64 



THE REPORT OF THE 



No. 19 



THE INSECTS OF THE SEASON. 

 By W. LocHHEAi), Ontario Agricultural College, Guelph. 



The year 1902 was one of many surprises for the economic entomologist. Several insects 

 which did serious damage in 1901, and which gave indications that their ravages would be even 

 more serious in 1902, were conspicuous by their absence, or by their very diminished numbers. 

 The Hessian Fly is an example. Again, other insects, which in the last few yoars were not 

 Considered serious, appeared in large numbers and did much damage. The Clover-seed Midge 

 is an example. Other examples will be given in their appropriate place in the following notes- 



The wet, cold season had its influence in checking the multiplication of some injurious 

 forms, but in the case of others there was no appreciable check. 



Insects Injurious to Farm Crops. 



For reasons, which can be only partially explained, the Hessian Fly {Cecidomyia destructor) 

 did very little damage in those regions where it was most abundant last year. While it is 

 true that a much smaller acreage of wheat was sown last fall, and as a rule the s(jwing was 

 done much later than usual, yet there remains some apparently unaccountable cause for tha 

 almost total absence of flies in those regions. The winter and fall were not unfavorable to 

 insect life, if we can judge from the condition of most insects in spring. It is probable that 

 the parasites were more abundant than were supposed, and that they were instrumental largely 

 in killing most of the Hessian Flies. 



In South Grey, however, the Hessian Fly did mush damage this year, some fields of wheat 

 being entirely broken down by the spring brood. There it appeared to attack certain varieties 

 of wheat in preference to others. For example, the Early Arcadian was untouched, while the 

 early Clawson, sown at the same time, and on the same kind of soil, and under other similar 

 conditions, was seriously aff"ected. 



The Pea- Weevil {Bruchus jjisl) continued its ravages with undiminished 

 vigour in the older sections, and spread to new areas where it had previously 

 been unknown. It is evident that concerted action must be taken or 

 else pea-growing will have to be abandoned. Already in some sections 

 the latter policy has been adopted. 



The Clover-seed Midge {Cecidomyia leguminicola) Figs. 39, 40 and 4l, 

 was abundant in the western portion of Ontario, and in many places com- 

 pletely destroyed all clover left for seed. Even that which was pastured 

 up to June 20th was destroyed, according to some reports. Here, again, 

 farmers must co-operate. All should cut or pasture their clover until the 

 20th of June. 



In many respects, Wireworms, Figs. 42 and 43, may be considered one 

 of the most injurious insects which attack farm crops. The extent of the 

 ravages is diflBcult to compute, for in some localities they are almost absent, 

 but in others they are very abundant. 



On account of their habit of working below the surface of the ground, 

 no reliable method has been devised for their destruction, or for the pre- 

 vention of their attacks. In fields which have been kept for several years 

 in sod, wireworms are almost certain to multiply. When the sod lands are broken up, the 

 f' worms" will be found in almost every stage of development. Some are very young and will 

 require two or more years before becoming mature ; some are a year old ; some two years old. 



Fig 39. 

 The Clover- seed 

 Midife : (a) larva 

 hifihly matjnified; b) 

 head retracted, still 

 more highly magni- 

 fied. (Riley.) 



