FEW new herbicides but new combinations of different chemistry plus upgraded labels are perhaps the main features of the 2017 edition of “Weed Control in Winter Crops”. Published by NSW DPI and authored by agronomists Greg Brooke and Colin McMaster, the booklet is regarded nationally as the “bible” of crop weed control.
Butisan (500 grams per metazachlor) is a new pre-emergent herbicide for control of annual ryegrass, wild oats and wireweed in canola.
Features include it is a new group K herbicide with high levels of weed control compared with other products like propyzamide, trifluralin and atrazine, even where resistance is not a major factor.
Butisan is suitable for use in all canola production systems; triazine tolerant, Roundup Ready, Clearfield and conventional varieties.
It is activated in low moisture conditions, and moves back into the furrow providing superior in-furrow weed control compared with commercial standards.
Residual control period is nine-12 weeks, depending on soil moisture and rainfall.
Arcade and Countdown (800g/L prosulfocarb), that both contain one of the two ingredients in Boxer Gold, are pre-emergent herbicides that controls annual ryegrass in wheat and barley with a seven-day incorporation window.
They are group J herbicides that offers an important alternative mode of action, useful for resistance management.
Bothe products are alternative to Boxer Gold (800g/L prosulfocarb, plus 120g/L S-metolachlor) when used in lighter soils or disc seeding systems.
They are compatible with a range of knockdown herbicides and can be mixed with trifluralin. Rexade (150 grams per kilogram pyroxsulam, plus 50g/kg halauxifen) is a newly registered post-emergent cereal herbicide to control grass and broadleaf weeds in wheat and triticale and will supersede Crusader.
Rexade controls brome, phalaris and wild oats, and suppresses annual ryegrass, barley grass and silver grass, plus controls a wider range of broadleaf weeds as well as giving more robust control of many of them.
Sentry (525g/kg imazapic, plus 175g/kg imazapyr) has been developed for imidazolinone herbicide-tolerant crops with the label including pre-emergent use in imidazolinone herbicide-tolerant canola, and wheat (single gene only). Sharpen WG (700g/kg saflufenacil) pre-plant cereal and winter pulses use patterns have changed to include standalone use rate, changed recommended adjuvant to a methylated seed oil (MSO).
Canola plant-back period is reduced from 16 weeks to six weeks. Additional weed species controlled includes melons.
Sharpen has also been registered as a harvest aid in winter pulse plus labelled rates for glyphosate or paraquat. Shogun (100g/L propaquizafop), an effective herbicide for controlling various grass weeds in broadleaf crops and is now registered for use in fallows before sowing summer or winter crops.
Shogun will help to manage feathertop Rhodes grass, barnyard grass, liverseed grass, and other grasses where glyphosate resistance is suspected, or where an alternative option to glyphosate is required. Vortex (6.25g/L florasulam, plus 300 g/L 2,4-D LV Ester) is a new herbicide for broadleaf weed control in winter cereals (wheat, barley and triticale).
The combination of the two active ingredients helps manage hard-to-control broadleaf species including wild radish, climbing buckwheat, spiny emex and volunteer pulses.
Herbicides that have been discontinued include Flame, Stomp 440, Sniper and Paragon.
Gesatop is no longer being manufactured for Australia.
Next week. Plan for all-year pasture growth.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.
