1924 



ENTOMOLOGICAL SOCIETY 



77 



As Essex county is the greatest corn-growing county of the province, with 

 a corn acreage of 80,000 acres, the conditions there will naturally be of interest. 

 Mersea township was found infested in 1921 and infested stalks were difficult 

 to locate. The remainder of the county was scouted but nothing was found. 

 In 1922, collections were made in each remaining township. Many fields of 

 corn were examined in the central and northern townships before larvae were 

 discovered, but in the southern townships collections were more easily made, 

 although the infestation was extremely light. Our records in Essex county this 

 season show a decided increase. Standard records were taken from five fields 

 at eight points in the shore townships, and also at Pelee Island, the results of 

 which are as follows: 



Township 



Locality 



Highest 

 Per Cent. 

 Infestation 



Lowest 

 Per Cent. 

 Infestation 



Average 

 Per Cent. 

 Infestation 



Mersea ' 



Gosfield — south 



Gosfield " 



Hillman 



Ruthven 



Arner 



Oxley 



Harrow 



Marshfield 



Comet 



Maiden Center 



Misc. (8 fields) 



5.5 

 1.2 

 0.4 

 0.8 

 0.4 

 0.9 

 0.9 

 0.6 

 13.66 



2.2 

 0.3 

 0.0 

 0.0 

 0.2 

 0.0 

 0.0 

 0.0 

 0.33 



3.48 

 0.86 

 0.14 



Colchester — south 



0.34 



Colchester " 



0.28 



Colchester " 



0.42 



Maiden 



Maiden 



0.42 

 0.3 



Pelee Island 



5.89 



Pelee Island was found infested in 1921. The degree of infestation was very 

 low at that time. In 1922, the Pelee Island conditions were not studied, but the 

 survey of 1923 showed a remarkable increase and the infestation was much more 

 intense than that of the neighbouring mainland. 



The infestation in Welland county, first found in 1920, is increasing, but 

 much more slowly than in the western territory. The results of the records in 

 the other counties listed also indicate an increase, although an exact degree of 

 comparison is impossible, owing to the lack of necessary information. 



In reference to the 1923 increase, in territory near the centre of the outbreak, 

 it has been most important to the north and east. The relation of the corn 

 borer to the corn-canning industry in general has always been regarded with 

 anxiety. This recent development is unfortunate in that it has affected canning- 

 corn crops in the Aylmer region very seriously. The infestation in all other 

 canning districts is as yet comparatively light. 



In 1920, the degree of infestation in the districts from which the Aylmer 

 canning factory received its corn supply would average five to ten per cent, stalk 

 infestation. In 1921, various canning-corn fields ran from 21 per cent, to 74 

 per cent, ear infestation. In 1922 the factory refused material with ten per cent, 

 ear infestation, with the result that corn was refused from one or two fields and 

 two loads from other fields were turned back. This year the situation became 

 serious. Corn delivered to the factory by twenty-two growers on September 

 4th was examined. Notwithstanding the fact that practically all growers had 

 already culled from five to thirty per cent, in the field, the corn presented to the 

 factory varied in ear infestation from six to fifty-six per cent., and from two to 

 forty-three per cent, of the cobs showed actual feeding. As a result of this 

 condition, a special control campaign has been started in the district under the 

 personal direction of Prof. L. Caesar, Provincial Entomologist. 



