Rice Extension Agronomy Newsletter, September 2026

Sam Rustom, Ph.D. // Tyler Musgrove, Ph.D. // Lina Bernaola, Ph.D.

Photo 1. Upper-nodal dominance in ratoon rice near Chesterville, TX.

Upper-Nodal Dominance

Growers often call this apical dominance. After harvest and stubble manipulation, the true apex is gone, so what we see are the highest leftover nodes starting regrowth first, and this can hold back basal tiller regrowth – what I’ll call upper-nodal dominance. If you aren’t familiar with ratooning rice, the upper nodes are not the nodes we want producing most of the ratoon rice panicles. Some upper-nodal tillers appear every year and are expected; however, the problem this year is when they dominate the stand (Photos 1 and 2). The upper tillers and panicles developed from these nodes can be puny, head too fast, and cause issues with yield and grain quality. An upper-nodal dominance pattern is common when non-structural carbohydrate (NSC) reserves are low in the remaining stubble after main crop harvest.

In an optimal ratoon rice stand, regrowth from basal and crown nodes is preferred (Photo 3). Buds from these nodes usually produce thicker, more uniform tillers and larger, higher-yielding panicles. When residual NSC in the stubble is low, the lower nodes are last in line for an energy source. Upper-node buds sit closer to what NSC remains, start regrowing first, and use these already depleted reserves. When NSC load is higher, the lower nodal buds get enough fuel to break, even if the upper nodes started a few days earlier.

Over the past month, we have observed increased levels of upper-nodal dominance across the state in ratoon crop regrowth. This is occurring primarily west of Houston and in some areas of Louisiana. A study by Xie et al. (2024) in Japan suggests that shaded conditions during grain fill resulted in a reduced NSC load available for ratoon rice regeneration.

Although my thoughts are purely theoretical, I think this is what we are seeing take place in this year’s ratoon crop:

1. The 2026 main crop in Texas was unusually rainy and cloudy, which reduced photosynthetic activity at critical growth stages.
2. Reduced main crop photosynthesis left less stored NSC to fuel the basal tiller regrowth we prefer.
3. Low residual NSC in the stubble is favoring upper-nodal regrowth over basal/crown-node bud regrowth.
4. In the field, this pattern has shown up across different varieties, hybrids, and stubble management practices, and seems to be occurring where rainfall and cloud cover were heaviest during the main crop.   

The good news is that this is not happening everywhere and some ratoon rice in the state looks great. Some impacted fields are reported to be recovering, but the basal tillers are well behind.  Only a combine will tell us just how much of an impact this issue had on the 2026 ratoon crop.

Bank’s Grass Mite and Pasture Mealybug in Rice

Dr. Tyler Musgrove, LSU AgCenter Extension Rice Specialist

In Louisiana, 2026 has definitely been the year of the insect. Now this doesn’t mean we’ve had widespread yield losses and control failures, but instead we’ve seen insects do things we don’t normally expect. South American Rice Miner showed up pretty consistently in most fields and didn’t go away. Chinch bugs took a bite out of stands all across southwest Louisiana and many replanted. Stink bugs and stem borers are building in the ratoon crop a little more than we’re comfortable with. However, this segment will focus on two newcomers that may be causing more concern than they’re actually worth. Both insects have also been identified this year in isolated rice fields in Texas, according to Dr. Sam Rustom, Texas A&M AgriLife.

Bank’s Grass Mite

A couple weeks ago, we began receiving calls about what appeared to be water weevil-type damage occurring on rice leaves in astounding number (Photo 4). It was clear water weevils wouldn’t cause this sort of injury and so I went under the microscope—mites (Photo 5). I scouted several fields around Acadia, Vermilion, Jeff Davis, and Calcasieu Parishes and the mites and their damage (stippling) was present throughout, although mostly found on the edges of fields. After consulting with other LSU entomologists, we landed on the Bank’s Grass Mite, which had shown up in sugarcane earlier in the year and in the same areas. These things are incredibly difficult to see with the naked eye but having a hand lens handy would help. These are different from the rice panicle mite which is an actual problem. These grass mites are only feeding on the leaves and appear to be causing superficial damage. We’ve been monitoring their progression, and they haven’t posed any threats that we can tell.

Pasture Mealybug in Rice

A ton of rice acres in Louisiana share a field road with sugarcane, and there’s no secret as to what the cane industry is currently dealing with. As a result, we’ve been receiving questions about mealybugs in rice and whether we should have any concerns. The short answer is—maybe, but not really. The mealybug (Heliococcus novovillei) affecting pasture fields and sugarcane requires access to the soil to complete its lifecycle. A flooded rice field doesn’t exactly allow for this. So, from this angle, mealybugs will not pose a significant threat to the US rice industry. However, there are three scenarios where I can see mealybugs getting into rice: 1) preflood early season 2) ratoon stubble that hasn’t been flooded yet and 3) furrow-irrigated rice (my big worry). For scenario 1, mealybugs need to emerge much earlier in the spring than they do based on observations from the last two years. However, we expect insecticidal seed treatments, especially neonics like Cruiser or NipsIt Inside, to bring a lot to the table. That being said, I’m hoping to verify this in greenhouse this off-season.

Before getting to scenario 2, furrow-irrigated rice or row rice is where I think mealybugs pose the greatest threat. In Louisiana, row rice does meet the most northern cane region across Rapides, Avoyelles, and Point Coupee Parishes, and I’ve even seen row rice share a turn row with cane. We don’t have many row rice acres in the state, but we certainly need to watch those. As for scenario 2, we observed mealybugs in preflood ratoon stubble in Vermilion Parish, right next to an infested cane field (Photo 6). We collected samples for genetic confirmation and sent them to USDA. I couldn’t determine if the damage I was seeing was from mealybugs or chinch bugs, but the mealybug pressure was only 5 or so insects per sq ft. This particular field was intended for crawfish, and the farmer was not planning to cut the second crop. Going forward, I do not anticipate mealybugs causing widespread issues in the rice producing regions of the Gulf South, but their presence warrants just a little attention.

Rice Delphacid Monitoring

Dr. Sam Rustom, Dr. Lina Bernaola

Current counties with confirmed rice delphacid presence are below. Counties in bold contained fields with visual main crop damage such as hopperburn and/or lodging. None of these symptoms have been observed so far in the 2026 ratoon crop.

• Victoria
• Wharton
• Colorado
• Matagorda
• Waller
• Brazoria
• Fort Bend
• Jefferson
• Liberty
• Chambers

If you read last month’s newsletter, you’ll notice this list has not really changed outside of the addition of Fort Bend and Colorado Counties. Overall, rice delphacid populations have remained relatively low and localized across much of the Texas Rice Belt through mid-September, although localized increases have occurred. Keep in mind that populations can ramp up at any time, so please continue to monitor fields diligently. Statewide, we have seen only one field in Matagorda County rapidly flare up in September (Photos 6 and 7). In this field, the rice delphacid population went from 1-2 in 10 sweeps on a Monday to way too many to count by Thursday. The good news is the Centric + Courier applied at the maximum rate is doing a great job 2 weeks after treatment.

From Dr. Lina Bernaola:

My research team continues its monitoring of rice delphacid (RD) populations across the Texas Rice Belt as the ratoon crop develops.

Recent observations continue to show that RD activity is highly variable among and within fields. In our research monitoring locations, adults and nymphs are being detected at some sampling points, while other areas within the same fields continue to have little or no activity. Localized concentrations of nymphs are also being detected through vacuum sampling, reinforcing the patchy distribution we have observed throughout the season.

More broadly, Dr. Rustom reported from the regional monitoring network that some RD activity has increased in some ratoon rice fields, particularly in Matagorda County. One field recently experienced a rapid and substantial increase in RD numbers, while increases reported from other fields have generally been much smaller. Observations from that field suggest that the increase may have been associated with movement of RDs from adjacent harvested and dried-down seed rice into neighboring ratoon rice.

At this time, these observations appear to represent localized population increases rather than a widespread increase across the Texas Rice Belt. However, the rapid increase observed in one field demonstrates that populations can change considerably over a relatively short period when conditions are favorable. 

As we move into late-September/October and the ratoon crop continues to develop, continued scouting will be particularly important. Attention to field edges and areas adjacent to recently harvested or drying rice may also be useful where movement between fields is suspected. Our research program and the broader regional monitoring network will continue tracking RD activity and population development through the remainder of the season.

In addition to our research monitoring efforts, our entomology team has initiated an insecticide efficacy trial in a commercial rice field to evaluate management options for rice delphacid. The trial is currently underway, and we will share relevant findings as the data become available.

Please feel free to reach out with any questions, comments, or field observations.

RTWG

The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Texas AgriLife Extension Service is implied.