Horsetail
Controlling horsetail in Enlist E3™ soybeans
A crop pest with spore-producing structures sounds like a fungus, right? Horsetail, a plant that’s millions of years old, is most definitely not a fungus, and it’s difficult to control.
A perennial weed, field horsetail has two growth stages:
- Spore-bearing shoot – single stems, grey to brown in colour, topped by elongated spore-producing cones, emerging in early spring.
- Vegetative shoot – single-stemmed, leafless, branchy green plants emerging from late spring into early summer (and beyond) as the fruiting bodies die off.
It’s below ground, though, where horsetail really gains its staying power. Here, a network of tuber-bearing rhizomes spread widely and penetrate deep into the soil – up to one metre (3.5 feet) deep is quite common1. New shoots, both spore-bearing and vegetative, grow from the rhizomes.
This robust underground lifeforce is impossible to eradicate through direct means, but by repeatedly controlling top growth from season to season, it’s possible that it may lose energy and mass over time. However, it will likely never completely disappear because if a rhizome dies or is detached through cultivation or some other disturbance, the dormant tubers will activate to produce new plants2.
Controlling field horsetail takes a consistent effort, year after year, using both herbicide and cultural tools, such as mowing, to remove top growth. On the herbicide front, a two-pass approach is recommended – the first aimed at spore-bearing shoots and the second at vegetative growth.
Field horsetail is particularly susceptible to 2,4-D so if you’re growing Enlist™ E3 soybeans, you have a powerful tool in the Enlist weed control system.
- For the first pass, apply Enlist Duo™ herbicide as a pre-plant or pre-emergence burndown to control spore-bearing horsetail shoots. A proprietary blend of 2,4-D choline (Group 4) and glyphosate (Group 9), Enlist Duo will also control glyphosate resistant weeds in Enlist E3 soybeans and Enlist corn.
Alternatively, you can apply Broadstrike™ RC herbicide (Group 2) as a pre-plant incorporated burndown3. Broadstrike RC suppresses horsetail while offering residual activity against a wide range of broadleaf weeds. - For the second, in-crop pass, apply Enlist Duo again or Enlist™ 1 herbicide tank mixed with either glyphosate or Liberty® 200 SN (Group 10 glufosinate) to control green top growth. Be patient and wait until the “leaves” open before spraying to get the best control.
The Enlist weed control system allows two applications of 2,4-D in one season, which is excellent for horsetail management, and both Enlist Duo and Enlist 1 and both have Colex-D™ technology for near-zero volatility and low drift.
To sum up
Field horsetail’s complex and robust rhizome root-like system makes this weed difficult to eradicate. To protect yields, focus on repeated removal of top growth throughout the season, and from year to year, by employing a two-pass herbicide plan that targets the spore-bearing shoots in early spring and the green top growth that follows, controlling horsetail should become more manageable. While two applications of 2,4-D are permitted within the Enlist weed control system, be sure to consider adding residuals and additional modes of action.
Controlling Horsetail in Enlist E3 Soybeans
Learn more about Canada Fleabane
1Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). Ontario Weeds: Field Horsetail. hhttp://omafra.gov.on.ca/english/crops/facts/ontweeds/fieldhorsetail.htm#:~:text=Habitat%3A%20Field%20horsetail%20occurs%20in,suppress%20crops%20and%20other%20plants.
2OMAFRA. Is it possible to control field horsetail? http://omafra.gov.on.ca/english/crops/hort/news/hortmatt/2015/03hrt15a3.htm
3Broadstrike RC is registered for suppression of field horsetail in conventional, conservation-tillage and no-till soybean production systems.