Scouting and Treating Sunflower Rust
Whether you’re well versed in sunflower production, or just getting into the commodity, there are several things you can do to ensure you produce a profitable crop. Controlling rust is at the top of the list. If left untreated, sunflower rust can result in a significant reduction in yield potential. However, with due diligence, you can effectively prohibit or control the disease.
Boots in field
Checking your fields and looking for rust is very important. Sunflower rust can infect plants anytime if inoculum is present and environmental conditions are favorable. Rust likes moderate to warm temperatures (between 55 to 85 degrees), as well as humid, moist and dewy conditions. Rust will first appear as cinnamon-brown pustules on the lower and then upper leaves. If left untreated, it can spread to the petioles, stems, bracts and back of the flower head.
Pick the right fungicide
There are a number of fungicides available for the management of sunflower rust. All of them can help reduce rust, but each acts a bit differently. The top two fungicide families for sunflower rust are strobilurins and triazoles.
Strobilurins: This class of fungicide is very effective in preventing rust from infecting plant tissue by killing the spores before they try to penetrate and spread within the plant. Headline® and Quadris® fungicides are two good products from this family. These fungicides are most effective when applied just before rust is found or when rust is occurring at a low level. Application timing is recommended between R1 and R4, or before actual flowering.
Triazoles: This class of fungicide has good systemic activity and more of a “kickback” than Headline® or Quadris®, making it better at halting a rust infection after it has occurred. Onset® 3.6L fungicide is an effective triazole product. Once applied, it moves with water from the site of application up and out through the plant. The best time to apply Onset 3.6L is between R5.2 and R5.5, or at the beginning of the flowering stage, but before the flower reaches 50 percent of its head area.
The key to managing rust is to get a head of it, or stop it as soon as it first appears. So, if you’re confident rust will appear in your fields because it’s in the area and environmental conditions are favorable, apply a strobilurin like Headline® or Quadris®. But if you find an early rust infection when scouting your crop, apply Onset 3.6L to keep it from getting worse. Include MasterLock® adjuvant in your tank to help optimize droplet adhesion, which reduces bounce and increases droplet spreading for improved contact and coverage.
Reach out to your locally owned and operated WinField® United retailer when it comes to determining application rates. They’ll help you create a customized sunflower rust management plan for your farm.
© 2020 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices, and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years, and be mindful of how such agronomic conditions could impact results. CROPLAN®, MasterLock®, Onset® and WinField® are trademarks of WinField United. Headline® is a registered trademark of
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