1922 



ENTOMOLOGICAL SOCIETY 



Variety 



Date 



Per cent of 

 stocks infested 



Per cent of 

 stocks broken over 



Per cent of 

 cobs infested 



Golden Bantam 

 sweet corn 



May 24 

 May 31 

 June 3 

 June 9 



30.18 

 34.4 

 15.33 

 7.52 



16.93 



20.00 



7.66 



4.30 



16.9 

 2.14 



1.89 

 1.19 



Dent Corn 

 Early Learning 



May 31 

 June 3> 

 June 9 



24.30 



13.45 



8.11 



69.44 

 1.50 

 1.62 



.4 



.99 



1.17 



Golden Glow 



May 28 

 June 3 

 June 9 



53.42 



21.08 



7.44 



17.81 

 9.73 

 4.65 



2.12 



.99 

 .63 



Wisconsin No. 1 



May 28 

 June 3 

 June 9 



54.44 



15.61 



3.66 



16.14 

 5.35 

 2.44 



2.65 

 1.29 

 1.16 



Flint Corn 

 Salzers' 

 North Dakota 



May 28 

 June 3 

 June 9 



70.9 



10.62 



14.74 



20.77 

 10.12 



2.17 



13.31 

 3.77 

 4.11 



Compton's Early 



May 28 

 June 3 

 June 9 



82.4 



44.14 



15.10 



50.00 



17.79 



4.17 



10.47 

 9.68 

 3.45 



Smut Nose Yellow 



May 31 

 June 3 

 June 9 



30.14 



28.57 

 3.45 



11.41 

 14.29 



.86 



6.10 

 4.11 



1.89 



The larval population in badly infested fields attained enormous magnitudes ; 

 a dent corn field sown May 18th carried an estimated total of 294,152 per acre, a 

 flint field sown on the same day suffered a total loss of at least 65%s supported a 

 total of 258,400 per acre and left when cut, in the stubble (less than 4 inches in 

 height) and the crop refuse, a residue of 43,487 caterpillars going into the winter. 



In o-eneral. all things considered, there seems to be no marked preference for 

 any particular type or variety of corri; the severe loss associated with sweet corns 

 and the flint varieties being due to the early planting, the ability of the larva? to> 

 establish themselves and the small dimension of the stalks. The obvious relatively 

 slight loss in the dent corns is due to the later planting,, its vastly greater 

 bulk and its harder and coarser texture preventing a large proportion of the 

 larva? establishing themselves in the first instance. 



Ttte Infestation of Plants Other Than Corn. 



About the middle of July in the very severely infested fields of' early sweet 

 corn, to a less extent in severely infested flint and to a very slight extent in dent 

 corn except in the one severely injured field, the nearly full grown and full grown 

 larvae become restless. At this time large numlbers of them leave the now breaking, 

 shrivelling and drying corn stalks an'd carry on an apparently haphazard migra- 

 tion throughout a period of about two weeks. In the course of this migration as 

 many as 24,400 larva? per acre found their way into the weeds in one field of 

 sweet corn sown April 25th. Others doubtless returned to the corn plants. Con- 

 siderable feeding was done in the larger weeds, the pigweeds, the lamb's quarters 

 and barnyard grass breaking over in a high percentage of cases. The barnyard grass 

 was infested as high as 88% and in one instance a plant with 26 stems was found 

 to contain 17 larvae. The weeds infested in this field in the order of frequency were: 

 barnyard grass (Echinochloa crus-galli, Beauv.), redroot pigweed (Amaranthus 



