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SClENTlF^iC AGRtCULTURE. 



March, 1921. 



The European Corn Borer 



II. a. CRAWFORD, 

 •Entomologist, Division of Field Crop and Garden Insects, Entomological Branch, Department of 



Agricnltnre, Ottawa. 



An address before the Lambton County Corn Growers Association at Petrolia, Ontario, February 10, 1921. 



Up to the present time the corn-growers of Canada 

 have been particularly fortunate in the freedom of 

 their crop from serious or regular losses due to inseat 

 pests. True, we have suffered from cutworms, white 

 grubs, wire-worms, and a few others but only sporadic- 

 ally and rarely seriously from year to year. 



Today, on the other hand within a fairly large part 

 of Ontario where corn is grown as an important grain 

 crop this happy day is past. We have been rudelj' 

 awakened to the realization of the fact that there is in 

 our midst an insect pest of great importance. An Eu- 

 ropean insect has invaded our corn-growing region and 

 has become established to such an extent and under 

 such conditions that it is difficult to see how it can be 

 exterminated. It, therefore, may eventually spread 

 over most of the continent, exacting an annual toll of 

 incalculable amount and bidding fair, if our fears are 

 not entirely misplaced and if vigorous control measures 

 are not instituted, in the meantime to further disorgan- 

 ize the whole corn-growing industry. What this means 

 when we realize that the corn crop of the county of 

 Lambton is valued at $1,679,000, that of Ontario at $36,- 

 000,000, while that of the continent is worth annually 

 approximately $3,000,000,000, 1 need not enlarge upon 

 to corn-growers. 



The insect i)est referred to is the European Corn- 

 borer, Pyrausta nubilalis Hbn. The discovery of the 

 presence of this insect in the late summer of 1920 over 

 a large area of the corn-growing region of Ontario 

 certainly came as a most unwelcome surprise to the 

 entomologists and agriculturists of Canada. 



Ttie present i-tatus of the Corn-borer in tiie United 

 States, where it was discovered in Massachusetts in 1917, 

 may be briefly sketched by saying that there are t,iiree 

 infested area-s — one in New England, Boston City and 

 neighboring counties of 8350 square miles, one in Cen- 

 tral New York of 1365 square miles and one in West- 

 ern New York of 936 square miles. 



In the New York infestations the actual damage is 

 not great and the infestation is chiefly in field corn, 

 and to some extent in weeds. The intensity of the 

 attack, however, is in no way comparable to that of our 

 own in the St. Thomas region. 



The New England infestation, though, in .sweet corn, 

 shows what we may expect of this pest under favourable 

 circumstances. Here 100 p.c. of the corn may be attack- 

 ed, single corn plants containing as high as 117 larvae; 

 an average of 46 larvae per stalk in one patch was sec- 

 ured. One hundred and sixty of the commoner weeds 

 are readily utilized as food plants and numbers of fields 

 and truck gardens not in crop have 100 p.c. of the 

 weeds infested. In each of these weeds may be found 

 from one to at least ten larvae. 



In addition most of the succulent stemmed truck 

 crops are infested to a greater or less extent, such as 

 celery, beets, potatoes, dahlia, chrysanthemum, etc. 



This variety of host food plant together with the fact 

 that in New England the borer has two generations, 

 produce an abundance of borers, impossible to realize 

 from description and astounding to see. 



The presence of the larvae in the stems of the truck 

 crops which are shipped widely from the Boston area, 

 (75 p.c. of the celery used in the New England States 

 is gi'own within the limits of greater Bo,ston) necessit- 

 ated a very rigid quarantine, inspection and certifica- 

 tion system to prevent general distribution of so serious 

 a pest. 



The efforts to control the liorer in the United States 

 were prompt and involved the first year, 1918-19, the 

 voting of .$100,000 by each of the states of Massach- 

 usetts and New York, and in the following year of 

 $250,000 by the federal authorities, while last year in 

 addition to a regular appropriation of $250,000, 

 $450,000 was set aside for this work by the Federal 

 tiepartment of Agriculture. The last report of the chief 

 of the Bureau of Entomologj^ which is for the year end- 

 ing June 10, 1920, states that there are 194 men en- 

 gaged directlj- in the control of this pest. Since this 

 report was published the staff has been considerably 

 augmented, at least some 30 men being engaged in in- 

 vestigation alone and 75 inspectors concerned with the 

 enforcement of the (juarantine. 



Ever since the discovery in the United States of the 

 borer the Entomological Branch has been aware of the 

 danger of the importation of this pest into Canada and 

 as a con.sequenee ha,s taken every reasonable step 

 both to determine its presence or to prevent its import- 

 ation. To this effect the border counties and corn- 

 growing sections in particular were circularized in post 

 offices and railway stations and through agricultural 

 officials, b.v means of illustrated posters as soon as 

 possible after the presence of the pest in the United 

 States was known. These placards described the insect, 

 its damage, warned the public against the danger of 

 importation, requesting at the same time that anyone 

 finding a borer in corn should send the same to the 

 Dominion Entomologist, Department of Agriculture, 

 Ottawa, so that it might be identified. In this way by 

 enlisting the cooperation of that part of the community 

 interested and likely to meet the pest first, its presence 

 would be noted at the earliest opportunity, and we 

 should be able to nip the infestation in the bud did it 

 actually occur. At the same time a rigid inspection of 

 the importation of com and corn products as well as 

 plants and materials likely to harbor the pest was es- 

 tnblis.hed at the border. 



As part of this protective and preventive system the 

 best of the experienced scouts and field men formerly 

 engaged in the Brown-tail moth work of the Entomo- 

 logical Bi-anch were .sent to the infested areas in New 

 York State in order to have fii"st hand knowledge of the 

 appearance of the infestation and to study the best 



