Cotton variety selection with and without Velum Total for root-knot nematode management in central Alabama, 2016

摘要

Five cotton varieties were evaluated along with Velum Total for control of the root-knot nematode. This test was conducted at the Plant Breeding Unit Research Station near Tallassee, Alabama. The field has a substantial population of the root-knot nematode (Meloidogyne incognita race 3). The soil type is Kalmia loamy sand, which contains 80% sand, 10% silt, and 10% clay. Seed varieties received standard seed treatment as sold based upon variety, and Velum Total was applied in-furrow with 8002 flat fan nozzles angled diagonally across the seed furrow after seed at a rate of 14 oz/acre on right two rows of each plot. Plots were planted on 16 May, and consisted of 4 rows that were 25 feet long with 36-inch row spacing. Seed was planted at 1-inch depth.The plots were arranged in a randomized complete block design with five replications of each treatment and a 20-feet-wide alley. All plots were maintained as recommended via the Alabama Cooperative Extension System with typical pesticide and fertility production practices, and an overhead irrigation system was used for watering as needed. Nematode densities and stand measurements were taken in the root-knot nematode infested field at 28 DAP (days after planting). Nematodes were extracted from the cotton roots using 6% NaCl and collected on a 25 um sieve. Harvest took place on 4 October at 141 DAP. Data was statistically analyzed by SAS 9.4 (SAS Institute Inc.) using ANOVA and means were compared using Tukey-Kramer with P < 0.1. Monthly average maximumtemperatures from planting in May through harvest in October were 82.3, 90.9, 93.5, 92, 92.1, and 85°F with average minimum temperatures of 57.5, 66.3, 69.9, 70.5, 64.9, and 51.2°F, respectively. Average temperatures from May to October was 69.9, 78.6, 81.7, 81.3, 78.5, and 68.1°F. Rainfall accumulation for each month was 1.76, 2.82, 2.94, 4.12, 0.95, and 0.23 in., respectively.