It is important to understand what mepiquat-containing PGRs do not do, as there are some misconceptions out there. Mepiquat does not stimulate flowering and does not create more bolls per plant. At best, mepiquat may improve retention of some bolls, but it does not cause the plant to produce more bolls.

Lastly, and most importantly, yield responses to mepiquat are inconsistent at best….yields are improved in some situations, reduced in other situations, and in many cases, PGRs have no effect on yield at all.

So why use PGRs? Some of the more beneficial effects, again which may or may not occur, are improved fruit retention on lower nodes and earlier maturity (generally more beneficial to later planted cotton, and especially later planted irrigated cotton), improved harvest efficiency, reduced impedance of insecticides/fungicides/harvest aids, reduced boll rot and reduced lodging of plants (all of which in the right circumstances could potentially increase yield).

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.

There are risks associated with mepiquat applications, especially when improper rates and/or premature application timings are implemented. Keep in mind that mepiquat should be used in a manner to prevent rank growth from occurring, but remember that plants still need to be tall enough to support an optimal boll load, thus an optimal yield.

An optimal plant height generally varies depending on the situation. This should be determined on a case-by-case basis and could be adjusted for other situations.