Archive for April, 2010

I put on my rubber gloves and slipped back into the role of insect physiologist for about an hour today.  A graduate student that Mike and I are co-advising is doing some research on the effect of rice insecticides on crawfish.  Srinivas is recording mortality in the field (at the rice station in Crowley).  Hes is also studying the effect of insecticides on the crawfish internal organs.  We had a little dissection lesson today.  Wow, dissecting a crawfish is so much easier than my USDA job where I dissected the brains out of ticks.  The large size of the crawfish makes this job pretty easy.  The ticks I used to dissect, all day long, were smaller than the eye of this crawfish. 

The inside view of a crawfish, before it is boiled.

Interestingly, that orange-yellow structure (that I always thought was fat body) is the tasty part if you like to “suck the head” when eating crawfish.  In fact, that is not fat body, but is called the hepatopancreas.  If you’d like me to label the rest of the structures, send me a message and I’ll add the labels.


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After wrapping up at the Hoffpauir farm, Barrett and I headed over to Jeff-Davis Parish to take stand counts at the demonstration that Mark Pousson has planted.  The rice is coming along nicely.  At this location, the seed treatments are planted side-by-side in the same cut.  This allows us to easily observe any differences in plant height, vigor, or stand thickness between treatments.  As we were taking stand counts, Barrett observed that if you stood on the edge of the field you could easily see a difference between the untreated seed and the CruiserMaxx treated seed.  I took a few pictures.

Rows of rice grown from untreated seed (no insecticide treatment) in comparison to CruiserMaxx treated seed. The rows are much more visible in the CruiserMaxx treated area.

In the picture above, the untreated area is to the left of the center, while the CruiserMaxx treated plants are to the right.  We don’t know if this will translate to a difference in yield, but it is interesting to note the difference in plant vigor in the early season.

While walking through the field, we also noticed some interesting clusters of eggs.

Egg mass in the water.

Barrett held the egg mass in his hand for a closer look.

I’m not sure if these are frog eggs, but that’s what they look like.  This is a nice reminder of the important job that rice fields serve as a home for a variety of wildlife.  It’s a great working environment for a weekend naturalist.

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Yesterday Barrett Courville and I took stand counts at the Hoffpauir Demo location that is just southwest of Rayne, La (Acadia Parish).  Boy, it was another beautiful day here in south Louisiana!  The fields are coming along well.  We took stand counts and plant height measurements in Dermacor X-100, Cruiser-Maxx and one untreated cut.  We will be entering and analyzing the data soon.  In the meantime, here are some pictures of the fields. 

Plants grown from Dermacor X-100 treated seed.

Plants grown from CruiserMaxx treated seed.

Plants grown from seed that had fungicide, but no insecticide seed treatments. The flush was starting to move across this field.

The next step with this field will be to scout for rww adults in the days leading up to permanent flood.  If rww adults and scarring are found in the field, we will apply a pyrethroid to two of the cuts at the eastern end of the series of cuts.

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Last Friday we took stand counts at the Morein Farm in Evangeline Parish.  This site is located on Miller Lake Road in Ville Platte.  It was selected because neighboring fields suffered a stand reduction due to colaspis larvae feeding on the seedling rice in the 2009 field season.  These particular fields were planted into fields where soybeans were grown last season.  There was no apparent visual difference between the treatments at this time.  The untreated area has a little thinner stand.  

Stand of rice grown from CruiserMaxx treated seed.

Plants grown from Dermacor X-100 treated seed.

Plants grown from seed that did not have an insecticide seed treatment. To the left of the white flags, are CruiserMaxx treated plants.

We did not observe any damage from colaspis.   The stand counts were taken 2 weeks after emergence.  The rice is growing strong.  To measure the stand emergence, we started in one corner of the field and then walked 11 paces between five different spaces in the field.  We measured 6 feet of drill row, counted the number of plants and took the height of 10 plants. The stand count data will be analyzed soon.

Dennis Fontenot and Anna Meszaros recording stand counts and plant height in the CruiserMaxx treated field.

Dennis will continue to closely monitor this field and let us know if any damage from colaspis begins to show up.  Last year, the first reports occurred in mid-May.

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On Friday we met with Stuart Gauthier and Alden Horton to scout for adult rice water weevils at the Vermilion Parish water-seeded test site.  This field is making good progress, and has an excellent stand, for the most part.  

We have a healthy water-seeded stand of rice.

  One of the high parts of the field had poor emergence due to a combination of dry soil and water mold. 

Standing in the thin stand of the field and looking to the nicely growing portion.

Some of the seeds germinated and then dried-out.

The un-emerged seeds, with the dark brown ring around them, were killed by water mold.

We visited the field to make a decision about rww insecticide applications.  We scouted ten sites in the field for the presence of rice water weevil adults and feeding scars.  We did not find any rww adults or feeding scars.  The decision at this time was to hold off on an insecticide application and scout again for adults or scarring before the final application of newpath on Friday.

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Today we met with cooperators in St. Landry to look at the differences in stand emergence between the insecticide treated (Dermacor X-100, CruiserMaxx) and non-insecticide treated seed (fungicide only).  This location is a joint effort between LSU AgCenter, Horizon Ag, DuPont and Syngenta.  We are evaluating CL151 planted at a variety of seeding rates (#40, #55, #65, #70, #85, #100).     

Dermacor X-100 treated seed to left of flag, untreated seed (fungicide only) to right of flag.


 There was no noticeable difference between the Dermacor X-100 and CruiserMaxx treated seed.  These were both planted at 65 lbs per acre.     

Dermacor X-100 treated seed to the left of flag, CruiserMaxx treated seed to the right. No visible difference in stand at this time.


 CruiserMaxx is applied at 3.3 fl oz/100 lbs seed, regardless of seeding rate.  One of the objectives of this test is to confirm that CruiserMaxx provides the same level of rww control at low and high seeding rates.  The seeding rates that we are evaluating include the following: 40, #55, #65, #70, #85, #100.  At this point, there is no real visible difference in stand, except when comparing the high (#100) to low (#40).    

CruiserMaxx treated CL151 - plants are just beginning to emerge from the ground. Planted at 40 lbs/acre.


CruiserMaxx treated CL151 seed planted at 100 lbs/acre.


 We dug around in the untreated area for a little while to see if we could find colaspis larvae feeding on the roots.  We did not find any today.  We’ll return to take stand counts in about two weeks.  These first few weeks of the test are critical for detecting colapsis damage, if it occurs.    

Scouting for colaspis in untreated check area.


In the above picture, Dermacor X-100 treated seed is to the LEFT of the white flag.  Untreated area is to the right of the flag.

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When I was scouting for aphids in Ville Platte, I was surprized to observe rice water weevil adult scarring on the seedling rice.

Rice water weevil feeding scars on a rice leaf blade.

Close-up shot of rice water weevil adult feeding scars on rice.

This was observed at the LaHaye rww demonstration site in Ville Platte, La (Evangeline Parish).  These fields are a perfect location for weevils for a couple of reasons: 1) they are near a lot of bayou areas and 2) the field is bordered by a break of trees – nice overwintering habitat for weevils.  It’s not suprising that we are finding rww in these particular fields, but a little surprising to see adults are already moving into fields even in this cool weather.  I would encourage you to start scouting for weevil now, particularly in rice that is currently under pin-point flood, or will be flooded soon.  If adults are entering your field, and the rice is flooded, then egg laying can begin to occur early in the season.  The application of a pyrethroid early in the season is a judgement call that you will have to make based on your observations scouting.

Rice water weevil adult - LSU AgCenter photo.

If you planted seed treated with either CruiserMaxx or Dermacor X-100 seed treatment, then you do not need to make an insecticide application for rice water weevil management.  You do, however, need to scout for other early-season pests, such as aphids, chinch bugs, south american rice miner, leafminers and fall armyworm. 

CruiserMaxx should control the following early-season pests: aphids, chinch bugs, rice water weevil adults and larvae.

Dermacor X-100 should control the following early-season pests: south american rice miner, leafminers, fall armyworm, and rice water weevil larvae.

For pictures of these early-season pests, please refer to the Louisiana Rice Production Handbook by clicking here.  For management recommendations please refer to the Rice Varieties and Management Tips by clicking here.

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