November 1 2010 - "2009 Louisiana rice insect survey"

8/9/2011 10:50:23 PM

Participants from the circled Louisiana parishes completed our survey.

Rice stink bug, Oebalus pugnax.

Originally posted November 1 and 9, 2010, by Natalie Hummel on Louisiana Rice Insects

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 Meszaros 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.

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 were broken down as follows: rice farmers (79%), consultants (12%), dealers (7%) and others (10%, e.g. county agents, researchers, manufacturer representatives, marketing managers and landowners). The length of time that respondents have been involved with rice production varied from less than five to more than 40 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 2,500 acres of rice in the 2009 production season.

The first series of questions related to insect infestations that 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 respondents 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) that should result in decreased weevil injury.

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

Thank you again to all who took the time to complete the survey.

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