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One chance to make best decisions before the furrow closes

Anticipating increased pressure from disease and nematodes helps to formulate a more robust management program.

Bob Kemerait, Plant Pathologist

February 12, 2020

4 Min Read
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When the furrow is closed, these decisions cannot be reversed unless the crop is replanted.Brad Haire

A grower I know dutifully used an in-furrow fungicide on his peanuts each season, though he had good crop rotation and had no stand problems. He asked if he should continue the practice. My advice to him was to spend that money elsewhere. That said, farming is neither for procrastinators nor the timid. The stark reality for controlling nematodes and some diseases is that one has limited chances.

Decisions at planting that have season-long impact include fumigation, planting date, crop planted in a field, variety selection, choice of seed treatment, and use of an in-furrow fungicide, insecticide or nematicide. When the furrow is closed, these decisions cannot be reversed unless the crop is replanted. For row crops, growers may have as many as 160 days from planting until harvest to enjoy the success of early-season decisions or to wish that some things had been done differently.

Growers can reduce the risk for diseases and nematodes with good crop rotation. While this is common sense, deciding which crop or resistant variety to plant in a field will impact management decisions over the entire season. Short rotations increase the risk of nematodes and diseases from the time of planting until harvest. If a field must be planted on a “short rotation” then the grower should incorporate other management tactics to mitigate the risk. 

Timing

Planting date effects disease. Early-planted corn is less likely to be affected by southern corn rust than is later-planted corn. Early-planted and late-planted peanuts are at greater risk to tomato spotted wilt disease than are those planted in May. Late-planted soybeans are at greater risk to soybean rust; late-planted cotton may be more at-risk to cotton leafroll dwarf virus.  Planting when soils are wet and cool, or when wetter and cooler weather is in the forecast, can result in increased seedling disease and stand loss. 

In-furrow fungicides and “extra” seed treatments can improve stand and reduce losses to seedling diseases. They offer insurance when conditions favor disease (cool and wet or hot and dry) or when other factors, such as seed quality, may pre-dispose the crop to stand loss. Thimet, an at-plant insecticide, reduces risk to spotted wilt disease of peanut. 

There is one best chance to fight nematodes, seedling diseases (e.g., Rhizoctonia soreshin and Aspergillus crown rot), and tomato spotted wilt of peanut.  At planting, cotton and peanut growers have the opportunity to plant a variety with increased resistance to root-knot nematodes.  If they plant one, then no nematicide is needed.  If they choose a susceptible variety, then it must be decided to protect the crop with a nematicide or not. 

If the grower decides to use a nematicide, will it be with Telone II?  AgLogic 15G?  Velum Total? Or, in the case of cotton, will the grower use a seed-treatment nematicide like COPeO Prime, AVICTA Complete Cotton, of BioST? 

No fearmongering

Because there are no nematode-resistant corn varieties, growers planting into nematode-infested fields should consider if Telone II, Counter 20G, Propulse, or AVICTA Complete Corn would be beneficial.  Once the furrow is closed, options management of nematodes on cotton and peanuts is limited to treatments meant to compliment, but not replace, earlier treatments.  You live with the consequences for the rest of the season if you don’t protect against nematodes.

Variety selection reaches beyond nematodes. Some corn varieties are more resistant to northern and southern corn leaf blights than are others. Some soybean varieties are more resistant to frogeye leaf spot than are others.  Peanut farmers can select varieties with greater (or lesser) resistance to tomato spotted wilt, leaf spot and white mold. If growers plant a disease-resistant variety, then there is less pressure on fungicides. If a more-susceptible variety is planted, then the grower should be ready with an appropriate fungicide program.

My emphasis on “one best chance” is subject to fearmongering. Consideration for diseases and nematodes is important before the furrow is closed.  Choice of insecticides, nematicides, and fungicides can protect the crop and yield, but also adds expense.  Before buying a product growers should ask, “Do I really need it?”  If risk is low, for example because of good rotation, nematode test results, or use of Peanut Rx, then there may not be reason to spend extra money.  A grower I know dutifully used an in-furrow fungicide on his peanut crop each season, though he had good crop rotation and had not had a stand problem.  He asked if he should continue the practice. My advice to him was to spend that money elsewhere.

I recited “Invictus," a favorite poem by William Ernest Henley, at a county meeting last week. Those in attendance listened in stunned silence, though they have come to expect such from me.  The final lines are, “I am the master of my fate; I am the captain of my soul.”  I told them, “Take charge Captain! The fate of the season is in your hands.”

About the Author(s)

Bob Kemerait

Plant Pathologist, University of Georgia

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