Thursday, June 30, 2022

LSU AgCenter offers glimpse of research at annual Crowley rice field day

Steve Linscombe
Dr. Steve Linscombe describes some of the varieties that were recently released or are nearing release.

Under cloudy skies and cool temperatures, attendees of Louisiana State University AgCenter’s 107th annual rice field day in Crowley June 29 got a glimpse of several new varieties, hybrids and crop protection materials in the pipeline.

Among those were a Clearfield line of aromatic jasmine rice, which will have natural tolerance to the imazethapyr herbicide, Newpath, or ammonium salt of imazamox, Beyond. Both herbicides are from BASF Co. Rice breeder Dr. Steve Linsombe said he hopes to release at least one of the lines to the industry in 2018.

Linscombe, also H. Rouse Caffrey Rice Research Station director, has two advanced long-grain lines, PVL 24A and PVL 24B, which are resistant to the quazalofop herbicide, Provisia, also from BASF.

“Whether we go with one or two, we haven’t made a decision yet,” Linscombe told attendees.

The Provisia program is designed to complement the Clearfield program and help control ALS-resistant weedy red rice.

Seed is expected to be increased in 2017 for commercial release in 2018.

Both herbicide-resistant traits were derived using conventional breeding techniques and not genetic engineering.

The quest for improved hybrids

The LSU AgCenter also is working on developing its own line of hybrids. Among those are LAH 169; CLH 161, which contains the Clearfield gene; and LAH 608, said hybrid breeder Dr. James Oard.

In replicated yield trials in 2015, the three yielded 18 to 24 percent more than leading varieties CL 152, CL 111 and CL 151. The stability of these hybrids over years and locations is similar to inbred varieties. And grain dimensions also appear similar to inbreds.

The chalk values of these hybrids appear lower than other commercial hybrids on the market.

seeding rate trials
Trials conducted by Extension rice specialist Dustin Harrell are looking at optimum seeding rates of the two candidate Provisia lines.

And for the first time, Oard said university breeders are evaluating a Provisia hybrid. Early results look promising.

“We’re pretty excited about it,” he said.

As part of its continuing effort to develop hybrids, LSU signed a research agreement this winter with the private hybrid developer, RiceTec, of Alvin, Texas.

“It will be a win-win situation for the AgCenter and RiceTec but mainly it will benefit the Louisiana rice producers as we move this material along,” said Qi Ren Chu, a consultant to RiceTec CEO Mike Gumina. Prior to joining RiceTec in 2005, he had been an LSU rice breeder for 11 years.

A plethora of weed products

LSU AgCenter weed scientist Dr. Eric Webster said he has multiple trials with 14 experimental herbicide, of which three were active ingredients new to rice.

“That’s the most I’ve ever had,” he said of the plethora of products. “Any time we have new modes of action, we have to see how they fit into our programs. But they should help with resistance management.

Benzobicyclon, an HPPD herbicide from Gowan Co. is one of those new modes of action. It works as a bleacher that targets plant chlorophyl and has been used in Japan since 2001. It has to be applied in the flood and the flood maintained for best efficacy.

Gowan plans to market it as Rogue Plus, a premix that also contains halosulfuron.

Webster’s graduate student, Ben McKnight, is conducting trials looking at rates of benzobicyclon. It provides good control of sprangletop and rice flatsedge but is weak on yellow nutsedge. But it does reduce tuber set in yellow nutsedge, which helps control populations.

Loyant, a synthetic auxin from Dow AgroSciences, has looked good on common aquatic weeds and a broad spectrum of grass and broadleaf weeds. It is weak on sprangletop and yellow nutsedge but strong on rice flatsedge. Webster said the product may gain registration in late 2017 or 2018.

Webster also is looking at tankmix partners for Provisia. Many herbicides, such as the auxins and Grandstand, are antagonistic, causing plant injury. Loyant, however, doesn’t seem to have as much antagonism with Provisia as some of the other products.

Don’t bug me

Mild 2015-16 winter conditions aided survival of overwintering rice water weevil populations, setting up major problems for growers this season who didn’t use insecticide-treated seed.

“We’ve had serious problems with rice water weevils,” said LSU AgCenter entomologist Dr. Mike Stout. “It’s our most damaging insect pest.”

rice water weevil trials
Entomologist Mike Stout conducts trials examining whether herbicides may affect rice water weevil infestation severity.

Rice water larvae feed on the roots of developing rice plants, weakening them and reducing yields.

The 2016 seasons appears to be the worst in the past 20 years for South American rice miner, a small fly pest, Stout said. In fact, the pest really hasn’t shown up in South Texas or South Louisiana in the past 12 or 13 years.

“Since that time, it really hasn’t been a consistent or serious pest for us,” he said. “I can only remember one other year where I ‘ve had it on the station. This year it’s very common throughout Southwest Louisiana. I’ve visited fields from Welch to Ville Platte and found it.”

The larvae burrow into the rice whirl of young rice plants, making the plants look ragged. But he didn’t expect significant yield losses.

“I think ultimately it really is a cosmetic deal,” Stout said.

An insect pest that has yet to be found in Louisiana is the rice delphacid, a type of rice planthopper native to Latin America.

The pest became a significant problem last season in several ratoon fields in the Texas rice belt west of Houston, said Dr. Mo Way, a Texas A&M AgriLife entomologist based in Beaumont. He has yet to find the pest in any fields this season, although he has been monitoring them throughout the winter and into this season.

“I expect it to show up eventually,” Way said during a similar presentation at the 42nd annual Texas A&M rice field day, June 28, at Eagle Lake. “We had that mild winter and really, really high populations. I just can’t understand how it could just disappear. My gut feeling is we’re going to start seeing it on the second crop again.”

The adult, about 1/6-inch long, has piercing and sucking mouth parts. It feeds on plant juices and excretes a sticky substance known as honeydew. Black sooty mold is attracted to honeydew.

Both the adult and nymph appear to have two racing stripes down their back, a key identifying trait.

In a few of the severely infested fields, second crop yields were reduced by about 20 percent.

Way encouraged growers and consultants to contact him at 409-658-2186 or if they suspect the rice delphacid.

–Vicky Boyd, Editor

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