34 THE EEPOET OF THE No. 36 



There are many different pests taking toll from these crops, six of which have 

 been especially noteworthy in the past. They are : The Western Wheat-stem Sawfly, 

 Cephus ductus; Grass-stem Maggots (Oscinidae) ; Hessian fly; Wireworms; 

 Locusts and Cutworms. Five of these are native species which before the advent 

 of farming occupied their allotted space in the scheme of nature just as any other 

 harmless creature might do. As usual, however, man upset the balance of things 

 in his attempt to increase production and in doing so provided an unlimited supply 

 of food for these insects. Thus we have the Western Wheat-stem Sawfly spreading 

 from wild grains to cereals and what is almost as important, in most cases, leaving 

 their natural enemies behind them. In their former state they were kept in check 

 by two agencies, namely, lack of flowering stems in which they bred, or parasitic 

 enemies. Under present conditions it would seem as if both these checks had been 

 overcome and there remains, therefore, but one means of keeping them under 

 control, namely, deep, well-turned, packed ploughing done either in the fall or 

 before June of the following year. 



The grass-stem maggots embrace many species and include such well known 

 pests as the Greater Wheat-stem Maggot {Meromyza americana) , Frit Fly {Oscinis 

 frit) and many more. There is much variation in the life-history of these flies. 

 Some are very injurious, others become so at times, while yet others actually do 

 good. A few years ago less than a dozen species were known from Canada but 

 within the last three years many more have been discovered including several that 

 are new to science. The life of these flies is extremely variable. Some produce 

 several generations in a season, others but one, while some again, pass the winter 

 in the adult stage, others doing so as larvae. They are by no means all grass 

 feeders and some prefer decaying matter to living. Thus there is endless variation 

 in their habits and much to be learned concerning them. 



The Hessian fly is the only one of those mentioned that is not a native of 

 our country and as is the case with many of our introduced animals it is subjected 

 to inconveniences at times, through our variable climate. We have had seasons 

 when fully 40 per cent, of the crop was injured by this insect, but its attacks, 

 as a rule are few and far between, due chiefly to a lack of humidity at critical 

 periods of the insect's life. In other words moisture is an essential factor in the 

 insect's increase, while dryness reduces it to insignificance. Thus it is only during 

 wet seasons that we have to be on our guard for possible outbreaks. Indeed, we 

 have had but two severe infestations in thirty-five years. 



Wireworms are with us always, but as is their habit elsewhere, they perpetuate 

 most freely in grass lands. Several species are involved in our losses, the life habits 

 of which are little known, but the average investigator is not anxious to undertake 

 their study owing to the length of time it takes to rear them through all their 

 stages. I personally have had an individual under observation for three years 

 and it has hardly grown in that time. 



One of the greatest scourges we have to contend against is that class of insects 

 known as cutworms. They are always present. Sometimes in one part, at others 

 in another. They come and go, but there are so many species involved that the 

 farmer is often at his wits' end to know what to do. When the outbreaks are 

 excessive large areas are swept off, much as army-worms would clear them. Thus 

 hundreds of miles of territory may be involved. At other times the outbreaks are 

 quite local ])ut we are never wholly free from them and in gardens they are a 

 permanency. There is much variation even in the life of these insects. Some 

 deposit their eggs upon weeds, others in or on the soil. Some hatch from eggs the 



