418 Report of the Department of Entomology of the 



soil with plants of desirable size, one man was able, without any 

 previous experience, to adjust the pads carefully at the rate of three 

 hundred of them per hour. On the basis of these items the cost 

 of protecting cabbage by this method will run approximately from 

 $1.35 to $1.50 per thousand plants. In addition to the expense 

 for protectors and labor, the actual cost will also vary according to 

 the character and condition of the soil as well as in the manner in 

 which the plants are set in the ground. Plants that are set low 

 in the ground or are wilted are not adapted to this method of pro- 

 tection. 



Considering the safeness to the plant, the ease of application, 

 cost and protection against the maggot, the use of tar pads seems 

 to be the most practical method yet devised for protecting early 

 cabbage from this insect. 



DESCRIPTION OF TAR PADS AND THE TOOL FOR MAKING THEM. 



The cards are cut in the shape of a hexagon (Fig. 19) from roofing 

 paper known as " single-ply tarred-felt." The tool used in cutting 

 these disks can be made by an expert blacksmith by reference to 

 the accompanying figures. The blade or cutting edge is formed 

 from a band of steel bent in the form of a half hexagon, with an 

 additional strip reaching from one end nearly to the center, as shown 

 in Fig. 20. The part making the star-shaped cut is formed from 

 a separate piece of steel bolted to the handle and so attached as to 

 make a close joint with the blade. The edge of the blade is beveled 

 from the outside all around, so that by removing the part making 

 the star-shaped cut the edge may be sharpened. It is important 

 that the angles of the cutting edge be made perfect and that its 

 outline represent a half hexagon. 



In order to cut the disks the tarred paper should be placed on 

 the end of a section of a log or piece of timber (Fig. 21) and the lower 

 edge notched, as indicated in Fig. 22, using only one angle of the tool; 

 then begin at the left side, placing the cutting edge as shown by 

 the dotted line. One man can cut from 300 to 500 disks per hour 

 and about 6 pounds of single-ply tarred-felt is necessary for a 

 thousand pads. Estimating the paper at 2| cents per pound and the 

 labor at 15 cents per hour, makes the cost of the pads per 1,000 

 about 15 cents for material and 30 cents to 50 cents for labor. 



