Archive for November, 2010

I’m passing along this important news release to you.  I’ll be attending the National Conservation Systems rice and cotton conference in Baton Rouge next year.  I hope to see you at the conference.

Dr. Donald Groth Presents Enhanced Breakout Session

Rice Blast- World’s Most Important Rice Disease

Dr. Donald Groth, Research Coordinator, Rice Research Station, LSU AgCenter, will be presenting an enhanced breakout session on rice blast at the upcoming 14th Annual National Conservation Systems Cotton & Rice Conference in Baton Rouge, Louisiana on Feb. 1-2, 2011.

According to John LaRose, Steering Committee Chairman, rice blast is the most important rice disease in the world and warrants growerʼs attention. “Dr. Groth attended the Fifth International Rice Blast Conference hosted by the University of Arkansas, Division of Agriculture and the USDAʼs Dale Bumpers Rice Research Center recently in Little Rock, Arkansas. The worldʼs top rice scientists gathered to share their research. Dr. Groth will bring the information back to growers.”

The International Rice Research Institute (IRRI) reports; in India, more than 266,000 tons of rice were lost, 0.8 percent of their total yield. In Japan, rice blast can infect over two million acres. In the Philippines many rice fields suffer more than 50 percent yield losses.

The University of Arkansas reported during last yearʼs rainy summer in Arkansas, some fields suffered yields losses up to 80 percent. “It is the second year in a row for a blast disease epidemic in the region, which produces about half of the rice grown in the United States. Yield losses were minimal in 2009 due to effective management by farmers,” said Professor Rick Cartwright, a Division of Agriculture plant pathologist based in Little Rock. “After the widespread damage in so many fields last year, and with our increasing tendency to plant rice after rice and use no-till systems, itʼs not surprising that we are having a lot of leaf blast already this year,” said Cartwright.

“During the 1980ʼs through 2000ʼs, blast and seedling diseases were among the most important diseases in Texas,” stated The Texas A&M University System. “A shift from long-term to short-term rotations of rice production tends to increase inoculums of pathogens, resulting in more severe rice diseases and more yield losses.”

Groth explained rice blast management is based on a combination of host resistance, cultural management and fungicide application. “These management practices are not effective unless the grower knows the basic pathogen biological information and have an understanding of how the disease develops.”

Factors favoring the disease include: presence of the blast spores in the air throughout the year, upland rice environment, cloudy skies, frequent rain, and drizzles, high nitrogen levels, high relative humidity, wet leaves and growing rice in aerobic soil in wetlands where drought stress is prevalent according to IRRI.

Grothʼs presentation at the 14th Annual National Conservation Systems Cotton & Rice Conference in Baton Rouge, Louisiana on Feb. 1-2, 2011 will feature biological, epidemiological, environmental and cultural information. “Water management, field selection, fertilization and fungicide time are critical for control,” said Groth.

For conference registration or more details visit; www.mafg.net.

News Release

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I’m pleased to announce the release of the Louisiana Online Rice Pest Identification Guide.   Click here to access the guide.

The purpose of this guide is to improve identification of arthropods (insects and mites) that damage rice in Louisiana.  Once the arthropod is properly identified, you will find a link to the Louisiana pest management guide with insecticide recommendations.  We have also included links to scouting videos for the rice water weevil, colaspis, and panicle rice mite.  Although the arthropods featured infest rice in Louisiana, this online guide should be a useful tool in other southern rice producing states.

Here’s how it works – the guide is structured as a dichotomous key – this is a fancy way of saying that you have two choices at each step.  Just click through the guide selecting the description or picture that matches your field problem.  At the final step you will see a picture of the arthropod and some information about scouting and management. 

This is the first public launch of the guide and you may find some glitches – if you see any errors please let me know at nhummel@agcenter.lsu.edu.  

Anna Mészáros and I worked together to build this guide.  We would like to thank Johnny K. Saichuk for providing insect pictures, Lisa West (IT coordinator, CMS), Lukas Thompson (student worker) and J’Nai Bayone (student worker) for technical assistance.  This project was supported financially by the Louisiana Rice Research Board.  We would also like to thank Evangeline Parish Rice Farmer, Richard Fontenot, for suggesting the development of this guide.

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This is a continuation of the 2009 rice insects survey summary.

The rice stink bug, Oebalus pugnax

88% of the respondents who completed the survey reported that they treated for rice stink bugs in the 2009 crop season.  Interestingly, this is an increase of 10% from the 2008 production season.  The next series of questions focused on rice stink bug management practices.  We are interested in these practices because we are currently re-evaluating LSU AgCenter rice stink bug management recommendations.  We are also testing some products that appear to have improved residual efficacy against rice stink bugs.

When asked – “how many times did you treat (a single field) with an insecticide for rice stink bugs in 2009?” – the majority of respondents from Louisiana reported that they treated with a single application of insecticide (47%), while in Texas the majority of respondents reported treating twice (42%).  33% of respondents from Louisiana reported that they did not apply any insecticides for rice stink bug management.  These figures are in agreement with many years of research and field work that have found that rice stink bugs are historically a more significant pest of rice in Texas than in Louisiana. 

When the most common insecticide use was reported, we found that the majority of respondents use a pyrethroid (Karate or Mustang) for control, followed by Malathion and Methyl 4ec.  While in Texas, producers have readily adopted a new chemistry – Tenchu 20SG.  40% of respondents from Texas reported that they treated some fields with Tenchu 20SG.  This is a neonicotinoid insecticide that provides efficacy equivalent to the pyrethroids, but has a longer window of residual activity.  This longer residual activity results in a reduction in the total number of insecticide applications to a given field.  This chemistry is currently not registered for use in Louisiana, but the company is pursuing a federal registration.

We also inquired about scouting practices, and fortunately 91% of Louisiana respondents reported that they scouted for rice stink bugs before making an insecticide application.  We recommend that scouting should precede all insecticide applications.  In Texas, 100% of respondents reported that they scouted before applying an insecticide for rice stink bug management.  If you have questions about rice stink bug scouting methods please contact your local county agent or me.

Respondents were asked to describe their perception of the severity of their rice stink bug infestation in 2009.  In Louisiana, most of the respondents (60%) reported a low infestation, while 36% reported a moderate infestation.  While, the reverse was reported in Texas, where 59% reported a moderate infestation and 31% reported a low infestation. 

We will be passing out these surveys again at the winter production meetings.  It will be interesting to see how insect infestations and treatments varied in the 2010 production season.  Thank you again to all who took the time to complete the survey.

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If you reach way back in your memory, some of you may remember completing the 2009 Louisiana rice insects survey at one of the winter production meetings back in January or February of this year.  The surveys were distributed in Louisiana, Texas, Missouri, Mississippi and Arkansas this year.  Anna and I have recently completed a summary of the responses and I’ll use this series of posts to provide an overview of a few observations.  Keep in mind that the trends reported in this posting relate to the 2009 production season, not the 2010 production season.  We will distribute a survey about the 2010 production season at the winter meetings in January.

Participants from the circled Louisiana parishes completed our survey.

184 survey sheets were processed from the following states: Louisiana (146), Texas (47), Missouri (5), Mississippi (2), and Arkansas (1).  In Louisiana, respondents from the following parishes completed surveys: Acadia, Avoyelles, Beauregard, Calcasieu, Caldwell, Cameron, Catahoula, Concordia, East Carroll, Evangeline, Franklin, Jefferson Davis, Lafayette, Madison, Morehouse, Ouachita, Point Coupee, Rapides, Richland, St. Landry, and Vermilion (see map above).  

We would like to thank all rice industry members who participated in this survey and helped to distribute the survey sheets. This survey was supported in part by the Louisiana Rice Research Board and the Southern Region Integrated Pest Management Program.

My comments will mostly be confined to the Louisiana responses at this time.  The demographics of the participants in Louisiana was broken down as follows: rice farmers (79%), consultants (12%), dealers (7%), and others (10%, e.g. county agents, researchers, manufacturer representatives, marketing managers and land owners).  The length of time that repondents have been involved with rice production varied from less than five to more than forty years, with the greatest percentage (18%) with 26 to 30 years of experience.  Approximately 76% of the survey respondents farmed or consulted on less than 2500 acres of rice in the 2009 production season.

The first series of questions related to insect infestations which were severe enough to warrant an insecticide treatment.  92% of Louisiana respondents reported that they had some fields that required treatment for rice water weevils.  88% of the respondents reported problems with rice stink bugs.  While fewer people reported infestations of grasshoppers (24%), armyworms (24%), and chinch bugs (23%).  The next most commonly reported insects were the rice leafminer (12%), stalkborers (11%) and colaspis (11%).  Less than 10% of repsondents reported infestations of rice seed midge, aphids, rice levee bill bug, or south American rice miner that warranted an insecticide treatment. 

We asked more detailed questions about rice water weevil management strategies.  A large portion of our time is dedicated to rice water weevil management because this insect traditionally causes the most significant damage to Louisiana rice production from season to season.

In both the 2008 and the 2009 production season survey, we asked the following question:

If rice water weevils were a problem in your rice field(s), which method did you use to control or prevent a rice water weevil infestation? Note that respondents could choose more than one answer since they are completing a survey that relates to more than one production field.  That will explain why the total response does not equal 100%.

In 2008, among 163 respondents in Louisiana, the most common method used to control or prevent rice water weevil was drained field (43%).

In 2009 among 130 respondents in Louisiana, the most common method used to control or prevent rice water weevil was Dermacor X-100 seed treatment (52%).  In 2009, this was the only seed treatment available for use in rice.

Method used to control rice water weevil in Louisiana rice fields

2008 Percentage (%) 2009 Percentage (%)
Drained field 43 34
Post-flood treatment with a foliar spray of pyrethroid 39 44
Pre-flood treatment with a foliar spray of pyrethroid 36 37
Pre-flood treatment with a pyrethroid impregnated on fertilizer 21 22
Post-flood treatment with Trebon 20 10
Early planting to avoid infestation 18 31
Dermacor X-100 Seed Treatment 17 52
Pre-flood and Post-flood treatment with a pyrethroid 13 N/A
Delayed application of permanent flood 13 27
Pre-flood treatment with Trebon 9 7
Nothing 6 7















There was a decrease in the percentage of respondents who reported that they drained a field for weevil management while their was a substantial increase in the adoption of seed treatments and cultural practices (early planting and delayed application of permanent flood) which should result in decreased weevil injury.

The next installation in this series of blog posts will focus on questions related to rice stink bug management.  Do these observations reflect what you experienced in the 2009 or 2010 production seasons?

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