INSECTS INJURIOUS TO BEETS AND SPINACH 



303 



besides destroying many kinds of weeds and grasses, it com- 

 pletely defoliated thousands of acres of sugar beets. In some 

 cases where the foliage of the beet did not furnish it sufficient 

 food, the root was attacked and the upper surface was com- 

 pletely gnawed away. 

 Late plantings, of 

 course, suffered most 

 severely, especially 

 when surrounded by 

 newly broken 

 ground. The weeds 

 most generally eaten 

 were pigweed, salt- 

 weed, wild sunflower, 

 and Cleome. Potato, 

 pea, and apple leaves 

 were also devoured. **^8ii^ 



9S&^tm 



These injuries oc- 

 curred about the 

 middle of August, at 

 which time the larvae 

 and pupae were abun- 

 dant, and a few moths laden with eggs were noticed." 



This species evidently hibernates as a moth, and at least 

 two broods of larvae may be looked for each year, the first about 

 June and the second in August. The species has been reported 

 thus far from Colorado and California, but it doubtless has a 

 more extended range in the mountain regions of the far West. 



" Professor Gillette's field-experiments showed that it could be 

 destroyed by dusting or spraying arsenical poisons on the leaves." 



Flea-beetles 



Several species of flea-beetles, chiefly Systena tceniala, Systena 

 hudsonias, Disonycha triangularis, and Phyllotreta vittata, often 

 do considerable injury by gnawing small holes in the upper and 

 lower surfaces of the leaves of beets, giving them an appearance as 

 if affected by leaf-spot, or puncturing them full of small holes, and 

 thus stunting the growth of the plants. 



, 



FIG. 2o6. The beet army worm (Laphygma exigua 



Hubn.): a, moth; 6, larva, side view; c, larva, 



back view >* d > head of larva ' e > e ^ from above ; /, 

 ogg from side _ all enlarged. (After Chittenden| 



U. S. Dept. Agr.) 



