Agronomy •  15/08/2018

Controlling Marshmallow in Summer Fallow

Marshmallow, or small-flowered mallow, has become a more prevalent weed in cropping districts over the years.  It has always been a difficult weed to control, with an extensive taproot that persists despite hard grazing and cultivation.  So ensuring a full kill is essential for a long-term result.  Dow AgroSciences has been a leader in marshmallow control for many years with Starane™ Advanced herbicide.  Now Pixxaro™ herbicide with Arylex™ active has been registered.  With a better spectrum to Starane Advanced, Arylex active gives Pixxaro extra power on key weeds such as marshmallow, volunteer legumes, thistles and deadnettle without the re-cropping issues to many crops.

A trial at Breeza, NSW, last year compared efficacy of various fallow treatments across a range of weeds, including caltrop, Boggabri weed, deadnettle, milk thistle and liverseed grass.  The trial (below) clearly shows the superiority of Pixxaro over Starane Advanced as a fallow herbicide.  Control of both treatments are improved with the addition of glyphosate (450 g IPA) at 1.6 L/ha.


Controlling Marshmallow in Fallow

A similar trial was conducted early 2017 by the Landmark Esperance agronomy team who tested a range of new herbicides on marshmallow.  The marshmallow was consistent across the paddock and had survived a summer knock of 1.2 L glyphosate 450 + 350 mL Ester 680, so the weeds were large (5-20 cm) with a well-developed tap root; this situation would normally require more than a one pass strategy to gain acceptable control.

All treatments were compared as a single application, at 7, 21 and 42 days after application.  The Group G contact herbicide Sharpen® gave the best results at 7 days as expected, but required the higher 34 g rate to achieve 100% control.  The Pixxaro treatments were the only other treatments to achieve 100% control; being a Group I, translocated chemistry, complete death was not observed until the 42 day rating.

Controlling Marshmallow in Fallow

As with most herbicides, best results are achieved with Pixxaro when weeds are small and actively growing, not subject to stress (water, heat, herbicide or insect damage).  In fallow, Pixxaro should always be applied with a minimum of 1.4 L glyphosate (450 g/L IPA); refer to the glyphosate label for the correct rate for the situation, the recommended rate of ammonium sulphate and surfactant.

Pixxaro has short plantback periods to both summer and winter cereals as well as canola and is rainfast in 1 hour.  It has a premier proprietary solvent package; it does not contain any petroleum distillates, which results in a non-volatile formulation with low odour and an exceptional toxicological package.  As an emulsifiable concentrate (EC) is it easy to pour, measure, mix and dilute.  The 20 L pack will treat 33-100 ha, depending on the rate used.


“Pixxaro has a great fit, particularly in cropping areas with hard-to-kill weeds, such as marshmallow.  Its ability to also be used in fallow this summer and again over winter adds flexibility of use often not available to growers in this segment” summarised Mr Dan Dixon, Cereals Portfolio Manager for Dow AgroSciences.

Pixxaro is also registered for use in winter cereal crops for the control of a range of winter weeds including bedstraw, burr medic, sub-clover, deadnettle, flax-leaf fleabane seedlings, milk thistle, prickly lettuce and small-flowered mallow across a wide window of application from Z13 to Z39.  Pixxaro can be tank-mixed with a wide range of other agricultural inputs, including grass herbicides, insecticides, fungicides and zinc which will see it being a product-of-choice this winter as well as toasting the marshmallow this summer-autumn