat to determine what the minimum death temperatures were at different lengths of exposure.

Tests with dry heat were run to deterLine the killing temperatures at one, fifteen, and thirty minutes. The insects were placed in glass jars with prunes. About 40 larvae and two pupa were in each jar.

A definite number of larvae could not be used because there were always a few inside the prunes that were not counted. Two series were run, all in duplicate, one using an electric oven heat, the other using water as the heat medium with jars immersed.

Temperatures were taken inside the jars, and it required about thirty minutes to reach the miximum temperatures. The reactions of the insects in both cases were the same. When the temperature reached 100 d.egree.

F. they became uneasy and began moving around, and those 20

inside the prunes came out. At 110 degrees F. they

began getting frantic and making every effort to escape.

At 118 degrees a few apparently were dead. The temper-

ature was held at 120-121 degrees for 30 minutes. All

the insects were dead and none revived later.

The next temperature was at l22-l3 degrees. The

time duration for this was fifteen minutes.

The next was 125-126 degrees F. at one minute

exposures. These results were obtained with a rising

temperature that drove the larvae from the inside of

the prune. The lower time of one minute might not be

sufficient in case a one minute exposure was made when

the larvae was webbed inside where the heat would not reach it at once.

Table IV

Results of Dry Heat Tests.

Number: Maximum : Time exposare : Results

Larvae: Temperature : to Max.Tenap.

42 : 120 F : 30 min. : All dead

44 : 122-123 15 min. : All dead

45 : 125-126 : i min. : All dead

Rot Nater Tests

These experiments were made by immersing infested prunes in water, under conditions similar to those to which the insects are subjected in the processing of prunes.

The work was begun with the idea of finding the

temperatures that would kill all stages of the insect

in the three time limits of one minute, thirty seconds, and instantaneously. One minute was used as the maximum time requirement because prunes are subjected

to at least one minute of heat while being processed.

Twelve larvae were used in each test. They were placed on prunes in a wire container which was immersed

In water of the desired temperature. The tests were run four times and the largest amount of living larvae founc at each temperature Is recorded in the following table.

Table V

One Second Exposure

No. Larvae : Temp. of Water Dead: Alive

12 118 degrees F. 8: 4

12 120 lo E s

12 123 " IT 11 1 j

12 126 12 O j

12 130 TI 12 O Thirty Second Exposure

No. Larvae Temp. of Water : Dead Alive

12 : 118 degrees F. : 8 4

12 : 120" 11 1

T! 12 : 123 " :11 1

11 12 : 12611 :12 0

" 12 : 130" :12 :0

One Minute Exp o sure

No. Larvae : Tern p. of Water Dead : Alive

12 : 118 degrees F. 11 1

T, TI 12 ; 120 i 12 i

n 12 : 123 12 0

T, n 12 : 126 12 0

¡

IT 12 130 i 11 1

Discussion of Hot Water Tests

The above work showed that larvae in contact with water at 120 degrees F. were dead in one minute, and

that 130 degrees F. would kill instantly, but tiere are

times when they are cemented in with frass and web so

that the heat failed to reach them in the short time

allowed. The extreme case found was where a larva was

alive after being subjected to 130 degrees F. for one minute. 23

Penetration of Temperature tiithin

The Prune.

The results in the above tests showed that the

procedure would have to be changed to get constant heat figures to cover all situations. So, taking 120

degrees F. as the death point of larvae in contact with water, a figure which was established in the above

tests, a series of' experiments were run to determine

the time required for different temperatures to penetrate to the inside of the prunes. The following

table shows the results of these experiments.

Table VI

Results of Hot Water Experiments.

Temperature Time required to raise

of water. . temperature of prunes

: to 120 degrees F.

120 degrees F. : 15 minutes

130 " 8- minutes

140 " 6 minutes

l0 " " 2j minutes

" 160 t, i minute

Fifty prunes were used in each of the above tests.

They were separated so that all surfaces had contact with tue water, and the temperature was taken on the inside of each individual prune, and the lowest tempere- 24

ture recorded was used for that length of time. In

most cases the temperatures were fairly constant, except

when the skins were broken allowing the water to

penetrate quickly.

Penetration of Heat Into Bunches

of Prunes.

This series of tests were run to determine the time

reQuired for heat to penetrate bunches of prunes which

were cemented together. The bunches were about three

inches in diameter, and four bunches were used in each heat given in the table. They were left in the water until the middle of the bunch reached a temperature of

120 degrees F. Because of the difference in the com- pactness of the bunches, and the difficulty in finding

the coldest place, the results in the following tables are only approximate.

Temperature Time required to raise of Water temperature of bunches to 120 degrees F.

120 degrees F. 30 minutes

130 " j 24 minutes

140 " " l minutes

" 150 " 12 minutes

160 " 8 minutes " , £5

Heat Experiments on Eggs and Pupa.

Eight pupa which were in cocoons attached to prunes

were subjected to a temperature of 120 degrees F. for

one minute. They were then taken out and placed in

separate vials. They were evidently killed by the heat

as no moths emerged. Controls taken from the saine box

and placed in the same location all matured and moths emerged.

Three lots of twenty eggs each were selected from glass jars where they had been laid the previous day.

They were placed in water of 120 degrees F. for one minute, then taten out and returned to the ssme contain- er where there were other eggs that had been laid at the same time. Al]. of the heated eggs failed to hatch, while ninety percent of the controls hatched.

Since eggs and pupa are always on the outside of the prunes, they will always be in contact with the highest temperature while the prunes are being processed and will,undoubtedly,all be killed.

Discussion of Heating Results.

The preceding experiments were carried out with the idea of making them conform as nearly as possible to the actual conditions to which the insects wuuld be subject-. ed. while the prunes were being processed. Each experi- ment was run with care and duplicated a number of times to eliminate all possibilities of mistakes.

The rate of penetration and. time required to raise

the temperature in a single prune was constant enough

to give accurate results, but the rate of penetration

and. time required to raise the temperature in the

bunches was so varied that the temperatures recorded

cannot be relied upon to always kill the insects.

Infestation of Boxed. Prunes

The prune packers have claimed that there is a

possibility of prunes becoming infested after they have been packed and stored. Many times infestation has

occured in fruit from packing plants which process with

steam, a temperature which should. be high enough to kill all insects.

To determine whether it was possible for infesta-

tion to occur after the fruit is packed two experiments were undertaken. Prunes were boiled for five minutes and packed and. boxed as nearly to standard pack as possible. The two boxes were then enclosed. in a larger box which was tight enough to exclude other insects. On

August 15, 1927 four female and three male moths were liberated in the larger box. A control box similarly treated. was kept in the same location without moths.

On September 15 the boxes were opened and the prunes heated to a temperature of 110 degrees F. for E? five minutes to drive the larvae to the outside. Exam-

ination of the prunes showed two larvae in one box and. five in the other. All seven larvae measured less than

3 mm in length showing they were newly hatched.

The second experiment was begun on March 2, 1928.

The prunes were handled the same as in the preceding experiment. Three female moths which had been fertil- ized were liberated in the large box.

On March 8 the box was opened and examined for eggs. Nineteen eggs were found along the cracks of the small boxes, all placed in good locations for the larvae to enter. Forty eggs were found in the corners of the large box. The box was closed again until April 1, when it was opened and exanined for larvae. Three larvae were found in one box and six in the other. A control in the same location showed no infestation. These tests show conclusively that boxes of prunes may become infested. while in storage, and. that apparently there is a large mortality among the larvae trying to reach their food.

Fumigation with Carbon Bisulfide.

To determine the effect of carbon bisulfide on the larvae a series of tests were run at different strengths the temperatures in most cases were about the same. All doses were figured for 1000 Cu. ft. of space 28

and. 24 hours exposure. All except high and low doses

were run in duplicate.

Table VIII

Fi.uiigation Results.

Larvae : Dose: Tenperature : Dead Alive

i 10 : 4j : Max.70,Min.66 : O 10

2 14 : lO# : Max.88,Min.62 14 0

3 3 13 : Bj : Max.82,Min.61 13 0

4 : 12 : 8 : Max.80,Min.63 : 12 : O

5 : 10 : 6 : Max.86,Min..58 : 10 ; O

6 12 6# : Max.84,Min.60 : 11 1

7 10 6# : Max.72,Min.56 : 4 6

8 6 8# : Max.78,Min.61 : 6

9 : 14 : 8 Max.82,Min.58 14 0

10 : 10 : 8# Max.89,Min.80 10 : 0

il : 10 8# : Max.84,Min.58 10 : O

Discussion of Fumigation Results

Eight pounds to 1000 Cu. ft. of space is the smallest amount that can be depended on to kill all the larvae.

Number 7, which had the lowest kill, was also made at the lowest temperature. The table shows 72 degrees

F. as the maximum, but this temperature was reached only 29

two hours before the completion of the test. The

temperature during most of the exposure was about 60

degrees F.

Numbers 8 and 9 were made on masses of prunes that

were stuck together and apparently tight, and about

eight by eight inches in size. The gas penetrated and

killed all the larvae.

Numbers 10 and li were run to observe the rate of

evaporation of carbon bisulfide under different condi-

tions. Number 10 was in a container 1 inches high, the

liquid. was 1/8 inch deep. It was completely evaporated

in two hours, and the larvae were apparently dead in an

hour and a half.

Number 11 was in a container seven inches high with

the liquid one and one half inches deep. It evaporated

in four days and the larvae were moving until the end.

of the third day.

The temperatures in numbers 10 and. 11 show a wide

variation at the minimum which was the night temperature

and could not be recorded for number 10. The day

temperatures for both tests were practically the same.

Control Recommendations.

Since the experiments have shown that the infesta-

tion of boxes of prunes can occur before processing, arid also after the boxes have been packed and stored, 30

any recommendations that are made would. 'nave to cover

both places in order to be effective.

The minimum death tenperature for the insect when

exposed. for one minute was found to be 120 degrees F.

The minimum temperature of the water that would give

120 degrees F. inside the prunes in one minute was

found to be 160 degrees F. One minute is the time

required. for the prunes to pass through the processer.

Therefore, control recommendations at this point, in

order to be effective, would have to be that of a

temperature of at least 160 degrees F. at the time of

processing. To make these temperatures effective all

bunches must be separated so that the heat will reach

each prune.

Infestations which occur after the prunes are packed can be handled in several ways. 1--Packing the prunes in insect proof boxes. 2--Cold storage. 3--. Vacuum famigation.

That food can be packed in insect proof containers was demonstrated by N. Parker (104) who exposed cereals to several stored product pests in paper cartons of two kinds. One carton had the loose edges covered with labels which were pasted on, the other was left open.

After several weeks exposure the sealed carton was free

f insects while the open one was badly infested. He 31

recommends sterilization of foods, which would be the

equivalent oÍ' processing prunes at 10 degrees F., or higher, and packing in containers which have no cracks

or holes for insects to enter.

Cold storage, although expensive, would pay in places where there is a good opportunity for infesta-

tion. It is a well-known fact that at a low, constant,

temperature, insects are dormant and the prolonged

exposure at a still lower degree may cause death, which

stage may be reached even more quickly by sudden alterations from low to high and the reverse. De 0ri

(36) conducted some cold storage experiments with raisins that were infested with several insects, among which was Plodia interpunctella,Hbn. He found that a constant exposure of three months or more at any temperature from 10 degrees to 36 degrees F. proved fatal to all stages of the insects experimented upon, and that a temperature of 45 degrees to 48 degrees F. caused dormancy with a low mortality. In conclusion he states that any temperature below 48 degrees will prevent infestation.

Vacuum fumigation to my knowledge, has never been tried on prunes, but experiments on dates by Mackie (91) were successful and there is no doubt but what the same results could be obtained on prunes. There is a question as to the value of fumigation.

Such a practice implies a certain amount of injury with

the unsightly frass and webbing to spoil the appearance

of the material. Arid, fumigation will not prevent re-

infestation. What is needed is prevention of infesta-

tion and that cannot be accomplished by fumigation.

Goods that have been infested must be cleaned before

they can be sold, this adds expense that should. be

applied. to preventive measures.

SUMMARY

Boxes of prunes that have been processed and packed are found infested with the Indian Meal Moth

Plodia interpunctella Hbn.

This insect is one of the most destructive that

infests stored. foods. The actual losses due to it are heavy but have never been estimated.

Plodia interpunctella Hbn. was described by Hubner in 1827. Its distribution is world wide.

Its hosts include all trie cereals and their milled products, all dried fruits arid vegetables, candy, drugs, honey comb, museum specimens, spices, sugar, yeast cakes, nuts, woolen cloth.

Life history--Winter is passed as larvae, they pupate about the middle of March. Pupa stage is 10 to

22 ds-s. The moths are active in April. ggs are laid. 24 hours after emergence. The moths live 5 to 10

days. The eggs hatch in from ô to 14 days. Larvae

are mature in from 60 to 90 days. They feed antil

August or early September, pupate and the second

generation have emerged. by the last of September. Two

generations a year under Oregon conditions. The

nu.nber of life cycles may be increased with a high

constant temperature. Larvae that have been disturbed

will pupate sooner than the others.

The death teiperatures for larvae with dry heat

are: 120 degrees i. for 30 Lninutes; 122-123 for 15

minutes; 125-12e for one ninute.

The death temperatures for larvae with hot water

are: 120 degrees F. for one minute; 130 degrees x. kills instantly if the insect is in contact with the water.

Heating the inside of the prune to 120 degrees F. reQuired 15 minutes at 120 degrees F., 8- minutes at

130 degrres F., 6 minutes at 140 degrees F., 2- minutes at 150 degrees F., 1 minute at 160 degrees F.

Heating the inside of bunches of prunes that were cemented together to 120 degrees F. recjuired 30 minutes at 120 degrees F., 24 minutes at 130 degrees F., 16 minutes at 140 degrees F., 12 minutes at 150 degrees F.,

8 minutes at 160 degrees F. 34

Fumigations experiments showed that eight pounds

of carbon bisulfide were required for 1000 eu. ft. of'

space at 60 degrees F. or above. The evaporation rate

of the liq.uid can be extended from two hours to four days depending on the height of' the containers used.

Control Recommendations.

1. Water tempersture of 160 degrees F. at time of processing is the minimum temperature that can be used for 100 per cent control.

2. Packing in tight containers that the insects cannot enter.

3. Cold storage at a temperature of 48 degrees F. or lower.

4. Atmospheric fumigation with carbon bisuluide eight pounds to 1000 eu. ut. of space.

5. Vacuum fumigation.

Prevention of infestation, by using number one with two or three, is much more desirable than the cure, number four or five. 35

4

Female moth en1arei four times.

i

Female moth natural size. Larva natural size. Egs enlarged ten times.

Larva enlarged five times. a 7

Drawing of moth enlarged 3 times f,

Drawing of larva and pupa Prune showing pupa in enlarged three times. natural position enlarged three times. unes natural size showirg web and. larva es.

une enlarged 20 time3 sowing white eggs. 3 :. BIBLIOGRAPHY

1--Aaron, S. F. 1900--The Pantry Moth Sci. Am. 20, P. 250, Oct.

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15--Biolette, F. T. 1916--Control of Raisin Insects Cal. U. Agri. Col. Cir. 134 Generai article on raisin pests.

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20 ------* 1e96--Insects Affecting Cereals nd Other Dry Vegetable Foods. U..D.A. Bui. 4 n.s. Generai on these insects, good. for hosts. 4G El--Corastock, J. H. * 1924--An Introduction to . Text book, P. 651.

22 ------* 1917--A Manual of the Study of Insects. Text book, P. 236.

* 1911--A List of Insects Affecting Stored Products U.S.D.A.Bul. 96. Lists most of these insects found in United States

24--Chapman, R. N. * 1921--Insects Affecting Stored Food Products. U. Minn. Agri. Exp. Sta. Bui. 19E, P. 55 Good general bulletin especially on control.

25--Curran, C. H. * 1926--The Identification and Control of Adult Lepibpterous Insects Attacking Stored Products Sci. Agri. Ottawa, 6, No. 11, P. 383. Good article on identification of different larvae found In stored products.

26--Cleare, L. D. 1913--The Flour Moth and its Control. Ji. Bd. of Agri. Br. Guiana, 6, No. 3, P.130,Jan. Brief resume of life history and control.

27--Caesar, L. and Ross, v.A. * 1922--Insects of the Season in Ontario. 53 Ann. Rpt. Ent. Soc. Ont., P. 3

28--Clemens, B. 1860--Contributions to American Lepid.opterology No. 5. Proc. Acad. Nat. Sci. Phil. June, P. 206. Systematic.

29--Dean, G. A. 1913--Mill and Stored Grain Insects. Kans. Agri. Exp. Sta. Bui. 189, P. i8 Good for hosts on P. interpu.nctella Heating experiments in mills.

30 ------Kans. Agri. £duc. 1, No. 4, P. 62 4]. 31--Davis, G. C. 1896--Some Injurious Insects iiich. Agri. Exp. Sta. Bui. 132 General bulletin.

32--Duponchel * 1834--Hist. Natl. 10, 2GO, 5--Suppi. 4, 121 Pl. 60, F. 6, 1842

3--DeOn, E. R. 1919--What Hinders Dried Fruit Sales Mthly. Bui. Cal. St. Cornai. Hrt. 8, No. 5,P. 240. Infestation and control o±' dried fruit pests.

34--De0n, E. R. 1918--Dried Fruit Insects. Mthly. Bui. Cal. t. Comm. Hrt. 7, No. L, P. 429 General article on these pests.

35--Dietz 1914--6th Rpt. St. Lnt. md. p 82.

3b--Deong, E.R. 1922--Cold Storage Control of Insects Jl. Econ. Ent. 14, No. 5, P. 144.

37--DeOng, . R. 1923--Habrobracon jugiandes Asmead, as a Parasite 0± Plodia interpunctella Ji. Econ. Ent. 16, P. 550 An account of the parasite and its work.

38--Essig, E. 0. 1920--Important Dried Fruit Insects in California. * Mthly. Bui. St. Agri. Dept.,Bul. 9, No. 3,P. 119 Good article on P. interpunctella infestation.

39 ------* 1921--Some interesting Economic Insects Recently Observed in California. Mthly. Bui. Cal. Dept. Agri. 10, No. 4, 2. 140

40 ------* 1926--Insects of Western North America Book, P. 712.

41--Felt, E. P. * 1910--Control of Fleas and Other Household Pests N.Y. St. Mus. Bul. 132. P. 42 Generai article. 42 42--Felt, E. P. * 1909--Control of Household Insects .Y. St. Mus. Bui. 129, P. 37 Mostly on control, general pests.

43--Fitch, A. * 1858--Affecting the Stored Grain and. Meal I.Y. St. Ent. Rnts. 1, P. 552 The first United States article written, named Tinea zeae and the common name Indian Meal Moth established.

44--Flint, W. P. * 1922--The Control of Household Insects U. Ill. Agri. Exp. ta. Cir. 257 On the control of household pests. 45--Frey 1880--Lep. Schw. 279.

* 46--Goodwin, vw. H. 1912--Flour Mill Fumigation Ohio Agri. Exp. Sta. Bui. 234. Good bulletin on fumigation in mills.

47 ------* 1922--Heat For Control of Cereal Insects. Ohio Agri. Ext. Sta. Bui. 54. Good. bulletin on Control in mills.

48--Girault, A. A. 1912--Insects Injurious to Stored Grains and. Their Grourd. Products. U.Ill.Agri.Exp.Sta. Bui. 156 Good for hosts.

49 ------* 1912--Insects injurious to Stored. Grains and Their Ground Products. 27th. Rpt. St. Ent. Ill. P.5o

50--Gibson, A. 1917--Reports on Insects of the Year. Div. No.1, Ottawa. 47th Ann. Rpt. Ent. Soc. Ont. P. 15

51 ------* 1916--Superheating as a Control Method forinsects Which Infest Stored Products. Proc. B.C. Ent. Soc. Ser. No. 9, P. 83. Heat and fumigation control. 43 52--Gibson, A. 1914--The Gontrol of Insects Infesting Mills and. Warehouses. Agri. Gaz. Canada, 1, No. 12, Dec. P. 961. Heat and fumigation control.

53--Go ssard 1909--Ohio Farm, May, P. 630.

54 ------* 1911--Fall Manual of Practice in Economic zoology. Ohio Agri. Exp. Sta. Bui. 233, P. 85 Only a short article.

55--Hubner 1827--Eur. Sehm. 310. Original description.

56--Howard, 1.0. 1901--The use of u1fur as a Remedy for the Indian Meal Moth. U.S.D.A. .nt. Bui. 30 n.s. P. 88 Iot much good.

57 ------* 192--Report of the l.ntomo1ogist U.S.D.A. 1924-25 Vacuum fumigation on stored product pests.

58--Holland, N.J. 1903--The Moth Book Mostly systematic, P. 415.

59--Hines, J.C. 1899--Notes on Ohio Insects Injurious to Stored. Vegetable Products. Jour. Columbus Hort. Soc. 14, P. 120.

LO--Herrick, G. W. * 1914--Injurious Insects Text book, P. 380.

61 ------1914--Insects Injurious to the Household. Text book, P. 252

62--Hurist, Geo. D. * 1890--The Phycitidae of North America Trans. Ann. Ent. Soc. 17, P. 201. Systematic 44 63--Hincles, V. E. 1914--Reducing Insect Injury to Stored. Grain Ji. 1con. Exit. 7, No. 2, P. 203.

64 ------1914--Ala. Poly. B.ul. 176, P. 52.

65--Herms, N. B. 1917--The Indian Meal Moth in Candy and. Notes on its Life History. Ji. Econ. Ent. 10, 1o. b, P. 563.

6'--Haseman, L. 1920--Insect Pests oÍ Field Crops. Mo. Agri. Exp. Sta. Bui. 170. General on field and stored product pests.

67--Herrick and Schaffer 1855--Eur. Schm. 4, 110.

68--Heinemann 1865--Pyr. 202

69--Imms, A.D. 1925--A generai Text book of Entomology P.248 Good article.

70--Jack, J. G. 1895--Another Herbarium Pest Garden and Forest, P. 223.

71--Johnson, W. G. 1896--Silk Fabric Lade by Insect Larvae Am. Miller, Aprii, P. 7i.

72 ------1901--Answers to Notes and Queries on Insects Injurious in Mills. Am. Miller, 34, P. 33, 35, P. 455

73 ------1895--Insects Injurious to Stored Grain. Am. Eli. and Grain Trade, Sept.March, 1696.

74--Kuzini, M. 1919--Plodia interpunctella Insect Viorld, Gifer, 23, No. 12, Dec. P. 445.

75--Kuwana, J. 1919--Observations on Injurious Insects. Ji. of Plant Protection, Tokyo 4, 1o. i P. 68. 7--Knibbs, Sir. G. H. 45 1923--Work in Progress 2nd Ann Rpt. Inst. Sci & Indust. Melbourne l92-23, P. 9.

77--Kellogg, V. L. 1908--American Insects Text book, P. 378.

78--Lyne, v. E. 1921--A talk on Insects Imported from the Orient Proc, B. C. Exit. Soc. Econ. Ser. No's 13,15, P. 146

79--.Lyne, V. H. 1921--l5th Ann. Rpt. B.C. Dept. of Agri. Victoria

80--Lockhead, V. 1919--Class Book of Economic Entomology P. 74, 214.

81--Lyne, W. H. 1920--Rpt. of hief Inspector of Imported. Fruit and Nursery Stock. 14th Ann. Rpt. Dept. Agri. Victoria, B.'.. No good.

82--Lyon, A. V. 1919--The Viticulture Industry Sci. & Indu.st. Melbourne, No. 8, P. 490 List of Insects on Grapes.

83--Lyon, A. V. 1924--Problems of the Viticulture Industry Comm. Australia Inst. Sei. & md. Bui. 8 Çontrol of P. interpunctella in grapes.

84--Lathrop, F. H. * 1919--Insect Pests of Stored Grains and Milled 2roducts. Ore. Agri. Exp. Sta. Exten. Bui. 228

85--Lovett, A. L. * 1921--The Indian Meal Moth loth Bien. Rpt. Ore. St. Bd. Hrt. P. 118

86--Lutz, E. L. * 1921--Field Book of Insects Text book, 2. 213 46 * 87--Mackie, V. W. 1925--Prevention of Insect Attack on Stored Grain U. Cal. Âgri. Exp. Sta. Cir. 282 Copper carbonate used to prevent attack.

86--Moschler 1884--Verh. Zool.-Bot. Ges. Vein. 310

89--Moore, W. * 1918--Fumigation with Chiorpicrin Ji. Econ. Ent. 11, No. 4, P. 357. Experiments with chiorpicrin

90--McCarthy, T. * 1921--Insects Attacking Nut Kernels Agri. Gaz. N...'. 32, No. 1, Jan. P. 9. Several insects in nuts.

91--Iackie, D. B. * 195--The Application of Vacuum Fumigation to Fresh and. Packed Dates. Mthly. Bui. St. Dept. Agri. (a1. 9, No. 8, P.321

9E--Miller, D. 1922--Insect Notes, Seasons 1921--22. N.Z. Ji. Agri. Wellington, 24, No. 5, P. 294

93--Malenotte, E. 1923--The Treatment o± Grain in Store Houses. R. Osservatorio Fitopatologico per Verona e Province Limetrope.

94--McKeown, K. C. 192--Insects in Dried Fruit. Experiments in Sterilization for their Control. Agri. Gaz. N.S.a., 33, No. 9, P. 642. He8t experiments for the control of P. inter- puxieteila.

95--Mendes, Candido 1913--Principie Lepidoptera Injurious to in the Neighborhood of S. Fiel. Beira Baixa, Portugal. Broteria Salamanaca, Ser. Zool. 9, P. 40.

96--MeNaught, Major, J. G. 19i3--TemDerature Reached in trmy Biscuits During Baking Ji. Roy. army Med. Corps, London, No.1, P. 136 47 -, * 97--Meyrick, . 1895--A Hand Book of British Lepidoptera Text book, P. 372.

98--Mac Cartney, B. F. 1900--Some Insects Injirious to Stored grain and Cereal Products. Penn. ..gri. Deot. Rpt. P. 83.

9--New South Vales 1924--Proclamation under the Plant Disease Act. Govt. Gaz. o.97. List of pests naned inact.

lOC-Niefert, D.E.; Cook, F.C.; Roak R.C.; Tonkin, Vi.H.; Back, E.A.; Cotton, R.T. 1925--Fumigation against Grain ieevils with various Volitle Organic Compounds. U.S.D.A.Bul. 1313. Results of fumigation tests with various compounds

101-New Zealand 1926--Ann. Rpts. Dept. of .gri. 1923,24,25.

102-C 'Kane 1914--Injurious Insects, P. 361.

103-Popenoe, C. H. 1911--The Indian Meal Moth and ..eevil Cut Peanuts U.S.D.A. Cir. 142 Life history, host, and control of Indian Meal 1oth.

104-Parker, 'I. 1913--A sealed Paper Carton to Protect Cereals from Insect Attack. U.S.D.A. Bui. 15. Bulletin is mostly on containers to prevent infestation.

105-Parker, N. B. * 1915--Control of Driea Fruit Insects in Calif- ornia. U.S.D.A. Bui. 235 A discussion of dried fruit pests and their control.

106_Plotnikor, V. 1915--RDt. of dork of Turkestan Exit. Sta. 48 107--Puitte, .. and Bernardini, R. 1920--The action of Chioropicrin on the Pests of Grain. Kaiserl. Biol. Austait. Lnd-v.Foslwirtsch Berlin Flubgiatt, 53, June l0E--uayle, H. J. * 1926--The Coaling Moth in ialnuts Cal. Agri. Exp. Sta. Bui. 402 iost1y Codling moth. i09--uaintance, A. L. * 1896--Insects Injurious to Stored Grain and Cereal Products. Fia. Agri. Exp. Sta. Bui. P. 358. The usual life history and control. il0--.vierezomb and ubcrsyy 1918--Review of the Pests of Agriculture Rpt. of work on Don Bureau for control of Agri. Pests. Rostoff, P. 8. ill--Riley, C. V. 1870--Bee Bread Devoured by diorrns. Am. Ent. & Bot. Dec. 2, P. 374.

112 ------* 1880--dorms Infesting Meal Sacks. Am. Erit. Sept. (y 3) n.s. Vol. 1, 2. 229

113--Riley, C. V. and Howard, L. 0. 1889--Extracts from Correspondence Insect Life, 1, ho. 10, P. 315.

114 ------_* 1889--The So Called Insect Life, 2, No. 5, P. 1o7--177. Discussion mostly on Ephestia ku.hniella with Comparison to Plodia interpunctella.

115 ------* 1890--The Indian Meal Moth in Kansas. Insect Life, 2, To. 9, P. 278 Correspondence

116 ------* 1890--Iotes on Ephestia interpunctella Insect Life, 3, No. 4, P. 134, P. 158. Discussion on synonyms. 117- * 1893--The Indian Meal Moth Infesting Lettuce Seeds. Insect Life, 5, No. 5, P. 349. Correspondence ne ------* 1894--Insects at '.Vorlds Fair at St. Louis Insect Life, o, No. 3, P. l List of insects found. 119 ------* 1895--General Notes, 7, No. 4, P. 360. new Grain Moth Parasite, 7, No. 4, 2. 428 Insect Life, 7, No. 4 & 5. 120--Kagnot * 1885--Revision of the British Species of Phycetidae and Galleridae. Ent. Lon. Mag. 22, P. 5, First Series. No good.

121--Rouband, E. * 1917--Insects and the Deterioration o± Ground Nuts in Senegal. L'AaÌ. et Me'm. Corn. d' Etudes Hist. et Seien. de L' Afrique occ. Francaise. Cultural and. pest article--no good.

122--Sanderson, E. D. * 1902--Insects Injurious to Staple Crops Book, 2. 295.

123--Sanderson, E. D., and Pesirs, L. M. * 1921--Insect Pests of Farm, GaHen, and Orchard Text book, P. 180.

124--Stevenson, H. A. 1894--An Attack of Lpestia interpunctella 25th Ann. Rpt. Ont. Ent. Soc. P. 57. No Good.

125--Smith, J. B. 1907--Some Household Pests N.J. Bui. 203, P. 32 Snort article.

126--Smith R. E. 19O9--Corn Veevi1s and Other Grain Insects. N.C.J3u1. 203, P. 17. Sbort article. 12? --SurTh ce 1913--P. D. A. Zool. 3, 1, P. 19.

128--Strong, L. Â. 1921--quarantine Reports, July and Auc'. 1921. Mthly. Bui. Cal. Agri. Dept. 11, No. 1, P. 67. Pests intercepted.

129 ------* 1921--quarantine Reports May and. June 1921. Mthly. Bui. Cal. Dept. Agri. 10, No. 8, P. 331. Insects intercepted.

130--Swenk, M. H. 1922--Insect Pests of' Stored Grain and Tneir Contrql. Neb. Agri. Exp. Sta. Cir. 15. Accousit of' insects tat injure stored grain in Nebraska.

131--Swezey, o. H. 1914--A Preliminary List of Hymenopterous Parasites of' Lepidoptera in Hawaii. Proc. Hawaiian Ent. Soc. 3. Io. 2, Jan. List of numerous parasites o± lepidoptera.

132--Sac'narov, N. 1915--The Injurious Insects noticed in the Government of Astrachan from 1912 to 1914. Ent. Sta. Astrachan.

133--Spencer, G. J. 1919--Results on sorne Preliminary Experiments with Chloropierin. bOth Ann. Rpt. Ent. Soc. Ont. 1920, P. 18. Results with chioropicrin on several insects. 134--Stainton 1859--Man. 2, 169. 135--Snellen 1882--Vilnd. eth. Micro. 1, lob. lÔb--Starldinger and Rebel 1901--Cat. Lep. Lur. 2, 253.

137--Treitchke 1832--Schm. Lur. 9, 1, 106. 51 136--Taylor, R. H. 1918--The Almond in California Agri. Exp. Sta. Berkley, Bui. 297. On control of almond. pests.

139--Trehune, R. C. 1921--Some Notes on the Fruit Worms of B.C. Sci. gri. March, 1921. General article on stored. product pests with keys to identify them based on claspers.

140--Vereshtchagin, B. 1921--Bio. Entomological Station. Viata Agricola, 12, No. 3, 2. 78, Bucharest.

141--Vitkovsky, 1. I. 1915--Pests of C-rain and Flour in the Govern- ment of Ekaterinoslar as observed in the current year. Govt. of Ekaterinoslar Pub.

142--Van Emden, F. 1925--Insect Pests in Vegetable Drugs in 124. Auz. Shadiingsk, 1, No. 6, P. 69. A good. reference on life history study.

143--Washburn, F. L. 1904--The Mediterranean Flour Moth. Spec. Rpt. Sta. nt. Liinn. Feb. 144--Whitmarsh 1912--Ohio Bui. P. 147.

145 -.Yilson, I. F. * 1914--Insect Pests of Stored Products. 2nd. Bi. Crop Pest & Hrt. Rpt. Ore. 1913-14, P. 12?. Good article on P. interpuxìctella.

146--Wilson, C. E. 1920--Report of the Entomologist Rpt. Virgin Islands Agri. Exp. Ste. 18th. P. 20

147--Waich, B.D. 1867--The Peach Worm Practical Ent. July 2, P. 110.

14E -Zeller 1875--Verh. Zool. Bot. Ges. Wein. 336 149- 52 1848--Isis, 598

150--Zacher, F. 1920--The Pests of Stored Products and their Control. Kaiserl, Biol. Austalt. Land-v.Forstwirtsch, Berlin, Flubgiatt, 63, June.