BLISTER BEETLES IX KANSAS. 6 



unable to spread so widely. Pasturage or other disturbance inci- 

 dent to the agricultural use of the land has proved a greater detri- 

 ment to the blister beetles than to the grasshoppers. Even in locali- 

 ties where blister beetles are most abundant repressive measures for 

 grasshoppers have been found necessary. Also, where blister-beetle 

 larvae infest a large percentage of the grasshopper egg capsules, they 

 must destroy man} T larva? of the beefty Anastoechus nitidulis Fab., 

 and of the hymenopterous egg parasite Scelio monticola Brues, 

 neither of which is known to be injurious in any stage. The larvae 

 of the beefly destroy a great many more grasshopper eggs than the 

 larva? of the blister beetles, but are helpless against the latter when 

 they enter the same egg capsules. 



It is questionable whether blister-beetle larva? have ever been suf- 

 ficiently beneficial to offset the damage done by the adults. Cer- 

 tainly they are now relatively of much less value than formerly. 

 The group, therefore, must be considered injurious and will be- 

 come more so with continued agricultural development of the semi- 

 arid sections. 



INJURY TO CROPS. 



Blister beetles may devour only the petals and pollen of the 

 flowers. They usually do this on beans, peanuts, and locust trees, 

 and largely on alfalfa. On Irish potatoes, sugar beets, and to a 

 lesser extent on the Russian olive, however, they commonly de- 

 foliate the plant. In either case the actual injury to the crop depends 

 on the stage of growth which the plants have reached. When they 

 are near maturity the yield is lessened, but the crop is not a total loss. 

 Unless drought prevails at the time of defoliation, sugar beets usu- 

 ally put forth new leaves and continue their growth, but the effect 

 of defoliation is recorded in decreased tonnage or sugar content, or 

 both. A defoliation of Irish potato is usually disastrous, as is also 

 the destruction of the blossoms of beans and of peanuts. 



FOOD PLANTS. 



Leaf -feeding insects, like the blister beetles, could not become as 

 numerous in the semiarid regions as they do without the presence of 

 some hardy native plant upon which they can feed during drought. 

 At Garden City, Kans., the beetles feed upon the blossoms of the 

 sunflower (Tlelianthus spp.), the goldenrod (Solid ago spp.), the 

 leaves and flowers of the few-flowered psoralea or scurvy pea (Pso- 

 raha tenuiflora) , and on other prairie legumes. They also feed ex- 

 tensively on an introduced weed, the ground burnut (Tribulus ter- 

 restris). 



The cultivated plants which they attack most extensively are the 

 Irish potato (Solanum tuberosum) , the sugar and garden beets (Beta 



