Mark VanGessel, Extension Weed Specialist; firstname.lastname@example.org
Ignite 280 (glufosinate) is now labeled for burndown and can be used postemergence in Liberty Link soybeans. For non-Liberty Link soybeans it can be used as the burndown, particularly in fields with heavy horseweed pressure, and in situations where 2,4-D is not an option for horseweed control. While Ignite 280 is very effective on horseweed (marestail), it is not effective on larger grasses or some winter annual species such as field pansy. As a result, it will often need to be part of a tank mix combination for burndown weed control, typically with a product that will control field pansy.
In Liberty Link soybeans, I see a better fit for Ignite 280 as a herbicide to control weeds four weeks after planting, rather than as a pre-plant herbicide. This does not mean you should consider Ignite 280 applied postemergence in soybeans as a viable option for horseweed control. Rather, always start with a clean field (everything dead at planting time), include a solid residual herbicide with your burndown, and a timely postemergence application of Ignite 280 about 4 weeks after planting.
● Starting clean often means your burndown application is made 4 weeks preplant so you can use an effective rate of 2,4-D for resistant marestail control
● A solid residual program should include a grass herbicide such as Dual, Outlook, or Micro-Tech plus a broadleaf herbicide since Ignite is not effective on large grasses. The residual herbicide will control grasses, or at least result in smaller more susceptible grasses at time of postemergence application.
● Postemergence applications need to be made timely, approximately 4 weeks after planting. While Ignite 280 is a broad-spectrum herbicide it is strictly a contact herbicide. It is difficult to get good coverage with larger weeds.
A couple of other items to consider with Ignite 280. As noted, good coverage is important for effective control, and this usually means effective spray volumes. Using low spray volumes may result in reduced levels of control. The label requires a spray volume of 15 gal/A, but even with that volume the spray boom needs to be well calibrated and provide a uniform distribution of medium sized spray droplets. Also, Ignite 280 requires the plant to have active photosynthesis at time of application for maximum effectiveness. Applications should not be made within 2 hours of sunset to ensure active photosynthesis.