Earlier this year, a new herbicide active arrived into the cereal market here. That active is halauxifen-methyl, a mouthful for most people, so it is best referred to by its better-known tradename, Arylex Active.

In spring, this was sold in combination with fluroxypyr as Pixxaro. Now, Arylex arrives into the list of winter options in a combination with florasulam called Zypar.

One of the major features of Zypar is its flexibility in cold temperatures. Florasulam originally came to the market here as Boxer and it was renowned for its flexibility of use in cold conditions.

Arylex is also said to be quite indifferent to application in cold and non-growthy conditions. So the combination lends itself to application whenever ground and overhead conditions suit the grower and not necessarily when conditions suit the crop.

Mix of families

Zypar is a very useful broad-leaved weed herbicide option. It contains two different modes of action, with florasulam being an ALS inhibitor and Arylex a synthetic auxin.

The presence of two different families of actives helps prevent ALS resistance development and also provides control in fields where ALS resistance is already present. But care is needed in this regard to prevent dependence on a single family where weeds already show resistance.

Synthetic auxin herbicides bind to receptors in plant cells to alter their growth, but the new arylpicolinates prioritise a different target site. And they bind with a high level of affinity. Arylex is also available in Pixxaro, and florasulam, as well as being in Boxer in the past, can be found in many other herbicides such as Broadway Star, Galaxy, Ally Ultra, Spitfire, etc.

Both actives cope well with application in cold conditions, so the product suits growers who need to tackle a range of broad-leaved weeds if dry ground conditions occur over winter. It is preferable to tackle weeds when they are still small.

The application timing for Zypar is from 14 September or GS11, if you have a crop that advanced, up to 30 June or GS45. But the maximum rate differs within this window. Up to 14 February, the maximum rate is 0.75l/ha and this increases to 1.0l/ha from then out to the end of June or GS45.

Dow says that it is a very suitable partner for use in spring, mixed with products like Alister or Pacifica. It suggests that a mixing rate of just 0.4l/ha will give a big boost to the control of cleavers, chickweed and others.

Good weed spectrum

Zypar has key strengths against a range of challenging weeds such as cleavers, poppy, chickweed, groundsel, fumitory, volunteer beans and volunteer oilseed rape.

It also has a useful effect on wild carrot. All of these are potentially challenging weeds in winter cereal crops. And both actives also tend to be complementary in terms of their weed spectrum.

Dow puts the efficacy of Zypar as being broad spectrum, relative to some other products, on our main weeds. This comparison in shown in Table 1. The product is also very active against most other autumn weeds, but large speedwell and large field pansy could escape if the product was to be applied late in the season on big weeds.

Poppy

Arylex is accepted as being good on poppy, so one would expect that Zypar will also be very effective. Application timing will have an impact due to the possibility of late germination. Weeds not emerged will not be controlled.

Poppy has become a more challenging weed where ALS resistance is present in the population. And while the Arylex component will be active against this weed, a programme will still need a second product which has activity to help protect all actives. So control needs a bit of planning for individual fields.

In this regard, Dow recommends that where ALS-resistant poppy are present, Zypar be used either:

  • In a programme with pendimethalin.
  • In a mix with another non-ALS product.

    • This does need planning, because Dow also recommends that Zypar should not be used as a fire-fighting action where sulfonylurea-based treatments have already failed to control it. And to help control, it is recommended that the weeds be targeted when they are still small (four to six leaves) and that full rates of Zypar be applied (suggested 0.75l/ha for autumn application and 1.0l/ha in spring).

    Volunteer beans

    Arylex is said to be highly active on legumes and significantly better than florasulam used alone. Because of this, it makes for a very useful active for the control of autumn volunteer beans.

    These can be a significant problem in some crops following beans and they can offer real competition in the early part of the growing season. And the fact that Zypar works well in low and fluctuating temperatures makes it especially suitable for the kind of winter conditions we get here on these islands.

    Its inherent activity means that Zypar is effective on volunteer beans at between 0.5l and 0.625l/ha when used in combination with another mixer product. This activity also points to the necessity to prevent drift on to legume crops during spraying.

    It can be applied up to the eight-true-leaf stage of the beans. It is suggested that Zypar may provide reasonable to good control of beans that have gone to flower.

    The umbelliferae

    Weeds from this family of plants are becoming increasingly common in fields and wild carrot is the main problem here. Dow suggests that Zypar has useful activity on young plants, saying that control efficiency will decline when the plant moves into stem extension.

    Zypar facts

    PCS Number: 05800.

    Ingredients: Halauxifen-methyl (Arylex Active) 6.25 g/l plus Florasulam 5.0 g/l.

    Conditions: Works down to 1°C. Rainfast very quickly.

    Formulation: Oil dispersion.

    Maximum rate: 0.75 l/ha up to 14 February and 1.0 l/ha to 30 June.

    Crops: Winter and spring wheat, barley and rye and winter triticale. Not for use on oats.

    Buffer zone: 5m.

    Application timing: 14 September (GS11) to 30 June (GS45).

    Pack size: 5 litres.