228 THE PEANUT— THE UNPREDICTABLE LEGUME 



ern range, where the winter may be passed on any green host plant such 

 as alfalfa, clovers, castor beans and other plants. Beyer (15) found it 

 throughout the winter on castor beans. It is possible that hibernation may 

 occur, either in the egg or adult stage, in part of the insect's range, but 

 all evidence on hibernation is negative. 



The time required for development from egg to adult is 18 to 24 days 

 during warm weather (42, 14). As the weather becomes cool, this period 

 may increase to 60 days. Approximately S to 10 days are required for 

 incubation of eggs and 8 to 15 for nymphal development. Females mate 

 and begin ovipositing in 3 to 5 days in the veins and petioles of the leaves. 

 Approximately 60 eggs per female are deposited over a period of 30 

 days during warm weather. A maximum oviposition of 131 fertile eggs 

 has been reported in Florida (15). 



The average longevity of the female is approximately 35 days, al- 

 though a maximum of 123 days has been reported in Virginia (114). 

 Longevity of males is somewhat shorter. Six generations per year have 

 been reported in Virginia and Florida. 



Additional research is needed on potato leafhopper to determine its 

 development on peanuts, overwintering habits, and the relation of de- 

 velopment on various wild and cultivated host plants to damage in 

 peanuts. 



Control. Natural enemies are apparently of relatively minor value in 

 suppressing the population of potato leafhopper. Heavy rainfall reduces 

 infestation in peanuts. A parasitic fungus, Entomophthora sphaerosperma 

 Fresenius, causes a disease which is of considerable importance. The 

 disease has been reported from Florida (15), Arkansas (1), Iowa (54), 

 and other localities. Eighty percent of the insects may be diseased, and as 

 high as 37 percent of those affected may perish. Chrysopid and coccinellid 

 larvae are important insect predators of the potato leafhopper, Chrysopa 

 plorebunda Fitch and Hippodamia 13-punctata being species commonly 

 observed. The predaceous bug, Triphleps insidiosus Say is also a natural 

 enemy as are certain spiders, ants and birds. Insect parasites in potato 

 leafhopper appear to be rare, although Anagrus armatus Ashm. is re- 

 ported common in Iowa. 



Numerous studies have been made on insecticidal control of potato 

 leafhopper on potatoes, beans and other crops. Some studies have been 

 made also on peanuts. Poos and Batten (117) found that 4:4:50 Bor- 

 deaux mixture applied to peanuts in Virginia increased the yield 21 per- 

 cent. In 1938 these investigators reported more extensive experiments 

 with sulfur and copper dusts and sprays which resulted in very substantial 



