Control of Slugs in No-Till Corn, 1987

Abstract

Abstract No-till corn plots were located in a Unadilla silt-loam field of pH 5.6 and 1% organic matter in Big Flats, N.Y. The previous crop was no-till corn in which the corn stalk and leaf residues provided a dense mulch. On 23 Apr, the no-till field was prepared by applying paraquat at 0.5 lb (AI)/acre to kill various weed seedlings. The field was seeded on 30 Apr using a tractor drawn Buffalo No-Till Planter to seed 4 rows/pass at 30-inch row spacing. Seed drop was set at 27,800 kernels/acre and planted at 1.0-1.5 inches deep. Simultaneously, chlorpyrifos (Lorsban® 15G) was applied at 2 lb (AI)/acre, and fertilizer (10-20-20) was applied at 330 lb/acre. On the following day, Lasso and Aatrex 4L were applied at 2 lb (AI)/ acre each. Treatment plots were 20 × 20 ft containing 6 rows of corn, including an additional untreated buffer row between treatments. Plots were arranged in a randomized complete block design with 6 replicates. In each plot three sampling holes, 4 inches in diam × 6 inches deep, diagonally and evenly spaced, were excavated between rows with a golf-hole digger on 6 May. Each hole was covered with a 1-sq-ft asphalt shingle wrapped with aluminum foil. The reflective shelter kept the hole dark, cool, and moist; hence, it provided an ideal hiding place for slugs. Larvin bait was prepared according to label by coating cracked corn with the 3.2% flowable using a mixture of water, beer, and molasses as sticking agent; and the bait was applied at 20 lb bait/acre. Bait and spray treatments were applied on 2 Jun when the corn was at the 2- to 3-leaf stage and slug damage to the corn plants was evident. The molluscicidal baits were broadcast by hand evenly over the corn rows. Larvin 3.2F was applied with a mechanical backpack sprayer at 50 gal/acre of water. On 15 Jun, liquid fertilizer was side-dressed at 120 lb/acre of nitrogen. Slug counts were taken by inspecting the holes and areas covered by the shingles for live slugs just before treatment and at 3, 7, and 14 days posttreatment. Corn damage ratings were taken by inspecting 20 corn plants per plot at pre- and posttreatment. Plants were rated as no damage (0% slug feeding damage), slight damage (1-20%), moderate damage (21-60%) and severe damage (60-100%). Corn stand was evaluated at pre- and posttreatment on 2 and 16 Jun by taking two 1/1000-acre samples per plot (17.4 foot-row per sample); the final corn stand and yield were taken on 23 Sep from two 17.4-ft rows.