Thursday, November 8, 2007 - 9:15 AM
336-4
Effect of Foliar Fungicide and Insecticide Application, Planting Date, and Seeding Rate on Soybean Yield and Yield Components.
Reduced soybean stands present growers with difficult decisions concerning replanting and management of the crop. When faced with reduced soybean stands, producers must assess yield potential based on existing population, stand uniformity, and the time of year, then decide whether to manage the existing crop or replant. Later in the season, the producers must weigh the costs and potential benefits of foliar fungicide and insecticide applications on profitability. To assist producers with these decisions, field studies were initiated in 2007 at two locations in Tennessee to evaluate the effects of foliar fungicide and insecticide applications on yield and yield components of soybean no-till planted in late April, mid-May, and early June at seeding rates of 198,000, 296,000, and 395,000 seed ha-1. Prior to planting, seed were treated with the fungicide mefenoxam and fludioxonil to minimize the impact of seedling diseases. Foliar treatments were pyraclostrobin at 0.11 kg a.i. ha-1 at soybean R3, 0.11 kg ha-1 pyraclostrobin + 0.014 kg a.i. ha-1 zeta-cypermethrin at R3, or 0.11 kg ha-1 pyraclostrobin at R3 followed by 0.014 kg a.i. ha-1 zeta-cypermethrin as needed. A nontreated check was also included. Dates of growth and reproductive stages were recorded, soybean stand was determined at harvest, and the center four rows of each plot were harvested for yield. Additionally, plants were collected from each plot at harvest to determine final soybean plant height and yield components, consisting of node number, pod number, seed pod-1, and seed weight 100 seed-1.
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