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Posts Tagged ‘Johnny Saichuk’

Last week, Dr. Saichuk handled some insect related rice field calls. I thought you’d like to learn about his observations and how he recommended handling the pest problems. The problems were reported on the Louisiana crop blog. Click here for a link to a field Johnny scouted that had a thrips infestation. Learn more about thrips in rice at this linkClick here for a field Johnny scouted that had a rice water weevil adult infestation that was causing defoliation and death of seedlings. Click here for a fact sheet on rice water weevils.

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About a week ago Calcasieu Parish County Agent Jimmy Meaux e-mailed me a picture of a borer larva in rice that he suspected was the Mexican rice borer (MRB). This was a highly suspect sample due to a combination of the morphology of the larva and where it was found – which was in the same area where LDAF caught the first adult MRBs in pheromone traps in Louisiana. This confirms our suspicion that MRB are now establishing and reproducing in Louisiana. I would strongly encourage you to familiarize yourself with identification of this pest. Below is some information on this particular field infestation from Johnny’s Saichuk’s field notes. Following this I’m including some information on identification of MRB.

Field Notes
July 14, 2011
Johnny Saichuk

“Well, it is official; we have the Mexican rice borer in Louisiana. Earlier reports were of male moths caught in pheromone traps. Last week county agent Jimmy Meaux was called to a field in Calcasieu parish where he tentatively identified borer larvae as Mexican rice borer. He sent them to Dr. Natalie Hummel whose associate Anna Meszaros and graduate student (under Dr. Gene Reagan) Julien Beuzelin examined the specimens. They confirmed the identity. This afternoon I visited the field with Jimmy where we easily found several borers including the one shown here. I sent the photo to the experts and they just confirmed it. That is one of the advantages of the technology we have today. The photograph was taken at 2:12 p.m. and by 5:30 it was confirmed.

Mexican rice borer larvae infesting a rice plant in Vinton, LA. Photo by Johnny Saichuk.

Jimmy told the farmer, Chris Habetz and his son Brad, we would put up a plaque at their farm. They did not see the humor. The field where this borer was collected had no insecticide seed treatment; however a nearby field is treated with Dermacor. We will follow up to see if borers are discovered there or if the insecticide prevents them from becoming a problem. This is a manageable albeit unwelcome pest. Dermacor and/or timely applications of the pyrethroids can keep them in check in rice.”

The LDAF MRB trapping program is an ongoing survey program in southwest Louisiana that is documenting the spread of this pest. LDAF state entomologist, Tad Hardy, sent me an updated map on the trap counts of MRB in Louisiana.

If you click here you will see a Map of MRB Finds as of July 2011. This map was provided by Mr. Tad Hardy of LDAF.

As Johnny said in his comments, fortunately the MRB is a manageable pest – in large part due to the efforts of LSU AgCenter sugarcane Entomologist Dr. Gene Reagan who has been studying this pest in Texas for decades. MRB effects both sugarcane and rice production in Texas and it appears that it will be something we will be managing in Louisiana also. The first step is to learn to properly identify the pest.

There are a few key characters that will get you most of the way toward identification, but to truly confirm the species you need to view it under a dissecting microscope. If you find specimens that you strongly suspect are MRB you can send them to me and we will confirm the identification. Following are two pictures taken by Anna Meszaros that illustrate the key character used to separate MRB from the rice stalk borer.

1, the color of the hairs:

MRB: light hairs

RSB: dark hairs

2, on the meso-and metathorax of the larva (right above the “prolegs”)

MRB has only one seta (hair)

RSB has two setae.

Mexican rice borer larvae - note the honey colored head capsule and the presence of a single seta (hair) on the meso and meta-thorax dorsal (above) to the proleg. Photo by Anna Meszaros.

Rice stalk borer larvae - note the dark brown head capsule and the presence of two setae (hairs) on the meso and meta-thorax dorsal (above) to the prolegs. Photo by Anna Meszaros.

For more information please refer to this publication: KEY TO SELECTED PYRALOIDEA (LEPIDOPTERA) LARVAE INTERCEPTED AT U. S. PORTS OF ENTRY: REVISION OF PYRALOIDEA IN “KEYS TO SOME FREQUENTLY INTERCEPTED LEPIDOPTEROUS LARVAE” BY WEISMAN, 1986, M. ALMA SOLIS

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It’s funny how when you work a field crop, life eventually moves in a pretty predictable cycle. Well, it’s that time of year again. Time to start scouting for rice stink bugs in headed rice, although it does seem to be coming a little bit earlier than usual. This is probably a result of very early planting of rice in some parts of south Louisiana. Unfortunately, field conditions are favoring a bad year for stink bugs. The drought conditions have killed off grasses that would normally serve as a host/reservoir for stink bugs, so there is a chance they will move more readily into heading rice. Recent reports from Arkansas and Mississippi indicate that large populations of rice stink bugs are present in the mid-south. We are already finding them in headed rice fields at the rice research station in Crowley, La.

Last Friday, Johnny Saichuk and I scouted a variety trial in Vermilion Parish where the CL111 was heading first and was already infested with rice stink bugs.

Rice stinkbugs are light tan in color with points on the corners of the pronotum.

I received a call about the field because they noticed quite a bit of blanking in the panicles. They also found a high population of grasshoppers and suspected they may have been causing injury.

Longhorned grasshopper adult in heading rice. You can tell it is an adult because of the wings.

When we assessed the situation, Johnny determined that the blanking was most likely physiological, some sort of effect of weather conditions when the rice was at panicle development (pd). You can read more about it in his field notes. If you don’t receive Johnny Saichuk’s Field Notes via e-mail, please send Johnny an e-mail to be added to his list: jsaichuk@agcenter.lsu.edu. As we examined the grasshopper situation, we found that the grasshoppers were long-horned grasshoppers, which are typically predators. We would not recommend treating for grasshoppers unless they are causing excessive defoliation. Click here to read more about long-horned grasshoppers in rice. Odds are that they were attracted by the rice stink bugs, which we did find to be abundant in the field. We advised holding off on an insecticide application until the rice reached 50% heading. It is very tempting to put out a pyrethroid with the fungicide application at early-heading, but research has shown that this is too early to prevent injury. Putting out an early application will probably just add to the number of times you need to spray the field, while not providing any additional protection. To learn more about rice stink bug management click here.

We have a graduate student, Bryce Blackman, who is currently studying rice stink bugs for his dissertation research. One aspect of his work is to re-evaluate treatment thresholds. At the moment, we continue to use the standard recommendations. To scout for rice stink bugs in the field, use a 15-inch diameter sweep net, take 10 sweeps at 10 different areas around each field. Count the number of bugs collected after every 10 sweeps. In the first two weeks of heading, treat fields when there are 30 or more bugs per 100 sweeps. Pesticides that can be used include malathion, methyl parathion and a variety of pyrethroids including Declare, Karate Z, Mustang Max, Prolex and a number of generics. From the dough stage until two weeks before harvest, treat fields when there are 100 bugs per 100 sweeps. When approaching two weeks before harvest, you can treat with any of the chemicals listed above with the exception of Karate Z and Prolex, which have 21 day pre-harvest intervals. You can learn more about rice stink bug biology by clicking here.

Resistance to pyrethroids has been increasing in Texas, and there is a chance that we could have some issues with resistance developing in Louisiana also. If you have a field where you are finding it particularly difficult to control the rice stink bugs with your traditional control strategies, please contact me so we can sample the insect population. If you have further questions about rice stink bug management, please contact your local County Agent.

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Dr. Saichuk sent out this message today:

The rice blog page I mentioned some time ago is finally up and running.  I have posted all 2010 editions of Field Notes on it.  However, because of the nature of the blog program it is abbreviated in comparison the Field Notes I send out via e-mail.  I will continue to do both.  Some of you may like the format in the blog and others may want the detail of the other form.  Until I learn the tricks of labeling the photographs in the blog I will have to just try to explain them a little better on the blog.

 The blog address is: www.lariceman.wordpress.com.

Let me know if you have any problems accessing it.  There is a way on the blog page to sign up to be notified via e-mail when one has been posted.  Some of you may like that feature especially if you are using portable devices in the field.

 I may also use the blog page to send out something urgent in between regular Field Notes editions so check it out and let me know what you think.

 Johnny

 John K. Saichuk, Ph.D.
LSU AgCenter Extension Specialist
Southwest Region
1373 Caffey Rd.
Rayne, LA 70578
Office: 337-788-7547
FAX: 337-788-7553
Cell: 337-849-6253

Rice Web Page:  http://www.lsuagcenter.com/en/crops_livestock/crops/rice

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