Growth Regulators

The growth regulators are compounds that alter or regulate the growth or behaviour of grass. There are 5 classes according to their mode of action:

Class A:

Trinexipac-ethyl, foliar-absorbed, inhibits the biosynthesis of the gibberellic acid in the final phase. It is most commonly used in sports surfaces. Reduces the need for mowing, increases uniformity, density and improves overall quality.

Class B:

Paclobutrazol and Flurprimidol, root absorption, inhibits the biosynthesis of gibberellic acid in its initial phase. It favours the elimination of Poa Annua on Agrostis greens.

Class C:

Mefluidide, foliar and root absorption, inhibits cell division in meristematic tissue. Its use is indicated for the reduction of flowering or seed head formation.

Class D:

Methyl-sulfometuron and Glyphosate, foliar-absorbed, are herbicides which, when used at low doses, reduce the growth of some species occurring alongside others on sports surfaces.

Class E:

Ethephon and gibberellic acid, foliar absorbed, are synthetically produced phytohormones or compounds which hydrolyse phytohormones, such as Etephon which generates ethylene. Their main use is for seed elimination in Poa Annua, Etephon is indicated for use during all seasons (it generates greater density, well-oriented growth, and greater vigour in summer stress), while Mefluidide is used mainly in spring.

One strategy on new Agrostis greens is the use of Paclobutrazol to control Poa Annua, while on old Agrostis greens heavily contaminated with Poa Annua, the use of Etephon is recommended to invigorate the greens. In both cases the use of Trinexipac-ethyl is recommended to increase the vigour of the greens and control overgrowth.