Rice Researchers Must Respond to Emerging Issues

Steven Linscombe  |  6/14/2013 6:49:14 PM

RRS arsenic research plots

LSU AgCenter rice research scientists must be continually ready to respond to issues that emerge periodically in the rice industry. Each research scientist has a fairly structured research program, but that program must have the flexibility to focus efforts on new problems as they arise. A few recent examples are below.

Resistance to the most commonly used rice fungicides was identified in 2011 in the rice production region of southwest Louisiana. These fungicides were azoxystrobin-type materials, which had been historically effective in controlling sheath blight disease. In 2010, Dr. Don Groth, Rice Research Station pathologist, began receiving reports of poor control of sheath blight disease by the azoxystrobin fungicides in a localized area near Mowata in Acadia Parish. Dr. Groth explored several potential factors, including sources of fungicides, application timing and methods, additives, water quality, and unusual weather patterns. None of this information could explain the consistently poor fungicide performance. Again in 2011, nonperformance issues arose with the azoxystrobin fungicides in the same general area. AgCenter scientists then assisted representatives from one of the companies producing one of these fungicides in collecting diseased leaf material from both rice and soybeans (same pathogen causes aerial blight in soybeans), and these samples were tested in a private lab. The testing of these samples confirmed that a number of them were azoxystrobin-resistant. Fortunately, Dr. Groth had been testing a different mode of action fungicide (Sercadis) in his ongoing program. This fungicide proved to be effective in controlling sheath blight caused by the azoxystrobin-resistant isolates. Through cooperation between the Louisiana Department of Agriculture and Forestry and the LSU AgCenter, a Section 18 label for Sercadis was obtained for use in the 2012 rice crop. The success in obtaining this approval for the use of the new fungicide on the problem fields was only possible because of Dr. Groth’s work. This Section 18 label has also been approved for use in the 2013 crop in several rice-producing parishes in southwest Louisiana.

Another example is the Mexican rice borer, which is a devastating pest of sugarcane and a serious pest of rice. The borer was first found in Louisiana in December 2008. The early detection of the pest in Louisiana was possible because of a joint effort of AgCenter and Texas A&M scientists to monitor the movement of the pest. The insect has been a pest in Texas rice since 1988, having moved north from Mexico. The borer has slowly moved to the northeast across the Texas rice belt since that time, taking 20 years to finally arrive in Louisiana. The monitoring of the movement of this pest across Texas and now into Louisiana has been a joint effort between Dr. Mo Way, Texas A&M entomologist, and Dr. Gene Reagan, AgCenter entomologist. This cooperation has also allowed time for preparation of the arrival of the pest into Louisiana. Dr. Mike Stout, AgCenter rice entomologist, has been working closely with Dr. Way on the most effective control strategies for this insect in case it does become a significant problem in Louisiana rice production. The insect was first detected in a Louisiana rice field in 2011 but has yet to become a serious problem.

The recent media blitz on arsenic content in rice is another example. First, it is important to understand that the issue of arsenic content in rice is not considered to be a significant problem by most knowledgeable scientists. It is true that rice grains typically have higher levels of arsenic than crops such a wheat, corn and soybeans. But this is only because rice is grown under flood irrigated conditions, which tend to lead to slightly more accumulation of the compound in the grain. The levels of arsenic in rice are considered quite safe by most nutrition scientists. Regardless, since this issue has been in the media lately, it should be addressed from a research standpoint. Dr. Dustin Harrell, AgCenter rice agronomist, has initiated a series of studies to evaluate how different cultural practices might affect arsenic accumulation in rice grains. This research will not only provide good scientific data on this topic but will demonstrate that the research community is seriously engaged on this issue.

Rice Field Day

The 104th Annual Rice Research Station Field Day will be held on Wednesday, June 26, 2013. Field tours will be departing between 7:15 a.m. and 9 a.m. There will be a poster session from 7:30 a.m. to 10:30 a.m., followed by the program at 10:45 a.m. The field day will conclude with a sponsored lunch at 12 noon. Please plan to join us on June 26 to see first-hand the advances in technology being generated by AgCenter scientists.

Permission granted June 14, 2013, by B. Leonards (LA Farm & Ranch), to republish article on www.lsuagcenter.com

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