Cost effectiveness of pest management strategies in peanut (Arachis hypogaea L.) grown in North Carolina

摘要

Reducing costs associated with pest management in peanut (Arachis hypogaea L.) production systems in the United States will become increasingly important due to changes in federal legislation that reduced support prices and removed the escalator provision. The federal peanut program may be eliminated completely in 2002 at which time peanut most likely will be marketed at the world price, which is substantially lower than the current quota price. Eight experiments were conducted during 1997 and 1998 to evaluate pest control, pod yield, gross value, and economic return with preventive and integrated pest management (IPM)-based disease, insect, and weed management strategies. Preventive strategies included prophylactic applications of herbicides, fungicides, fumigant, and insecticides. IPM strategies involved host-plant resistance, targeting pesticide applications based on economic thresholds, and other thresholdbased practices to manage pests. Preventive and IPM weed management strategies provided similar economic return in seven of eight experiments. Early leaf spot, caused by Cercospora arachidicola, control was similar when fungicides were applied biweekly or based on weather advisories. However, scheduling fungicide sprays using weather-based advisories eliminated one to three fungicide applications per year. Biweekly applications of fungicides increased damage from twospotted spider mite (Tetranycychus urticae) in one experiment compared with applications using weather-based advisories. Fumigation by metam sodimn for Cylindrocladium black rot (CBR), caused by Cylindrocladium crotalarie, was needed in one of three experiments where this disease was present. Resistance of the cultivar NC 12C to CBR was not sufficient to prevent yield and economic loss where damage exceeded 10% plant loss. Iprodione was applied preventatively for suppression of Sclerotinia blight, caused by Sclerotinia minor. However, this disease developed in only one of four experiments where fungicide was applied. Aldicarb applied infurrow and acephate applied postemergence based on damage thresholds controlled tobacco thrips (FranklinieUa fusca) similarly in seven of eight experiments. In one experiment, aldicarb was more effective than acephate. Failure to apply chlorpyrifos for southern corn rootworm (Diabrotica undecimpunctata) control resulted in yield and economic loss in three experiments. Chlorpyrifos controlled potato leafhopper (Empoascafabae) and prevented possible yield loss caused by this insect. Collectively, these data demonstrate the complexity ot pest management in peanut and some of the weaknesses associated with current pest control and IPM practices. The importance of accurate identification of pests and detailed field histories also was demonstrated in these studies. Likewise, a thorough understanding of the impact of production practices on pest development and timely implementation of pest control tactics is critical for adequate plant protection.