The release of elite Provisia® rice varieties like PVL03 and new PVL04 is driving increased interest in the Provisia Rice System as an important tool to control weedy rice and resistant red rice.
Last year, Horizon partnered with university and other industry leaders to help farmers best manage the Provisia Rice System. Their efforts resulted in significantly fewer confirmed instances of weedy rice outcrossing than the previous year.
Ahead of 2024, Horizon asked university rice experts to again weigh in on practices to maximize results with Provisia rice.
“The Provisia system is an excellent tool and will likely be the only tool of this type available for the foreseeable future,” says LSU AgCenter rice breeder Dr. Adam Famoso. “It is not as forgiving as the Clearfield® system and Newpath® herbicide, however, and will require more effort and attention.”
It is unlikely that we will see a new trait for weedy rice within the next 5 to 6 years,” adds Dr. Jason Norsworthy, University of Arkansas weed scientist. “The Clearfield/Fullpage® technology is ineffective on more than 90% of the weedy rice in Arkansas. If a similar level of resistance is to be prevented in Provisia, growers must take the steps necessary to preserve the technology.”
PVL03 was planted on almost a third of Louisiana’s long grain rice acreage in 2023. “PVL03 yields were solid this year and the Provisia herbicide system resulted in great weed control and one of the cleanest red rice-free crops we’ve had in many years,” Dr. Famoso says.
Dr. Famoso recommends farmers plant early to maximize yield potential and mitigate disease, using a 55-60 pounds per acre seeding rate for PVL03.
In the north Delta, Dr. Jarrod Hardke, Arkansas extension rice agronomist, agrees PVL03 and PVL04 perform best when planted early, preferably beginning in late March. Yield potential drops off once planting runs into May. He says a 50-75 pound per acre seeding rate should produce the optimal 20-30 seed/ft2.
Protecting plant health minimizes the risk of adverse impacts from the environment or herbicide antagonism in Provisia rice. Critical practices include using a recommended seed treatment, timely fertilizer applications, and monitoring for disease to keep plants healthy from the start.
Don’t make herbicide applications in rice showing bronzing, cold stress, or nutrient deficiency. Wait until the health problem has been addressed and the rice is healthy.
Dr. Hardke recommends using a full seed treatment package (insecticide plus fungicide). He adds that nitrogen rate response is similar to most common varieties but it’s important that potassium is adequate. Farmers also should consider a triazole application starting at 2-inch panicle (~1/2” + 7 days) to minimize the potential for Cercospora issues.
The Provisia Rice System has consistently proven its ability to result in clean fields and control costly weedy rice and red rice. Industry specialists say farmers can reduce the potential for antagonism and outcrosses by:
• Starting clean, applying a residual burndown grass herbicide or using tillage in the fall to control weeds and limit early competition.
• Relying on a stale seedbed approach to achieve an effective herbicide burndown and minimize weed flushes after planting.
• Overlapping residual herbicides, applied at planting and with each Provisia application before flooding.
• Applying Provisia as a solo application, when possible, especially on larger grasses.
• Combining Provisia with Rogue® herbicide if fields are zero grade or side inlet.
• Holding off on the first application of Provisia until the temperature is 65 degrees or above for three consecutive days, and rice is beyond the 2-leaf stage.
• Spraying actively growing grasses, red rice and volunteer rice.
• Making three applications of Provisia versus two at the higher labeled rate. • Having at least one Provisia application after the field is flooded.
• Using proper carrier volumes for ground and aerial applications. “Carrier volume should be 10 GPA if you can find a pilot that will spray that volume,” says Dr. Norsworthy.
• Practicing “zero tolerance” for weedy rice and red rice escapes.
• Spot-treating any escapes, using drones if necessary.
• Following the Provisia Rice System with soybeans if weedy rice is not being controlled with the Clearfield technology.
“Most importantly, make sure you are using residual herbicides up front, minimizing the risk of antagonism by knowing what not to mix with Provisia, trying to get at least one application of Provisia by itself, and making sure you are using an adequate carrier volume to maximize your coverage,” says Dr. Connor Webster, LSU AgCenter weed scientist. “I always recommend a crop oil concentrate with ACCase herbicides to maximize uptake of these herbicides.”