Control weeds with the Big 6

Dec. 15, 2023 | 5 Min read
The WeedSmart Big 6 are a set of chemical, mechanical and cultural tactics to help growers control crop weeds across all cropping systems. A diverse approach including both chemical and non-chemical tactics places downward pressure on the weed seed bank and reduces herbicide resistance risk.

The WeedSmart Big 6 are a set of chemical, mechanical and cultural tactics to help growers control crop weeds across all cropping systems. A diverse approach including both chemical and non-chemical tactics places downward pressure on the weed seed bank and reduces herbicide resistance risk.

The Big 6 is all about the grower calling the shots, not the weeds.

Rotate crops and pastures - crop and pasture rotation is the recipe for diversity

· Use break crops and double break crops, fallow and pasture phases to drive the weed seed bank down.

· In summer cropping systems, use diverse rotations of crops including cereals, pulses, cotton, oilseed crops, millets and fallows.

· Add greater diversity to weed management strategies by adopting herbicide tolerance traits

Increase crop competition - optimise crop growth

· Adopt at least one competitive strategy, but two is better.

· Target higher plant populations using increased seeding rates, weed-free seed tested for germination, vigour and 1,000 seed weight.

· Aim for even seed distribution and establishment.

· Sow competitive crop types and varieties. ƒ Improve soil health (fertility and structure) and crop nutrition, e.g., soil amelioration (if necessary), no-till, stubble retention, nutrient budgeting.

· Utilise early sowing and adopt east/west sowing if practical.

· Reduce row spacing where possible.

Mix and rotate herbicides - rotating buys you time, mixing buys you shots

· Rotate between herbicide modes of action.

· Mix different modes of action within the same herbicide mix or in consecutive applications. Always use full label rates.

· Incorporate multiple modes of action in a double knock e.g., glyphosate/Group 1/Group 2 knockdown followed by paraquat and Group 14 and pre-emergent herbicide.

· Test weeds for resistance to know what herbicides will and won’t work for you.

· In cotton systems, aim to target both grasses and broadleaf weeds using two non-glyphosate tactics in crop and two non-glyphosate tactics during the summer fallow, and always remove any survivors (2 + 2 and no survivors).

Optimise spray efficacy - make every droplet count

· To maximise efficacy and reduce spray drift, follow spray application guidelines and ensure the correct speed, nozzles, water volume, boom height, and adjuvants are used. Avoid antagonistic tank mixes.

· Always use the largest spray droplet feasible that gives the highest efficacy and consider water quality.

· Avoid spraying during inversions (particularly from evening through to early morning), in high temperatures, frost and dew conditions, and when the wind speed is below 5km/h or above 20km/h.

Stop weed seed set -take no prisoners

· Aim for 100 per cent control of weeds and diligently monitor for survivors in all post weed control inspections.

· Crop top or pre-harvest spray in crops to manage weedy paddocks.

· Consider hay or silage production, brown manure or long fallow in high-pressure situations. Use all appropriate strategies in the pasture phase to reduce the weed seed bank prior to cropping phase.

· Consider shielded spraying, optical spot spraying technology, targeted tillage, inter-row cultivation or chipping.

· Windrow (swath) to collect early shedding weed seed.

· Use two or more different weed control tactics (herbicide or non-herbicide) to control survivors.

· In cotton farming systems, consider late season strategic tillage operations for better overall weed and Helicoverpa pupae control.

Implement harvest weed seed control - capture weed seed survivors

· Capture weed seed survivors at harvest using weed seed impact mills, chaff lining, chaff tramlining/decking, chaff carts, narrow windrow burning, or bale direct.

· Ensure optimal harvester set-up.

Categories Integrated weed management Market insight

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