Thanks for signing up!

Look for the Digest in your email twice a month.

Follow Us

Sign up for our Digest to receive the latest agronomic insights and crop management advice for your primary growing region delivered twice a month to your inbox.

Overwintered Rice Water Weevils Increase 2020 Pressure

June 21, 2020
This illustrated image shows rice water weevil

Winter 2019 brought unusually warm temperatures across the South, giving rice water weevils throughout the region a better chance to overwinter and maintain populations into the spring. Rice water weevils overwinter at the base of grass clumps, in weedy debris on levees and ditch banks. Arkansas entomologist Gus Lorenz, Ph.D., noted in a recent pest patrol alert that rice water weevils could be tough this season, and he’s already seeing lots of activity in rice.

The rice water weevil is one of the most economically damaging pests found in rice crops. Adults feed on the upper surface of rice leaves, leaving behind narrow, elongated slits of scarring. It’s worth noting, however, that most of the economic damage to rice crops is caused by larvae feeding on the roots of developing rice. This “root pruning” stunts seedling plants and reduces yield when excessive damage is found.

Because water-seeded rice fields are often flooded during early plant growth, rice seedlings are susceptible to early infestation. As a result, yield losses tend to be higher.


Lorenz encourages rice growers to diligently scout for scarring as fields go to flood. He’s seen some fields where the scarring was so intense that it took the plants out – a grower’s nightmare that can significantly impact an operation’s bottom line.

  • Sanitation and scouting are excellent ways to stay ahead of rice water weevils. Remove weed debris on levees near seeding time to help reduce infestations.
  • Seed treatments like Cruiser® 5FS provide immediate protection against early-season pests to increase plant stands, uniformity and vigor. They also improve yield potential and reduce stress on young seedlings. Lorenz reminds growers to be mindful of the length of seed treatment protection. If you’re past 35 days, crops may call for a foliar insecticide application.
  • Apply a foliar application of a pyrethroid like Warrior II with Zeon Technology® insecticide that contains lambda-cyhalothrin before or after flooding to control adults by disrupting their life-cycle. Warrior II with Zeon Technology is a quick-release, micro-encapsulated formulation with a powerful UV blocker that ensures fast knock down and long residual control of the most damaging insects.

Timing is critical. Take control of your rice crops with thorough sanitation, efficient management plans and regular scouting to get the best yield potential at harvest.

Sign up for the 2020 Pest Patrol alerts to receive timely text updates on insect and disease threat levels, outbreak predictions and more from leading experts and Syngenta agronomic service representatives.

Sign up for the Know More, Grow More Digest to receive twice-monthly agronomic e-mail updates pertinent to your area.

All photos are either the property of Syngenta or are used with permission.

Syngenta hereby disclaims liability for third-party websites.

No Comments

Post a Comment