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Updated Redbanded Stink Bug Threshold in Soybeans

Updated Redbanded Stink Bug Threshold in Soybeans published on No Comments on Updated Redbanded Stink Bug Threshold in Soybeans

The LSU AgCenter has revised the redbanded stink bug threshold in soybeans from 6 per 25 sweeps to 4 per 25 sweeps. The 2013 Louisiana insect management guide has the threshold listed as 6 per 25 sweeps, please use the revised threshold of 4 per 25 sweeps when making application decisions.  The LSU AgCenter is in a transitional phase between publication times of the  insect management guide and the revised threshold will be in the 2014 edition. We are sorry for any confusion this may have caused.

For more information or if you have any questions or concerns please contact Sebe Brown, or Drs. David Kerns , Julien Beuzelin or Jeff Davis.

Sebe Brown   Cell: 318-498-1283   Office: 318-435-2903

Dr. David Kerns   Cell: 318-439-4844    Office: 318-435-2157

Dr. Julien Beuzelin   Cell: 337-501-7087  Office: 318-473-6523

Dr. Jeff Davis  Cell: 225-747-0351    Office: 225-578-5618

Unconfirmed Report of Kudzu Bugs in Madison Parish

Unconfirmed Report of Kudzu Bugs in Madison Parish published on No Comments on Unconfirmed Report of Kudzu Bugs in Madison Parish

I received an unconfirmed report of kudzu bugs in soybeans in Madison Parish, Louisiana near Mound this evening. David Kerns and I will be in the field first thing tomorrow morning to confirm this report. Please stay tuned for details.

Soybean Insecticide Formulation, Rate and Pre-harvest Intervals

Soybean Insecticide Formulation, Rate and Pre-harvest Intervals published on 2 Comments on Soybean Insecticide Formulation, Rate and Pre-harvest Intervals
Soybean Insecticide Formulation, Rate and Pre-harvest Interval
Soybean Insecticide Formulation, Rate and Pre-harvest Interval

Beware, generics were not included in the above list, rates and formulations may be different. 

If you have any questions or concerns please contact:

Sebe Brown   Cell: 318-498-1283   Office: 318-435-2903

Dr. Jeff Davis  Cell: 225-747-0351    Office: 225-578-5618

Dr. David Kerns  Cell: 318-439-4844    Office: 318-435-2157

Dr. Julien Beuzelin Cell: 337-501-7087  Office: 318-473-6523

Redbanded stink bug nymph

Soybean Loopers and Redbanded Stink bugs in Soybeans

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Lately I have been receiving more calls about soybean loopers and redbanded stink bugs in late soybeans. Soybean loopers are late season pests that usually do not arrive in large numbers until August. These defoliating insects are often intensified by the use of broad-spectrum insecticides for control of three-cornered alfalfa hoppers and redbanded stink bugs. These applications effectively sterilize soybean fields; this often includes natural enemies which can keep soybean looper populations in check.  The threshold for soybean loopers in Louisiana soybeans is 8 worms ½ inch or longer per row foot or 150 worms in 100 sweeps.

Soybean looper immature
Soybean Looper: Photo by LSU AgCenter

Soybean loopers have developed resistance to many insecticide chemistries and effective control measures are primarily limited to lepidopteran specific insecticides. However, the LSU AgCenter Soybean Entomology Lab (under the direction of Dr. Jeff Davis) has documented soybean looper insecticide resistance to methoxyfenozide (Intrepid 2F) in areas of North and South Louisiana. Rates of Intrepid below 6 oz/acre and prophylactic applications, with a fungicide, before the presence of loopers are not recommended. Belt (2-3 oz/acre) and Steward (5.6-11.3 oz/acre) are effective in controlling soybean looper populations with Belt providing residual efficacy of 14 days or more depending on application volume and rate.

Redbanded stink bugs have become the dominant stink bugs species in Louisiana

Redbanded stink bug adult
Redbanded Stink bug Adult: Photo by LSU AgCenter

soybeans. Redbanded stink bugs are part of a complex of pod feeders that feed directly on soybean seeds reducing seed size, quality and yield. This pest is more difficult to control than other stink bug species often requiring 3-5 insecticide applications. Pyrethroid efficacy against redbanded stink bugs has declined in recent years resulting in the use of tank mixes and premix applications. The threshold for redbanded stink bugs in Louisiana soybeans is 24 bugs in 100 sweeps. Endigo and Leverage 360 have demonstrated satisfactory control of redbanded stink bugs as well as tank mixes of acephate plus a pyrethroid. Beware only 1.5 lbs of acephate can be applied per crop per season for soybeans. Redbanded stink bugs are strong fliers and re-colonization after an insecticide treatment may occur quickly.

Redbanded stink bug nymph
Redbanded Stink bug Nymph: Photo by LSU AgCenter

Routine scouting is required for both of these insects in soybeans. The flighty nature of redbanded stink bugs and large populations of soybean loopers can result in significant yield losses if populations are allowed to increase unchecked.

For more information or if you have any questions or concerns please contact Sebe Brown, or Drs. Jeff Davis, David Kerns or Julien Beuzelin.

Sebe Brown   Cell: 318-498-1283   Office: 318-435-2903

Dr. Jeff Davis  Cell: 225-747-0351    Office: 225-578-5618

Dr. David Kerns  Cell: 318-439-4844    Office: 318-435-2157

Dr. Julien Beuzelin Cell: 337-501-7087  Office: 318-473-6523

Richland Parish Soybean and Corn Update

Richland Parish Soybean and Corn Update published on No Comments on Richland Parish Soybean and Corn Update

Corn yields in Richland Parish continue to be good.  With 40-50% of the corn harvested, we are averaging 10-15 bushels per acred higher than last year. We had corn planted into late April so some producers have not started harvesting yet while others have completed harvest or will be in a day or so.

Soybeans planted in late March and early April are being harvested. A couple of dryland yields were 40 bu/a or better which is excellent and irrgated beans much better.  Soybean dessication will continue on a weekly basis from this point forward.  Stink bugs have been very light this year but we had to treat some beans for stink bugs in some fields I have been scouting. Some of these had to be treated for loopers as well. These were soybeans planted the last week of April.

Kudzu Bug Adult

PEST ALERT: Kudzu Bugs Found in Vicksburg, Mississippi

PEST ALERT: Kudzu Bugs Found in Vicksburg, Mississippi published on 2 Comments on PEST ALERT: Kudzu Bugs Found in Vicksburg, Mississippi

PEST ALERT:The Kudzu Bug (Bean Plataspid) has been found in Vicksburg, Mississippi. This is an invasive soybean pest that has not been detected in Louisiana. The Kudzu Bug can cause significant injury to soybeans and migration from Kudzu is common. If this insect is found, or for more information, please contact the LSU AgCenter. Below is contact information for LSU AgCenter entomologists and LDAF personnel.

Kudzu bugs on soybeans
Kudzu bugs on soybeans: Photo by J. Greene

Jeffrey A. Davis: LSU AgCenter Assistant Professor-Research Soybean Entomologist and Soybean IPM

Kudzu Bug Adult
Kudzu Bug Adult

Office: 225-578-5618   Cell: 225-747-0351  jeffdavis@agcenter.lsu.edu

David Kerns: LSU AgCenter Associate Professor- Macon Ridge

Office: 319-435-2157       Cell: 318-439-4844   dkerns@agcenter.lsu.edu

Julien Beuzelin: LSU AgCenter Assistant Professor-Field Crops Insect Ecology & Pest Managment

Office: 318-473-6523         Cell: 337-501-7087     jbeuzelin@agcenter.lsu.edu

Sebe Brown: LSU AgCenter Extension Entomologist Northeast Region

Cell: 318-498-1283  sbrown@agcenter.lsu.edu

Richard Miller: LDAF Administrative Coordinator Quarantine Programs  Office: 225-952-8053

rice strain fall armyworm on soybean

Rice-Grass Strain of Fall Armyworm in Soybeans

Rice-Grass Strain of Fall Armyworm in Soybeans published on 2 Comments on Rice-Grass Strain of Fall Armyworm in Soybeans

I have been receiving phone calls regarding fall armyworms moving into late planted soybeans.  Most of these calls come after a producer has applied a Round up application to control grasses that may have been missed with previous applications. Fall armyworms moving off of these grass hosts are the “grass or rice strain” armyworms preferring grass hosts over legumes.

rice strain fall armyworm on soybean
T    Rice Strain of Fall Armyworm in Soybeans: Photo by Gus Lorenz

The problem is often exaggerated by the size of fall armyworm larvae moving off of grass into soybeans with large, late, instar worms causing severe foliage loss in a short time period.  Many lepidopteran insects will consume more foliage in the last 3 to 4 days of development than throughout their entire life cycle as a caterpillar. This means that once the grass hosts have been removed by a herbicide application, soybeans can experience severe defoliation from migrating armyworms.

Thus, grassy fields should be scouted before an herbicide application is applied. If fall armyworms are found, a pyrethroid can be added to effectively control these insects before they move into beans.

If you have any questions or concerns please contact Sebe Brown or Dr. David Kerns for more information.

Sebe Brown         Cell: 318-498-1283        Office: 318-435-2903

Dr. David Kerns          Cell: 318-439-4844        Office: 318-435-2157

 

The dangers of irrigating with low quality water

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Figure 1. Typical visual symptoms of salt injury in soybeans
Figure 2. Canopy view of early salt injury with no evident signs of damage
Figure 3. Early visual symptoms beginning at 2nd node

By Dr. Josh Lofton, Agronomist – Macon Ridge Research Station

Throughout the month of May and the first week of June the majority of the state experienced hot and dry conditions. Coupled with the rapid growth rates experienced by corn, soybeans and cotton, this situation has required some producers to irrigate for almost two months. While this is a mild concern for some, this intensive irrigation season is a major concern for producers with irrigation water containing elevated levels of salt. Many may not be aware of their potentially low quality irrigation water or may be experiencing this threat for the first time this year, and if current trends continue, irrigation water with high salt concentrations will become an increasing threat to crop production in coming years.

What is the best way to identify crops suffering from salt injury? Plants will usually resemble drought injury, such as wilting and a reduction in leaf area, even though adequate moisture is present within the soil system. Other visual symptoms include pale green and yellow leaves followed by necrosis. These symptoms usually begin exhibiting themselves around the leaf margins (Figure 1). Continuous salinity problems will cause these symptoms to spread throughout the plant and if severe issues are present the plants will eventually die. Because these symptoms first appear in the lower leaves, early identification may be difficult to spot until serious conditions exist. An example of this occurred in soybean trials at the Macon Ridge Station, where there appeared to be no signs of damage across the canopy (Figure 2); however, there was clear evidence of salt injury in the under-canopy (Figure 3). Therefore, in-field scouting may be needed to help identify this problem.

If salt damage has been identified, how detrimental is this to your current crop? The answer can be difficult to determine for every situation not only because crops are affected by salt levels differently but also soil texture and location within the field can influence salt injury. Areas that receive higher rates of low quality irrigation, such as within the first third of a field under furrow irrigation, usually show higher incidence and intensity of salt injury than areas further through the field. Lower portions of the field, where irrigation water can accumulate, will show worse salinity problems than higher, well drained areas. Further, sandier soils have greater leaching of salts during rainfall events than soils with higher clay content. However, it takes approximately 5 to 6 inches of rainfall to decrease the salt level of the topsoil by 50%. The crop itself can be highly influential on the severity of the salt injury that occurs. Some crops such as rice, soybeans, and corn, can show a rapid decline in yield compared to cotton and to a lesser degree wheat and grain sorghum (Table 1). In addition, soybean varieties can show higher salt tolerance, termed salt excluders, than others, termed includers. Damage ratings are currently available for soybean varieties through the 2011 soybean OVTs at the Macon Ridge location.

If a problem field is identified, what is the next step? Since salt injury can vary in severity and symptoms can be similar to other deficiencies or toxicities, proper samples need to be collected from the soils and irrigation wells. Samples can be sent to the LSU AgCenter Soil Testing and Plant Analysis Laboratory (STPAL) located on the LSU campus in Baton Rouge. A soluble salts test, at $5 per sample, can be used to determine the amount of salts in your soil that could potentially be affecting your crops. Additionally, irrigation samples can be submitted to the STPAL with a “quick water analysis” for $6 per sample, determining not only total salts in the irrigation water but also electrical conductivity (E.C., estimate of soluble salts), sodium, and chloride concentration.

If your soils are found to be at toxic levels for salts/, what steps can be taken within this growing season to minimize the detrimental effects? Unfortunately, based on the current data available unless another fresh source of water can be obtained, little can be done in-season. However, at this point one of the greatest concerns is high salt accumulation in the soil. If this salty irrigation water continues to be applied to the soil, irreparable damage can be done within a very short time and will be detrimental to crops and soils for many years. The best management practice for the long term sustainability of the production system would be to limit irrigation events or even completely stop irrigating if water is found to be severely low quality.

What steps can be taken during future growth seasons to minimize the impact to production and soil systems? As mentioned previously there are varieties within sensitive crops that are more tolerant to salinity than others. However, if salt levels in the irrigation water are high, switching production systems to a crop that has a lowered irrigation demand, such as grain sorghum or cotton, may be the best alternative. In these instances this would change how both producers and landlords determine the crop rotations and land allocations; however, long term productivity of our valuable resources and being a good steward needs to be a consideration in these situations.

As we continue to see this problem become a greater issue across many areas of Louisiana, everyone within the agricultural community must become more knowledgeable about salinity issues and the damage to our production systems that this issue can cause.

 

 

Year of the Pigweed

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By Dr. Daniel Stephenson, LSU AgCenter Weed Scientist

 

We have all seen or heard about the tremendous troubles glyphosate-resistant Palmer amaranth is causing producers in Arkansas, Georgia, Mississippi, Tennessee, and other states as well as the steps they have to take to manage it.  Applications of residual herbicides preplant, preemergence, early-postemergence, postemergence-directed, and post-harvest in addition to hand-hoeing have been become a requirement.  In Louisiana, the LSU AgCenter confirmed the presence of glyphosate-resistant Palmer amaranth in 2010.  Prior to 2012, we knew it was primarily located in Concordia, Madison, and Tensas Parishes.

Unfortunately, Louisiana is experiencing an explosion of instances where glyphosate is not controlling Palmer amaranth in 2012.  Whether I have personally seen locations or had numerous calls from producers, consultants, or industry representatives telling me about the failures, the problem is ballooning.  Locations where I have received calls in 2012 include Northeast, Northwest, Central, and South-central Louisiana, so it isn’t just a problem for a few Mississippi River parishes anymore.

Although corn weed control in-crop is over, producers need to utilize post-harvest weed management techniques.  Considering the early corn crop Louisiana will have this year, we will be left with many months of excellent growing conditions for Palmer amaranth and all other weedy species.  Post-harvest weed management techniques include multiple tillage operations, applications of a non-selective herbicide plus a residual herbicide, or a combination of both tillage and herbicides.  The goal is to prevent weeds from producing seed.  Another consideration is sanitation during and after crop harvest.  Harvesting and tillage equipment are excellent tools for spreading weed seed.  All equipment should be thoroughly cleaned to remove weed seed before moving to the next field.

Hand removal of weeds that escaped herbicide applications is very important also.  For example, a soybean field has lapped and you spot a couple of pigweeds still growing out in the field.  It is not that difficult to walk out in the field, pull them up, take them out of the field, and burn them.  The old saying is “an ounce of prevention is worth a pound of cure”.  With potentially glyphosate-resistant weeds, prevention is worth much more than a pound.

LSU AgCenter weed scientists feared that we’d have a year were pigweed populations exploded.  Well, 2012 is that year!  If you suspect a problem, call your local county agent for help and remove the weeds from your field.  Don’t just ignore this issue.  It must be taken seriously.

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