644 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



half inch long. When full grown the larva molts for the fifth 

 time and loses its olive-green slimy appearance, becoming a 

 light orange-yellow color, clean and dry, with a light-colored 

 head marked by only the small circular black eye-spots on the 

 sides. 



The larva now enters the ground for an inch or two, where 

 it forms a small cell, which is moistened with saliva so that the 

 walls become somewhat impervious to water. In six or eight 

 days it transforms to the pupa and in about two weeks after 

 the larva entered the ground the adult fly digs its way out of 

 the soil. Some of the larva; of each generation, and all of those 

 of the last generation remain in the soil over winter and trans- 

 form to pupa? the next spring. At Washington, U. C., the first 

 generation of larva? disappear by the end of June and the second 

 generation are most abundant in early July, w r hen the principal 

 injury is done, which is probably followed by a third generation. 

 Further north there are but two generations, the second appearing 

 in August. 



Control. By spraying w r ith any of the arsenicals when the 

 work of the slugs is first noticed on the foliage they may be 

 quickly destroyed. Whale-oil soap, or other soap, 1 pound to 

 4 gallons, will also destroy the larvae as a contact insecticide. 

 Hellebore, air-slaked lime, or almost any finely divided dust, 

 thoroughly dusted over the trees will also destroy most of the 

 larvae, which arc very readily killed. In gardens where water 

 under pressure is available, the slugs may be washed off by a jet 

 from a hose, as they are frequently washed off by heavy rains, 

 and are much less injurious in wet seasons. 



