Evaluation of Liquid Carbofuran as a Rescue Treatment for Corn Root Aphids, 1993

Abstract

Abstract Field corn was planted on 10 May near Rockford, IA, in a field that was corn the previous year and a grass-alfalfa mixture 4 yr before that. No soil insecticide was applied at planting. The field was rotary hoed 3 times between the time of corn emergence and 22 Jun. Pretreatment counts were taken on 22 Jun. The plant population was highly variable and ranged from 0 to 17,000 plants per acre based on 1/1,000 acre counts. Plants were in the V2-V4 stages of growth. Fifteen randomly-selected plants were pulled from the soil and roots were examined for colonies of aphids. All 15 plants were infested with corn root aphids. Ant mounds of the symbiotic cornfield ant, Lasius alienus (Foerster), were abundant around the plants but densities were not determined. Plots 50 ft long were marked with flags and inside these plots 1/1,000 acre (17.4 ft) were staked off for the section of row to be evaluated. Live plant counts were taken in the 1 /1,000 acre plots prior to treatment. Treatments consisted of an untreated check and a rescue application of 1.0 qt of Furadan 4F (1.0 lb [AI]/acre) broadcast in 10.0 gal of water with a tractor-mounted sprayer. Treatments were replicated 6 times in a RCBD. The Furadan 4F was not cultivated into the soil. Approximately 0.2 inches of rain fell on the field 2 DAT and a total of 3.2 inches occurred between the treatment date on 22 Jun and the evaluation date on 7 Jul. Plots were evaluated 15 DAT. Live plant counts were taken within the staked 1/1,000 acre plots. Five plants, consisting of every 2nd or 3rd plant (depending on plant population), in each plot were pulled from the soil and examined for colonies of corn root aphids.