The rice water weevil – along with several other rice insect pests – will be looking for a new home after getting booted out of the rice field as more and more producers load up on seed treatments this season.
At the end of 2009, CruiserMaxx Rice insecticide and fungicide combination seed treatment was approved for use on rice, and very recently, Dermacor X-100 insecticide seed treatment received its Section 3 registration on rice.
Dermacor targets rice water weevil, fall armyworm, South American rice miners and stalk borers (Mexican rice borer/sugarcane borer). This seed treatment is designed for for dry-seeded systems, not water-seeded.
In Arkansas, Extension entomologist Gus Lorenz has evaluated Dermacor on large plot trials for the last two years and small plot trials for the past three years. “Through all of the studies that we have done, regardless of the insect situation, about 75 percent of the time we are getting almost a 10-bushel yield increase,” Lorenz says. “We have two major pests in Arkansas – rice water weevil and grape colaspis. We’ve determined that Dermacor provides suppression of grape colaspis and very good control of rice water weevil.”
Lorenz also notes that in Arkansas armyworms will come out of wheat and oftentimes move into seedling rice.
“Dermacor does control these armyworms moving into rice, so it has good activity on the lep pests,” he adds. “We have also noticed some plant growth enhancement when using Dermacor. We are seeing increased stand count and plant height at times, and it looks really good in those situations where growers have a history of rice water weevil.”
The Arkansas entomologist says if you are debating whether seed treatments are worth the up-front investment, he recommends using them under the following conditions:
• High value seed with low seeding rates
• Less than optimum planting conditions, such as extremely early planting date, no-till and marginal seed quality
• Known problem fields with a history of rice water weevil or colaspis infestation
• Varieties with poor seedling vigor.
Borer control in ratoon crop
Texas Extension entomologist Mo Way says growers, particularly in the Southern part of the Rice Belt, have an increasing problem with stalk borers.
“Dermacor would be a real good fit for them,” he says. “It gives good control on stalk borers on the main crop, and based on our one year of data from last year, it appears to be doing a pretty good job on the second crop, too.”
Way says stalk borers are usually worse on the second crop, yet with Dermacor, he has seen some growers harvest as much as half of the main crop.
“We were seeing about 70 percent reduction in whiteheads – a measure of stalk borer activity – on the second crop compared to the untreated check,” he says. “And, if you consider the low economic injury level from rice water weevils, farmers will make money using seed treatments.
“Even given the late registration, I think there will be more rice treated with Dermacor this year than last year.”
Observations from Louisiana
LSU AgCenter Extension entomologist Natalie Hummel, who has been working with Dermacor for the past two years, says it fits into a dry-seeded system and provides excellent control of rice water weevil.
“It also controls borers and the South American rice miner,” she says.
During the 2010 rice-growing season, Hummel says Dermacor X-100 will be evaluated in side-by-side comparisons with CruiserMaxx, pyrethroids and an untreated check in at least five commercial farm demonstrations. Meanwhile, producers in rice-growing states will be making their own on-farm assessments to see if the new seed-applied technology lives up to expectations and blows the rice pests right out of the fields.
Contact Carroll Smith at (901) 767-4020 or firstname.lastname@example.org.