THE CABBAGE MAGGOT 



13 



In'these trials the soil was carefully smoothed and the discs were laid flat and 

 evenly on the soil. W'here there was 77 percent injury to the untreated plants, 

 none of those protected with tar paper discs was commercially injured. Eggs 

 were observed on the soil near the discs and 7 percent of the plants were lightly 

 infested but showed no measurable damage to the growth of the plants. Several 

 thousand discs were used by commercial growers with generally satisfactory 

 results, although there was some difficulty in getting the discs laid carefully by 

 inexperienced help. 



The discs are considered an excellent substitute for preferred mercury treat- 

 ments for the commercial grower and are highly recommended to all home gar- 

 deners. In 1943 a commercial supply of tar paper discs was available at a cost 

 of 2 to 3 cents each depending on the number purchased. 



Table 7. Mulch Paper and Tar Paper Discs as Repellents 

 FOR the Cabbage Maggot. Waltham, Massachusetts. 



♦Corrosive Sublimate 1-1280, two applications at weekly intervals beginning when the first 

 eggs are laid. 



**In 1931 cabbage and cauliflo.wer received four applications of Corrosive Sublimate. 



Mulch Paper 



About 1930 mulch paper prepared by treating paper with various asphalt 

 mixtures created considerable interest as a means of stimulating plant growth by 

 conserving moisture and providing more uniform soil temperatures. The paper 

 was applied either by laying a strip about 12 inches wide on each side of the row 

 usually after the plants were set, with the plants growing in a strip of exposed 

 soil about 1 inch wide in the center, or by laying strips of paper about 36 inches 

 wide and setting the plants at regular intervals through slits cut in the paper, 

 thus providing a solid coating of paper over the field. The mulch paper was held 

 in place with wire staples. 



Experiments with wide strips of mulch paper as a repellent for cabbage maggot 

 were made at Waltham in 1930 and 1931; but the results, as shown in Table 7, 

 were generally unsatisfactory, especially in 1931 when a heavy infestation de- 

 veloped on the untreated plants. Poor control resulted when the paper curled 



