Pioneer Seed Treatment With Dynasty® Fungicide

• Pioneer is offering Dynasty® fungicide plus Poncho® seed-applied insecticide on all Pioneer® brand corn hybrids for 2008. This treatment will also include Maxim® XL fungicide.
• Dynasty (azoxystrobin) is a seed treatment fungicide from Syngenta that provides additional control of seed-borne and soil-borne fungi causing decay, damping-off and seedling blight from Rhizoctonia, Pythium, Fusarium and Penicillium.
• Adding Dynasty in combination with a neonicotinoid in-secticide seed treatment (IST) like Poncho 250 or Poncho 1250 provides greater early season pest and stand protec-tion than just adding an IST or Dynasty alone.
• Pioneer's seed treatment combination is ideal for difficult emergence environments such as early planting, high-residue farming systems, and fields with a history of seedling diseases, soil insect damage and stand establishment problems.
• This seed treatment will be available across all Pioneer hybrids and maturities. Dynasty is registered in Canada as well as the U.S.
• This Crop Insights will describe Dynasty fungicide, the combination with ISTs, and research results that demonstrate improved stand establishment and yield.

Pioneer will offer Dynasty fungicide as part of a seed-treatment combination with Poncho 250 or Poncho 1250 insecticide seed treatment on all Pioneer brand corn hybrids for 2008. This treatment will also include Maxim XL fungicide and a new seed treatment polymer that further improves seed plantability and reduces dust-off. This premium seed treatment combination is unsurpassed in the industry for corn stand establishment and seedling protection. Pioneer's customers validated this seed treatment option by ordering almost 80% of corn volume with this premium offering in 2007.

Dynasty was developed by Syngenta as an additional fungicide for seed corn to provide a greater spectrum of early season pest control. This seed treatment package is ideal for difficult emergence environments such as early planting, high-residue farming systems, and fields with a history of seedling diseases, soil insect damage and stand establishment problems. Dynasty has activity against soil fungi that cause corn seedling diseases, including the most common damping-off organism, Pythium.

Corn seedling showing severe symptoms of
seedling disease.

Pioneer surveys have shown that a majority of corn acres are planted nearly 10 days earlier than just a decade ago. And because growers now have more corn acres to plant, they may start even earlier to ensure that most planting is completed during the optimum window.

Corn acres increased by about 15% in 2007, and may grow even more in future years due to increased grain demand for ethanol production. Corn produces more residue than soybeans, which keeps seedbeds cooler and wetter in the spring. This can lead to delayed germination and emergence and increased seedling disease pressure on corn-after-corn acres.

As a result of earlier planting and more corn residue on the soil surface, stand establishment problems have increased in recent years. These problems are not limited to northern areas or heavy soils traditionally associated with Pythium or other seedling disease issues. Rather, high residue tillage systems and earlier planting have created environments at risk for stand establishment problems practically everywhere corn is grown in the U.S. and Canada.

Corn seedling showing initial
symptoms of seedling disease -
radicle deterioration and seminal
roots showing rot.

Dynasty® seed treatment is a formulation of azoxystrobin, a broad-spectrum fungicide also used as a foliar application for many crops. According to the product label, Dynasty targets seed-borne and soil-borne fungi causing decay, damping-off and seedling blight from Rhizoctonia, Pythium, Fusarium and Penicillium.

Dynasty was developed to be used as a co-fungicide with Maxim® XL or Apron® XL in combination with an insecticide seed treatment. According to the manufacturer, the combination supplies a higher level of activity on Fusarium and Pythium, and also provides post-emergent Rhizoctonia protection. The manufacturer also states that studies have shown improved plant stand, vigor and yield for the combined fungicide compared to Maxim XL alone.

On-Farm Trials
Pioneer conducted research in 40 side-by-side strip plots on farmer's fields in both 2004 and 2005 to determine the value of adding Dynasty to the standard seed treatment mix. These large, on-farm plots were located in critical seedling blight areas in Iowa, Illinois, Indiana, Ohio and Michigan. Treat-ments included:

Treatment 1 - Maxim XL + IST
Treatment 2 - Maxim XL + Dynasty + IST

In 2004, excellent conditions for emergence resulted in fewer seedling disease problems and little difference between seed treatments. In 2005, greater early season stresses resulted in more reports of corn seedling diseases and stand establishment issues. Stand establishment results from the Pioneer study are shown in Figure 1.

Figure 1. Corn stand establishment for two seed treatments: Maxim XL + IST vs. Maxim XL + Dynasty + IST. 40 on-farm locations each year in Iowa, Illinois, Indiana, Ohio and Michigan.

As the graph above demonstrates, addition of Dynasty to the seed treatment mix resulted in significantly higher stands in 2005, but not in 2004. When stresses accompany planting and corn emergence, Dynasty offers additional protection against stand reduction due to seedling diseases from Pythium, Fusarium and Rhizoctonia infection.

Another measure of the value of a seed treatment is how often the treatment prevents significant stand loss and possible replant when stressful conditions occur after planting (Table 1.)

Table 1. Number and % of test locations in 2005 resulting in stand increases greater than 2000 and 4000 plants/acre.

The addition of Dynasty® resulted in stand improvements of 2000 plants/acre or more in 18 of 40 locations, and improvements of 4000 plants or more in 4 of 40 locations.

Grain yields from the Pioneer on-farm research trials are shown in Figure 2. The inclusion of Dynasty fungicide improved yields by an average of 6.7 bu/acre in 2005 when stressful emergence conditions were widespread. Yield results were reported for 20 on-farm locations in 2004 and 37 in 2005.

Figure 2. Corn grain yield for two seed treatments: Maxim XL + IST vs. Maxim XL + Dynasty + IST. 37 on-farm locations each year in Iowa, Illinois, Indiana, Ohio and Michigan.

Replicated Trials
In 2006, Pioneer Agronomy Sciences researchers conducted studies in eight Corn Belt locations to compare the perfor-mance of Dynasty-Maxim XL-Poncho 250 seed treatment vs. Maxim XL-Poncho 250 treatment (Figure 3). The check treatment was plain seed with no fungicide or insecticide applied.

Figure 3. Corn grain yield for two seed treatments and an untreated check. Pioneer Agronomy Sciences replicated research trials, 2006. 8 locations.

Results showed that treating seed with Maxim XL-Poncho 250 increased grain yield by 8 bu/acre, a significant difference. Addition of Dynasty to the seed treatment increased yields by another two bu/acre.

Several recent research studies have indicated that increased activity may result when a strobilurin fungicide such as Dynasty is combined with a neonicotinoid insecticide seed treatment like Poncho®.

Kansas State University research demonstrates both the value of Dynasty and neonicotinoid ISTs in increasing fungicidal activity of seed treatments, and thereby increasing plant stands of corn (Figures 4 and 5.)

Figure 4. Effect of various seed treatments on corn stand establishment. Parsons, KS, 2003. Kansas State University.

Figure 5. Effect of various seed treatments on corn stand establishment. Parsons, KS, 2004. Kansas State University.

As Figure 4 shows, addition of Dynasty to Maxim® XL increased stands by over 1000 plants/acre, although this difference was not statistically significant. Addition of an insecticide seed treatment to Maxim XL increased stands by nearly 2000 plants/acre over Maxim XL alone, which was statistically significant. Highest stands were obtained by adding a combination of Dynasty and an IST to the seed treatment mix. A similar experiment was conducted in 2004 (Figure 5). 2004 results were very similar to those of 2003. Incremental stand increases were achieved by adding Dynasty and insecticide seed treatments to the base Maxim XL treatment.

Agri-Tech Consulting of Janesville, Wisconsin also tested seed treatments in 25 field trials (Figure 6). Addition of Dynasty increased stands by 2400 plants/acre. Addition of Dynasty and a mid-rate (0.25 mg/kernel) IST increased stands by 4500 plants/acre over Maxim XL.

Figure 6. Effect of seed treatments on corn stand establish-ment. Average of 25 field studies. Courtesy of Dr. Timothy Maloney, Agri-Tech Consulting, Janesville, WI.

Pioneer's 2008 seed treatment offering will allow growers to choose either Poncho® 250 or Poncho 1250 ISTs. These ISTs add control of most seed-damaging soil insects common in no-till, high residue, and other stressful emergence environments. Soil insects can be particularly problematic under cool soil conditions that slow growth of corn and reduce the seedling's ability to outgrow insect feeding damage. More information on insect control of Poncho 250 and Poncho 1250 is included below.

Poncho 250 IST
Poncho 250 IST is a formulation of clothianidin, a broad-spectrum, systemic neonicotinoid insecticide. Applied at a rate of 0.25 mg active ingredient per kernel, this product delivers early-season protection against wireworm, white grub, seedcorn maggot, flea beetle, grape colaspis, chinch bug and black cutworm, according to the manufacturer's label. Because it comes on the seed and in the bag, Poncho 250 has advantages in convenience and safety over soil insecticides or hopper-box treatments.

Poncho 1250 IST
Poncho 1250 insecticide seed treatment, a formulation of clothianidin applied at a rate of 1.25 mg/kernel, was first introduced on Pioneer® brand corn hybrids in 2004. The primary pest target for Poncho 1250 is corn rootworm (CRW), but in addition, it offers the broadest insect protection available in a seed-applied insecticide for a number of other problematic insects. Secondary soil insects on the Poncho 1250 label include wireworm, white grub, grape colaspis, and seedcorn maggot. Above-ground insects are billbug, chinch bug, flea beetle and black cutworm.

Poncho 1250 has proven effective in low and moderate corn rootworm infestations, but is not necessarily recommended under high infestations. Poncho 1250 eliminates the cost and time required to install soil-applied insecticide equipment, calibrate equipment and load products during planting, and handle and return insecticide containers.