62 



THE REPORT OF THE 



No. 38 



Me. Walton", Entomologist in charge of Cereal and Forage Insect Investiga- 

 tions, briefly stated his Division was continuing a series of investigations on the 

 biology, habits, etc., of the corn borer and had established a laboratory at Arlington, 

 Mass. Branch laboratories were also located in the vicinity of Schenectady and 

 Silver Creek, N.Y. 



In addition to the investigational work arrangements, were being completed 

 for the importation of parasites from Europe. A laboratory was also established 

 at Auch, France, in charge of Mr. W. R. Thompson. It was expected that a large 

 importation of parasites would be made this coming winter. It is also expected 

 that additional laboratories would be established in Europe as necessity arose. 



Map of Western Ontario, showing area scouted for European Oorn Borer in 1920. 

 Townships in isiolid black were' found to be infested, those crossed by the diagonal 

 lines OBly, were scouted but no borers were found. 



Mr. Crawford spoke in general of his investigations in the Union Village area 

 about six miles from St. Thomas, Out., in the autumn of 1920. It was in this 

 area, an essentially flint growing region where the greatest infestation was found. 

 In some fields from 70 to 99% of the stalks were infested, while pure stands of dent 

 corn in the same vicinity had a 45% stalk infestation. 



One field of flint corn in which 93% of the stalks were infested had been 

 studied closely. The attack in this field was distributed over the different parts 

 of the plant as follows: Tassels, 50'% injured; nodes, 17%; internodes, 25%; cobs, 

 55%; shanks, 51%; nubbins, 45%; stubble, 29%. This infestation resulted in the 

 falling of 50% of the tassels, a devouring of 3% of the kernels and a breaking down 

 of 42% of stalks at one or two points. 



Mr. Crawford referring to the infestation in dent corn stated that this variety 

 was very markedly less intensely attacked than flint corn and the effect upon the 

 plant much less. Thus the field of dent corn 45% infested lost but 7.7% of tassels 

 and only 8% of the stalks were broken over, almost no cobs infested and the stubble 

 but very slightly infested. Even in a mixed field of flint and dent corn where 

 the flint cobs were 38% infested, the dent corn showed but 9%. 



