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  • Writer's pictureCoral Blaikie

Manipulator Application and Timing

Manipulator is a plant growth regulator with the active ingredient chlormequat. It is registered on wheat (durum, spring and winter). It does not have efficacy on barley. Chlormequat reduces gibberellic acid (GA) production in the plant to reduce plant height and thicken the stem. This may give producers the opportunity to apply more nitrogen while reducing the risk of lodging. However, for Manipulator to work properly, it must be applied at the right stage of plant development.


Manipulator has a wide window of application (2 leaf to flag leaf) but going at the early stage will reduce its efficacy by the time it needs to go to work. GAs do not start forming until stem elongation, so the optimal timing is 5-6 leaf (GS 30-32) as shown in Figure 1. If timing must be sacrificed, it is better to apply late (flag leaf) than to apply early. The bottom internode may not be shortened and thickened when applying late, but the remaining internodes will be. It is important to note with wheat, if you are planning to spray a fungicide for fusarium, tank mixing will not be an option because the timing will be wrong. A separate pass is required to hit optimal timing.

Figure 1. GS 30 stage, just prior to stem elongation

Application and Tank Mixing

Manipulator is applied at 0.7 L/ac (14 ac/jug). Ten gallons of water is needed if it is applied with a tank mix or 7 gallons if applied alone.

Limited testing has been done on Manipulator tank mix partners. To hit the optimal timing for Manipulator, you would have to sacrifice optimal herbicide or flag leaf fungicide timing. If the goal is to do herbicide and manipulator application in one pass to save time, choose fields with low weed pressure where you will not be sacrificing yield or weed control by waiting until as late as possible to spray. The remaining fields should be done in separate passes.

Tested Tank Mixes

Table 1. Tank mix products that were tested and recognized as safe in 2014


Manipulator is used to shorten and thicken wheat stems to decease lodging and increase yield. If tank mixing with herbicides, choose to do so only on clean fields and apply as late as possible. Manipulator is best used at the 6 leaf stage which would require its own application pass.

Hana Ruf

Precision Agronomist


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