DECISION

Not sure exactly what you're dealing with? Getting the weed right is the first step to good control, and it helps you pick the right rate and timing.

Browse the Rainbow & Brown Weed File library to view photos of common New Zealand weeds and the best control options for each one.

Our Weed File covers the broadleaf weeds you'll find in pasture and crop, so you can match the right product to the right weed.

Tip: Annual buttercup and giant buttercup are treated differently. Identifying which one you have will help you get the timing and rate right.

• Dairy and drystock pasture under buttercup pressure, annual or giant
• Clover-based pasture where you need to keep the clover
• New pasture, once the clover has developed its trifoliate leaves
• Lucerne, chicory and maize crops
• Autumn or spring buttercup programmes
• Growers wanting a low-rate, clover-safe broadleaf option

Decision contains flumetsulam, a Group 2 herbicide from the triazolopyrimidine chemical group. It works by inhibiting an enzyme called acetolactate synthase (ALS), which the plant needs to grow.

It's taken up mainly through the leaves, with some uptake through the roots, then moves through the plant to the growing tips where it stops cell division. From there the weed slowly loses vigour and dies off. It's not a fast burn-down, so give it time to work.

Clover tolerates flumetsulam, which is what makes Decision clover-friendly. It's a broadleaf herbicide, so it won't control grasses.

Active ingredient: 800g/kg flumetsulam in a water-dispersible granule

Herbicide group: Group 2 (ALS inhibitor), triazolopyrimidine

Registered uses: post-emergent broadleaf weed control in new and established pasture, clover, lucerne, chicory and maize

Guide rates (product per hectare): these are a guide only, always follow the label and directions leaflet.

• 30g/ha – chickweed, spurrey, wild radish, hedge mustard (apply before the 4th leaf)
• 50g/ha – redroot (amaranthus), cleavers, black nightshade, fathen, shepherd's purse, mallow (before 4th leaf); annual buttercup, creeping yellow cress (before flowering)
• 65g/ha – stinking mayweed, wireweed, sorrel (young seedlings); willow weed, oxeye daisy (young seedlings, suppression only); giant buttercup (before flowering)

Do not apply more than 65g of product per hectare (52g flumetsulam active/ha), with a maximum of one application per year.

Water rates: ground and aerial, 100–300L of water per hectare (use the higher rate where weeds are dense). CDA, 250–300 micron droplet at no less than 30L/ha.

Spraying oil: always apply with a suitable spraying oil at 500ml per 100L of water, such as BioWet, unless the label specifically says otherwise.

Rainfast: do not spray if rain is expected within 6 hours.

Withholding period: do not graze crops or treated pasture for 14 days after treatment.

Animal safety: poisonous plants (including giant buttercup and black nightshade) can become more palatable to stock after spraying. Keep stock off treated areas until those plants have died down. It is an offence to use this product on animals.

Crop rotation: do not plant susceptible crops (all brassicas, sunflowers, lupins and beans) for 3 months after application, and avoid spray drift onto them or onto land to be planted with them.

Compatibility: Decision is compatible with most commonly used herbicides, and adding an MCPB herbicide widens the range of broadleaf weeds controlled. The spraying oil note above applies to Decision used on its own. Two exceptions apply only when tank-mixing: do not add spray oil to Decision plus a triazine in lucerne, and do not add spray oil to Decision plus 2,4-D on pasture unless the pasture is well grazed first (the oil increases clover damage in that mix).

Resistance management: Decision is a Group 2 herbicide. Rotate with products that use a different mode of action to reduce the risk of resistance. See resistance.nzpps.org for guidance.

Pack sizes: 200g, 500g, 1kg, 2kg

ACVM registration: P8368. HSNO approval: HSR101014.

Will Decision kill my clover?

No. Decision is clover-friendly, so it's a good choice when you want to control broadleaf weeds but keep the clover in your pasture. In new pasture, wait until the clover has developed its trifoliate leaves before spraying.

When's the best time to spray buttercup?

You can spray buttercup in either autumn or spring. For giant buttercup, apply before flowering. Repeating a spring treatment for two seasons in a row gives the best control of giant buttercup.

Do I need to add a spraying oil?

Yes. Decision should be mixed with a suitable spraying oil at 500ml per 100L of water, unless the label says otherwise. We recommend BioWet. The Buttercup Enforcer Pack bundles the two together.

Will it control grass weeds?

No. Decision is a broadleaf herbicide, so it won't touch grasses. That's part of what makes it useful in pasture, it targets the broadleaf weeds and leaves the grass alone.

How quickly will I see it working?

Decision is a Group 2 herbicide, so it's slow-acting rather than a fast burn-down. Treated weeds lose vigour and die off over a few weeks. Spray weeds that are actively growing, and avoid cold, wet conditions.

Can I use it on lucerne, chicory or maize?

Yes. Decision is registered for post-emergent broadleaf weed control in lucerne, chicory and maize, as well as pasture and clover. Check the directions leaflet for the right growth stage in each crop.

Always read and follow the label and directions leaflet completely before mixing or applying.

Decision is very toxic to aquatic life with long-lasting effects. Do not contaminate waterways and do not apply directly into or onto water.

Wear appropriate protective equipment when mixing and applying, and avoid spray drift onto gardens, crops and desirable plants.

Use must be under the control of a suitably qualified person, and records must be kept in line with NZS8409 where more than 3kg is applied in one location within 24 hours.

For full application rates, mixing instructions and safety information, refer to the product label and Safety Data Sheet, available from rainbowbrown.co.nz.

Registered pursuant to the ACVM Act 1997, No. P8368. Approved pursuant to the HSNO Act 1996, EPA Approval Code HSR101014.