Alfalfa in Kansas. 



395 



The ant colonies are too few seriously to decrease the yield, although 

 occasionally they will destroy the alfalfa on from one to two per cent of 

 the total area of a badly infested field. Their claim to rank as alfalfa 

 pests lies principally in the increased difficulty of harvesting the crop 

 when they are present. 



Methods of Control. 



Extended experiments have shown that the ants can most easily and 

 efficiently be controlled by fumigating the nest with carbon bisulphide, as 

 follows: Set fumigation only when gateways are open. Invert a gal- 

 vanized-iron vessel, such as a common washtub, over one or more of the 

 openings, covering as much of the mound as possible; firmly pack soil 

 over such holes as the tub will not reach. Introduce under the tub and 

 near the holes a shallow dish containing from one to three ounces (de- 

 pending on the size of the nest) of carbon bisulphide. Set the tub down 

 and quickly pack soil about the rim, making it as nearly air-tight as pos- 

 sible; allow to stand for five hours. The forming vapor, being heavier 

 than air, sinks downward and comes to fill every chamber and gallery, 

 destroying all the occupants. 



CAUTION. It must be remembered that carbon bisulphide is as ex- 

 plosive as gasoline and must be used with equal care. 



\ 



FIG. 343. Ash-gray blister- 

 beetle (Maorobasis unicolor). 

 Female beetle; nearly twice nat- 

 ural size. (After Chittenden, U. 

 S. Dept. Agr.) 



FIG. 344. Three- 

 lined blister-beetle (Epi- 

 cauta lemniscata) ; about 

 twice natural size. (Af- 

 ter Headlee, Kan. Eicp. 

 Sta.) 



BLISTER-BEETLES. 



(Meloidse.) 



Ash-gray, black, yellowish, or black and yellow striped beetles with long 

 legs and elongated bodies, that sometimes suddenly appear in alfalfa 

 fields and quickly destroy the foliage. (Figs. 343 and 344.) 



Habits and Life History. 



Several species of blister-beetles are common in central and western 

 Kansas, and sometimes very destructive to alfalfa. Some of these have 

 sort of a migratory habit; that is, they suddenly come in large numbers 

 in a field, ruin a part or all of the crop in a few days, when they go 



