ii' t "·.) 1 "I ' ,, ·· ...,CJie"l Bulletin 198 Revised Jfine 1932 UNIVERSITY OF MINNESOTA AGRICULTURAL EXPERIMENT STATION INSECTS INFESTING STORED FOOD PRODUCTS BY ROY AL N. CHAPMAN FORMERLY OF THE DIVISION OF ENTOMOLOGY AND ECONOMIC ZOOLOGY REVISED BY H. H. SHEPARD · MEAL WORM, ADULTS AND LARVAE, IN BRAN (SLIGHTLY ENLARGED) UNIVERSITY FARM, ST. PAUL • CONTENTS Page Introduction . 5 Purpose of the bulletin. 5 How to use the bulletin. 5 Losses caused by insects attacking stored food products. 6 General causes of losses and methods of prevention..................... 6 Insect problems of seedsmen............................................... 8 Losses that insects may cause to seedsmen. 8 How insects get into storehouses of seedsmen. 9 Conditions that make it possible for insects to exist in seedhouses. 9 Insect problems of millers and grain dealers. 10 Losses caused to grain dealers and elevator managers. 10 How insects get into elevators and granaries. 11 Conditions that make it possible for insects to live in granaries and elevators 11 Losses that insects cause to millers. 12 Conditions that make it possible for insects to get into mills. 13 Conditions that make it possible for insects to live in mills.............. 14 Insect problems of manufacturers of special products-breakfast foods, maca- ro~i, pancake _flour, drug;s. 15 How msects get mto factories. 15 Conditions that make it possible for insects to live in factories. 16 How to keep insects out of factories. 16 Insect problems of transportation companies. 17 Insect problems of warehousemen and wholesale grocers. 18 How insects get into wholesale groceries and warehouses. 18 Conditions that make it possible for insects to live in warehouses....... 19 Damage caused by insects in warehouses. 20 How to keep insects out of stored food products in wholesale houses. 20 Insect problems of retail grocers...... 22 Losses caused by insects to retail grocers. 22 How insects get into retail grocery stores. 23 Conditions that make it possible for insects to get into retail grocery stores 23 How to keep insects out of groceries in a retail store. 24 Insect problems in bakeries. 25 Injuries caused by insects in bakeries. 25 How insects get into bakeries. 26 Conditions that make it possible for insects to exist in bakeries. 27 How to keep insects out of bakeries. 28 Insect problems in connection with stored food products in the home......... 29 Losses that insects cause to the housekeeper. 29 How insects get into the home. 29 Conditions that make it possible for insects to live in the home.......... 30 Insects that cause damage to stored food products............ 31 Structure of a typical insect. 32 Life history of a typical insect as found in stored food products.. 34 Table for determining the species of insects. 34 Description of the insects. 38 Granary weevil (Sitophilus granaria Linn.)............................. 38 Rice weevil (Sitophilus orysae Linn.)................................. 39 Drugstore beetle (Sitodrepa panicea Linn.)............................. 40 Cigarette beetle (Lasioderma serricorne Fabr.)......................... 41 White-marked spider beetle (Ptinus fur Linn.)........................ 41 Square-necked grain beetle (Silvanus gemellatus Duv.).................. 42 Foreign grain beetle (Cathartus advena Walt!.)........................ 42 Flat grain beetle (Laemophlaeus pusillus Schon.)....................... 42 Bean weevil ( M ylabris obtectus Say) . 43 Pea weevil (Mylabris pisorum Linn.).................................. 45 Cadelle (Tenebroides mauritanicus Linn.).............................. 45 "Meal worm" (Tenebrio molitor Linn. and Tenebrio obsrnrus Fab.)..... 47 Black fungus beetle (Alphitomius piceus Oliv.)........................ 48 Confused flour beetle ( Tribolium confusum Duval and Red rust flour beetle ( Tribolium ferrugineum Fab.).................... 48 Saw-toothed grain beetle ( Orisaephilus surinamensis Linn.) . 50 Broad-horned flour beetle ( Gnath.ocerus corn~tfu,s Fab.) and Slender-horned flour beetle ( Gnathocerns nza.r:iliosus Fab.) . 53 Page Small-eyed flour beetle (Pal<Yrus ratzeburgi Wissm.)................... 54 Larder beetle (Dermestes lardarius Linn.) . 54 Red-legged ham beetle (Necrobia rufipes DeG.)........................ 55 Large cabinet beetle (Trogoderma ornata Say)......................... 55 Varied carpet beetle (Anthrenus verbasci Linn.) and Museum beetle (Anthrenus museorum Linn.).......................... 56 Black carpet beetle (Attagenus piceus Oliv.)........................... 56 Angoumois grain moth (Sitotroga cerea/ella Oliv.)..................... 57 Indian meal moth (Plodia interpunctella Huebn.)....................... 57 Meal snout moth (Pyralis farinalis Linn.)............... 58 Mediterranean flour moth (Ephestia kiihniella Zell.).................... 59 Cockroaches . 61 Silverfish (Lepisma saccarina Linn.) and . Fire brats (Lepisma domestica Pack.)................................ 61 Ants . 62 Cheese skippers (Piophila casei L.) ..... ,............................ 63 Book lice (Atropos divinatoria Mull.).................................. 63 ~ite~ (Tyroglyphus sp.).............................................. 64 Stenhzation . 66 Oven heating for small quantities. 66 Hot-room method for grains, beans, peas, and other seeds. 66 "Continuous process sterilization" for "sterilizing" products in factories. 68 Heat method of treating mills and warehouses. 70 Special high temperature quarantine room. 72 ~ow: temperature method, or "freezing out". 72 Fum1gat10n . 72 Fumigating grain or seeds, flour, and other cereal products in sacks or bins 72 Penetration and retention of fumigants by food products. 79 Effect of fumigants on baking quality of flour. 81 Effects of fumigants on seed germination. 81 Spraying floors, walls, and other surfaces. 82 Miscellaneous preventive methods for grain treatment. 82 Storing cereals and other food products. 82 ILLUSTRATIONS Meal worm, adults and larvae, in bran (slightly enlarged) ................ Cover Fig. 1. Course of cereal. products from farm to consumer. 7 2. Body of adult beetle separated to show parts. 32 3. Granary weevil (Sitophilus granaria).............................. 38 4. Granary weevil and its work in spaghetti. 39 5. Drugstore beetle (Sitodrepa panicea).............................. 40 6. Cigarette beetle (Lasioderma serricorne).......................... 41 7. Beans infested with bean weevil (Mylabris obtectus)................ 43 8. Cadelle ( Tenebroides mauritanicus) . 46 9. Meal worm ( Tenebrio molitor) . 47 10. Flour containing adults, larvae, and pupae of confused flour beetle.... 49 11. Saw-toothed grain beetle ( Orizaephilus surinamensis). 52 12. "Bran bugs," saw-toothed grain beetle, foreign grain beetle, and flat grain beetle in moist oats (slightly enlarged).................. 53 13. Slender horned flour beetle ( Gnathocerus maxillosus) . 54 14. Larder beetle (Dermestes /ardarius).... 54 15. Red-legged ham beetle (N ecrobia rufipes)........................ 55 16. Black carpet beetle (A ttagenus piceus) . 56 17. Angoumois grain moth (Sitotroga cerealella)...................... 56 18. Indian meal moth (Plodia interpunctella).......................... 58 19. Meal snout moth (Pyralis farinalis)............................. 58 20. Mediterranean flour moth (Ephestia kiihniella).................... 60 21. Silk spun by larvae of Mediterranean flour moth................... 60 22. German cockroach (Blatella germanica)........................... 61 23. Silverfish (Lepisma) . 62 24. Small house ant ( M onomorium pharaonis) . 62 25. Mite ( Tyroglyphus sp.). 65 26. Temperature of cereals during process of heating in oven of gas range 67 27. Temperature of cereals during process of sterilization and packing. 70 Plate I. Life History of Tribolium confusum.............................. 51 INSECTS INFESTING STORED FOOD PRODUCTS ROYAL N. CHAPMAN1 REVISED BY H. H. SHEPARD INTRODUCTION Purpose of the Bulletin The object of this bulletin is to make it possible for any one who is troubled with insects in stored food products to determine for himself what insects they are, where they came from, and what to do to get rid of them. Many insects are not described in these pages, or a special product may not have been discussed. For additional information write to the Division of Entomology and Economic Zoology, University Farm, St. Paul, Minnesota. References are made to papers and bulletins which give more de­ tailed information on some of the subjects. No attempt has been made to give a complete list of literature on any subject. The references given are chosen because they refer to publications easily obtainable and contain detailed information that can not be included in a small bulletin. Treating the insect problems of the grain dealers, the millers, and others separately has necessitated a considerable amount of repetition. This gives each one concerned with the manufacture or distribution of food products a better understanding of his own problems and at the same time makes it possible for him to obtain a similar understanding of the problems of those who are co-workers with him in the handling of stored food products. It is hoped that readers may have a better understanding of the causes of insect attack and that it may hasten the time when manu­ facturers and dealers will no longer believe that insects come from "the germ of the wheat" or from any other source than insect eggs. Then the problem of properly protecting our stored food from insects will be attacked from a more practical