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Farmers need to build a wall around their crop from seed until a time when the crop (and yield) is no longer threatened.

Bob Kemerait, Plant Pathologist

January 30, 2019

4 Min Read
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Talk of building a wall can be a useful image for farmers when it comes to protecting crops from diseases and nematodes. 

News is filled with talk of building a wall, a debate that has embittered seemingly everyone on either side of the fence and those stuck in the middle.  Farmers need to build a wall around their crop from seed until a time when the crop (and yield) is no longer threatened.

While the challenges of building a wall along our southern border of the United States are formidable, building a wall to protect our crops has its own complications and difficulties. Seeds are planted into a hostile environment, one where the “bad guys,” the fungal pathogens and plant-parasitic nematodes, are waiting for their next meal. 

A wall to protect seeds and young seedlings must be in place immediately, or else damage and injury that threaten yield occurs quickly. 

Early-season protection is the foundation upon which the rest of the wall will be built. A poor foundation will haunt the grower through harvest. These are the important steps to building a strong foundation:

  • Rotate fields away from a crop or crops that share the same nematodes and diseases. This reduces the impact of the enemy that must be faced from the “get-go”. 

  • Plant into soils that are warm and with sufficient moisture to support rapid germination, growth and development of the crop.  Planting-time can be likened to a “horse race” where young plants struggle to develop to a point where they are able to fend off attack from fungal pathogens.

  • Seeds must be treated with an effective suite of fungicides to defend against the fungal pathogens and nematodes that surround them.

  • It is said that the “best defense is a good offense," and treating the soil surrounding the seed by fumigation or use of in-furrow products can go a long way to protecting a crop.

A wall along our southern border would be stout and strong, but also static. Farmers do not have the benefit of “static” as the wall they build is not complete until harvest approaches. 

Failure to be diligent and timely with any fungicide application leaves the crop open for attack and for damage to occur. Once a disease or nematodes become established, it is difficult or impossible to remedy the situation. 

Steps to building an effective wall throughout the season include the following: 

  • Resistant varieties should be planted if possible. Resistant varieties come with a wall that is ready-made to protect against important diseases and nematodes and are often much cheaper than are chemical control strategies. 

  • To build the wall, be timely in application of fungicides. The most effective way to control diseases is to have fungicides applied before disease occurs, or at least before it is broadly established in a field. To be tardy in a fungicide application is to compromise the impact of any wall built to protect the crop. 

  • Good protection also requires good coverage. Getting coverage can be difficult but it is essential. Coverage is achieved by care in selecting the volume and spray pressure of an application. 

  • Coverage can be impacted by choice of spray tips and by the speed travelled through the field. Coverage is affected by the timeliness of irrigation and rainfall after a fungicide application. Coverage can be affected by the time of day (or night) that the application is made.

To build the most effective wall around your crop requires attention to timing and coverage; no matter what product is chosen. Growers may invest significant dollars in a management program that does not meet expectations because a) it was late in initiation, b) was delayed by weather or other factors, c) was washed off too quickly or not at all, or d) had some other unexpected problem. 

Timeliness and coverage are essential no matter what program is used. However, results from research trials reinforce that as risk to disease and nematodes increases, the importance of investing in better, and often costlier, products is merited. 

A grower wouldn’t use Telone II where nematodes are only a minor issue. However, there is no other product in my world to compare to Telone when nematodes are a major issue and in-furrow applications are often more effective than seed treatments. 

Tebuconazole can be an effective tool for disease management on peanuts, corn and soybeans when risk to disease is reduced. However, in situations where threat of disease is high, especially from multiple diseases, the efficacy of newer products with more than one mode of action is warranted.

As in our nation’s debate now over a wall; the cost of a protective wall is something every farmer must address. Building the wall around a crop to maximize yields and profits takes careful planning, attention to detail, and thoroughness.  

A strong foundation and a dynamic management program are keys to a successful crop and profitable season.

About the Author(s)

Bob Kemerait

Plant Pathologist, University of Georgia

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