19 



ing paper. These discs are circular or polygonal, about 3 

 inches in diameter, and have a star-shaped cut at the center 

 and a radial slit reaching from the center to the outer edge. 

 As soon as the plants are set in the field, slip a disc around 

 each and press the points formed by the star-shaped cut snugly 

 around the stem. These discs should lie flat on the ground, 

 and care should be taken to keep the upper surface free from 

 dirt when adjusting them. If applied properly they should 

 furnish almost perfect protection. 



Late cabbages and cauliflowers should be grown in cheese- 

 cloth screened beds until ready for transplanting. A week to 

 ten days before the plants are to be transplanted gradually 

 remove the . cheesecloth covering In order to harden the seed- 

 lings so that they will be able to stand field conditions. As 

 the damage from root maggots is very slight after July 1, 

 it is rarely necessary to use tarred felt pads on the late crop. 

 Radishes may also be protected from root maggot injury if 

 grown in a screened bed. 



Another method used for the control of root maggots when 

 attacking radishes, turnips and onions in small areas consists of 

 repeated applications of carbolic acid emulsion, at weekly 

 intervals, during the months of May and June. For method 

 of making this emulsion, see onion maggot control, page 25. 



5. Cabbage aphis. Aphis brassicae L. For control, see plant 

 lice, page 11. 



6. Cabbage worms. 



Several species of green, leaf-eating caterpillars are often 

 injurious to cabbages and related plants. The most injurious 

 species is the imported cabbage worm, Pontia rapae L., whose 

 parent is the common white butterfly seen flying in the vicinity 

 of cabbage fields. These caterpillars may all be controlled in 

 the same manner. 



Control. — The most effective means of control is spraying or 

 dusting with lead arsenate (see page 4). As the foliage of 

 cabbage is extremely smooth, it is advisable to add 2 or 3 

 pounds of resin-soap sticker to make the spray more adhesive 

 (see page 4). Plants should be kept well covered with arse- 

 nate of lead from the time they are transplanted until the heads 

 are half formed, after which treatment should be discontinued. 



