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Year of the Pigweed

Year of the Pigweed published on No Comments on Year of the Pigweed

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.

Insecticide Seed Treatments and Early Season Insects in Soybeans

Insecticide Seed Treatments and Early Season Insects in Soybeans published on No Comments on Insecticide Seed Treatments and Early Season Insects in Soybeans
Thrips Damage to Soybeans (Photo by Angus Catchot)Girdled Soybean Stems from Threecornerd Alfalfa Hoppers. Photo by David AdamsColaspis Beetle Photo by Natalie HummelBean Leaf Beetle Damage to Soybeans Photo by Lee Jenkins

by Sebe Brown, Dr. David Kerns, Dr. Rogers Leonard LSU AgCenter Entomologists, Dr. Ronnie Levy, Soybean Specialist

 Soybeans are affected by a number of insect pests from emergence to harvest in Louisiana. Damage by these pests can cause reduced stand, foliage damage, stem girdling, and ultimately yield losses if extensive injury is incurred early in soybean seedling development.

 With most soybean production practices involving some level of reduced tillage, soil dwelling insects have a favorable environment for overwintering and reproduction. Increased production costs and high soybean prices have made getting the soybean crop off to a healthy start an important consideration for growers. Planting in late March to early April exposes seedling soybeans to cool weather that can stall plant growth and increase susceptibility to insect pests. Actively growing plants can sustain considerable insect populations without any evidence of injury.  Insecticide seed treatments (ISTs) have been documented to help control threecornered alfalfa hoppers, colaspis, thrips and suppress bean leaf beetles in seedling soybeans.

 During dry weather conditions, when soybeans grow slowly, thrips populations can build to damaging levels and occasionally cause significant injury with some seedling mortality. Plant stress caused by herbicide injury can compound thrips injury causing plants to appear very poor. However, thrips rarely justify the use of an overspray except in cases where severe stand loss and defoliation are a possibility.

Threecornered alfalfa hoppers are small, wedge-shaped insects that damage young soybeans by puncturing the main stem resulting in a girdle near the soil surface. Girdling in soybeans 12 to 15 inches in height will result in some stand loss but rarely reduces yield. Early season damage in often compensated for by adjacent plants.

Colaspis beetles are small, oval shaped insects that can injury soybean roots as larvae and defoliate leaf tissue as adults. Larvae appear as small c-shaped grubs that can be found near the soil surface. Colaspis beetles rarely contribute to any appreciable damage; however, with large populations of larvae consuming lateral roots and soft portions of underground stems soybean plants may exhibit symptoms similar to nematode infestations.

 Bean leaf beetles are small, (1/5 inch) in length, insects that are characterized by four large quadrangular markings on the elytra (wing covers) with a black triangle located centrally on the thorax behind the head.  Bean leaf beetles overwinter in litter adjacent to soybean fields and damage to emerging seedlings can be extensive. Adult damage is characterized by round holes chewed into new leaves and the transmission of bean pod mottle virus is also a concern.

 Producers have a variety of options with regard soybean ISTs. Monsanto and Pioneer’s base IST package utilizes imidacloprid with an upgrade to Poncho (clothianidin)/Votivo upon request. Syngenta’s Avicta Complete Beans and CruiserMaxx soybeans utilize thiamethoxam for the IST and Valent’s Inovate is based around clothianidin.

 Research from the Mid-South has demonstrated an average yield increase of 3.5 bu/a with ISTs; while early season soybeans resulted in a 6 bu/a average increase in yield.

 ISTs are effective in suppressing bean leaf beetles and controlling a number of early season soybean insect pests including thrips, colaspis and threecornered alfalfa hopper. ISTs are one of the BMPs recommended by the LSU AgCenter for soybean integrated pest management.

 For more information concerning insect pest management, contact your local LSU AgCenter parish agent, LSU AgCenter specialist, or Louisiana independent agricultural consultant.

 

 

 

 

 

 

 

Nematode Ratings of the Highest Yielding Soybean Varieties for 2012

Nematode Ratings of the Highest Yielding Soybean Varieties for 2012 published on No Comments on Nematode Ratings of the Highest Yielding Soybean Varieties for 2012

Charles Overstreet, Extension Nematologist

Highest yielding cultivars in Group III and Early Group IV Soybean Varieties

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

Delta Grow 4460RR

R 3

NA

S

Pioneer 93Y92

R 3, MR 14

NA

NA

Progeny 3911RY

S

S

S

Progeny 4211

R 3, MR 5, 14

S

S

Rev 44R22Tm

S

NA

S

S42-T4 Brand

R 3

S

S

S44-D5 Brand

R 3,  MR 14

NA

NA

 Highest Yielding Group IV Late Soybean Varieties

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

Armor 55 R 22

R 3, MR 14

NA

NA

Armor X1210

S

S

S

Armor X1211

S

S

S

Asgrow 4832

R 3

S

S

Asgrow 4932

R 3

S

S

Delta Grow 4670 R2Y

S

S

S

Delta Grow 4875 R2Y

R 3, MR 14

S

S

Delta Grow 4975 RR

MR 5

NA

S

Dyna-Gro 31RY45

R 3, MR 14

S

S

GoSoy 4810 LL

R 3

NA

NA

HBK R4829

MR 3

NA

S

HBK R4924

R 3, MR 14

S

S

HBK RY4721

R 3, MR 14

S

S

Miami 949LL

R 3

NA

NA

Morsoy 4707

R 3

S

S

Morsoy Xtra 46X29

NA

S

S

Morsoy Xtra 46X71

R 3

S

S

Pioneer 94Y70

R 3, MS 14

NA

S

Pioneer 94Y80

R 3, MS 14

NA

S

Pioneer 94Y82

R 3, MR 14

NA

S

Progeny 4510RY

S

NA

S

Progeny 4611RY

R 3, MR 14

S

S

Progeny 4710RY

S

NA

S

Progeny 4750RR

MR 3

NA

S

Progeny 4807RR

R 3

NA

S

Progeny 4811RY

R 3, MR 14

S

S

Progeny 4906RR

S

NA

S

Progeny 4911RY

S

S

MR

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

Progeny 4928LL

MR 3

NA

NA

REV @46R73TM

NA

S

S

REV @47R53TM

NA

S

S

REV @48R10TM

R 3

NA

S

REV @48R21TM

NA

S

S

REV @48R22

NA

NA

S

REV @48R33TM

NA

S

S

REV @49R10TM

NA

NA

S

REV @49R11TM

R 3

NA

S

REV @49R22TM

NA

NA

S

REV @49R43TM

NA

S

S

S08-14087 RR

R 3, MS 14

S

S

S08-17361

R 3, MS 14

NA

NA

Schillinger 457.RCP

R 3, MS 14

NA

S

Schillinger 458.RCS

MR 3

NA

S

Schillinger 478.RCS

MR 3, MS 14

NA

S

Schillinger 495.RC

MR 3, MS 14

NA

S

Highest Yielding Group V Soybean Varieties

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

AGS 568 RR

S

NA

MR

AGS 5911 LL

NA

NA

NA

AGS 597 RR

S

NA

S

Armor DK5363

MR 3

NA

S

Armor X1213

S

S

S

Armor X1215

S

S

S

Asgrow 5232

R 3

S

S

Asgrow 5332

R 3

S

S

Asgrow 5632

R 3

S

S

Delta Grow 5110R2Y EX

MR 5

S

MR

Delta Grow 5545RR

S

S

MS

Delta Grow 5555RR

R 1, 3, 5, 9

NA

S

Delta Grow 5625R2Y

S

S

S

Dyna-Gro 32RY55

R 3, MR 14

S

R

Dyna-Gro 35F55

R 1, 3

NA

S

Dyna-Gro 35P53

MR 2

NA

S

Dyna-Gro 37RY52

R 3, MR 14

NA

S

Dyna-Gro 39RY57

R 3

NA

R

GoSoy 5111 LL

R 3

NA

NA

HBK R5529

MR 1, R 2

NA

S

HBK RY5121

R 3

S

S

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

HBK RY5421

NA

S

S

HBK RY5521

NA

NA

S

Morsoy 5168

NA

S

S

Osage

S

NA

MS

Pioneer 95Y01

R 3, MR 14

NA

S

Pioneer 95Y10

R 3, MR 14

NA

NA

Pioneer 95Y20

NA

NA

NA

Pioneer 95Y31

R 3, MR 14

NA

S

Pioneer 95Y50

NA

NA

S

Pioneer 95Y70

NA

NA

S

Progeny 5111RY

R 3

S

MR

Progeny 5330RR

R 1, MR 2

NA

MR

Progeny 5610RY

R 3, MR 14

NA

R

Progeny 5655RY

S

S

S

Progeny 5711RY

R 3

S

S

Progeny 5811RY

S

S

S

Progeny 5960LL

NA

NA

MR

REV @51R53TM

S

S

S

REV @56R63TM

MS 3

S

MS

S54-V4 Brand

R 3

NA

S

USG 75Z98

S

NA

NA

 Letter designations for nematode reaction are: S = susceptible, MS= moderately susceptible, MR= moderately resistant, R= Resistant, and NA= no information available. All information in this table was provided by the seed companies or the University of Arkansas variety testing program at http://www.arkansasvarietytesting.com/crop/data/5.

 Soybean cyst nematode (SCN) continues to be a very minor nematode pest in our state. Currently, selection of a variety based on this nematode is not very important. None of the varieties on our list have any resistance against the reniform nematode which is found in 60% or more of our soybean fields. A few varieties have some level of resistance against the root-knot nematode.

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