Beet or Spinach Leaf -miner Aphids or Plant-lice 



Clean Culture 



As in the case of many other insect pests, preventive measures are 

 of more value than curative ones. The beet leaf-miner feeds in the leaves 

 of lamb's-quarters, or white pigweed, as it is sometimes called. The 

 destruction of this weed will do much to reduce the number of miners 

 in a vicinity. 



DESCRIPTION AND LIFE HISTORY 

 The Egg 



The eggs, which are placed on the under side of the leaves of the 

 host plants, are shown natural size in Figure 1 "A," Plate III, Page 15. 

 Usually they are laid side by side in groups of from two to five or six. 

 Their surfaces are finely reticulated. Figure 2, Plate III, Page 15 repre- 

 sents three eggs much enlarged, showing this reticulation of the surface. 



The Miner 



The miner (Fig. 3, Plate III, Page 15) hatches in about four days. 

 It is a whitish maggot, pointed at the head and broadening toward the 

 opposite end. When fully grown it is about one-fourth of an inch long. 

 As soon as hatched it burrows into a leaf and begins to feed upon the 

 pulp. 



The Pupa 



At the end of seven or eight days the fully grown miners drop to the 

 ground and after burying themselves just below the surface or beneath 

 trash lying on it, they pass into the pupal stage within the puparium 

 (Fig. 4, Plate III, Page 15). The pupal state lasts from ten to twenty 

 days during warm seasons of the year. The last generation of miners in 

 the fall is thought to pass the winter in the pupal stage, the flies emerging 

 the next spring. 



The Adult 



The adult miner (Fig. 5, Plate III, Page 15) is a two-winged fly 

 belonging to the same order as the common house fly. This fly has no 

 very distinctive markings. The face is silvery white between the eyes, 

 which are brownish. The body, which is dull grey, is sparsely covered 

 with quite long stiff hairs. 



B. SUCKING LEAF FEEDERS 



(Aphids or Plant-lice, True Bugs, Leaf-hoppers) 

 1. APHIDS OR PLANT-LICE 



Aphids, or plant-lice, as they are commonly called, are small, soft- 

 bodied creatures which usually feed in compact masses on the stems, 

 leaves or roots of plants. Some feed exposed upon the plant (Fig. 20, 

 Page 112), others cause the leaves upon which they feed to curl over them 

 (Fig. 21, Page 112), and still others, like the sugar beet root-louse, spend 

 a part of the season, at least, within galls produced by their feeding upon 

 the host plant (Fig. 22, Page 113). 



Ill 



