102 THE rtEroirr of the No. 36 



with potted potato plants which were kept well watered. Here the results were 

 -quite different : leaf -burn developed on the infested plants whereas the check (one 

 plant) showed no indications of it at all. The interpretation of these results 

 ■would appear to be that two factors caused the leaf -burn this year, namely the 

 drought (probably the more ini|)ortant) and the leaf-hopper, 



(JxiON Theips (TJirips tahaci). This pest exacted a very heavy toll this 

 year from the truck gardeners of Ontario. In the counties of Kent and Essex 

 the thrips, aided by the hot, dry weather, reduced the onion crop to one-third of 

 41 normal yield. 



Taexished Plant Bug (Lygus 2^ ''at en sis) . This well known bug was pre- 

 sent in exceptionally large numbers this year and caused a considerable amount 

 ■of damage especially in gardens. Asters and dahlias were attacked so freely that 

 in many sections they were a complete failure. At the Dale Estate, Brampton, 

 ■only about one thousand flowers were cut from twenty thousand plants. At 

 Kingston spinach grown for seed was injured to such an extent that the plants 

 failed to produce any seed. Plant bug injury, in the form of blasted compound 

 leaves was common in potato fields. The black joint disease of celeiy caused by 

 •the bugs feeding at the joints was prevalent throughout the province. It should 

 be mentioned here that Mr. MacLennan, Ontario Vegetable Specialist, is positive 

 that the tarnished plant bug is the chief agent concerned with the spread of 

 bacterial soft rot or black heart of celery. 



Potato Flea-beetle {EpHrix curvnieris). In June this species and its 

 work were conspicuous in potato patches in tlie Niagara district. It was nlso 

 injurious to tomatoes. 



The Theee-lined Leaf-beetle {Lema trUineata) was unusually common 

 •on potatoes in the Niagara peninsula. 



The Steiped Cucumbee Beetle (Diahrotica vittata) occurred in more than 

 ■usual numbers in parts of Norfolk County, but around Burlington and in many 

 ■otlier localities it was scarce. 



Insects Attacking Field Ceops. 



Clovee Leaf Weevil {Phijtonomus punctatus). The larva? of this pest 

 ■occurred in exceptionally large numl^ers in parts of the Niagara peninsula and 

 southwestern Ontario. In Norfolk County a whole field of clover was ruined. 

 However, in most fields serious injuiy was prevented by the almost complete 

 destruction of the grubs by a fungus disease. 



Chinch Bug (BU^sus Uucoptenis). The chinch bug appeared in large 

 numbers this summer in Gainsboro' Township, Lincoln County, and caused a 

 considerable amount of alarm among the farmers. The centre of infestation was 

 at the village of Bismark and the infested area extended, roughly speaking, about 

 two miles around tlie village. Meadow grasses, particularly timothy, were in some 

 instances killed outright. Oats were injured to a considerable extent. One six- 

 acre field was completely destroyed and in another field a strip about the width 

 of a drill was also killed outright. However, as a general rule the infested oats 

 (lid not die but ripened ]>rematurely and produced little or no grain. Some damage 

 was also done to corn. 



Late in September we found large numbers of the adults destroyed by Ihe 

 chinch bug fungus (Sporolriclnim gl oh id if c rum). The percentage of mortality 

 varied from 25 per cent, to 75 per cent, in the fields examined. 



