226 THE PEANUT— THE UNPREDICTABLE LEGUME 



called peanut leafhopper, but the official common name is potato leaf- 

 hopper, a name suggested by Ball (12) to indicate potato as a preferred 

 host. 



Both adults and nymphs of the insect feed upon peanuts by sucking 

 juices principally from the lower epidermis and veins of the leaves. Some 

 damage may result also from the deposition of eggs. As a result of leaf- 

 hopper damage to peanuts, the tips of the leaflets turn yellow and as the 

 damage becomes more acute the yellowing progresses toward the base 

 of the leaflets and some of the tips may appear burned. Damage is more 

 severe during dry weather. A field of infested peanuts may have a yellow- 

 ish appearance rather than characteristic green. Batten and Poos (14) 

 reported a dwarfing as well as yellowing of foliage in severe infestations 

 in Virginia. Metcalf ( 102) reported a disease called "pouts" resulting in 

 peanuts from the mass effect of toxins injected by E. fabae; the leaflets 

 turned dark at the tips, and the whole leaf sometimes blackened and 

 died. Apparently, this condition was severe "hopperburn" ; it should not 

 be confused with a dwarfed condition, also sometimes called "pouts," re- 

 sulting from thrips damage. 



There is considerable evidence that leafhoppers reduce the yield of 

 peanuts (117, 14, 104, 7). In some instances, however, there has been 

 no clear differentiation between the effect of damage from leafhopper 

 and Cercosporo leafspot. There is need for more exact information on 

 losses caused by potato leafhopper to Spanish, runner and jumbo types of 

 peanuts. The losses should be measured in terms of yield of peanuts and 

 yield and quality of hay. 



Description of Stages. The potato leafhopper was originally described 

 by Harris in 1841 (66) as Tettigonia fabae and the Genus Empoasca was 

 established by Walsh in 1864. Subsequently, numerous descriptions have 

 been published under several synonymous names. The descriptions of im- 

 mature stages given below are from Ackerman and Isely ( 1 ) ; that of the 

 adult is from DeLong (42) : 



Egg 



Egg elongate, subcylindrical, very delicate, slightly curved from end to end, some- 

 what rounded at both ends, but more so at the anterior end. When first deposited it 

 is rather transparent, but in a few days it changes to a pale yellow while a small 

 white cap forms at the anterior end through which the red eyes of the immature 

 nymph are perceptible. Average length 0.82 mm., width 0.25 mm. 



Nymph 



First instar. Pale white, changing to a light yellowish green after feeding. Eyes 

 dull red. Small pale spines on the dorsal side of the head, thorax, and abdomen ; the 

 latter with four spines to each segment arranged in two longitudinal rows along 



