28 



BULLETIN 1103, U. S. DEPARTMENT OF AGRICULTURE, 



Table 7. — Monthly departures from normal temperature and rainfall for the 

 fall of 1920, the tmnter of 1920-21, and the groiving season of 1921 in the 

 region infested by the sorghum wehworm during 1921. 



DEPARTURES (IN DEGREES FAHRENHEIT) FROM NORMAL TEMPERATURE. 





1920 1921 





Sept. 



Oct. 



Nov. 



Dec. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Missouri 



+ 1.4 

 -I-.6 

 -fl.2 



+4.3 

 +3.8 

 +2.2 



-3.5 

 —4.4 

 -3.9 



+2.6, +7.2 

 +3.2! +6.9 

 + 1.2i +5.7 



+9.1 

 +9.0 

 +6.3 



+8.5 

 +7.3 

 4-8.3 



+0.9 



+.9 



-1.1 



+2.0 

 +2.4 

 + .7 



+3.4 

 + 1.6 

 +2.1 



4-2.9 



4-0.8! 4-4. r 





4-1. li -t-1.4' -i-4.6 



Arkansas 



+2.2, +2.4i +6.0 









Regional mean 



+1.0 



+3.4 



-3.9 



+2.3! +6.6 



i 



+8.1 



+8.0 



+.2 



+ 1.7 +2.3 



+2.0! +1.5 +5.1 





DEPARTURES (IN INCHES) FROM NORMAL RAINFALL 







Missouri 



+0. 92 



+.22 

 +.06 



+0.25 

 + 1.04 

 + 1.68 



-1.09 

 +.19 

 -1.47 



-0.22 

 -.07 

 + 1.92 



-0.38 



+.37 

 -2.08 



-1.33 

 -1.01 



-.18 



+ 1.68+L52 

 +.08 +.72 

 +2. 10 +3. 02 



-1.20 

 -L31 

 -2.83 



1 

 + 1. 15 -L 771 + 1. 63 

 +.81 -.37; +.26 

 + .60—1.43+1.40 



+3. 15 



Kansas 



+.58- 





4-.oa 









Regional mean 



+ .40 



+.99 



-.79 



+.54 



-.69 



-.84 



+1. 28 +1. 75 



-1.78 



+ .85 



-1.19J+1.09+1.25. 



EUROPEAN CORN BORER. 



(Pyrausta nuUlalis Hiibn.)* 



The outstanding developments in the corn-borer situation for 

 1921 were, first, the serious injury to field corn and the development 

 of a much greater area of infestation than was believed to be present 

 in the Province of Ontario, Canada ; second, the discovery by Bureau 

 of Entomology scouts of the presence of the insect along the entire 

 southern shore of Lake Erie from the extreme western line of New 

 York State through Pennsylvania and Ohio to southeastern Mich- 

 igan, just south of the city of Detroit. The latter infestation is a 

 very mild and uniform one and, so far as has been ascertained, does 

 not extend far inland. No commercial injury whatever has been 

 done in this area as yet ; nevertheless, its establishment there becomes 

 of great importance, as indicating that this insect is in a position to 

 invade the area of most intensive corn production in this country. 

 The conditions in the various other areas of infestation prevailing^ 

 at the beginning of the spring of 1922 are as follows (Fig. 14) : 



The corn borer is known to be present throughout a total area of 

 7,696 square miles within the United States, as compared with an 

 area of 7,690 square miles in Ontario, Canada. The area of infesta- 

 tion in eastern New England comprises 2,670 square miles. The 

 spread there during the past year has been comparatively small^ 

 and in every case is contiguous to the area of infestation as known 

 in 1920. A very small incipient infestation discovered during the 

 summer of 1920 in the township of Eliot, Me., was cleaned up and 



* Reported by W. R. Walton, Bureau of Entomology. 



