Alfalfa in Kansas. 397 



may crawl, a line of men and children may go into the field and slowly 

 drive the beetles ahead of them with branches. Before doing this, wind- 

 rows of hay, straw or other dry vegetable material should be prepared or 

 placed along the side of the field. When the beetles have run in under or 

 have taken refuge in the windrows, it is fired and the beetles burned. 

 This method has been used with success in the West and Southwest. The 

 important thing in the successful control of blister-beetles is to apply 

 whatever remedy is used just as soon as the beetles are discovered. 



LEAF-HOPPERS. 



(Jassidse.) 



Small, green, gray or yellowish insects that, when disturbed, hop and fly 

 swiftly about among the plants. They suck the sap from the leaves 

 and tender shoots, causing the leaves to turn yellow. 

 While there are several species of leaf -hoppers attacking alfalfa, prob- 

 ably the most injurious and the most widely distributed one in the al- 

 falfa districts is the clover leaf-hopper (Agallia 

 sanquinolenta) . (Fig. 345.) Another one that is 

 also fairly common in the alfalfa fields is the apple 

 leaf -hopper (Empoasca mali) . In several districts 

 species of the genus Deltocephalus are rather com- 

 mon. (Fig. 346.) 



Habits and Life History. 



The leaf-hoppers can usually be distinguished 

 from other insects in the alfalfa field by their habit, 

 when disturbed, of hopping, jumping and flying 

 swiftly about. When abundant, swarms of them 

 will jump up as one walks through the field. So 

 per eaceaus far as nas been determined, the species affecting 



times natural size. (Af- alfalfa lay their eggs in the leaves or stems of the 



ter Headlee, Kan. Exp. 



Sta.) leaves. In some cases the eggs are pushed into the 



. margin of the leaf or the stem, and thus are pro- 

 tected by the thin covering of the leaf. The eggs hatch in a few days, 

 except in the case of hibernating eggs, and the young forms, instead of 

 consuming the stems and foliage, thrust their heads into the leaves and 

 tender shoots and suck the sap. The feeding punctures cause pale yellow- 

 ish spots, and if very numerous give the foliage a distinctly yellowish or 

 bleached appearance. With most of our species there are probably two 

 generations in a single season. The leaf -hoppers winter mostly as adults, 

 in rubbish. In some cases the winter is passed in the egg stage. 



Methods of Control. 



Owing to the habit of the adults hibernating during the winter, the 

 fall, winter or early spring burning of dead leaves and rubbish around 

 the edges of the field, along ravines and bordering on orchards and 

 woodlands, is undoubtedly one of the most effective means of destroying 

 them. Where they occur in destructive numbers the spraying of alfalfa 

 fields with a nicotine sulphate or kerosene emulsion spray directly after 

 cutting the crop would kill large numbers of them. It is claimed by 

 some that the most efficient method of destroying them lies in the use of 



