INSECT PESTS 249 



cephalonica Staint. in Senegal (131) ; Homoeosoma vagella Z. in Aus- 

 tralia ; Embia (Monotylota) vayssierei Navas in stored peanuts in Sene- 

 gal (123); Sitotroga cerealella (Oliv.), Angoumois grain moth, and 

 Tenebrio sp., (meal worm) in stored peanuts in the United States (17). 



Control. Natural enemies are of value in controlling pests of stored 

 peanuts, but the species of hosts and parasites involved are so numerous 

 and varied that a detailed discussion here is not feasible. Among the 

 more important parasitic and predaceous forms are Microbracon hebetor 

 (Say), M. jugeandis Ashm., Idechthis canescens (Grav.), Omorgus 

 jrumentarius Rond., and Scenopinus fenestralis (L.) (136, 11). 



Sanitation and proper bagging have been found helpful in preventing 

 insect damage to stored peanuts. Bissell and DuPree (17) found that 

 peanuts could be protected from serious infestation by storing them im- 

 mediately after shelling in cotton bags made from heavy material having 

 60 threads by 104 threads per inch. Jute bags counting 11 or 12 threads 

 per inch did not give satisfactory protection. For maximum protection, 

 properly bagged peanuts should be stored in clean, insect-free bins. To 

 free bins, storehouses, boxcars and the like of insects, the walls, floors 

 and ceilings may be sprayed with DDT in a 5 percent solution in light oil 

 (36, 37) or in the form of a 5 percent emulsion in water. 



Heat and cold have been employed satisfactorily in preventing insect 

 damage to peanuts and peanut products in storage. It was found (19) 

 that a temperature of 125° F. for 6 hours destroyed insects in loose piles 

 of dry peanuts without injury to the peanuts. Also it was reported (36) 

 that a temperature of 120° to 130° F. maintained in all parts of flour mills 

 for 10 to 12 hours destroyed all insect life. Forced circulation of air was 

 necessary to maintain proper temperature throughout the treated area. 

 The use of heat is limited by facilities for maintaining suitable tempera- 

 tures within masses of stored products. Refrigeration is also effective 

 in preventing insect damage. Protection against insect infestations has 

 been reported when peanuts and peanut products are stored at 50° F. 

 or below ( 164) . The keeping qualities of the products were also enhanced. 



Fumigation is perhaps the most feasible method of destroying insects 

 in stored peanuts, once they are infested. Materials which have been used 

 for this purpose include carbon disulfide and hydrogen cyanide (19, 33), 

 a mixture consisting of three parts ethylene dichloride and one part 

 carbon tetrachloride (80), ethylene oxide, 4 ounces plus 2.8 pounds of 

 carbon dioxide per 100 cubic feet in a vacuum tank filled with peanuts 

 (34), and methyl bromide (97, 139). Chloropicrin has been found efifec- 

 tive, but it is absorbed and increases the acid content of the peanuts as 



