INSECT PESTS 235 



sp. have been reported as predators of F. tritici (157) and these forms 

 probably prey on F. jusca also. 



Chemical control of tobacco thrips is feasible. The first treatments 

 consisted of nicotine-soap sprays {77, 49) and rotenone (86). Following 

 the use of tartar emetic ( 108) against onion thrips, Thrips tahaci Lind., 

 the material was used on peanuts and other plants in the greenhouse with- 

 out injury to the crops (3) . Tartar emetic sprays were used on peanuts in 

 the field, but the applications were too late for successful control (115). 

 Poos (116) reported successful control with DDT in the form of 2 per- 

 cent dust, 0.66 percent sprays, and 10 percent aerosols and with tartar 

 emetic sprays. Satisfactory control of tobacco thrips on peanuts with 

 significant increase in yield from the use of DDT and BHC dust and 

 sprays has been reported ( 120) . The most efifective treatment consisted of 

 three applications of an emulsion containing 4 percent DDT applied by 

 atomizing at the rate of 10 gallons per acre. The author (5) found 3 per- 

 cent DDT dust more efifective than 20 percent Sabadilla, 1 percent 

 rotenone, or 1 percent nicotine. A spray containing 1.5 percent water- 

 dispersable DDT was much more efifective against the thrips than 3 per- 

 cent dust. In 1948, he reported 2 percent Gamma BHC and 20 pdtcent 

 toxaphene applied as dusts at the rate of 20 pounds per acre gave much 

 better control than 2 percent DDT dust. 



Data on gains in yield of peanuts resulting from control of tobacco 

 thrips are somewhat contradictory. One study (120) reported increases 

 as high as 36 percent in the weight of green pods in some experiments 

 and no increases in others. A second study (7) reported an increase in 

 the weight of peanut pods set early on DDT and BHC plots but, as men- 

 tioned previously, most of the early crop was lost in the ground at harvest. 

 In a nonreplicated preliminary test 20 percent toxaphene dust applied for 

 thrips and leaf hopper control resulted in 810 pounds dry peanuts® per 

 acre more than was harvested from undusted peanuts. It appears that 

 gains in yield from control depend upon the severity of the thrips infesta- 

 tion, the efficiency of the control, the type of peanut concerned, fertility of 

 the soil, weather conditions, and other factors. Additional research is 

 needed on these points. 



White-Fringed Beetle 



Importance. The white-fringed beetle, Pantomorus leucoloma (Boh.)^ 

 is potentially the worst pest of peanuts in southeastern United States, 



s Seven percent moisture content. . ,t. i. n ^t j: • , j- „ . 



' Also known as Graphognathus leucoloma fectmdus (Buch.) ; other forms including Pantomorus 

 (.Graphognatkus) peregrinus Buch., G. leucoloma striaius (Buch.),G. leucolqma dubius (Buqh.J 

 are also of economic impprtanc?i 



