79 



Table XXIX. 



■Percentage of infestation of corn plants at different localities in the 

 cotton belt. 



Locality. 



Date of 

 exami- 

 nation. 



Age of 

 corn. 



X5 • 



^ 2 



o 





1 



Locality. 



Date of 

 exami- 

 nation. 



11 



Time 



of 

 plant- 

 ing. 



Calvert, Tex 



Comanche, Tex... 

 Do 



June 27 

 July 22 

 July 27 

 July 26 

 June 25 

 May 29 

 July 26 

 July 25 

 May 15 

 July 20 

 Aug. 4 

 July 16 

 June 27 

 July 30 

 Aug. 9 

 June 29 

 July 15 

 June 30 



'Ears'!! 



Ripe . . 



Ears . . 

 ...do.. 

 ...do.. 

 ...do.. 

 ...do.: 

 ...do.. 

 ...do .. 



80 

 500 

 500 

 500 

 168 



60 

 500 

 500 



60 



20 

 150 



42 



790 



47 



58 



790 



54 

 500 

 470 



484 



102 



58 



484 



67 

 100 

 94 

 97 

 60 

 96 

 97 

 80 

 70 

 80 

 91 

 99 

 68 

 80 

 100 

 70 

 96 

 95 



Elm Grove, La 



Do 



June 24 

 July 17 



50 

 78 

 62 

 87 



100 

 80 

 90 

 90 



100 

 75 

 80 



100 

 W 



100 

 65 

 95 

 90 



100 





Shreveport, La . 





Cooper, Tex 



Corsicana, Tex . . . 



Dallas, Tex 



Gilmer, Tex 



Groesbeck, Tex . . . 

 Hempstead, Tex. . 



Ladonia, Tex 



Mineola, Tex 



Morgan, Tex 



Navasota,Tex 



Quinlan, Tex 



Do 



Montgomery, Ala. 

 Do 



Sept. 12 

 do 



Early. 

 Late 



Albany, Ga 



Do 



Sept. 7 

 .... do . 



Early. 

 Late 



Augusta, Ga 



Do 



Memphis, Tenn... 

 Birmingham, Ala. 

 Do 



Sept. 10 

 ....do... 

 Sept. 15 

 Sept. 10 

 do 



Early. 

 Late. 

 Early. 

 Do. 

 Late 



66 



42 



...do.. 

 ...do.. 

 ...do.. 

 ...do.. 

 ...do.. 

 ...do.. 

 ...do.. 

 ...do.. 



404 

 125 



60 

 100 



40 

 245 



75 



80 



"74' 

 30 



"185' 

 52 

 69 

 137 



370 

 124 

 41 

 80 

 40 

 173 

 72 

 76 



Lake City, Fla .... 



Lakeland, Fla 



Archer, Fla 



Do 



Batesburg, S. C ... 



Do 



Sept. 14 

 Sept. 7 

 Sept. 6 

 ....do... 

 Sept. 10 

 do 



Early. 

 Do. 

 Do. 



Rosenberg, Tex... 

 Do 



Late. 

 Early. 



San Antonio, Tex. 



Late 









The progress of infestation during the season is shown by the next 

 table, which gives results of counts made during season of 1904 on 

 two fields near Paris, Tex. 



Table XXX. — Progress of infestation during season. 



Date of 

 exami- 

 nation. 



Age of corn. 



Per cent of 

 infestation. 



Date of 

 exami- 

 nation. 



Age of corn. 



Per cent of 

 infestation. 



May 31 

 June 16 



3 to 4 feet high 



5.4 

 27.0 

 56.0 



May 31 

 July 21 



3 to 5 feet high 



1.4 



Silk and tassel 



Roasting ears 



97 2 



July 20 













CANNIBALISM. 



The difference in mortality on corn and cotton is mainly due to the 

 cannibalistic habits of the larvae themselves. When A^oung, this habit 

 does not manifest itself very strongly unless the bollwoi'ms are 

 pressed for food, but after they are half-grown or larger they become 

 extremely vicious and attack one another on the slightest provocation. 

 If two larvae are feeding in one ear of corn and their paths acciden- 

 tally cross, they become irritated at once and snap at each other with 

 the mandibles. Usually the larger one is victor and makes a meal of 

 the smaller. If, as is sometime the case, both are of approximately 

 the same size, it is not unusual for both to be so injured as to die. 

 Even two larvae peaceably crawling about will almost always fight if 

 they come together unexpectedly. They do not evince any desire to 

 hunt out their fellows, however, and it appears to be merely chance 

 which brings them into contact. Observers have often been inclined 

 to think that cannibalism was induced by external annoyances caused 

 22051— No. 50—05 6 



