Control of Thrips and Leafhopper on Peanuts

Abstract

Replicated small-plot and field-scale experiments were conducted at the Wiregrass Substation of the A.P.I. Agricultural Expt. Sta. for control of thrips, Frankliniella fusca, and potato leafhopper, Empoasca fabae, from 1946 to 1950 inclusive. Two to 5% DDT, 10-20% Toxaphene, and 2% gamma_ BHC, applied 20 lb./acre, were highly effective in reducing the population of thrips. Twenty per cent sabadilla dust was moderately effective; 1% rotenone and 2% nicotine were ineffective. Two to 5% DDT and 10-20% Toxaphene were effective in reducing populations of leafhopper. Three per cent methoxychlor, 20% sabadilla, and dusting sulfur also reduced the infestation of leafhoppers. Two per cent gamma-BHC 5% chlordan, 1% rotenone, and 2% nicotine were ineffective against this pest. There were no consistent gains in yield of Spanish or runner peanuts from 2 applications of 10% Toxaphene or 5% DDT applied at 10-day intervals for thrips control, beginning when the plants were in the seedling stage. In small-plot and field-scale expts., Spanish and runner peanuts receiving 4 applications of 2_2.5% DDT or 10-20% Toxaphene at 20 lb./acre during July and August for leaf-hopper control yielded significantly more peanuts than untreated checks. The insecticide used in a mixture with 3.4% Cu and a minimum of 65% sulfur gave yields usually significantly greater than with insecticides applied without the fungicide. The treatment recommended as a result of this research consists of an insecticidal-fungicidal dust containing either 2.5% DDT or 10% Toxaphene in a mixture with 3.4% Cu and at least 65% sulfur. Treatment of runner peanuts should begin about the time of last cultivation near the middle of July. Four applications should be made at 20 lb./acre at 7- to 10-day intervals. Treatment of Spanish peanuts is the same as for runners, except that the control program should begin 2-3 weeks earlier.