The Halo Effect


The Halo Effect – The Mark of Protection Against SDS

ILeVO® seed treatment from Crop Science is the first and only solution for soybean Sudden Death Syndrome (SDS) with activity against nematodes. It protects the soybean root system against the SDS fungus, and it has activity against nematodes in the seed zone, producing healthier plants for higher yield potential.

In most instances, growers will see the Halo Effect – a visual confirmation that ILeVO is working to protect the plant. The Halo Effect is a discoloration that appears on the edge of the cotyledons, appearing first as light green to yellow to brown as the seedling emerges. The discoloration is limited to the cotyledons and does not appear on the unifoliates or trifoliates.

The Halo Effect is an indication that ILeVO is being localized in the soybean root and seedling where it is needed for protection against the fungus causing SDS and against nematodes as well.

What does the Halo Effect look like?

The Halo Effect discoloration is a visual side effect, which will not harm the plant, and is a symptom showing that ILeVO seed treatment is working to protect the plant from the fungus that causes SDS.

The Halo Effect 

How long does the Halo Effect discoloration last?

The discoloration lasts until the cotyledons fall off. Once plant growth results in unifoliates and initial trifoliate production, the plant will again appear normal in color. Since SDS symptoms are rarely seen in seedlings, the Halo Effect provides growers with the confidence that ILeVO is defending the plant.

What if there is no Halo Effect? Does that mean that ILeVO is not working?

While all crops will experience some form of the Halo Effect, growers should not be concerned if they miss the visual signs. If seeds are treated with ILeVO, growers can be confident that their crops are protected from SDS.

How does ILeVO work?

ILeVO is absorbed by the germinating soybean seed and moves into the seedling’s roots, stem and cotyledons, where its unique mode of action provides early plant protection against SDS.

Is there a growth response to ILeVO?

In some instances, growers may initially see a slower growth response as the soybean plant begins to process or metabolize ILeVO. The slower growth allows the developing plant time to build up its internal resistance to SDS, effectively jump-starting the plant’s defense response in a manner similar to the way the human body reacts to vaccines. However, 20 to 30 days after emergence, growers will begin to see a healthier-looking plant, compared to untreated soybeans, due to the effective control of SDS.

ILeVO® Halo Effect and Growth Response over 28 Days 

Is there an effect on seedling emergence, plant stands or yield?

The Halo Effect has no detrimental impact on the speed of emergence, plant stands or yield. After three years of field testing, soybeans treated with ILeVO emerge at the same speed as untreated beans. The presence of ILeVO does not impact emergence or plant stands. In fact, field trials showed plants treated with ILeVO produced yields 2–10 bushels per acre higher than with other fungicide/insecticide seed treatments.

Does ILeVO trigger a response to herbicides?

Crop Science research in 2013 and 2014 showed no interaction with pre-emergence herbicides. Both Crop Science and university researchers performed field and greenhouse trials to identify any potential herbicide interactions. Testing will continue throughout the 2015 season. To learn more visit the Iowa State University and Purdue University report page.

How does ILeVO impact Root rot and nematodes?

SDS is one of the most aggressive soybean root rot pathogens. Initial SDS infections occur on the roots and crowns of young soybean plants causing a phase that impacts the early-season health of the soybean seedling. Even when no SDS visual symptoms are experienced, root rot effects can still contribute to yield loss. ILeVO controls this early-season root rot at the initial infection site before symptoms become visible, thereby reducing the incidence and severity of the impact SDS has later in the season.

Additionally, ILeVO has a mode of action new to the market which provides broad-spectrum activity against nematodes including lance, reniform, root lesion, root-knot and Soybean Cyst Nematodes (SCN). SCN is the number one yield-robbing soybean pest and has caused an average loss of 126 million bushels per year over the last five years.*

*A. Wrather, University of Missouri, United Soybean Board-funded project.

What is the yield benefit of ILeVO?

During research and field trials between 2011 and 2015, ILeVO® was used on 285 fields and showed an average yield increase of 2 to 10 bu./A depending on SDS severity. At a soybean commodity price of $9/bu., this would create an additional value of $18-$90 per acre.

ILeVO®-treated plants (right) reduced the intensity of SDS symptoms and retained leaves longer than untreated plants (left). 

Are there university studies available on ILeVO and/or the Halo Effect?

For more information on ILeVO and SDS, please contact your local Bayer representative or visit the ILeVO product page and SDS page.

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