Broadstrike Herbicide

Description

Where can Broadstrike Herbicide be used? 

While Broadstrike Herbicide was originally registered for post-emergent broadleaf weed control in field peas and winter cereals, usage has since been extended to include post-emergence and salvage control of broadleaf weeds in these contexts: 

• Winter cereals (including those undersown with clover, lucerne, or medic)
• Seed crops and pastures
  • Clover
  • Fenugreek
  • Lathryus
  • Lucerne
  • Medic
  • Serradella
  • Vetch (Popany vetch only)
• Chickpeas
• Field peas
• Lentils
• Maize
• Peanuts

It is also registered for the pre-emergence control of certain broadleaf weeds in maize and soybeans.

Which weeds does Broadstrike Herbicide target? 

Broadstrike Herbicide is registered to control the following weeds: 

• Amsinckia (yellow burrweed) [Amsinckia spp.]
• Annual ground cherry (Physalis ixocarpa)
• Anoda weed (Anoda cristata)
• Ball mustard (Neslia paniculata) 
• Black (giant) pigweed
• Bladder ketmia (Hibiscus trionum)
• Boggabri weed (Amaranthus mitchellii)
• Buchan weed (Hirschfeldia incana)
• Calepina (white ball mustard) [Calepina irregularis] 
• Caltrop (Tribulus terrestris)
• Capeweed (Arctotheca calendula)
• Charlock (Sinapis arvensis)
• Cobbler’s pegs (black-jack) [Bidens pilosa]
• Cotula (Cotula spp.)
• Dead-nettle (Lamium amplexicaule)
• Doublegee (Emex australis)
• Dwarf marigold (Schkuhria pinnata)
• Fat hen (Chenopodium album)
• Fierce thornapple (Datura ferox)
• Fumitory (Fumaria officinalis) 
• Hedge mustard (Sisymbrium officinale)
• Indian hedge mustard (Sisymbrium orientale)
• Lesser swinecress (Lepidium didymum, formerly Coronopus didymus)
• Lupin (Lupinus spp.)
• Marshmallow (Malva parviflora)
• Narrow-leaved lupin (Lupinus angustifolius)
• New Zealand spinach (Tetragonia tetragonioides)
• Paterson’s curse (Salvation Jane) [Echium plantagineum]
• Peppercress (Lepidium africanum)
• Pheasant’s eye (Adonis microcarpa)
• Red pigweed (Amaranthus retroflexus)
• Shepherd’s purse (Capsella bursa-pastoris)
• Spiny emex (Emex australis, current accepted name Rumex hypogaeus)
• Spurrey (Spergula arvensis)
• Stagger weed (Stachys arvensis)
• Three-horned bedstraw (Galium tricornutum)
• Turnip weed (Rapistrum rugosum)
• Volunteer canola (Brassica napus)
• Western Australian blue lupin (Lupinus cosentinii)
• Ward’s weed (Carrichtera annua)
• Wild gooseberry (Physalis minima)
• Wild radish (Raphanus raphanistrum)
• Wild turnip (Brassica tournefortii)
• Wireweed (Polygonum aviculare)

Frequently asked questions

What is the active ingredient in Broadstrike Herbicide? 

The active ingredient in Broadstrike spray is flumetsulam at 800g/kg, formulated as a water-dispersible granule. It is a Group 2 herbicide (formerly Group B), meaning it works by inhibiting the enzyme acetolactate synthase (ALS), which plays a key role in a plant’s growth functions.

What are the signs of Broadstrike activity in weeds? 

Typical symptoms of Broadstrike Herbicide activity in weeds include cessation of growth and chlorotic yellowing, which then turns into reddening of the leaves when plants are actively dying. 

Under usual winter conditions, 6 to 8 weeks will elapse before the maximum effects of Broadstrike are visible, although susceptible plants will cease growing immediately following application. In summer, expect to see activity much faster (2 to 4 weeks).

Is resistance management common when using Broadstrike Herbicide?

Weeds can develop resistance to Group 2 herbicides relatively readily. As a result, when using Broadstrike Herbicide, it’s important not to rely on repeated Group 2 use in the same paddock. Rotate modes of action, use effective tank-mix or sequential partners from other groups, and follow an integrated weed management program to protect your chosen chemistry as much as possible.

What is the application rate of Broadstrike Herbicide per ha (hectare)? 

According to the Broadstrike label, the application rate will vary based on crop and target weed — so always adhere to the rate table for your specific situation. Across most registered uses, however, the standard application rate is 25g/ha, with 50g/ha used in some situations (e.g., grazing lucerne, the higher end of the maize and soybean ranges). 

Because Broadstrike Herbicide is a granule formulation dosed in grams per hectare, measure carefully and confirm the label rate for your crop and weed before mixing. 

When should Broadstrike Herbicide be applied?

It is recommended to spray Broadstrike Herbicide early while target weeds are small and actively growing. The product label sets out specific maximum weed sizes by species, provided either as a leaf number or plant diameter in centimetres, rather than a blanket stage — so be certain to check the table for your target weeds and treat before they exceed the listed size. 

Best results will come from application on warm (above 5°C), sunny days with good spray coverage. Do not apply if rain is likely within 4 hours of a post-emergence treatment, and avoid waterlogged soils. 

Is Broadstrike Herbicide safe for use on clover and lucerne?

Yes, Broadstrike can be used for clover and lucerne, according to the product label. It is noted for its selectivity to medic, lucerne, clover, and most forage legumes when used as directed. The label allows application from the 2-3-trifoliate leaf stage of these legumes, and grazing lucerne uses a rate of 25g/ha (rather than 50g/ha). The 50g/ha rate should only be used from the 4-trifoliate stage onwards.

Note that the label directs not to apply Broadstrike Herbicide to lucerne seed crops fewer than 8 weeks before flowering. Always confirm your crop, growth stage, and application rate against the Broadleaf label before spraying. 

Which herbicides can Broadstrike Herbicide be tank-mixed with?

According to the product label, Broadstrike Herbicide can be tank-mixed with registered partners including MCPA, 2,4-DB, bromoxynil, diuron, terbutryn, pendimethalin and trifluralin. However, specific compatible partners will depend on the crop (e.g., MCPA is not to be used on lucerne and clover), so first check the label for your situation.

Should I use a wetter with Broadstrike Herbicide?

A wetter or spraying oil is required in some situations and prohibited in others. For example, in cereals, the label directs users to always apply with Uptake Spraying Oil at 500mL per 100L (excluding barley and oats), or a non-ionic wetting agent like BS-1000 at 200mL/100L. Meanwhile, in chickpeas and field peas, the label cautions against using any spray additives or tank-mixing with other chemicals.

Ultimately, whether you use an adjuvant should come down to the mixing directions for your specific crop as stated on the product label. 

What are Broadstrike Herbicide’s grazing withholding and plant-back periods?

Once again, the grazing withholding periods and plant-back intervals are reliant on your crop. 

The Broadstrike product label specifies no grazing or cutting for stock foods for the following periods: 

• Cereals, chickpeas, field peas, lentils, peanuts, vetch, and soybeans: 4 weeks
• Fenugreek, lathyrus, lucerne, medic, and serradella: 3 days
• Maize: 14 days
• Pastures: 7 days

Plant-back (re-cropping) intervals also vary significantly, ranging from immediate for crops like cereals, maize, and soybeans, to around 3 months for barley, oats, chickpeas, clover, lucerne, and peanuts, all the way out to 6 to 12 months for canola and 24 months for cotton.

Always check the specific grazing and plant-back directions on the product label before treating or re-sowing. The listed withholding periods assume Broadstrike is being used on its own, not in a tank-mix.