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PRIMO MAXX® is a unique management tool that allows golf course superintendents to manage clipping yields while elevating turf to a new level of playability. Primo Maxx helps develop a stronger root system and a thicker more compact turf canopy. Primo Maxx contains Trinexapac-ethyl at a guarantee rate of 11.30%. Read more.


Label & SDS Summary

Active Ingredient: Trinexapac-ethyl

Approved Province(s):

Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan

Approved Uses:

Sod Farms, Turfgrass

Product Benefits
  • At the recommended rate, one application will give a reduction in fresh weight of grass clippings of up to 50% and a reduction in grass height of up to 20% for up to four weeks.
  • Primo MAXX can be used for pre-stress conditioning to prepare the turf for extreme conditions of summer - such as heat, drought, disease, and everyday wear and tear.
  • Primo MAXX for turf growth management reduces the frequency of mowing and the amount of grass clippings by reducing the growth of turfgrass.
  • Primo MAXX helps develop a better root system and a thicker, stronger turf canopy.
Mode of Action
  • The active ingredient in Primo MAXX, trinexapac-ethyl, causes a temporary halt to the production of gibberellic acid, a plant growth hormone which is responsible for the top growth of the plant.
  • Trinexapac-ethyl is taken up by the foliage of the grass plant and is translocated systemically to the growing point of the plant.
  • After application the turfgrass grows more slowly than in untreated areas, with shorter leaf blades.
  • Primo MAXX does not control dicotyledonous weeds and these should be controlled before application of the growth regulator.
  • Turfgrass absorbs trinexapac-ethyl very rapidly and it is rainfast 3 hours after application

Mode of Action: Gibberellic acid inhibitor (late GA synthesis)

Class of Chemistry

Primo MAXX is micro-emulsion concentrate (MEC) liquid formulation containing 121g/L trinexapac-ethyl.


Turf Safety:

Environmental conditions, management, and cultural practices that affect turf growth and vigour will influence the response of the turf to PRIMO MAXX applications. Fertility level, moisture availability, plant vigour, height, and frequency of mowing, have been shown to influence the activity of PRIMO MAXX.

PRIMO MAXX may cause temporary yellowing. This usually disappears about one week after application. To minimize yellowing and to enhance the green colour of turf, apply readily available nitrogen at 0.1- 0.25 kg of actual nitrogen per 100m2. If desirable, recommended rates of iron per 100m2 can also be used.

Note: In the absence of a repeated application, turf treated with PRIMO MAXX may grow more rapidly than untreated turf for several weeks following a period of suppressed growth.

For Control Of:

Plant Growth Regulation


Case Size: 2 X 3.78 L jugs

Case Coverage: 2.36 - 18.9 ha (5.83 - 46.7 acres)

Application Information

Use Rates:

Recommended PRIMO MAXX Application Rates1 See below for notes.

Water Volume:

2.0 - 15 L water / 100m2

Application Information:

  1. Apply only to turf species/mixtures on sites for which a rate is shown in Table 1. Rates shown in Table 1 should provide 50% suppression of turf growth under good growing conditions for a minimum of 4 weeks with minimal yellowing. Growth suppression may be less with use of rates that are one-half those shown in Table 1.
  2. Canopy height should be at least 3.8 cm for Kentucky bluegrass and perennial ryegrass and at least 5 cm for tall fescue.
  3. Includes edging/banding applications along curbs, parking lots, cart paths, bunkers and around trees, shrubs and flower beds. Apply Primo MAXX in a 20 to 30 cm band with a single nozzle sprayer.
  4. About one-third suppression of turf growth can be expected. Primo MAXX has not been tested at a rate of 2 mL/100m2. Therefore, results may be unsatisfactory with use of the one half rate on greens.
  5. Where yellowing of annual bluegrass (Poa annua) is a concern, use half the rate and apply every 2 weeks or later as required. Where temporary discoloration of annual bluegrass can be tolerated, use the rate shown in Table 1 and apply every 4 weeks or later as required.
  6. Use 8.0 mL/100m2 on fairways (and fairway height turf on commercial sod farms) consisting of a mixture of annual bluegrass and Kentucky bluegrass.

Mixing Order:

  • Primo Maxx should be mixed with ONLY ONE fungicide partner. Always check the compatibility of Fungicide tank mixes using a jar test with proportionate amounts of PRIMO MAXX, and the water, before mixing in the spray tank.
  • Provide sufficient jet or mechanical agitation during filling and application to keep the tank mix uniformly suspended.
  • Fill tank at least 1/2 full of clean water before adding Primo Maxx.
  • Follow the www.WALES mixing sequence for all tank mixes.
  • Do not leave tank mix combinations in the spray tank for prolonged periods without agitation. Mix and apply them the same day.

Use Restrictions:

  • Do not make more than 7 applications at the rates shown in Table 1 or 14 applications at the half rate per year.
  • Field data have indicated that PRIMO MAXX may not be rainfast soon after application. Application should be completed at least 3 hours before irrigation or rain.