Location, Variety, and Seeding Rate Interactions with Soybean Seed‐Applied Insecticide/Fungicides

Abstract

Cool conditions aft er soybean [Glycine max (L.) Merr.] planting may increase soil pest incidence and reduce emergence. Fieldscale studies were conducted in 2009 and 2010 at three locations in New York on two varieties at four seeding rates (272,000, 346,000, 420,000, and 490,000 seeds ha -1 ) with and without seed-applied insecticide/fungicides to determine if treated seed enhances plant establishment, allowing for lower seeding rates for maximum yield and partial return. Plant density and yield had location × variety × seed treatment interactions. A treated vs. untreated Asgrow variety had 16 to 22% plant density increases and 4% yield increases at two locations, whereas a Pioneer variety had a 16% density increase at one location but no yield increases. At a third location, the treated vs. untreated Pioneer variety had 19 and 4% increases, respectively, whereas the Asgrow variety had no increases. Yield, which had no seeding rate × seed treatment interaction, had quadratic responses to seeding rate and early plant densities (maximum yield at 478,300 seeds and 295,300 plants ha -1 , respectively). Partial return, which had a seeding rate × seed treatment interaction, had quadratic responses to seeding rate with maximum values at 398,800 and 341,800 seeds ha -1 for untreated and treated seed, respectively. Maximum partial returns at these seeding rates ($1241-1245 ha -1 , respectively) were similar because seed treatment cost off set lower seed cost. Maximum partial return occurred at early plant densities of 248,400 plants ha -1 , but the variety × location × seed treatment interaction complicates selecting seeding rates for this plant density.

Soybean Seed Yield Response to Multiple Seed Treatment Components across Diverse Environments

“…Looking further into the 2013 results indicated the addition of thiamethoxam (CM) increased yield by 4% (175 kg ha −1 ) over the UTC and by 3.6% (145 kg ha −1 ) over its fungicide only counterpart, AM (Table 5). This yield increase over AM is consistent with the 2011–2012 results in the current study, and the 4% increase over the UTC is identical to results from Gaspar et al (2014) and Cox and Cherney (2011). However, the addition of the nematicide abamectin to CM, which results in CMA (4235 kg ha −1 ), did not increase yield any further (Table 5).…”

“…As seed costs increase, the use of seed treatments may allow producers to lower their seeding rates and therefore reduce the cost of soybean seed per hectare. This is confirmed by Gaspar et al (2014) and Cox and Cherney (2011) who reported that seeding rates should be lowered by approximately 50,000 seeds ha −1 to maximize partial profit when a fungicide/insecticide seed treatment was used compared to no seed treatment. Commodity prices have a direct relation to the profitability of a seed treatment and ultimately producers are more interested in products that are cost effective, implying they are able to increase yield enough to increasing profitability (Marra et al, 2003; Pannell et al, 2000).…”

“…Specific active ingredients have been documented to provide yield gains with certain environments and varieties (Bradley, 2008; Cox and Cherney, 2011; Lueschen et al, 1991; Schulz and Thelen, 2008). Our analysis of the four groups of different pesticide components within each environment (Table 3) agrees with these previous findings where we observed environment‐specific yield responses to seed treatment in 10 of the 28 environments.…”

“…This has increased from only 8% of soybean seed treated in 1996 and 30% in 2008 (Munkvold, 2009). The dramatic surge in soybean seed treatment use is likely due to earlier planting (USDA‐NASS, 2011), increased seed costs (USDA‐ERS, 2012), and higher soybean commodity prices (USDA‐ERS, 2012), in addition to yield gains reported by various studies (Cox and Cherney, 2011; Esker and Conley, 2012; Gaspar et al, 2014).…”

Soybean Seed Treatments Interact with Locations for Populations, Yield, and Partial Returns

“…The location × seed treatment yield interaction was not associated with planting equipment at different locations, as indicated by a positive yield response to the rhizobia–biological–fungicide–insecticide seed treatment at a grain drill (Seneca County) and a row crop location (Yates County) and no response at a grain drill (Livingston County) and a row crop location (Tomkins County). Other researchers have also observed an inconsistent yield increase with the use of fungicide and/or insecticide seed treatments, despite increases in early plant populations (Bradley et al, 2001; Poag et al, 2005; Murillo‐Williams and Pedersen, 2008; Schulz and Thelen, 2008; Cox and Cherney, 2011b; Esker and Conley, 2012). The addition of the biological compound PPST 2030 to fungicide and/or insecticide seed treatments did not reduce the inconsistent yield response to soybean seed treatments in this study.…”