INJURIOUS TO CABBAGE AND RELATED CROPS 37 



table iniitttT, for at the time of tlie great outbreak of migratory 

 loeusts in the West, the maggots attacked the eggs of these 

 grasshoppers which then occurred in great abunthmce. Gen- 

 erally, however, the maggots feed on planted seeds which have 

 softened in germination or from decay. They are sometimes 

 very destructive to seed beans especially in cold, wet, backward 

 seasons. In some cases more than half of the crop is destroyed 

 over large areas in this way. The maggots burrow into the 

 seed-leaves, destroying them, and then mine into the stem. 

 Some of the injured beans fail to germinate ; more often, 

 however, the seed-leaves push up through the soil, but as the bud 

 is injured the })lants fail to leaf out. 



The flies of the seed-corn maggot closely resemble those 

 of the cabbage root-maggot, but the males may be distinguished 

 by lacking the tuft of hairs on the under side of the base of the 

 hind femur, and by having on the under side of the hind tibia 

 a row of short spines (Fig. 26 C). The females of the two 

 species are indistinguishable. As far as known, the life histories 

 of the two species are very similar. 



Control. 



The seed-corn maggot, when attacking cabbage and related 

 crops, may be controlled by the means suggested for the cabbage 

 root-maggot. The injury to germinating beans may be pre- 

 vented in large measure by planting the seed shallow in cold 

 wet seasons. Beans planted in tliis way come up more quickly 

 and, being in a vigorous condition, are able to outgrow any slight 

 injury to the seed-leaves. 



The Western Radish Mac, cot 



Phorbia planipalpit^ Stein 



On the Pacific Coast the cabbage root-maggot is replaced by a 

 closely related species with similar habits. The maggots of this 



