Mepiquat-containing PGRs reduce plant hormones called gibberellins, which help regulate cell expansion. Mepiquat hinders the elongation of the internodes near the terminal of the main stalk or the lateral branches may not elongate to the degree that non-treated plants would. You get a shorter plant with more compact nodes.

“Most mepiquat-containing PGRs, with the exception of Stance, generally have similar effects on plant growth. When applied at similar rates (except for Stance), similar results should be expected. Stance contains a higher concentration of mepiquat than other meqiquat products, and also includes cyclanilide. This product is used at much lower rates than standard mepiquat products,” they say.

Mepiquat does not stimulate flowering and does not create more bolls per plant. At best, mepiquat may improve retention of some bolls. Mepiquat essentially has no effect on yield.

Why use PGRs? Well, these things may or may not happen, but PGRs can:

  • Improve fruit retention on lower nodes and earlier maturity.
  • Improve harvest efficiency.
  • Reduce impedance of insecticides/fungicides/harvest aids.
  • Reduce boll rot and reduce lodging of plants.

“The likelihood of achieving one or more of these positive results greatly increases if the environment is likely to result in (or has historically and consistently resulted in) excessive vegetative growth, but even then, these results may or may not occur,” they say.

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