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Rice delphacid management with Transform® WG insecticide
Everything growers need to know about rice delphacid management
In rice, often the unseen threat is the most potent. Not only is rice delphacid — a pest poised to make big waves across the southern rice belt in upcoming seasons — difficult to scout for, it also poses potentially disastrous effects for growers if not properly monitored and managed.
As such, this tiny planthopper has growers and entomologists on high alert heading into the new season.
“There’s a ton of unknowns out there. The best thing we can do is scout early and often and try to stay out in front of it.”
—Dr. Nick Bateman, Extension entomologist with the University of Arkansas System Division of Agriculture
Where did rice delphacid come from?
Rice delphacid are both an old story and a new challenge. First identified in the late 1950s in parts of Louisiana, the pest largely disappeared until resurfacing and flourishing throughout Texas in 2015.
“Texas growers know about it big time — they got impacted hugely this past year,” Bateman said. “Then, in the upper Mid-South, around last September, is when populations exploded all through the region.”
Since then, rice delphacid populations have transformed from an intermittent threat to a critical issue, with signs pointing to their continued expansion into Arkansas, Louisiana and Mississippi in 2026 and beyond.
Three major threats in one
As phloem feeders, both rice delphacid nymphs and adults can cause serious rice crop damage. That damage comes in three primary forms:
- Nutrient loss and stress: By sucking sap from the plant, rice delphacid deprives the crop of essential nutrients, reducing overall yield potential. They also excrete honeydew, which promotes sooty mold growth on leaves and interferes with photosynthesis, compounding stress on the crop.
- Hopperburn: Heavy feeding can cause leaves to yellow, brown and desiccate, a symptom known as hopperburn. Hopperburn begins with yellowing at the rice leaf tips, which quickly progresses to drying as the infestation worsens. In severe cases, this leads to stunted growth, plant dieback and lodging before harvest.
- Infection: Rice delphacid is the primary vector of the Rice Hoja Blanca Virus (RHBV)— or “white leaves” disease — which can turn plants bleach-white. This impacts growth and can cause severe yield losses.
Taken together, the impact is significant. Surveys from Texas estimate losses ranging from 7-17%, with additional concerns around milling quality due to plant stress.
“If we’re seeing symptomology, we’re late,” Bateman warned. “We don’t need to wait until we start seeing hopperburn out there before we do something.”
Identifying rice delphacid
Rice delphacid are small planthoppers — about one-quarter inch long. Males have dark-colored wings, while females are a muted tan. Neither particularly stands out in a sweep net.
“They just look like some other little midge or hopper,” Bateman said. “Almost like a mosquito.”
Immature delphacid are even more difficult to spot — some are see-through, no bigger than a pen tip.
Still, identification signs exist: As they mature, rice delphacid develop distinct dark “racing stripes” down their sides that help distinguish them from other pests, and hatched nymphs leave red lesions on the mid-rib of rice leaves, indicating feeding has begun.
Monitoring: Start early and scout often
Because rice delphacid populations can explode quickly — and because waiting for visible damage means the pest has already taken a significant toll — early and consistent scouting is key.
“I would scout extremely hard during the booting stages through early heading,” Bateman said. “So as early as late June or early July.”
To scout, use a sweep net, but adjust your technique: unlike rice stink bug, which stay high in the canopy, delphacid nymphs dwell lower in the plant.
“You’re digging down through the canopy,” Bateman explained. "And if you're catching a bunch of pollen [or other particles], take fewer sweeps and do more sets — three or five sweeps at a time — so you can actually see what you've got."
As for who should be scouting the most? Growers with late-planted rice — mid-May or later— are especially vulnerable, as the crop reaches susceptible stages when populations are most likely to arrive.
Treatment: Getting ahead of the problem
Because rice delphacid is new to the Mid-South, research on management strategies is still evolving. Transform® WG insecticide with Isoclast™ active has proven effective in combating difficult infestations — including as one of the best labeled options for rice delphacid control.
"From what we currently have, Transform is right up there with the best," Bateman said.
For fields where delphacid show up later in the season — two to three weeks into heading— a standalone application of Transform may be sufficient. For earlier-stage infestations, pairing Transform with other tools as part of a broader management approach can help extend control.
Looking ahead
Rice delphacid is a pest with more questions than answers — for now. As entomologists and growers learn more about its impact, the fundamentals of proper pest management are more important than ever: scout early, scout often and act before damage becomes severe.
“We’re going to try and be out in front of this thing as much as possible,” Bateman said. “But be sure to do some scouting — this is going to be a learning curve.”
Learn more about developing a strong insecticide control program for rice at Corteva.com/Rice.
Transform WG insecticide is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Isoclast® is a registered active ingredient. Always read and follow label directions.
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