INSECTS INJURIOUS TO ONTARIO CROPS IN 1905. 

 By James Fletcher, Dominion Entomologist, Ottawa. 



In nearly all parts of Canada, weather reports have shown favourable 

 conditions for the growth and maturity of crops, and Ontario has been no 

 exception in this respect. Although reports have mentioned a large number 

 of different kinds of insects which have been more or less noticeable by their 

 attacks upon crop-plants, there have been fewer bad outbreaks of injurious 

 insects than has been the case for many years; and the general report of the 

 year in Ontario is that there have been no attacks of special importance and 

 no new enemies which are likely to be the cause of serious loss in the future. 

 Notwithstanding this, however, there are still plenty of the old and well 

 known enemies which require the attention of the fruit grower and farmer; 

 and this seems an appropriate time to again reiterate the warning that the 

 most effective time to fight injurious insects which are known to have ex- 

 tensive powers of injury, is just when they occur in small numbers, as evi- 

 denced by slight injury. It becomes more and more apparent every year 

 that preventive measures for warding off insect attack should become general 

 principles of agriculture to be applied as a matter of course every year. 



Now that spraying fruit trees to protect them against injury by the 

 Codling Moth and the Black Spot fungous disease, has become such a matter 

 of course with the leading fruit growers, there are numberless instances which 

 might be cited in proof of the statement that orchards which are sprayed 

 every year gradually become so free of their enemies that practically they 

 may be said always to produce clean fruit, whereas in neighbouring orchards 

 where no spraying is done, the opposite to this is the case. 



Cereal Crops. 



The worst enemies of grain crops have been conspicuously absent during 

 the season of 1905. There have been no complaints at all of Hessian Fly; 

 and, although, if looked for carefully, it was possible to find in one or two 

 localities the orange larvae of the Wheat Midge, there have been no reports 

 received from farmers of their occurrence. Neither Wireworms nor White 

 Grubs were mentioned in grain crops. The only exception to the general 

 immunity was in the case of a locally rather severe occurrence of the Wheat 

 Joint Worm (Isosoma tritici, Fitch). This was at Millbrook, Ont., where 

 it did considerabe harm. Mr. T. D. Jarvis, of Guelph, also mentions Joint 

 Worms as the cause of injury to both wheat and barley in western Ontario. 



In Ontario there is only one annual brood of the Joint Worms, the 

 insects passing the winter as larvse within cells which they have hollowed out 

 inside galls made at joints of the swollen and distorted straws. Fig. 29, 

 These are, for the most part, so near the ground that a large proportion of the 

 larvse are left in the fields in the stubble. The ploughing down deeply 

 or the burning over of stubble in autumn reduces the numbers of the larvse 

 which can turn to flies the following spring. That part of the stem which 

 is attacked, generally swells and makes a distorted and bent gall; but this 

 is not always the case, the attacked portion of the stem simply becoming 

 thickened and hardened. These hardened portions frequently break off 

 in threshing and are either carried through with the grain or with the small 

 seeds. When cleaned out, they should be destroyed and not left on the 

 ground, where the flies can hatch the following spring and fly to the fields. 

 When the screenings are fed, these should always be crushed; but, if fed 



6 EN. [ 81 ] 



