Plan PGR Use in Cotton Carefully

Plant growth regulator use has become commonplace in cotton production over the past 30 years, notes Darrin Dodds, Mississippi State University cotton specialist. Yet, as he points out in a recent blog post, over-application has occurred in some instances as PGR prices have dropped.

“While some areas of the state have enjoyed adequate rainfall this year, others have gone long periods of time with very limited rainfall,” he says. “In areas where drought has been an issue, caution is urged with respect to PGR use.”

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Dodds offers five tips for growers to consider when planning PGR use this season:

  • Let the plant dictate application timing and rate. The youngest fully expanded internode occurs between the fourth and fifth node down from the terminal. If this internode begins to exceed 2.5″ in length, a PGR application may be warranted. The longer the length of this internode, the greater the application rate warranted.
  • Be mindful of weather conditions in the 14 days following PGR application. If dry weather is predicted in the 14 days following a PGR application, consider cutting the rate back or delaying the application altogether.
  • Use whatever product you like best. Research at Mississippi State has shown that no one product offers superior performance to another. If you prefer to go as cheap as possible, by all means do so. If you would rather handle less product, use a formulation that is typically applied at 2-4 oz/A versus 8-16 oz/A.
  • A good fruit load is the best PGR on the market. Maintaining a good fruit load will help naturally regulate growth and development of the cotton plant. In areas where the fruit load is reduced, PGR applications may be warranted to prevent excessive vegetative growth.
  • Do not apply a PGR with the intention of increasing yield. A quick search of previous research will reveal that PGRs may increase yield, decrease yield, or have no effect on yield. Plant growth regulators should be applied to manage vegetative growth. Period. Managing excessive vegetative growth will help with penetration of insecticides, aid in leaf removal at the end of the year and facilitate a quicker harvest.

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