FUNGICIDES may be an option for 2012 soybeans

FUNGICIDES may be an option for 2012 soybeans.

Southeast soybean crop may get extra care this season

• Getting maximum value for soybeans will likely be a bigger issue than ever for growers in the Southeast this year. • Putting higher cost, yield-enhancing inputs into soybeans may be more common, especially if soybeans stay in the $13-$13.50 range at planting time.  

Some economists are projecting 2012 soybeans will sell for more than $13 a bushel, placing beans among the elite crops, in terms of net value per acre, for growers in the Southeast to plant in 2012.

Getting maximum value for soybeans will likely be a bigger issue than ever for growers in the region.

Typically, soybeans have been planted on poorer soils in the Southeast, but that may not be the case in 2012. If so, putting higher cost, yield-enhancing inputs into soybeans may be more common, especially if soybeans stay in the $13-$13.50 range at planting time.

Wheat growers in the Upper Southeast are coming off a big year and acreage is again expected to be high for the 2012 planted crop. With prices good, a similar scenario to soybeans is in place for growers in the area.

Virginia Tech Plant Pathologist Pat Phipps has tracked the use of fungicides on soybeans and wheat for a number years and has scientific data that may play a big role in getting maximum yield from these higher than usual input costs on soybeans.

Since the introduction of triazole and strobilurin fungicides to the market a few years back, there has been an ongoing debate as to whether application of these fungicides pays on a regular basis in soybeans in the Southeast.

There is no question about the efficacy of these materials, especially applied when beans are at high risk from a particular disease.

Whether preventative treatments of these highly efficacious fungicides pays when used as a preventative application on soybeans isn’t nearly so clear.

Since 2006, Phipps has tracked the yield response and the yield increase on soybeans when a number of strobilurin and triazole fungicides are applied in replicated tests at the Tidewater Agricultural Research Center in Suffolk, Va.

“All these fungicides, whether used alone or in combinations with other triazole or strobilurin-based fungicides worked well in disease control in our tests,” Phipps says.

Over the six year history of the tests in Virginia, Phipps says the average yield response from using strobilurin and triazole fungicides was 5.1 bushels per acre in fields where common foliar and pod diseases were present.

Return would double cost

At $13 a bushel, the net return from using these materials is roughly double the cost of the fungicides and application costs.

The biggest yield response came in 2009, with an average yield increase of 11.6 bushels per acre for treated versus untreated plots. 

By comparison, the lowest response to fungicides in the Virginia researcher’s ongoing six-year study came last year with a 2.9 bushel per acre yield response to fungicides. In 2010 and 2011 there was no significant yield increase using fungicides.

However, Phipps points out that strobilurin/triazole tank-mixes did reduce disease incidence significantly in both years.

In general, a lower response to fungicides came in years with persistent hot-dry seasons (2011). This trend could be particularly important to soybeans growers in the Upper Southeast for the next few years.

For the past two years, the region has been dominated by a persisting La Niña weather pattern. Reoccurring La Niñas have been infrequent and sporadic over the past 50 years.

However, for as long as weather records have been kept, there has never been a three-year reoccurring La Niña system.

Take away weather-influenced hot and dry patterns over the past six years, and the yield increase from pre-mix application of triazole-strobilurin fungicides would almost certainly have been higher.

There are a number of pre-mix fungicide options for use on soybeans for 2012. While any of these can be used effectively as a stand-alone product, best results have come from tank-mixing these two families of chemistry.

Mixtures of different chemistries will likely lengthen their longevity by reducing or delaying resistance problems associated with over-use of any one family of active ingredients.

In a series of ongoing tests over the past 11 years (2000-2011), Phipps has tracked similar responses to fungicides when these materials are applied to wheat. The average yield increase over the 11-year period, ending with the 2010-2011 wheat crop, was 11.35 bushels per acre.

In 2004 and 2005, wheat yields were increased an average of more than 23 bushels per acre by fungicide treatments. As with soybeans, the lowest response to fungicides came in 2010 and 2011 when yields increased an average of about four bushels per acre.

Would more than pay for treatment

Phipps points out that, as was case with soybeans, even at the lowest levels of wheat yield increases, use of fungicides still would more than pay for itself at current price levels for the crop.

Fungicides used in the 11-year fungicide test of wheat included: Headline, Quilt, Quilt-Excel, Stratego Pro, Prosaro, Priaxor, Headline fb Caramba, Headline fb Twinline and Stratego fb Prosaro.

Headline is a strobilurin that has performed well on both soybeans and wheat throughout the Southeast. It also tends to promotes growth efficiency through better use of nitrogen fertilizer.

According to BASF, the company that markets Headline, the fungicide, “this means healthier plants and higher yield potential.

Quilt combines triazole and strobilurin active ingredients and has been in great demand for use on a number of crops since its introduction into the marketplace in 2007.

Stratego is a popular triazole fungicide that can be used as a stand-alone or in a pre-mix with a number of popular strobilurin fungicides.

Prosaro is a newer fungicide with two different modes of action to protect plants from a broad spectrum of yield-robbing diseases and reduces the likelihood of developing resistance .

Priaxor is a new fungicide scheduled for labeling in 2012, and the new Xemium family of chemistry developed by BASF, the company that markets the product.

Preliminary results from 2011 field trials, showed excellent disease control of a number of diseases, including frogeye leaf spot and septoria brown spot in soybeans.

Caramba is a new triazole fungicide that has provided excellent control of head scab and other common diseases of wheat in tests across the Southeast.

Twinline combines the strobilurin found in Headline with a unique triazole formulation that provides broad spectrum control across multiple wheat diseases, and is especially active on diseases that occur at the flag leaf stage.

These materials range in cost (based on 2011 prices) from $14-$25, with average prices in the $13-$15 per acre range.

The combination of market prices and normal to wetter-than-normal growing season weather could make fungicides a key part of reaching maximum profitability in soybeans and wheat in 2012.

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