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Archive for the ‘Insect alerts’ Category

I had planned to write about rice stink bugs today, but something else came up during our field work. Yesterday, at the Simon field site tour stop, Mr. Eddie Eskew told me about a field of rice that was suffering from a severe infestation of armyworms. Up to this point in the season, I’ve had a few calls about armyworms, but nothing out of the ordinary. We wanted to collect caterpillars to add to our lab colonies on campus, so we headed to the field today. I thought you would like to see what can happen when armyworms march across a rice field.

Last week this field of XL729 was progressing nicely. You can see in this picture how nice the surrounding fields are looking.

Field suffering from armyworm infestation to the left of the levee and a healthy field to the right of the levee.

The grower called Eddie on Tuesday when he found armyworms infesting the field. They had marched in from the tree line on the edge of the field and quickly progressed across to the field road. No appreciable damage was observed in surrounding cuts, although we did notice birds in a neighboring field, which were probably feeding on armyworm caterpillars.

Cattle egrets (the white birds) and "trash birds" (the black birds) as they are called by my student worker. Birds are a good indication of an insect infestation.

When we pulled up to the field it was not hard to observe the significant injury the armyworms were causing to the plants.

Eddie Eskew (G&H) collecting armyworm caterpillars in an infested field.

This particular field was planted in late April with the intention to harvest a rice crop. It will also be stocked with crawfish for harvest next spring. This creates complications when it comes to pest management. Insecticides which would effectively control the armyworms will be toxic to crawfish. For this reason, we cannot recommend any insecticides for control. If the armyworms were younger (most were large and probably near pupation) we would consider using Bt to control the population. The only measure that can be used is to bring flood water and drown them out. In this field, water had been on the field for about 48 hours and many of the caterpillars were still feeding on plants. On the positive side, they no longer had access to the crown of the plant. This is important for a rice plant because the leaves arise from the crown. You can think of this as being similar to your lawn. You can hit it with a mower and it will regrow every week (if we get any rain). This is also true for rice. Ideally we would not be mowing the rice plants, the plants that survive will likely be stunted. We collected some caterpillars to add to our lab colony. There is a good chance that most are either parasitized or will die of disease. This is what we typically find in field-collected armyworms. Unfortunately, the naturally occuring pathogens and parasitoids that attack armyworms in the field usually do not act quickly enough in a rice field to provide natural control and prevent severe injury. Following is a series of pictures of the field injury and caterpillars in the rice.

Field of XL729 that is suffering from an armyworm infestatiohn. The armyworms have been in the field for about 72 hours. Flood was applied about 24 hours after the initial infestation.

 
 

Many armyworm caterpillars feeding on a rice plant.

 

The armyworms were clustered onto the stubs of the plants mowing them down to the surface of the water.
On our way to the field I received a call from Kent Guillory, a consultant in Evangeline Parish, who also was treating a field infested with armyworms. I’d deduce from these two calls, that it is now time to start keeping an eye out for armyworms. You can see from our observations at this field that they can move in and cause significant injury in as little as a day. If you can preserve the crown of the plant it should be able to recover.
 
Tomorrow we will discuss rice stink bug infestations and management recommendations.
 
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The Mexican rice borer (MRB) has now been found near Lake Charles, LA.  This link will take you to an LSU AgCenter press release that provides the latest update: http://www.lsuagcenter.com/news_archive/2011/may/headline_news/Mexican-rice-borer-advances-in-La.htm

Fortunately, LSU AgCenter Professor Gene Reagan has conducted intensive research on this pest for the past ten years, and we are prepared with management options in hand and ready to use as needed.  He has provided an Agent training in Texas for a number of years.  Following is a link to a blog posting about the most recent site visit.  Within the blog you will find a link to the handout, which contains information on recent management recommendations:

https://louisianariceinsects.wordpress.com/2010/10/01/lsu-agcenter-mexican-rice-borer-site-visit-beaumont-tx/

It is important that you learn to identify this pest, and distinguish it from other borers that can be found in rice or cane. You can study up on the pest by downloading these two LSU AgCenter numbered pubs:

This publication includes images of SCB and MRB for comparison:

http://www.lsuagcenter.com/en/communications/publications/Publications+Catalog/Crops+and+Livestock/Rice/Rice+Pests+of+Louisiana.htm

This publication provides images of MRB:

http://www.lsuagcenter.com/en/communications/publications/Publications+Catalog/Crops+and+Livestock/Rice/Mexican+Rice+Borer+Identification+Card.htm

Following is a Louisiana Agriculture article that includes the latest information on MRB research that has been generated by Dr. Reagan’s lab:

http://www.lsuagcenter.com/en/communications/publications/agmag/Archive/2010/fall/Advanced-Management-Research-and-the-Mexican-Rice-Borer.htm

In sugarcane, there are a number of recommended management practices to prevent injury from MRB.

In rice, the seed treatment Dermacor X-100 should provide control of this pest. Pyrethroids can also be used, but timing of application is critical. It is necessary to detect an infestation when larvae are still feeding in the sheath area. Once the larvae penetrate the stem, pyrethroid insecticides will not provide acceptable control because they are not able to come into contact with the larva.

If you find a larvae in rice or cane and suspect that it is MRB, please call me and we can arrange to pick up the sample.

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On Friday, Nick and I made the trek to West Carroll Parish in north Louisiana to scout a rice field that Richard Costello had called me about on Thursday. The field was initially thought to be suffering from herbicide drift injury.

Field infested with thrips.

LSU AgCenter County Agent Myrl Sistrunk had called Weed Scientist Bill Williams out to investigate. Upon a detailed inspection they found a damaging infestation of thrips.

The thrips could easily be found on virtually every plant we inspected. The best scouting method for thrips is to visually inspect plants. The thrips were often found on the leaf sheath near the collar or inside the leaf sheath.

Thrip on leaf blade near collar - this is a typical location to find them on the plant.

They will quickly run/hop when disturbed. You can also tap plants onto a white sheet of paper and look for the thrips on the paper.

Thrip on rice leaf blade.

I learned first-hand that they will in fact “bite” you with their rasping mouthparts. They annoyed us for most of the ride home. Thrips injure plants by using a scraping mouthpart to macerate (tear) the leaf tissue. They then extract the plant liquids. This causes desiccation and would typically not be a problem, except for the dry, windy conditions we are experiencing this season.

Thrip feeding injury on a rice leaf. In many cases there were streaks of white near the leaf tip.

I have not had the chance to confirm the species yet, but it looks like they may be tobacco thrips. The infestation and plant damage in this particular field is disconcerting because the field is CruiserMaxx treated hybrid planted at a 25 pound seeding rate. The situation is complicated by the fact that the field has received about 10 inches of rain since planting. This was received in five separate rain events.

 The field started to head south after a flush was applied about a week ago. At this point the field is very dry and plants appear to be desiccating and stressed from the thrips feeding on the leaves. The field isn’t ready to hold a flood yet. We could not find any natural enemies in the field, and due to the ongoing injury caused by the thrips feeding I recommended a pyrethroid application to knock back the thrips population and buy some time before flood.

Also, the lack of apparent activity against the thrips caused some concern about the ability of the CruiserMaxx to provide effective control of rice water weevil larvae after application of permanent flood.  They may consider a second application of pyrethroid at permanent flood if weevil adults are present in the field. Overall the field still has a good stand of rice, which appears to be thicker than many hybrid rice fields I have scouted this season.

On our way back to Baton Rouge we took the levee road and witnessed the Morganza Spillway flooded with water.

You can see in this picture how close the water came to the top of the levee - just south of Vidalia, north of Blackhawk Farm.

We also saw some deer grazing in a soybean field that was mostly flooded. If you’ve read Johnny Saichuk’s field note for this week you’ll notice that we observed the same herd of deer. Apparently they are well-settled in this field. It looks like whatever the water doesn’t take, the deer will finish off.  

I have more pictures to share, but I don’t have the files with me at the moment.

Also, this week I had reports of sugarcane beetles, armyworms, chinch bugs, and colaspis in Louisiana rice. Many of these early-season insect pests should go away as we approach permanent flood. Then we’ll need to make sure good plans are in place for rice water weevil management.

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I had more calls this week about sugarcane beetles, chinch bugs, colaspis and bill bugs in rice in Southwestern Louisiana. In the majority of these fields, no insecticide seed treatment had been applied to the seed. The best response is to bring a flood as soon as possible. If this isn’t possible, some crop advisors have reported substantial improvement in the stand following  a pyrethroid spray and holding a light flush for a couple of days.

If you’d like to see a video of a sugarcane beetle digging back into the soil after I removed it from the soil you can click here. Thanks to Extension Entomologist Kathy Flanders at Auburn University for posting the video on my behalf. I shot this video at a field we scouted with Barrett Courville and Benet Augustine last week.

After doing more research on the bill bugs we collected, we found that we have not one, but four species of bill bugs that were collected from a single field. We are doing more work to tease out the species complex that occurs in south Louisiana. If you find any bill bugs in rice please get them to your local county agent and ask them to deliver to me. You can simply throw then in a ziploc bag and kill in the freezer. Please write the farmer name (or some other way to note the field location) and date on the bag. If you can record gps coordinates and e-mail to me that would be a real help. 

Update on the LSU AgCenter rice water weevil demonstration test:

We planted our final field location in Avoyelles Parish on April 27, 2011. We have a stand of rice and will take data on the stand on May 23, 2011. The majority of our other demonstration locations are at or near permanent flood. We will be running around pulling core samples from all the locations in the middle of June. To learn more about rice water weevil biology and our sampling methods you can watch this video

Field meeting season will kick off soon.

Please mark the following dates on your calendar:

June 1, 2011: Rice field tour in Welsh, LA. I will post an agenda soon. I’ll be in hand to discuss rice insect management and field observations.

June 15, 2011: LSU AgCenter South Farm Tour in Crowley, LA. We will have a meeting at our rice water weevil demo test site on the Simon Farm, which will include a sponsored lunch (Special thanks to our sponsors: John Bordlee – Valent; Toby McCown – Dupont, and Josh Zaunbrecher – Syngenta). 

June 30, 2011: LSU AgCenter Rice Research Station Field Day in Crowley, LA.

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 I had some technical difficulties with the blog last week, so this posting is a little delayed.  Also, before you get into it, I’d like to talk about more insect problems. The dry conditions are continuing to create headaches. I’ve had about 5 more calls about chinch bugs, rice levee bill bugs in rice. Some are reporting successful control with a spray of pyrethroid to control the insects. I would caution you to avoid using an insecticide unless you can confirm the presence of the insect causing injury. There are some mystery problems out there and it is easy to blame insects in some cases.

 

The bottom line is that if you can’t find any insects causing injury, then there is no point paying for an insecticide application.I know it is hard to scout in the wind and the dry conditions. Scouting early in the morning will increase your chances of finding chinch bugs in rice. Also, scouting the vegetation of the edges of the field – particularly sweeping grasses with a sweep net – is another good scouting method for chinch bugs. Tomorrow we will be in Vermilion Parish for a morning meeting and a walk with Dr. Saichuk at the verification field. In the afternoon, we will head to Jefferson-Davis Parish to scout some of these fields that are/have suffered injury from chinch bugs, rice levee bill bugs, and/or colaspis.

 
St. Landry Parish Vince Deshotel and Anna taking plant heights.   
 

 

St. Landry Parish rice water weevil demonstration site field map.
 
After we found colaspis in Jefferson-Davis Parish last week, we headed over to St. Landry to take stand data at Charlie Fontenot’s farm. We met with Valent company representatives Karen Arthur, John Bordlee and Bill Odle to discuss this location and the other sites.  Charlie Fontenot, Crop Consultant Dean Reed and County Agent Vince Deshotel also met us at the field. We did not notice any obvious visual differences between treatments, but all treatments looked a little better than the untreated. We will report the overall stand observations once we have take data at all sites.  

 
 
 All plots are marked with colored flagging, so feel free to contact County Agent Vince Deshotel if you’d like to drive by and visit the test site.

 

Bill Odle, Dean Reed, John Bordlee and Charlie Fontenot examining the stand at the St. Landry Parish demo location.

 

Plants grown from NipsitInside to the left and Dermacor X-100 to the right.
Plants grown from untreated rice seed to the left and CruiserMaxx treated plants to the right.

 We intend to plant our last site – located in Avoyelles Parish – on Wednesday. We will take stand data at the Calcasieu site on Thursday. Busy week of field work ahead!

 

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This morning I admired the moon setting over University Lakes on my way into campus. Wait a minute, I was biking into campus by moonlight? Yep, a sure sign of field season – early mornings and long (but exciting) days. Today we headed down to Jefferson-Davis Parish to scout a couple of fields that were suffering from stand loss due to an unknown cause. In one location we are still trying to determine the cause. In the second field we scouted we confirmed a fairly severe colaspis infestation. We met with Farmer Kyle Fontenot, Consultant Ron Smith and Nicky Miller at the field which is located between Hathaway and Elton.
 

Kyle Fontenot, Anna, Nicky Miller, and Ron Smith. Note that Kyle and Nicky were both on their iPhones connecting with me on the blog and facebook.

 
Within a few minutes of digging we had no trouble finding many plants with colaspis larvae feeding on the roots, causing the plants to decline and eventually die.

Stand reduction in a hybrid rice field that was caused by colaspis larvae feeding on the roots of the plants.

 

We typically found the larvae on dying plants approximately 2 inches below the soil line.
A colaspis larva.
A colaspis pupa near the tip of a knife blade to give you an idea of the size.
 

 

It is worth noting the history of this particular field. In 2010 it was used as cattle pasture. To prepare the field for rice, the farmer plowed in the fall, burned the vegetation (with fire) in December/January, then plowed again, and finally plowed, shanked, and fertilized before planting. Rice was broadcast and then packed. The planting method made it even harder to determine the cause of injury because we did not observe the typical loss of plants along a drill row that we have seen in the past with colaspis infestations.

Visit this website for more information on the biology and scouting for colaspis in rice: http://www.lsuagcenter.com/en/crops_livestock/crops/rice/Insects/LSU+AgCenter+Rice+Training+Session+How+to+Scout+for+Grape+Colaspis+in+Rice.htm

This field was planted with hybrid rice seed that was treated with Apron, Maxim, Dynasty and Dermacor X-100. Dermacor has a registration for suppression of colaspis and previous research has indicated it will provide about 40% control. It is possible the injury would have been worse without the Dermacor X-100 treatment. If CruiserMaxx or NipsitInside would have been used, then we probably would not have experienced this much stand reduction. Dermacor was selected because of the history of rice water weevil pressure at the field site. It was determined that a replant was not necessary. At this point, the only option is to bring a light pin-point flood to hopefully stop the feeding of the colaspis larvae and prevent further injury of the rice.

I suspect that the colaspis problems may be more widespread. After they left this field Ron Smith called to say that they also found colaspis in another nearby field. I’ll be back down that way next week to further investigate the situation.

 

 

 
 

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I knew my phone was too quiet last week…

Today I’ve have four calls about insect problems in rice. Yesterday I ran the battery down on my phone between phone calls, e-mails and tweeting field observations. Which reminds me, if you are using twitter, you are welcome to follow me @NatHummel for field updates.

These dry conditions are exacerbating problems in drilled rice, which in many cases is dry, dry, dry. We need some rain. The wind is not helping the situation. One consultant, who has decades of experience in rice, called today to tell me he would appreciate more training in identification of uncommon insect problems – namely aphids, thrips and chinch bugs. As we shift away from water-seeded to drill-seeded rice these insects have the potential to become more common pest problems. It looks like that might be happening this year.

This blog posting will focus on many of those “secondary pests” which we happened to observe in Evangeline Parish yesterday. Before I get to that, just a quick update on what is becoming the chinch bug situation.

In Jeff-Davis Parish I have now heard of four additional locations which suffered from infestations of chinch bugs. This brings the count to about 8 to 10 sites with chinch bugs infestations. Some had been treated with Dermacor X-100, but remember Dermacor will not control chinch bugs. CruiserMaxx and NipsitInside should provide control (refer to previous postings about difference in seed treatments for more details). It has been noted that drilled hybrid rice, planted at low seeding rates, needs to be carefully scouted for chinch bugs. This is true primarily because in a field with a low seeding rate, the number of plants per acre is substantially lower than in field planted at a conventional seeding rate. When an insect (such as chinch bugs) infests a field with few plants to begin with, they can cause substantially more injury more quickly than in a field with a thicker stand.

Chinch bugs can be difficult to scout because they have a habit of hiding in cracks during the heat of the day and also because they often feed at the soil line near the base of the plant. This injury caused by feeding on the heart of the rice plant is what causes the rice to throw a red or orange leaf and eventually die from injury. To treat an infestation it is best to apply a flood or flush water across the field and then follow with a pyrethroid insecticide – this strategy drives the insects up onto the plant allowing them to be exposed to the insecticide.

You can click on the pictures to make them larger.

In Evangeline Parish we found a few chinch bugs feeding on the plants.

Chinch bug near base of rice plant.

 We also found a mating pair of chinch bugs on the soil surface between the rows.  Just to illustrate how difficult these can be to scout, can you find the chinch bugs in this picture?

Chinch bug mating pair on the soil surface.

 As I was taking pictures, they shifted position – here is a close-up.

Chinch bug mating pair.

After mating, chinch bugs will deposit eggs, from which first instar nymphs will hatch. We did see some first-instar chinch bugs near the base of the plant.  The first instars look very different from older stages – are very small and bright orange in color.  Here is a composite picture from my files for your reference – these pictures were taken in Jeff-Davis Parish a couple of years back.

 

Yesterday, Anna and I took stand data at the Evangeline Parish Demo test site.  Here is the field map. (I’m in the process of building LSU AgCenter websites for each of the test sites, but suddenly time at my desk is precious and rare). The field is located between Ville Platte and Vidrine at these GPS coordinates: 30°41’42.66″N, 92°24’23.80″W. The plots are flagged with colored flagging according to treatment.

The variety XL745 was planted at a 25 pound/acre seeding rate on March 21, 2011.  First emergence was noted on April 5, 2011. Yesterday, we visited the site two weeks after emergence to take observations on the stand. At this location we are comparing the three seed treatments (CruiserMaxx, Dermacor X-100 and NipsitInside) to an untreated check.

In general, there does not appear to be a significant difference between treatments, but the untreated cuts do not look quite as vigorous.  We will wait to summarize all the stand count data from all sites before making definitive statements about any effect of seed treatments on the stand vigor. Following is a series of field shots comparing the treated strips.

 

Plants grown from Dermacor X-100 treated seed to the left and CruiserMaxx treated seed to the right.

Plants grown from NipsitInside treated seed to the left and Dermacor X-100 treated seed to the right.Plants grown from untreated seed (fungicide only) to the left and NipsitInside treated seed to the right.

Plants grown from Dermacor X-100 treated seed to the left and untreated seed to the right.

Plants grown from NipsitInside treated seed to the right and Dermacor X-100 treated seed to the left.

Plants grown from CruiserMaxx treated seed to the left and NipsitInside treated seed to the left.

Plants grown from untreated seed to the left and CruiserMaxx treated seed to the right.

As we walked across the field site we noticed many fire ants and also parasitoid wasps, which led us to believe there must have been some insects in the field that these predators/parasitoids were consuming.  Sure enough, after some searching we started to find aphids, thrips and chinch bugs.  None are present at levels that are causing noticeable injury in the plots, but we will certainly keep an eye on the populations.

 

Fire ants foraging in the Evangeline Parish test site field.

In this situation, the fire ants are helping us by eating some of the insects that are attacking the rice – including aphids, thrips, and possibly chinch bugs. Of course, they also took a couple of bites out of me  as I was attempting to take picture in the windy conditions at the field. 

Fire ant foraging for insects infesting a rice plant - in this case, it looked like it was searching for thrips.

 

Thrip on a datasheet after it hopped off a rice plant. The datasheet is printed in 10 pt font, so you can see the miniscule size of the thrip adult.

Thrip adult on a rice plant leaf blade - we commonly found them on the blade or in the leaf sheath area. It appeared that feeding injury was causing discoloration on the sheath, but this was not confirmed.

 

We found a few aphids on some of the plants. It is likely that populations would be higher if they were not being attacked by ladybugs.

Ladybugs were also present in the field eating the aphids.

 The herbicides had not gone out yet, they will probably go out today, and so we took a few moments to enjoy a sweet gift of nature – wild blackberries on the edge of the field.

Anna picking blackberries during lunch break – ah the sweet rewards of field work…

Tomorrow we will make some site visits in Jeff-Davis where possible colaspis injury has been reported. In the afternoon, we will head to St. Landry Parish to take stand counts at our demonstration site.

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