945 5 M6 py 1 \\ SPECIAL REPORT OP THE STATE ENTOMOLOGIST OF MINNESOTA TO THE GOVERNOR THE MEDITEERANEAN ELOUR MOTH FEBRUARY 29, 1904 AGRICULTURAL EXPERIMENT STATION, ST. ANTHONY PARK, MINN. JUL io 1904 D, of D, ^^:_:, ■\ r^^ r \U\ ^ ( IT*"' ' >^\j^ ff..:M wv .,.(_.^.V4/ EDITH REED, DEL. ET PINX. ft. HOEN 4 CO., LITH., BALTO., MD. THE MEDITERRANEAN FLOUR MOTH. THE MEDITERRANEAN FLOUR MOTH El^hcsfio kiicJiiiicIld, Zcll. His E.vccHcJicy, S. R. J\vi Saiit: Many millers arc asking' for information as to how to rid their mills of this much dreatled pest, which has recentl}' ap- peared in alarming numbers in this vicinity, apparently for the first time. 1 say a])parently, for, altiiough there is no record until the present time, of its ])resence near here, we have reason to believe that it has from time to time appeared in various parts of th.e state. Naturally if a mill is infested, the matter is not discussed, and this fact makes an outbreak all the more serious, for no pest calls more for co-o])eration in combating-, and more general consultation and comparison of results of different treatments than the Mediterranean Flour Moth. The millers have every reason to dread this insect, since it sometimes completely stops the machinery of a Hour mill, and w hen ])resent alwa^'s calls, sooner or later, for the expenditure of much effort and much money before a mill can be free from its de])redations. The fact that a mill is new is no safe-guard against con- tamination from returrie3 of an inch broad. We figure one of these enlarged twentv-fi\e times on colored plate (Fig. 11). Also same egg in text. Fig. 3, enlarged fifty times. /:\i.[,i;\s-, as zccll as larz'ac. may be brdiijj^ht into a l^crfcctly clean mill in i)ifcstccl material, thus sowing the seed of trouMe: sacks, barrels, and second-hand n;achinery from S(mie infested mdl being the chief sources. ( )ne female which we had under observation in the labo- ratory at St. Anthony l^ark began egg laying February 9th, continuing until and including February 14th, five days, lading during that period 247 eggs. Copulation lasts a long time and evidently one female may mate with several males, laying eggs l)etween the dififerent matings. THE IMEDITKRRANEAN FLOUR MOTH, 7 As regards the food liabits of this insect ; rice Hour is a dainty dish for the larvae, as is flour made from buckwheat. Any infested mill which keeps flour in sacks before shi]:)ping may hear sooner or later from the consumer or retailer that '"the flour is wormy." This is caused by the female moth pushing her ovipositor through the sack and laying her eggs in the flour inside. Crackers, germea, rolled vvheat, oatmeal and corn meal are all said to suffer. The moth is evidently a continuous breeder in warm local- ities, in warm mills for instance. It is a well known fact that cold retards and warmth hastens its developiuent, luillers sometimes taking advantage of the first point to keep the pest in check. \-ig. 4. — <;. cocoon from beluw showing pupa tlirough the 'thin silk attaching cocoon to some surface: h. same from above, enlarged — Riley & Howard in Insect Life. Dr. Fletcher of Canada, says in connection with the out- break there, that there are probably two normal broods, one in the spring, another in the autumn, but he thinks he raised as many as three distinct 1>roods in a warm room during the winter. F. H. Chittenden, of Washington, claims that in the warmest weatlier in that locality, the life cycle occupies only five weeks. Prof. \\\ G. Johnson states, in C(^ntradiction to Mr. Chittenden's experience, that he has been unaljle to get a 8 THE xMEDlTERRANEAN FLOUR MOTH. full grown larva in less than five weeks from the time it emerged from the egg. Preventive Measures. Clco'iliiicss: Because a mill is clean or new is no reason why the moth cannot be introduced, if sacks containing eggs or larvae, or second-hand machinery from an infested mill are allowed to enter. At the same time, scrupulous cleanliness has much to do with immunity, for eggs and larvae are dislodged by pro- cesses involved in the term, and not allowed to develop. Fig. -I'lour niatU'd together by web spun by larvae, one-half natural size. — Lugger. Every mill, it would seem, should, and many do, have cleaners or sweepers, whose sole duty it is to see that every floor and all machinery, purifiers, spouts and elevators are kept clean. Naturally such an employe or employes should have some knowdedge of insects found in Houring mills. Fiiniigation House: The writer is convinced, from talking with millers who have had experience with this pest, that the chief source of contagion lies in receiving into the mill returned sacks, and also second-hand machinery from an infested mill, which may THE MEDITERRANEAN FLOUR MOTH. 9 harbor the eggs or larvae. Some mills, in order to avoid in- fection, will not take back old sacks. If a milling company- must do this such material should be thoroughly treated before being allozced in the ntill. A fumigation house, or room, might be constructed, wdiere sacks or machinery could be fumigated. If sacks have been in transit for more than nine days, and during that time free from all sources of contagion, all eggs which may have been originally in the package have hatched, hence, one need not seek for a treatment which will kill them (the eggs), but only for such as will kill the worms which have hatched from the eggs. Carbon bisulphide is the best and safest fumigating material at our disposal, and could be well used in this instance. The gas generated by this liquid, when mixed with air, is highly explosive, and no lighted match or lamp, or lighted cigar or pipe should be brought near it. As it is definitely known just how much of this liquid is required to create a "death atmosphere," the cubical contents of this room, or better, house, should be accurately determined. From experiments tried with this gas by the writer, he would suggest one part of liquid for every one thousand parts of at- mosphere. To determine, if possible, whether this strength of gas would penetrate to the center of the bale in killing quantity, the entomologist inclosed "worms," pupae, and moths in vials loosely stoppered with cotton. These vials were placed in a flour sack, which was tightly rolled up. This bundle was placed in a second flour sack, which in turn was tightly rolled, and the package placed in a burlap sack and rolled again. This compact bundle with the worms in the very center was then exposed for three days, in a tight iron box, to fumes of carbon bisulphide, one part of the liquid to I, GOO parts of atmosphere. This killed every "worm," pupa and moth. The fumigation house or room must be absolutely tight to retain the gas. The liquid should be placed in shallow trays, and the room closed for at least three days if the sacks are left in the bale. A longer time than that, under such conditions, would be highly desirable. If the worm cannot be reached in the bale by fumigation for three or five davs with the above strength, millers should be 10 THE MEDITERRANEAN FLOUR MOTH. willing to open up the bales. This involves extra handling, and means added expense, but might be an imperative neces- sity, for tvork not thoroughly done in this connection represents time and money thrown atcay. After fumigation the house or room should be thoroughly aired before allowing a light of any kind inside. Fig. ij. — Silk felt spun by larvae in crawling across bolting cloth on top of breeding jar; showing also larvae, pupa cocoons and moths somewhat reduced. Original. The gas from bisulphide of carbon will sink through a mass of wheat in a large bin, and also through a chestful of woolen clothing, if in each case the liquid is placed in shal- low dishes on tcjp of the wheat, or clothing. It is probable, therefore, that it wdl penetrate a loose bale of sacks. Possibly heat alone might be profitably used in this connection. THE MEDITERRANEAN FLOUR MOTH. 11 Cyliiidrical Metal Spouts: L. C. Schroeder of Olean, N. Y., has in- vented and patented a metal spout, shown in Fig. 7, which is reported as giving satisfaction, since it presents a smooth surface within, and no corners, thus being a great improvement, as regards the flour moth, over the wooden spouts which aiTord such an excellent oppor- tunity for the larvae and the laying of eggs. It is claimed that the metal spouts cost less than those made of wood. This principle, for reasons which will at once be obvious to prac- tical mill men, cannot well be applied to the elevator legs, although it is said that the same party has patented a metal elevator leg. Belt Brushes: Since metal elevators cannot be economic- — Adjusta- ally introduced into our mills as they are now ble metal spout. — j. j. i 11 ^ j • r 1 From w. G. John- Constructed, an excellent device for keeping eport. ^1^^ wooden elevators clean, if we are to be- lieve statements of those who have used them, consists of an elevator brush as shown in Fig. 8, constructed as follows: "To make the brush, take a piece of i 1/2-inch plank of the same dimensions as the elevator cups, and fasten bristles to three sides. The side A is fastened to the elevator belt with flat-headed JD bolts running through the plank, as shown at B, B, the bolts being 1/4 or 3/8 of an inch. The bris- tles on the sides C, C, should be 3/4 of an inch long, but those at D should be longer, so that they will give a good brushing to the The brush is easily made, and the mil- ler can make it of any size to fit his elevators." yf C Fig. 8.--Elevator Brush.-From W. outer sidc of the clcvator. G. Johnson s Report. 12 THE MEDITERRANEAN FLOUR MOTH. Co-opcratioii: Co-operation on the part of all millers, particularly where mills are in the same district, seems absolutely necessary. If one fumigates returned sacks, and goes to the expense of freeing his mill of this pest, all should. Otherwise, moths from the untreated mills are almost sure to enter a cleaned mill, rendering the work of the more careful miller, in this connection, of little value. Screening windows and doors might be resorted to, and form at least a partial protection, though occasioning additional expense. Observations at the Experiment Station indicate that the moth cannot pass through the mesh of ordinary wire mosquito netting (144 meshes to the square inch.) Freezing: This most excellent and inexpensive method is available for Minnesota millers during almost any winter. The spouts, elevator legs, purifiers and all machinery should be first freed from masses of webbed flour, etc., left open (this does not mean the unscrewing of the sides of the elevator legs or spouts), and then all windows thrown open for a period of four or five days, after which windows should be closed and heat turned on. The importance of exposure to heat after the freezing must not be underestimated. The owners of one infested mill stopped their machinery this winter, opened all machines, spouts and elevators to allow access of cold air, and then kept their windows open for a period of four days. This was done in a time of extremely severe weather, the thermometer ranging at the time from ten degrees be- low zero to thirty-two degrees below, the average tempera- ture of the mill during that period being 5 degrees below zero. At the expiration of this period windows were closed and heat turned on. Some larvae ("worms") and moths col- lected, and subjected to examination for several days, did not revive, killed by the extreme cold, aided possibly by the sud- den change from warm to cold and cold to warm. Eggs sub- jected to the above freezing, and kept under observation for fifteen days and over, did not hatch ; nor did the weevils, and THE MEDITERRANEAN FLOUR MOTH. 13 other pests found with the Flour Moth, survive this treat- ment. These statements were made to the writer ; they are not his observations. However, while millers in Minnesota can secure at some time, during almost any winter, a temperature sufficiently low to kill by freezing, yet such a condition is not always present, even in Minnesota, when wanted (if outbreak occurs in early spring and summer for instance), and surely millers in the South could rarely, if ever, take advantage of this method. The bisulphide method (not fumigation) must of necessity have to be resorted to, when temperature conditions are not favorable for freezing. In one or two mills subjected to this freezing process fire had to be kept in the basement, and a sufficiently low temper- ature could not be secured, the treatment in consequence resulting unsatisfactorily. See also results of experiments by the entomologist on page 14. In one mill, however, where the entire mill was exposed to severe cold for eight days or more, the process was an absolute success. Observations and Results of Experiments by the Entomologist. In the short time between the report of the recent out- break of this moth and the placing of copy in the hands of the printer, the entomological department has been able to make some observations and try a few experiments in con- nection with its extermination, the results of which are here given. Mating and egg laying: time elapsing bctzveen laying of egg and hatch- ing of same. Pairing is evidently protracted, one isolated pair under observation remaining in copula four days. Ovipositing in one case lasted six days, a female beginning egg laying on February 9th and continuing until the 15th, on which date she died. During this time the one female laid 247 eggs. These eggs began hatching on the i8th, nine days after the first were laid, a recording thermometer registering an average temperature of 70 degrees Fahr. in the room during that time. Two freshly laid eggs were measured, each measuring .6 millimeters in length by .35 millimeters in breadth, or, in round numbers, 1/42 of an inch long by 1/63 of an inch in breadth. 14 THE MEDITERRANEAN FLOUR MOTH. The night of the Moth: The question as to whether moths would fly from one mill to another suggested observations along this line. The insects if left to themselves did not fly in the morning. Late in the afternoon and in the evening after the light was turned on, an assistant reports them flying freely across the room, although not attracted to the lights, but rather avoiding them. Observations elsewhere indicate that they will fly at least no feet, and probably farther. Can the Moth get through zvire mosquito netting f Moths confined for several days in a cage made of wire netting, 144 meshes to the square inch, did not escape, dying within the cage. Effect of liquid Carbon Bisulphide on eggs, larz'cc, pupce and moths: One contact for a few seconds with this liquid killed eggs, young and full- grown larvae and moths. The pup^e were not killed immediately, but died later. Effect of vapor of Bisulphide of Carbon on egg: Eggs exposed directly to this gas for a few hours did not hatch. Effect of knotvn low temperature on the eggs: Experiment in progress when this report goes to press. Least z'ohwic of Carbon Bisulphide (CSi) and least time of exposure necessary to kill full-groii'n larz'cc and moths by fumigation: Condition of Insect. Full-grown larvae Full-grown larvae Full-grown larvae and moth Full-grown larvae and moth vStrength of Gas. I Part liquid CS2 to 1,500 parts atmosphere I Part CS2 to 3,000 parts atmos- phere I Part CS2 to 6,000 parts atmos- phere I Part CS^ to 12,000 parts atmos- phere Time Exposed. I hr. 4omin. 1 hr. 2 hrs. 3 hrs. Results. Killed. Killed. Killed. Killed. Effect of exposure of moths, eggs, larvce and pupce to known lozv tem- peratures for definite lengths of time. Lot No. I. Exposed out of doors in breeding jar, for three days, to a temperature ranging from 18 degrees above to 12 de- grees below zero. All killed. Lot No. 2. Placed in cold storage at 32 degrees for four days. Living at expiration of that time. Lot No. 3. Placed in cold storage at 14 degrees above zero for four days. A few worms survived. THE MEDITERRANEAN FLOUR MOTK. 15 Lot No. 4. Placed in cold storage at 6 degrees for four days. One or two "worms" survived. Lot No. 5. Placed in cold storage at i degree above zero for four days. All killed. Lot No. 6. Placed out of doors for four days, temperature ranging from 18 above to 21 below zero. One or two worms survived. It would seem, then, from the above, and from the experience of millers cited on page 13, that the "freezing process" to be thoroughly effective must be most thorough. Mills should be so constructed that all water pipes can be emptied, allowing all parts of the mill to get extremely cold. Further, since we know that a long continued even cold temperature is not always fatal to insects (note the hibernation of Minnesota insects, for example), but that exposure to cold and thawing alternately is fatal, we would suggest that millers in this work arrange to alternate the extremely cold temperature with warm, that is, after the first exposure to cold for a few days, allow the mill to become warm and follow this with another cold exposure. The above lots, Nos. I to 6, were masses of matted flour containing the worms, the latter being thus somewhat protected. Spraying with Bisulphide of Carbon. This method, wliich has been very successfully practiced, consists in forcing the Hquid by a syringe made for the pur- pose into all the machinery infested, inside of spouts, etc. Parts of the mill or fittings which do not come in cc^ntact with grain or products made from same can be well treated with kerosene, squirting it into cracks between joists, and into cracks between joists and iron braces, into cracks about windows, along baseboards, and into cracks in floor, walls and ceilings. It is evident that this must be done most thor- otighly to reach all eggs or worms concealed in such places. Fig. 9 represents a syringe itsed for spraying the bisulphide or kerosene. It may be made of iron pipe, of brass, or of tin. It is eighteen inches long, two inches in diameter, and will hold, at those measurements, about one quart. The rose is detachable, unscrewing from the barrel, and it (the rose) is filled on the end with many very small holes, as small as the finest needle, in order that the liquid may not be wasted. In filling the syringe the rose can be unscrewed and the end of the syringe immersed in the can holding the bisidphide, or, and this is much better, a little screw cap, not shown in the illustration, mav be made on the side of the rose and the 16 THE MEDITERRANEAN FLOUR MOTH. liquid drawn in through that. This is by far the best plan, for when the rose is unscrewed and the liquid drawn into the syringe it necessitates the holding of the filled barrel up- right in order to screw on the rose, under which circum- stances the liquid will run out below, near the handle, unless the piston rod fits very snugly. When the syringe is used with kerosene, the rose is unscrewed and a small nozzle with one aperture, con- siderably larger than the holes in the rose, put on in its place. This is used when treating cracks in lioors, etc. Before the work with carbon bisulphide or with kerosene is begun, elevator legs, spouts, purifiers and all infested machinery must be thoroughly cleaned, in other words freed from all matted flour. When the spouts are lined with tin. affording a retreat for the worms beneath the tin, the wooden sides must be removed to get at the culprits. Swabs of cotton waste or pieces of old sacks should be run through the eleva- tors (stuffing these swabs into cups), takmg off caps of elevators and having men, stationed at the top, take out the ascending swabs when they reach them, and put in other swabs in the descending leg. The eleva- tor brush. Fig. 8, might be well used in this connection, or brushes made from the same material as the belting, frayed on three sides and riveted to cups. All conveyors should be taken out and thoroughly cleaned. Purifiers and reels and insides of conveyor boxes, all machinery in fact, should be thorough!}' si)rayed with carbon bisulphide after having been cleaned. The cloth tubes on dust machines should be burned. In treating elevator legs with carbon bisulphide, the same method can be used as in cleaning, described above, saturat- ing the swabs with the liquid. A swab should take up about one pint of the liquid. All this means the expenditure of time, and monev for material. An ordinary sized mill may, in this process, use from i,ooo to 1,500 pounds of carbon bisulphide, or even more, to say nothing of the large amount of kerosene employed. We are reliably informed that bisulphide of carbon can be Fig. 9. THE MEDITERRANEAN FLOUR MOTH. 17 purchased for 6 1/2 cents per pound of a dealer in New York City and St. Louis. This price does not include container, credit for which is allowed upon its return. Caution: The gas generated by bisulphide of carbon is inflammable. Therefore, while it is being used and until the mill has been thoroughly aired after treatment, no light of any kind should be allowed in the mill. A lighted cigar or pipe, lantern, or lighted match, if brought into the mill when filled with gas might cause an explosion. Effect of the Gas on Human Beings. This liquid can be safely handled by workmen in the mill if they will take the precaution to go at once into the open air when they feel any bad effects from inhaling the gas. The mill, during this process, should be tightly closed to make the work more ef- fective, and in consequence is filled with fumes. If these fumes are inhaled by the men for some length of time with- out the precaution above mentioned of going frequently to the fresh air, temporary nausea and sickness may result, while prolonged exposure to dense fumes in a tight room might result very seriously. Nature, however, gives one warning in plenty of time to avoid danger. Then, too, in a case which came under the writer's observation, men working with the stuff became more or less immune, and one indi- vidual was hardly affected at all. As is evident, the treatment of a mill in this way should be in charge of a reliable and competent man of intelligence, one fully posted as to the nature of the chemical his men are handling. Methods Which Have Been Tried and Found Ineffective or Less Desirable than the Preceding. Fumigation zcith Bisulphide of Carbon : Although this has been the common practice in the past, and is generally rec- ommended in cases of attack of this insect, actual experience with its use does not bear out the recommendation, in that it does not appear to kill the moths or worms under the condi- tions which prevail in almost every mill. It may be effective against other insect pests with which flour mills are troubled, 18 THE MEDITERRANEAN FLOUR MOTH. thus giving rise, from published report, that it is effective also against the Mediterranean Flour Moth, but we know of at least three instances where it was tried in large mills and proved valueless. The process consists in placing pans of carbon bisulphide on the different floors, using a definite amount of the liquid (about one part to every one thousand parts of atmosphere), first making the room as tight as possible, opening up all spouts, spindles and other apparatus in which the moth or its larva is found. The chief obstacle here is the almost utter impossibility of making the large rooms air tight. Then, too, as evidenced by the testimony of a Pennsylvania miller a few years ago: "When placed in plates it does not evapo- rate quickly enough to produce the death atmosphere re- quired." This firm used three hundred soup plates half filled with bisulphide and distributed throughout the mill, besides saturating balls of cotton with the same and placing them in all reels and purifiers. The mill was left from Saturday night to Monday morning, and although thousands were found dead, many thousands more appeared from cracks and corners after a few days. SiilpJiiir: The burning of sulphur not practical, besides injuring the flour in sacks in the mills. Steam: Not practical, requiring too elaborate prepara- tion, and too frequent application; seriously injuiing grain or flour, and rusting machinery. Kerosene: Good for washing walls, machinery, floors, etc., where it cannot injure flour or grain. See reference to kero- sene on pages 15 and 16. Soliitioji of Soda and IVafer: Used strong for washing in- side of machines. Biihach, or Persian Insect Powder: Has been burned in a mill with only partial success, and expensive. Ammonia: Not successful. Hydrocyanic Acid Gas: Coming quite generallv into use. Placed in this list on account of danger of application unless in the hands of experienced parties. Deadly to all animal life. Prof. W. G. Johnson, author of "Fumigation Methods," THE MEDITERRANEAN FLOUR MOTH. 19 says he has freed a number of mills of the Mediterranean Flour Moth by the use of this gas. Corrosive Sublimate: Not desirable. Lime: Whitewash to which a little glue has been added excellent for ceilings and walls ; the tendency to rub off can be stopped, it is said, by adding a handful of common salt, and a half teacupful of lard to each gallon of wash, which should be thoroughly strained before being used. Sulphuric Acid: Not recommended. Tobacco: Not particularly effective, either as smoke or infusion. Flour Paste: Compound of flour, water and vinegar and boiled by steam found to attract insects when paste was at a certain stage of fermentation. Moths fall into paste and perish. Too expensive, and has to be renewed every few days. Vinegar and Water: Not desirable. Molasses and Jl)iegar: Will attract and destroy some moths. "Tanglefoot" or Sticky Flypaper: Something like the sticky mixture used to coat Tanglefoot Fly paper can be made with- out much expense. Hundreds of moths have been caught in a single night on sticky fly paper. The paper should be placed in such places as are frequented by moths for egg laying, notably on piles of sacks filled with flour, etc. It is evident that if one can catch many female moths before egg laying, the process is well worth the expense incurred, and is a desirable measure. Coal Tor: Not desirable. Coal Tar and Vaseline: Better than coal tar alone. This and preceding used in the same manner as "Tanglefoot." Hand Picking: Not feasible. Hay Ropes: A German miller is the authority for the statement that ropes of new mown hay placed about the mill in coils afford attractive retreats for the moth. These coils were burned with the contained moths each week. High Temperature: Exposure to a temperature of 120 to 130 degrees Fahr. for two or three hours is claimed to be fatal 20 THE MEDITERRANEAN FLOUR MOTH. to the larva in the flour, and the same temperature for five or six consecutive hours is said to kill the eggs. This may prove of practical utility. Natural Enemies of the Flour Moth. Mr. Johnson describes in the American Miller for Novem- ber, 1895, the discovery of one parasite in America, Bracon hebetor, Say. In Europe Bracon brcvicornis and Chrcmyliis rubiginosus are mentioned as parasites. Poultry, seemingly fond of the "worm." has been kept in warehouses with some good efifect, though the hens appeared to tire of the diet. Mr. Johnson records the eating of a large number of pupae by a mouse, but no millers care to introduce mice into their mills for this purpose. Mice, as all entomologists know, readily eat insects, whether alive, or dead and pinned. Tribolimn confusmn, a little brown beetle, a common pest in flour mills, and discussed in this connection elsewhere in the report, has been known to devour the pupae of the flour moth. The so-called "bolting cloth beetle" (Tcncbroidcs iiiauritaii- icus) of California eats larva and pupa of flour moth and larva and adult of Triboliuiii. History of the Moth and Its Geographical Distribution. The origin of this pest cannot be stated definitely. It is probable that it always has been a widespread species, but not arousing attention until, attracted by flour and related products in mills, it changed its habits and became prominent as a menace to the flour milling industry. When first named by Zeller it was supposed by him to have been introduced from America, and it was so stated, but it was found by him in an inland town of Germany, Halle, before he knew of it at any seaport, and the same thing could be said of its first officially reported appearance in France. One miller has said with em- phasis that he knew of its occurrence in Paris as early as 1840, and another claims that it was in Constantinople in 1872, both statements, coming from different sources, affording addi- tional proof that it is not of American origin, where it was THE MEDITERRANEAN FLOUR MOTH. 21 not officially reported until 1889 (Canada). There is evidence that it was in America a few years previous to this date, not however, until long after it was known in Europe. In 1885 it was declared to be a dreaded pest in many Mediterranean ports, though no statement was made as to how long it had existed in those places. It is reported from Chili, from Mex- ico, New Mexico, from the island of Jamaica, and in 1890 what was evidently this species was reported from South Africa. A practical miller who has since had experience with the pest in California, asserts that it was in Schleswig-Hol- stein, Germany, in 1858, although the first recorded observa- tion from Germany is in 1877. Freight cars and ships may easily be the means of carrying it. either as egg, worm or moth, to regions remote from the scene of its earlier appear- ance. It would be impossible to review in this publication the extensive literature upon this pest, nor is it necessary to list the bibliographical references. In order, however, to give an idea of its spread which is approximately correct, we list the following dates taken chiefly from Johnson's bibliographical list, and under each date insert the locality or localities where the moth appeared that year, as far as reported. In some instances, the outbreak may have been in the year preceding the report, but with these few exceptions, we be- lieve the dates are correct. 1877. Outbreak at Halle, Germany. 1879. Outbreak of 1877 referred to and insect named by Zeller. 1884. Belgium. Supposed then to have been introduced in an American cereal. Reported also on lower Rhine. 1885. Reported at Bremervorde, Germany. 22 THE MEDITERRANEAN FLOUR MOTH. 1886. Appeared in England. 1887. London. Trieste. In the 39th Annual Report of New York State Museum of Natural History, J. A. Lintner pub- lishes his reply to an inquiry of the German consul general at New York City, asking for information about the Flour Moth. He states that he (Lintner) knew of no such insect in America. This is believed to be the first published state- ment in America regarding the pest. 1888. T. D. A. Cockerell in the Entomologist for November, 1888, page 779, declares that certain larvae found in flour which came from America may have come from infested Trieste flour in the same warehouses. 1889. First report of its occurrence in North America, in Can- ada. May have been present a few years earlier. Reported as being in very destructive numbers in England. 1890. Still present in England and spreading. A pest reported from South Africa which, from its habit, must have been this insect. 189T. Reported in Venezuela (or a closely allied species). 1892. California. Island of Jamaica. 1893. On the increase in California. THE MEDITERRANEAN FLOUR MOTH. 23 1894. Still present in California. Reported from New York State, from North Carolina, and said to have been found in meal and bran from Mexico on exhibition in Chicago. 1898. New York State. Pennsylvania. been present there for three years.) ada. 1899. Wisconsin. (Reported as having New outbreak in Can- Wisconsin. Minnesota. 1900. 1901. 1903. Minnesota. The Flour Moth is found in Illinois, in Colorado and other states ; it is, in fact, of very general distribution. Fig. 10.— Mediterranean Flour Moth: Ephcstia KuehnicUa, Zell. : a. larva; b, pupa; c, adult, enlarged; d. head and thoracic joints of larva; c, abdominal joint of sarne; still more enlarged; /, moth from side, resting; g. front wing, showing more im- portant markings; h, venation of fore wing; j. venation of hind wing, somewhat enlarged, (a, b, c and c, Riley & Howard in Insect Life; d, f, g, h and i, after Snellen.) 24 THE MEDITERRANEAN FLOUR MOTH. SOME OTHER INSECTS FOUND IN FLOUR MILLS OR AFFECTING STORED GRAIN. Many of the following" insects are also found in flour mills, and are frequently spoken of collectively as "weevils," which term is also sometimes, though not often, applied to the Mediterranean Flour Moth. That this is a wrong appellation is evinced by the fact that only two of the insects listed be- low are true weevils. Treatment which is successfully di- rected against the Flour Moth will kill any of the following insects, when occurring in the mill treated. The Granary Weevil. Fig. 11.— 0, b, c, different stages of the Granary Weevil (Calandria granaria), d, Rice Weevil (C. oryza).— F. H. Chittenden, Division of Entomology, U. S. Depart- ment of Agriculture. Fig. II illustrates this species and its congener, the Rice Weevil. The hair lines bv each show the natural size of the THE MEDITERRANEAN FLOUR MOTH. 25 insect. The female (jranary Weevil punctures a grain of wheat with her snout and lays an Qgg in the opening, the larva after hatching feeding upon the interior of the kernel. There may be from four to six broods of the Granary Weevil during the year, depending on the temperature. It is esti- mated that one pair, under favorable circumstances, will produce six thousand descendants in a year. This beetle is of a shining brown color. It cannot fly. Its cousin, the Rice Weevil, is a dull brown, its back provided with four reddish spots. It has well developed wings. In the southern states this latter weevil is a serious pest. The Angoumois Grain Moth. d "f Fig. 1-. — Angoumois Grain Moth, Sitolrnga ccrcalcUa: a, eggs; /'. larva at work; f, larva, side view: J, pupa; c. iiiotli; /, same, side view. — F. 11. Chittenden, Divi- sion of Entomology, V . S. Department of Agriculture. This pest is shown in Fig. 12. It is named from a prov- ince in France, where it has been known since 1736. It is claimed to have been found in America since 1728. More injurious in the South than in the North, it attacks not only wheat in the field and bin, but is partial to all the cereals. It is a brownish moth, resembling in a general way the Clothes Moth in size and apj^earance. 20 THE MEDITERRANEAN FLOUR I^IOTH. The Indian Meal Moth. This insect, resembHng somewhat the Mediterranean Flour Moth, not only feeds upon grain, flour, meal and bran in mills, but is seen in stores and elsewhere, where it af- fects spices, herbs, roots, seeds, dried fruit, etc. The larv?e or "worms" wdiich pro- duce these moths fasten together the kernels of grain, or the seeds or J:^-;'^:^i:tc:"^^r^l': Jil- -^ther material upon which they are Stf^fSar'va'^t^?^.o^ret feeding, with silkcu threads. These iecf I'iTe^'"^^ '"""' "''"'"'' '" ^"" masses, fouled with their excrement, greatly impair the value of tlie in- fested foodstuffs. It is said to have from four to six or uine broods amuially, depending upon the temperature of the rooms where it is found. It is shown in its various stages in Fig. 13. The Meal Snout Moth. Fig. 14. — I'yralis fari:uilis: a. ,'ulult moth; b, larva: c. pupa in cocoon, twice natural size.— F. H. Chittenden, Division Entomology, L'. S. Department of .Agricul- ture. This is a brownish moth, having darker brown patches at the outer edges of the front wings. Fig. 14 gives a very good, idea of its appearance ; the wavy white lines bordering the dark spots are characteristically striking. The larva makes tubes of silk, to which kernels of grain (if the worm is working in grain) adhere. (See Fig. 15.) Grain kept in dry and clean places is not likely to be affected. THE MEDITERRANEAN FLOUR MOTH. 27 Fig. 15. — Silken lubes covered witli wheat made by larvae of I'yralis fannalis, half natural size. — Lugger. The Confused Flour Beetle. The accompanying- figure (16) gives an excellent idea of this little pest, coninion enough in our flour mills. I'he beetle is dark br()\vn, and practically <)mniv<:)nnis, attacking. Fig. ll'i. — 1 riholiuii! confusiiiii: a, beetle; b, larva; c. pupa, all enlarged; d'. lateral lobe of abdomen of pupa; i', head of beetle showing antenna; /. same of 7'. fcrrugincum, all greatly enlarged.— F. H. Chittenden, Division of Entomology, U. -S. Depart- ment of Agriculture. according to Chittenden, flour, baking powder, red pepper, beans, peas, rice chaff, ginger, slippery elm, nuts and seeds 28 THE MEDITERRANEAN FLOUR MOTH. of various kinds. We have found it attacking dried insects in our cabinets. Like the other insects under discussion, a high temperature invites more rapid reproduction than when the temperature is low. It is said to attack and eat the larvae of the Mediterranean Flour Moth. The Slender-Horned Flour Beetle. This insect is more common in the south, but deserves a place here. Indian corn is its special food. The beetle is brown, having on its head between its eyes, two small pro- jections, readil}^ seen in the illustration. Fig. 17. The Broad- Fig. 17. — Echoceriis ma.villosns: a. larva; l>, pupa; c. adult male, all enlarged. — F. H. Chittenden, Division of Fntomology, U. S. Department of Agriculture. horned h'lour lieetle, and the Small-eyed Mour Ueetle should be added here ; the first more abundant on the Pacific coast, the second abundant and injurious in bakeries, feed stores and mills. The Yellow Meal Worm. This, F^ig. 18, is one of our more common pests in Indian meal and found in almost any mill products allowed to ac- cumulate in neglected places. The "worm" is round, smooth, waxen as to its surface, and nearly an inch long and yellow. The adult beetles fly and are attracted to ligh.ts. Another allied form common in America, but probably introduced from THE MEDITERRANEAN FLOUR MOTH. 20 Q):iX3::x:ccx:^ Fig. IS. — li'iicbno niolilor: a, larva; h, pupa; c, female beetle; (/. egg with surround- ing case; c-. antenna; a. b, c, d, about twice natural size; c. more enlarged. — Chit- tenden, Division of Entomology, U. S. Department of Agriculture. Europe or Asia, is the Dark Meal Worm. The Yellow Meal Worm or its beetle, or both, are said to make holes in b(^lting eloth. The Saw-Toothed Grain Beetle. Fig. 19. — Sil-'oiuis siiriiwiiu'iisis: a. adult beetle; b, pupa; f, larva._ all enlarged; d, antenna of larva, still more enlarged. — Chittenden, Division of luitomology U. S. Department of Agriculture. Very eommonly. though wrongly, called "weevil." It gets its name from the little teeth on each side of the thorax. (See 30 THE MEDITERRANEAN FLOUR MOTH. Fig. 19.) 'J he l)ectle is reddish brown, and frequently very common in grain, also, according to Chittenden, feeding in fiour. meal, dried fruits, seeds, breadstuffs, etc., and has been reported as having been found in starch, tobacco and dried meats. One or two other allied beetles we pass over as not beingf abundant enough to merit discussion here. The Cadelle. Fig. 20. — 7 cncbyoidrs maiiritaiiicus, Linn. : a, adult l)eetle with greatly enlarged antenna above; b, pupa; r, larva, all enlarged. — Chittentien, Divi-^iioti of Entomology, U. S. Department of Agriculture. Sometimes called "The Bolting Cloth Beetle," living upon grain, is blackish, one-third of an inch long, and comes from a fleshv, whitish larva with a brown head. (See Fig. 20.) Both beetle and larva attack and eat other grain or flour in- sects which are met with. They are, therefore, not an un- mixed evil. THE MEDITERRANEAN FLOUR MOTH. 31 1 ACKNOWLEDGMENTS. The two successful uiethods of conibatiu"" the Mediter- rauean Flour Moth iu uiills, frccciiig aud slrayiiig i^nth C. ^S"-, were told me in detail l)y practical millers who had resorted to these processes with happy results. To these parties my thanks are due and cheerfully given. I have not hesitated to use information contained in W. G. Johnson's article on "The Mediterranean Flour Moth (Ephcstia kiicliniclla, Zeller) in Europe and America,"" ])uhlished as an a])pendix to th.e 19th report of the state entomologist of Illinois, h^-om Farmers' Bulletin No. 45, Ignited States Department of Agriculture, "Some Insects Injurious to Stored Grain,"" by F. H. Chitten- den, statements were obtained bearing upon the habits and life histories of insects other than the Flour M(jth found in flour mills and elevators. A number of Chittenden"s illus- trations have also been used. The Booth Packing Company of Minneapolis very cour- teously allowed the use of their cold storage rooms in con- nection with experiments on the effects of dift'erent temper- atures on the pest under discussion. Acknowledgments are also due Director W. M. Liggett and yourself for recognizing the urgency of the situation, and enabling the Entomologist to place this information before the millers of the state quickly and in proper form. Respectfully, F. L. WASHBURN. State Entomologist. February 29th, 190^. LIBRftRY OF CONGRESS 000 914 848 6