928 Popular Editions of Station Bulletins of the 



inches high. On plants one or two inches high the same emulsion 

 was very injurious, in tests on .transplanted cabbage, in two 

 fields' — one heavy clay and the other light sand — an emulsion 

 slightly stronger than one-third of one per ct. acid caused serious* 

 injury to recently set plants. Plants longer set were not injured. 

 As a result of all these tests with insecticides, then, even the one 

 commonly regarded as best is a very uncertain dependence against 

 cabbage maggot. Although it will destroy eggs and young mag- 

 gots when used at a strength of one- third of one per ct. carbolic 

 acid, it will not kill older larva? ; and it is certain to injure small 

 or recently set plants and liable to do some harm even to older 

 plants. 



There remains, therefore, only one resource' — 

 to prevent the flies from laying their eggs on 

 the plants. The so-called "repellent" materials — lime, ashes, 

 tobacco dust, tar, etc. — have proved either wholly ineffective or 

 too expensive to use; but one mechanical obstruction to egg-> 

 laying — the ""tar-pad" or hexagonal tar-paper collar — has 

 given excellent results and can be applied at only slight expense. 



These pads are made from single-ply tarred felt, are hexagonal 

 disks about 3 inches from angle to angle, slit to the" center at one 

 angle and with a short cross cut at the center which allows the 

 collar to fit about the stem of the plant. When placed in position 

 it should lie close upon the ground and fit snugly about the 

 stem, so that the flies of the cabbage maggot are mechanically 

 prevented from reaching the stem at the point where the eggs 

 should be laid, just at, or slightly below, the surface of the ground. 

 These pads can be easily and rapidly cut by the use of a special 

 tool, not patented, and easily made by any good blacksmith. The 

 pads can be made for from 50 to 55 cents 'a thousand. 



The idea of using -such pads was first proposed about 25 years 

 ago, and they have been used with good success in several localities 

 since that time. In New York State, however, their adoption has 

 not been general, though they are made commercially by firms on 

 Long Island and at Rochester. 



