17 



after they hatch from getting to the feeding places, and in some 

 instances thev act also as contact insecticides and kill the freshly- 

 hatched young. Hence the necessity of making the applications 

 early, frequently and thoroughly, beginning just as soon as the 

 plants are well established or have made their appearance above 

 ground, or -when there is evidence of the fly's presence about the 

 plants. Some of the substances which have been recommended 

 and tried with more or less success are here noted, and the differ- 

 ences in the results which have been obtained may have been due 

 to the differences in the time, amount and thoroughness of the 

 applications, and in this connection what has been said about the 

 ovijDGsition of the fly should be remembered. 



Tarred Paper Cards. 



These are simply discs or cards of tarred paper, measuring two 

 and one-half to three inches in diameter, applied around the stalk 

 of cabbage or cauliflower plants at the surface of the ground. 

 They may be round, square or any other shape, but for convenience 

 and economy they are made hexagonal with the tool and in the 

 manner shown in Fig. 13. The tool consists of a piece of wood, to 

 the k'wer end of which has been attached a band of steel, bent so 

 as to form half a hexagon, with a line running to the center, where 

 is situated another metal piece which makes a star-shaped cut. 

 The piece of tarred paper is cut along the lower edge, as indicated 

 in the lower left-hand outline of Fig. 13, and then l)eginning at 

 the left a cut is made by the tool as represented by the dotted line. 

 The result is a perfect hexagon with a slit extending from one of 

 the angles to the central star-shaped cut, as shown in the upper 

 left-hand figure. The lower cutting edge of the tool should be 

 beveled on the outer side, so that it may be readily sharpened when 

 required. The paper used is that known as "one-ply tarred felt." 



The method of a}q>lying the card is to separate the two edges of 

 the slit limning to the center, slip tlie card around the plant when 

 it is set. and see that it fits snugly about the stem. This can readily 

 be accomplished because of the star-shaped cut at the center of the 

 card. The object is to have the cards fit snugly around the stem at 

 the center and lie flat on the ground so that the fly cannot get under 

 it. She will then be forced to lav her eji'S's, if at all, on the card or 



