No abstract

Recent peanut cultivar releases are trending to a larger seed size, but have great resistance to tomato spotted wilt virus (TSWV). Larger-seeded cultivars cost more to plant than smaller at an equivalent population. Reduced seeding rates could save growers on seed costs and impede the spread of southern stem rot, but can reduce plant stands which can lower yields and increase TSWV incidence. Therefore, the objectives of this experiment were to compare seven peanut cultivars (Georgia Green, Georgia-06G, AT 3085RO, Florida-07, Tifguard, AP-3, and Georgia-03L) in single and twin row patterns at three seeding rates (17, 20, and 23 seed/m) on a sandy loam soil at Plains, GA for disease incidence, agronomic, and economic performance. Measured variables included yield and grade, plant height and stand, TSWV and southern stem rot incidence, and adjusted net revenue in 2008 and 2009. Twin rows outperformed single rows whenever differences occurred. The only factors consistently affected by reducing seeding rate were plant height and stand, both decreased at the lowest seeding rate. There was a trend toward lower yields (approximately 6% reduction) at the 17 seed/m rate in twin row pattern, although net returns were not diminished compared to the higher seeding rates since lower seed costs offset yield reductions. The cultivars Georgia-06G and Florida-07 had the highest yield and adjusted net revenue among the seven cultivars in both years. Tifguard and Georgia Green had lowest overall yields and would not be preferred cultivars in sandy loam soils. This study demonstrates that twin rows have higher yield, plant stands, and net revenue, plus reduced TSWV incidence than single row pattern, and a reduction in seeding rate to 17 seed/m can be made without serious risk of lost revenue. However, benefits of reducing seeding rate in twin rows were not as pronounced as they were for single rows, and exhibited a greater potential for lower yield. A grower planting in single rows would likely have the most to gain from planting fewer seed, especially under heavy southern stem rot pressure, but planting in twin rows would still be a preferred option over single rows.

conservation practices to qualify for government subsidies, which promotes conservation tillage.

Growers who utilize strip tillage and a winter cover crop can utilize seed treatments for mitigation of early-season thrips infestation.

Field experiments were conducted at Gainesville and Marianna, FL in 2004 and 2005 in which severity of spotted wilt, caused by Tomato spotted wilt virus, and pod yield were compared in six peanut (Arachis hypogaea) cultivars. The six cultivars included the moderately field resistant cultivars ANorden, C-99R, and Georgia Green; the highly field resistant cultivars AP-3 and DP-1; and the susceptible cultivar SunOleic 97R. There were four trials at each location, with four planting dates that ranged from late March to early June. Tomato spotted wilt severity in moderately resistant and susceptible cultivars was lower at Gainesville than at Marianna in both years in moderately resistant and susceptible cultivars. Trends in incidence for the two locations were less evident for AP-3 and DP-1. At Gainesville, there were few differences in tomato spotted wilt severity, and severity ratings were similar for Georgia Green and SunOleic 97R in two of four trials in 2004 and across all trials in 2005. At Marianna, severity ratings were lower for Georgia Green than for SunOleic 97R in six of the eight trials, and severity of tomato spotted wilt was lower for AP-3, C-99R, and DP-1 than for Georgia Green in all eight trials. In 2004, there was a trend toward decreasing severity ratings for Georgia Green and SunOleic 97R with later planting dates, but not for AP-3 or DP-1 at Marianna. Split-plot field experiments were also conducted at Tifton, GA in 2005 through 2007 in which incidence of tomato spotted wilt and pod yield were compared for peanut cultivars AP-3 and Georgia Green across planting dates ranging from late April through late May. Incidence of tomato spotted wilt was lower for AP-3 than for Georgia Green within each planting date of all years, and planting date effects were smaller in AP-3, if observed at all, than in Georgia Green. In most planting dates of all three trials, yields were higher for AP-3 than for Georgia Green. The relationships between yield and planting date were not consistent. These results indicate that the level of field resistance in AP-3 and DP-1 cultivars is sufficient to allow planting in late April without greatly increasing the risk of losses to tomato spotted wilt.