Brown Rust Starting To Show Up On Sugarcane

Dr. Jeff Hoy

LSU AgCenter

Apparently, brown rust is showing up in the far south of the industry in HoCP 96-540 plant cane on good land and some HoCP 09-804. Rust usually shows up later in L 01-283 but then hits this variety hard. Temperatures are now favorable for rust with night temperatures in the 60s. So, we are tracking for the need to apply fungicides to protect the yield potential of susceptible varieties, firstly in plant cane on good land. Here is the link to a description of all the best management practices for brown rust: https://www.lsuagcenter.com/profiles/lblack/articles/page1553195579511

The main fungicides available will be Priaxor (5-7.5 oz/acre), Quilt Xcel (16-20 oz/acre), generics of Quilt Xcel (the concentrations of active ingredients and rates the same), and a newly available product, Trivapro (13.7 oz/acre). The lower rate of Priaxor has worked well. The higher rate of Quilt Xcel will give better results. We do not have much experience with Trivapro yet. It appears to have similar efficacy to Priaxor. If you get a 4 week window of protection from a spray, it is early to make a first application. Two applications will only get you to mid-May when conditions are often most favorable for rust and with maximum negative impact on yield. I hope most people will be able to wait until April to start treating. This time of year, a banded application will be effective and reduce the cost but only if there are LOW WIND CONDITIONS. A banded application under windy conditions will result in a half rate broadcast application.

It would be very helpful if y’all could let me know when and where rust in showing up in your area. This will be very helpful in deciding when to consider a fungicide application. The fungicides we have are effective and will allow cane to recover, but spraying cane that already has severe rust symptoms (a recovery mission) is much less effective than preventing it from getting established. In a bad rust year, fungicides will protect your yield potential in some of your highest yielding cane and will definitely be cost effective.