Having earned a doctorate studying Clearfield rice, Tomilea Baldwin is an expert on the crop. As of now, she says, the Clearfield technology “isn't perfect but is undeniably the best way” to control red rice within a rice crop.
Baldwin works with her weed scientist husband (and Delta Farm Press contributor), Ford, at Practical Weed Consultants near Austin, Ark. She recently spoke about her experiences with Clearfield and why piracy is especially threatening to the technology. Among her comments:
On Clearfield rice physiology/environmental interactions:
“Cultivated rice and red rice are of the same genus and species. It's very possible for out-crossing or hybridizing to occur through transfer of pollen.
“If pollen is transferred from Clearfield to red rice, the possibility of the Clearfield gene being transferred is likely because it's a dominant trait. Meanwhile, the properties of red rice are also dominant. That could possibly lead to a Newpath-tolerant red rice plant.
“If hybridization occurs, when you spray Newpath, you're selecting for those hybrid plants. They'll thrive in that environment. Once you begin selecting with Newpath applications, competition from susceptible plants is reduced and they'll multiply very quickly.”
On how rapidly a hybridization problem can spread:
“In my research plots, beginning in 1998, we were doing efficacy studies of Newpath on red rice. By 2000, we were noticing that all the red rice wasn't being killed in the plots. We also noticed red rice and Clearfield plants were flowering at the same time.
“The following year, we tilled up the plot area as if we were going to plant a rice crop. We didn't plant one, though — we just let the volunteer rice plants come up. We made three Newpath applications: two at an X rate, and another at a 2X rate.
“What we found was very surprising. We had a segregating population of Newpath-tolerant red rice. Out-crossing was happening in the previous years right under our noses and we had no idea.”
Are out-crossing concerns overblown?
“Out-crossing concerns aren't bogus at all. I'm seeing this in our research plots again. Just recently, I ran across a red rice plant in an alley between plots. The plots and the alley were all sprayed with Newpath and this plant was very healthy.
“We have efficacy studies that generally include untreated checks, plots that give incomplete control and others that should give 100 percent control. And that's what we've found: the various levels of Newpath applications gave us various levels of control.
“What that created was an environment where red rice and Clearfield rice were simultaneously flowering. Even though red rice is an earlier-maturing plant than cultivated rice, it has so many tillers and panicles it's still flowering when the Clearfield begins. The point is: out-crossing can happen.”
On recommendations, new products and labels:
“BASF suggests two applications of Newpath at 4 ounces. They recommend that the applications be made when a field has adequate moisture. If the field is dry, you should flush it.
“But how many growers are going to flush when there's a chance of rain in two days? If you're chasing a rain, the next thing you know, the product has been in the field two weeks and hasn't been flushed in. These are things that concern me.
“There's another BASF herbicide, Beyond, that's coming out. It's very similar to Newpath with a short residual.
“Beyond is targeted at escaped red rice plants. We've used it in plots and it works well.
“Currently, though, the way Beyond is labeled doesn't do much good. It's labeled for use too early. It needs to be sprayed after flooding when red rice is emerging through the canopy and farmers notice it. I believe (BASF is) working on expanding that label.
“However, since it's the same (type of chemistry as Newpath) it won't be effective against hybridized red rice. If you've got tolerant red rice and it came through two applications of Newpath, Beyond isn't going to get it either.”
What's your reaction to reports of illegally planted Clearfield rice?
“I haven't looked at any of those fields. Obviously, the growers wouldn't have taken the risk and planted it if red rice hadn't already been there. Besides being flat-out illegal, if they had any escapes at all, that's real trouble.
“It's hard to police something like this. Brown-bagging seed is one thing. But there's also those few outlaw farmers saying, ‘Last year, this technology worked great on my back 40 acres. I'm going to plant it again on the same spot now. No one will see it back there.’
“That's not supposed to happen either. Crop rotation is the best way to keep Clearfield viable.
“I have sympathy for producers who lease land that's a mess. They say, ‘It's all red rice and I can't afford to grow soybeans on it. I'm going to ride the Clearfield horse until it drops dead. After that, I'll let go of the land.’
“But while I sympathize, that doesn't make it right. That scenario is just as scary as brown-bagging. And I suspect that's happening more than folks brown-bagging seed.
“By doing these things, we're shortening the life of this technology. We can't afford that. There are no good red rice alternatives at hand — Clearfield is all we've got. They may come up with Roundup Ready rice in the future, but it isn't imminent and farmers shouldn't be planning for it.”