Influence of the Insect-resistant Peanut Cultivar NC 6 on Performance of Soil Insecticides

The cultivar NC 6 was released in 1976 as a peanut, Arachis hypogaea L., with multiple insect resistance. It has a low level of resistance to the tobacco thrips, Frankliniella fusca (Hinds), moderate resistance to the potato leafhopper, Empoasca fabae (Harris), and corn earworm, Heliothis zea (Boddie), and a high level of resistance to the southern corn rootworm, Diabrotica undecimpunctata howardt Barber. Since ‘NC 6’ is not immune to insects, tests were established to determine minimum insecticide dosages, in a management or integrated control program. ‘NC 6’ was compared with ‘Florigiant’ for insect damage, insect control with a minimum amount of insecticide, and yield. Tests were established in fields with a history of high southern corn rootworm damage. Insecticide doses currently recommended for rootworm control on commercial susceptible peanuts may be reduced 75 to 80% on ‘NC 6’ and still result in comparable insect control. Systemic insecticides applied for thrips and leafhopper control may be reduced ca. 60% on the NC 6 cultivar. ‘NC 6’ yielded ca. 20% more peanuts than ‘Florigiant’ in the absence of insecticides. When low doses of insecticides were applied, ‘NC 6’ yielded ca. 16% more peanuts than ‘Florigiant.’