SPRING PRACTICE IN ECONOMIC ZOOLOGY. 33 



burn, scatter straw over the field and on cool days, when the insects 

 have crept beneath it for shelter, set on fire. If the surface of the 

 ground is level, a heavy roller run over it will crush many of the 

 nymphs, especially on cool days or in the morning and evening. 



When the nymphs are very numerous over large areas it is best 

 to resort to ditching. The ditches are made two feet wide and two 

 feet deep, with vertical sides. The sides next to the field to be 

 protected must be kept finely pulverized and not allowed to become 

 washed out or hardened. The right condition may be kept by 

 dragging a brush composed of dead branches through the ditch as 

 often as necessary. Pits should be sunk in the bottom of the ditch 

 at short intervals in which the insects will accumulate, where they 

 can easily be buried. Where it is possible to flood the ditches with 

 water, the water may be covered with a film of coal oil, and the 

 insects can be rapidly and certainly destroyed by being driven into 

 the ditches. 



The hopperdozer, much used in the northwest to destroy the 

 nymphs, consists of a shallow receptacle of any convenient size, 

 furnished with high back and sides, mounted either on wheels or 

 runners. Large pans are provided with transverse partitions which 

 prevent slopping of the water and oil when the machine catches a 

 jar. The pans are filled with water and coal oil or gas tar, and are 

 then pushed by hand or horse power over the infested fields, a set 

 of shafts and handles being so arranged that the front edge of the 

 pan can be elevated or depressed at will to adjust it to the jumps of 

 the nymphs. A suggested form for operation by hand power is 

 made of ordinary sheet iron eight feet long, eleven inches wide at 

 the bottom, and turned up a foot high in the back, and an inch high 

 in front. A runner extending some distance behind is placed at 

 each end and a cord is attached to each front corner. This may be 

 drawn by two boys. With more hands, several dozers may be 

 placed end to end in a row, one man holding the cords of each pair 

 of continuous ends, and thus the work may be done rapidly and 

 well. 



WHEAT INSECTS. 

 MARCH-APRIL. 



The Wheat Joint Worm, Isosoma tritici, is carried over in the straw 

 or stubble of the preceding year. In sections where winter wheat 

 is grown, if care was not taken the preceding fall to sow as far as 

 possible from the infested stubble fields, the best remedy where it 

 can be applied is to burn the stubble. Where the wheat was sown 

 as a nurse crop for grass and, therefore, the stubble cannot be 

 burned it may be worth while to rake over the field with a hayrake 



