Effect of Soil-Applied Carbofuran on Transmission of Maize Chlorotic Dwarf Virus and Maize Dwarf Mosaic Virus to Susceptible Field Corn Hybrid1

Abstract

The effects of carbofuran on the transmission of maize chlorotic dwarf virus (MCDV) and maize dwarf mosaic virus (MDMV) to a susceptible field corn hybrid were evaluated in a greenhouse-laboratory study. The incidence of MCDV and MDMV in plants treated with an amount of carbofuran equivalent to 1.46 kg (AI)/ha of soil incorporated at planting was compared with that in untreated control plants. Graminella nigrifrons (Forbes) and Rhopalosiphum maidis (Fitch), the respective vectors of MCDV and MDMV, transmitted MCDV and MDMV to untreated, three-leaf-stage corn plants at rates averaging 89.2 and 64.4%, respectively, when 7 leafhoppers or 15 aphids were used per plant. Carbofuran treatment significantly reduced transmission of MCDV by G. nigrifrons , resulting in a disease incidence of 12.8%. Reduction of MCDV in treated plants was due to the 90.8% mortality of G. nigrifrons within 4 h after placement on the plant. Carbofuran treatment did not affect the transmission of MDMV by R. maidis but did reduce R. maidis populations by 80.4% within 24 h, thus suggesting possible reduction of the secondary spread of virus in field situations.