Control of Germinating Seed Pests on Field Corn, 1990

Abstract An experiment was conducted on 23 Apr in Northumberland County, Va., to determine the effectiveness of several granular insecticides and a seed treatment against pests of germinating corn seeds. The recent cropping history for this field included field corn planted in 1988 and 1989 followed by a cover crop of crimson clover each yr. Soil type for this field is characterized as a Suffolk fine sandy loam. The experimental design involved a randomized complete block experiment with 4 replications. Each plot consisted of a single, 15- ft row in which furrows were hand dug to a uniform depth of approximately 1.5 inches. Seeds were spaced 6 inches apart within the furrows providing about 30 seeds per plot. Each block was separated from adjacent blocks by a distance of 6.3 ft. All granular insecticides were applied in-furrow using pint canning jars (Mason) with lids in which a single opening had been drilled. Lid openings were laboratory-calibrated to deliver accurately the labeled rate for each insecticide while walking at 3 mph. The possibility of mixing one or more insecticides was avoided by using a separate jar and lid for each treatment. For the treatments involving Agrox D-L Plus, the rates of 1- and 2-oz product/bushel of corn seed were used. In addition to recording whole-plot stand counts on 7 May, the roots and attached seed for each corn seedling, as well as seeds which had not germinated, were removed from the soil and inspected for evidence of feeding damage. Back transformed percentages are presented in the table.</jats:p

Corn Rootworm Larval Control on Field Corn, 1990

Abstract An experiment was conducted in Orange County, Va., to determine the effectiveness of several commercial and experimental granular insecticides against corn rootworm larvae. The field used in this experiment has been in continuous corn for more than 20 years. The predominant soil type for this field is a Manassas silt loam, with some areas of Penn silt loam and Rapidan silt loam. The experimental design involved a randomized complete block wtih 4 replications. Plots were 30-ft long and consisted of 2 rows spaced 30 inches apart. A John Deere, 2-row Max-Emerge planter was used to plant all plots on 7 Jun at a plant population density of 26,000 plants/acre. Insecticide granules were applied in front of the press wheels either directly in the seed furrow or in a 5-inch T-band over the furrow, depending on the treatment. Prior to application, the regular granular insecticide applicators were removed from each side of the planter in order to accommodate 2 wooden boxes designed to hold inverted pint canning jars (Mason) for dispensing the insecticide granules. Attached to the underside of both wooden boxes was a plastic funnel and tube through which the insecticide granules flowed. A single opening, drilled into the lid of each jar, was laboratory-calibrated to deliver insecticides accurately at a speed of 3 mph. The possibility of mixing one or more insecticides was avoided by using a separate jar and lid for each treatment. At the start of application, 2 jars containing the appropriate insecticide granules were inverted and placed in the box holders. This method helped minimize soil compaction because the tractor made only 2 pass/plot. Stand counts were made on 29 Jun, by determining the number of corn plants in 3 separate, 3.3-row ft sections/ plot. The roots of 5 consecutive corn plants were dug from each plot on 19 Jul and washed of excess soil. Corn rootworm damage ratings were based on the Iowa 1-6 scale (1—no feeding; 6—3 or more root nodes completely destroyed).</jats:p

Control of Wireworms on Field Corn, 1989

Abstract An experiment was conducted on 20 May in Northumberland County, VA to determine the effects of several commercially-available granular insecticides and a seed treatment for controlling wireworms on germinating corn seeds. The cropping history for this field included no-till soybeans planted in the spring of 1987 with no subsequent fall planting of a cover crop. In 1988, field corn was planted followed by a fall planting of crimson clover. Soil type for this field is characterized as a Suffolk fine sandy loam. A pretreatment sample of corn seeds (var. Pioneer 3184) from 30 separate, 3.3-ft row sections was made on 12 May to determine the level of wireworm feeding damage in the recently-planted field. Of the 146 seeds that were found, 71 (48.6%) exhibited feeding damage. Because of the severity of the damage the grower was forced to replant; however, in a portion of the field that was not replanted we conducted a randomized complete block experiment with 5 replicates and 7 treatments. Each plot consisted of a single, 15-ft row in which furrows were hand dug to a uniform depth of approximately 1.5 inches. Seeds were spaced 6 inches apart within the furrows providing about 30 seeds/plot, or 150 seeds/treatment overall. Each block was separated from adjacent blocks by a distance of 6.3 ft. All granular insecticides were applied in-furrow using pint canning jars (Mason) with lids in which a single opening had been drilled. Lid openings were laboratory-calibrated to deliver accurately the labeled rate for each insecticide while walking at 3 mph. The possibility of mixing one or more insecticides was avoided by using a separate jar and lid for each treatment. For the treatments involving Agrox D-L Plus, the labeled rate of 2 oz product/bushel of corn seed was used. On 4 Jun entire-plot stand counts were made, and on 5 Jun, the roots and attached seed for each corn seedling, as well as seeds which had not germinated, were removed from the soil and inspected for evidence of feeding damage.</jats:p

Corn Rootworm Larval Control on Field Corn, 1989

Abstract An experiment was conducted in Shenandoah County, VA to determine the effects of several commercial and experimental granular insecticides for controlling corn rootworm larvae. The field used in this experiment has been in continuous corn since 1960. Soil type for this field is characterized as a Unison silty loam. The experimental design was a randomized complete block with 4 replications. Plots were 30-ft long and consisted of 2 rows spaced 30 inches apart. A John Deere, 2-row Max-Emerge planter was used to plant all plots at a plant population density of 26,000 plants/acre on 19 May. Insecticide granules were applied in front of the press wheels either directly in the seed furrow or in a 5-inch T-band over the furrow, depending on the treatment. Prior to application, the regular granular insecticide applicators were removed from each side of the planter in order to accommodate 2 wooden boxes designed to hold inverted pint canning jars (Mason) for dispensing the insecticide granules. Attached to the underside of both wooden boxes was a plastic funnel and tube through which the insecticide granules flowed. A single opening, drilled into the lid of each jar, was laboratory-calibrated to deliver insecticides accurately at a tractor speed of 3 mph. The possibility of mixing one or more insecticides was avoided by using a separate jar and lid for each treatment. At the start of application, 2 jars containing the appropriate insecticide granules were inverted and placed in the box holders. This method helped minimize soil compaction because the tractor made only one pass/plot. On 19 Jul, the roots of 5 corn plants were dug from each plot and washed to remove excess soil. Corn rootworm damage ratings were based on the Iowa 1-6 scale (1, no feeding to 6, 3 or more root nodes completely destroyed). Stand counts were made on 9 Aug, by determining the number of corn plants in 3 separate, 3.3-row ft sections per plot.</jats:p

Corn Rootworm Larval Control on Field Corn, 1991

Abstract An experiment was conducted in Augusta County, VA, to determine the effectiveness of several commercial and experimental granular insecticides against corn rootworm larvae. The field used in this experiment has been in continuous corn production since 1980 and has not been treated with granular insecticides at planting since 1988. The soil type for this field is a combination Allegheny-Cotaco fine sandy loam and Buchanan cobbly fine sandy loam. The experiment consisted of a randomized complete block design with 4 replications. Plots were 30-ft long and consisted of 2 rows spaced 30 inches apart. A John Deere, 2-row Max-Emerge planter was used to plant all plots on 2 May at a population density of 26,100 seeds per acre. Insecticide granules were applied in front of the press wheels either directly in the seed furrow or in a 5-inch wide T-band over the furrow, depending on the treatment. Each of the regular granular insecticide applicators was removed from the planter and replaced with a wooden device designed to hold inverted pt canning jars (Mason) used in dispensing the insecticide granules. Attached to the underside of the wooden holders was a plastic funnel and tube through which the insecticide granules flowed. A single opening, drilled into the lid of each jar, was laboratory-calibrated to deliver insecticides accurately at a speed of 3 mph. The possibility of mixing 1 or more insecticides was avoided by using a separate jar and lid for each treatment. At the start of application, 2 jars containing the appropriate insecticide granules were inverted and placed in the wooden holders. This method helped minimize soil compaction because the tractor made only 1 pass per plot. The roots of 5 consecutive corn plants were dug from each plot on 7 Jul and washed of excess soil. Corn rootworm damage ratings were based on the Iowa 1-6 scale (1°no feeding; 6°3 or more root nodes completely destroyed). Stand counts were not made because of irregular seed spacing that occurred in one of the rows during planting. Statistical analysis involved a two-way ANOVA with Duncan’s new multiple range test used to test for differences among treatment means.</jats:p