Overview of 2010 Insects in Rice and 2011 Outlook

Jeff Gore, Research and Extension Entomologist
By Jeff Gore, Research and Extension Entomologist March 3, 2011 08:33

Last year was a challenging year for insect pests of rice in Mississippi. In general, we experienced higher than normal populations of rice water weevil, rice stink bug, and fall armyworm.  Luckily from the rice water weevil standpoint, the two seed treatments Cruiser and Dermacor received Federal labels during the spring of 2010.  Cruiser was labeled early enough that approximately 50% of the rice acres in Mississippi were treated with Cruiser.  Dermacor was labeled a few weeks later, in the prime planting window, and very little Dermacor was used in 2010.  Despite the higher than normal weevil pressure, both of these seed treatments performed very well.  As a result, the use of both of these seed treatments is expected to increase in 2011. 

Rice stink bug populations were extremely high during 2010 and most of the rice acres were treated at least once for this pest. Additionally, several fields required multiple pyrethroid applications in 2010 to maintain stink bug populations below economically damaging levels. We began seeing high populations of rice stink bug on wild hosts as early as May last year, which gave them plenty of time to build high populations before panicle emergence in rice.  For the most part, the pyrethroids did what they were expected to do.  Because of the high densities, many fields were quickly re-infested after the pyrethroid had worn off and aditional applications were needed.

Numerous fields across Mississippi were treated for fall armyworm during the mid-season window.  Fall armyworms were higher in all crops, including pastures, during 2010 compared to the previous few years. This is typical for a hot dry summer like we had in 2010. We received several calls in 2010 about less than adequate control of fall armyworms with pyrethroids in mid-season rice. Typically, the rice/grass strain of fall armyworm is extremely sensitive to pyrethroids.  Low rates of a pyrethroid in pastures or early season rice do a good job of controling fall armyworms where there is not a lot of foliage.  In mid-season rice, where there is bigger plants and more foliage, mid to high rates of the pyrethroids should be used.

The LSU AgCenter has an online survey where they are asking growers, consultants, and anybody that works in rice in the mid-South to share their thoughts on insect pests of rice in 2010. The survey is short and should only take a few minutes to complete. The link to their survey is:    http://www.zoomerang.com/Survey/WEB22BQUV8J35H/ 

As for 2011, there is no way to predict what rice water weevil populations will be like this early in the year.  Rice water weevil will most likely occur in all fields at some level in Mississippi and an insecticide seed treatment is recommended. The seed treatments have provided more consistent control of rice water weevil than foliar applications of insecticides.  For rice stink bug, early indications suggest that 2011 may be more similar to 2010 than previous years. There is a lot of time between now and when rice is susceptible to stink bug damage. As we make collections from wild hosts through the spring and summer, we will continue to post updates here about what rice stink bug populations are doing in the landscape.  Early predictions are that this will be another hot dry summer.  As a result, this summer may be another year that is conducive for fall armyworm.  Fortunately, fall armyworm is a migratory pest and we should be able to get a handle on what 2011 will be like based on reports from southern locations. Like with stink bugs, we will continue to post updates through the summer concerning fall armyworm populations as they migrate north.

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Jeff Gore, Research and Extension Entomologist
By Jeff Gore, Research and Extension Entomologist March 3, 2011 08:33
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