ENTOMOLOGY. 913 



mold (PlasmodiopJiora hrassiccv). The disease and maggot attacks 

 may, however, and frequently do, occur on the same plant. 



The flies first appear in the latter part of April and the first of May, 

 when the female flies may be seen running over the ground about the 

 cabbage plants endeavoring to find some crevice by means of which 

 they can creep beneath the surface of the soil and deposit their eggs 

 cl.se to the cabbage stem. About 55 eggs are probably laid by each 

 i\y, although some hundreds of eggs may be laid about a single plant 

 by different flies. The eggs are white, irregularly ridged and grooved 

 longitudinally on one side, and 0.04 in. in length. The eggs hatch iu 

 froui 4 to 10 days, depending on the weather, but efforts made to breed 

 the insect from eggs in continemeut were unsuccessful. The young 

 maggots immediately attack the surface of the root, rasping out bur- 

 rows aloug the surface, and first devoting themselves to tlie rootlets, 

 after which the main root is eaten and often girdled. The burrows are 

 slimy, and the decaying roots upon the death of the plant give out a 

 sickening odor. The larval stage is believed to be about 3 weeks, 

 when the maggots work their way into the soil an inch or two from the 

 roots and there pupate. The pupal stage continues from 15 days to 

 over 3 months, but the majority of flies issue in about 20 days. 



It has been believed that there are 3 or 4 annual broods of the insect, 

 but the investigatious show that there are but 2 distinct broods, with 

 possibly a third. The flies of the first brood appear in April and 

 shortly deposit their eggs, from which about three fourths of the sec- 

 ond brood appear in June, the remainder emerging at varying times 

 throughout the summer. The maggots of this second brood work on 

 the plants in July, pupate, and some of them emerge as adults the lat- 

 ter part of that month or in August as a third brood, but the majority 

 hibernate as pupse to emerge the following spring. 



As natural enemies are mentioned chickens and rooks, which are fond 

 of the maggots, but in eating them usually pull up the cabbage plants, 

 so that aid of this kind is not advised. In England several small 

 hymenopters are parasitic to the cabbage root maggot, none of which 

 are found in this country. However, a cynipid {Tryhliographa antho- 

 myim) has been bred Irom pupse in various parts of the United States, 

 and it is believed will play an important part in checking the pest. In 

 addition a staphylinid beetle {Aleochara nitida), in both its larval and 

 adult forms, attacks the maggots and piipse. In some instances the 

 larvae of the beetle gnaw their way into the pupoe of the pest, devour- 

 ing the contents, and undergo their metamorphoses within the shell. 

 A species of Tromhidium also is an enemy of the cabbage fly, sucking 

 the eggs. 



About 70 different methods have been recommended for combating 

 the cabbage root maggot and many of them were employed in the 

 experiments here given. Only 6 are regarded as effective and recom- 

 mended to be employed, although 9 others are classed as doubtful or 



