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Cotton Fleahopper Adult

Cotton Fleahopper Numbers Increasing

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Currently, Dr. David Kerns has been finding increasing numbers of cotton fleahoppers in cotton on the Macon Ridge Research Station. Fleahoppers are small, 1/8 inch, insects that have an oval shaped, elongated body. These insects are yellow to green and resemble other Hemipteran true bugs. They essentially look like a very small, green tarnished plant bug.

Cotton Fleahopper Adult
Cotton Fleahopper Adult. Photo by David Kerns

Cotton should be scouted for fleahoppers the first three weeks of squaring.  Detection can be difficult due to the flighty nature of these insects. Simply casting a shadow over the pest will often make them take flight. Louisiana pre-bloom thresholds for fleahoppers are 10 to 25 insects per 100 sweeps with adjusted pre-bloom treatment levels to maintain between 70 and 85% first position square retention.

However, scouting small cotton with a sweep net is difficult and produces questionable results.  Additionally, detecting small fleahopper nymphs in a sweep net is difficult as well.  A better technique is to simply examine the terminal of plants watching for adults taking flight and then examining the terminal very closely for small nymphs.  Morning is the best time to scout for fleahoppers and if the wind is blowing, they take shelter in the plant canopy.

Control of cotton fleahoppers can often be obtained with lower label rates of insecticides than rates used for other plant bug insect pests. Fleahoppers are typically fairly easy to control with insecticides.  Insecticides that are commonly used include Acephate at 4 oz/ac, Centric at 1.5 oz/ac and Bidrin at 3.2 fl-oz/ac.

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

Dr. David Kerns    Cell: 318-439-4844    Office: 318-435-2157          Sebe Brown     Cell: 318-498-1283      Office: 318-435-2903

Section 18 approved for Tenchu 20SG to control rice stink bugs in Louisiana – 2012 season

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This blog was originally post at the Louisiana rice insects blog.

A Section 18 request has been approved by EPA for the use of Tenchu 20SG on up to 100,000 acres of Louisiana rice to control rice stink bugs. Click here to read about biology and management of rice stink bugs. This product will provide an alternative mode of action to the pyrethroids that are currently registered for use in Louisiana. The exemption expires October 31, 2012. The distributor in Louisiana is Mr. Michael Hensgens with G&H in Crowley. According to Mr. Hensgens, the suggested retail price is $24.30 lb at ½#per acre = $12.15/ac.

Rate and restrictions: Please contact your local County Agent for a copy of the Section 18 registration before using this product. Remember that the label is the law! The registered rate is from 7.5 to 10.5 oz of product per acre. A maximum of two applications can be made per acre per season. A seven day pre-harvest interval must be observed. Be aware that this product is toxic to honeybees – read the Section 18 registration for precautions to avoid bee injury.

Treatment threshold:We do not recommend treating until you exceed the recommended thresholds as described on the Section 18 label (the current label reads that you should follow the Texas guideline – this has been amended to reflect LSU AgCenter recommendations in pub 2270). 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 and then treat if they exceed the threshold as described in LSU AgCenter Publication 2270. During the first two weeks of heading, treat when there are 30 or more stink bugs per 100 sweeps. From the dough stage until 2 weeks before harvest, treat fields when there are 100 stink bugs per 100 sweeps.

Before we consider applying for an emergency exemption next field season (should we feel it is warranted) we need to gather some specific data. We need your assistance gathering this information.

1. Resistance. Please notify us if you believe that you have a stink bug population that is resistant to pyrethoids. We will gather insect samples to run laboratory bioassays to screen for insecticide resistance.

2. Efficacy. If you use Tenchu 20SG we would appreciate any data you gather on residual efficacy of the product. Data from Texas has indicated that it provides a longer window of activity than pyrethoids. This will potentially result in a reduction of the number of insecticide applications to a field in one season. We will be conducting efficacy trials in Louisiana to measure residual efficacy when compared to pyrethoids. If you’d like to participate in a field demo, please contact your local County Agent and they can work with me to make arrangements.

3. Milling. We also need your assistance in gathering data on milling quality of rice. Specifically, we need more data on reductions taken at the mill in the form of peck and broken grains which is attributed to Rice stink bug feeding injury. Any information you can provide on grade reductions attributed to rice stink bug feeding injury will be appreciated.

For more information, please contact Natalie Hummel, Associate Professor, LSU AgCenter at nhummel@agcenter.lsu.edu or 225-223-3373.

Insecticide Seed Treatments and Early Season Insects in Soybeans

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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.

 

 

 

 

 

 

 

Western Flower Thrips

Western Flower Thrips in Cotton

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Currently, Dr. David Kerns has been finding large numbers of western flower thrips in cotton trials located on the Macon Ridge Research Station. Western flower thrips were a problem in Louisiana cotton last year and it appears that this trend will continue for the 2012 season.

Western flower thrips are more difficult to control than other thrips species found in cotton. Insecticide seed treatments offer 10-14 days of control after plants emerge and western flower thrips can cause these treatments to give out sooner. The use of acephate, dimethoate, bidrin etc. will not give satisfactory control of established western flower thrips populations and will likely flare spider mites and cotton aphids.

Western Flower Thrips
Western Flower Thrips. Photo by David Kerns

LSU AgCenter research has demonstrated that Radiant, when used with an adjuvant, effectively controlled all species of thrips including western flower thrips in seedling cotton.  Radiant effectively kept thrips populations controlled for 7 days after application and did not flare spider mites or aphids.

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

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

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

For more information on early season thrips management in cotton please see the link below.

http://louisianacrops.com/2012/04/09/early-season-thrips-management-strategies-in-cotton/

Cutworm damage in corn

Cutworms in Corn

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 Sebe Brown, Dr. David Kerns, LSU AgCenter Entomologists, Dr. John S. Kruse, Cotton and Feed Grain Specialist

 This week, Dr. David Kerns and I scouted corn fields at V1 in Evangeline Parish for cutworm damage.  Cutworms are usually problems in reduced tillage or no till fields that received a late burndown application leaving weed hosts. However, the fields we scouted were very clean and above ground damage was evident with clipped leaves and larvae being easily found on the tops of rows. Starting clean can help alleviate many problems from early season insect pests; however, clean fields should be routinely scouted for cutworms.

Cutworm damage in corn
Cutworm damage in corn

The largest amount of the damage was found in non-Bt refuge corn. Fortunately, the larvae were feeding above the soil surface clipping early leaves and not burrowing down to the root zone damaging the growing point. Seedling corn (up to V4) can withstand injury from cutworms as long as the growing point has not been damaged.

Thresholds for cutworms in Louisiana corn are 6 to 8% damage from above ground cutting or 2 to 4% from below ground boring. With cooler weather moving into Louisiana, cutworms may be located closer to the soil surface in seedling corn. Warmer weather drives the cutworms to burrow down deeper into the soil increasing the risks of having corn injured at the growing point.

Cutworm next to damaged corn
Cutworm next to damaged corn

 

Insecticide seed treatments should not be expected to give adequate control of cutworms and Bt technology can provide some protection. VT3 Pro, VT2 Pro, Herculex and SmartStax technologies should help reduce cutworm injury: however, large larvae may overcome these traits. Large larvae are less susceptible to Bt toxins than small larvae.

 

If an insecticide application is deemed necessary, a relatively low label rate of a pyrethroid will reduce cutworm injury. Bifenthrin would be a good choice due to its soil activity.

 

Thrips on Seedling Rice

Thrips in Rice

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Last week we were called to a hybrid rice field where there were issues with stand loss.  We could not determine any specific cause, but did note the presence of thrips on nearly every plant.  While the number was fairly large there presence was not especially alarming to me because I have always seen them on seedling rice.  The field was treated with Dermacor which is not expected to control thrips.  We also suspected some seedling disease.  In the past we planted at high enough seeding rates to compensate for seedling loss, but the low seeding rates of hybrids magnifies any stand loss.  Without a definitive cause we could only make a couple of suggestions; apply an insecticide or add some starter nitrogen.  I followed up with the farmer who said he chose to add starter fertilizer and while the stand is still thin the seedlings are growing better.  Nearby crawfish ponds may have had some influence on the decision.

Thrips on Seedling Rice
Thrips on Seedling Rice
Colaspis Larva

Colaspis strike Concordia Parish rice

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Originally posted by Dr. Natalie Hummel  LSU AgCenter Extension Entomologist on her Louisiana Rice Insects blog.  The link to the original article can be found here: http://louisianariceinsects.wordpress.com/2012/04/17/colaspis-strike-concordia-parish-rice/

Over the weekend Sebe Brown scouted a field in Concordia parish where the stand was being severely reduced by colaspis larvae feeding on seedlings. Problems with this field started on March 16 when the stand began to decline. The plants were described as yellow and stunted. This was a Dermacor X-100 treated hybrid rice field no-till drill-planted at a 23 lbs/acre seeding rate. Surrounding fields were growing nicely. When Sebe scouted the field on Saturday he confirmed that the injury was being caused by Colaspis larvae feeding on the roots of seedlings. The stand was reduced about 40% by this injury. The recommendation was made to establish a shallow permanent flood to avoid further injury. In a situation like this, where the rice isn’t quite ready for a flood, you may lose some injured plants to the flood. The alternative is to wait to establish flood, during which time the colaspis will continue to injure the seedlings and further reduce the stand. Establishment of a flood on the field will prevent further feeding injury by the colaspis larvae and eventually the larvae will die. Note: according to experts in Arkansas it may take up to a month for colaspis larvae to die in the permanent flood. Click here to read more about colaspis. You can watch a video on how to scout for colaspis here. The Dermacor X-100 should provide about 30% suppression of the colaspis infestation. Next season, they will consider using a CruiserMaxx or NipsitInside seed treatment to target control of colaspis. The use of pyrethroids will not provide control of colaspis because they are injuring the crop below the soil line.

Colaspis Larva
Colaspis Larva. Photo by Natalie Hummel
True Armyworms Damage to Corn

True Armyworms and Chinch Bugs in Corn

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I have been receiving reports of true armyworms and chinch bugs in corn. True armyworms will usually move into corn once grass hosts have been exhausted or a recent burndown application has been made removing their primary host source.

Corn planted in close proximity to wheat is also susceptible to damage by migrating armyworms. Infestations are typically found around field margins where armyworms have migrated from a wheat field or grassy area. True armyworm damage gives corn plants a tattered appearance with frass (insect feces) present on the leafs or in the whorl of the plant during active infestations.

True Armyworms Damage to Corn
Photo Courtesy of Ron Hammond OSU extension

Most transgenic corn varieties offer protection against armyworm damage. However, single gene varieties such as Yield    Guard and Herculex 1 may be overwhelmed when large populations of armyworms are present. Adverse environmental conditions can influence the expression of Bt genes in corn, and larval size is also a contributing factor for control. Normally large larvae are more difficult to control than small larvae.

As long as the growing point has not been injured, young corn (up to V4) can withstand substantial amounts of defoliation and not see a significant drop in yield. Grass control around fields can help prevent outbreaks of armyworms.

Chinch bugs are small insects 1/5 to 1/6  inch in length, with a black body and white front wings creating a white X when viewed from above. Immature chinch bugs resemble the adults only smaller and lacking wings.  Nymphs range in color from reddish brown to black in later instars.

Chinch bugs are typically active on grasses in and around fields and movement to seedling corn is common. Damage by both adults and nymphs causes corn to have a reddish appearance on the stem and leaves.

Chinch Bug Damage in Grain Sorghum
Chinch Bug Damage in Grain So

 

Continued feeding can cause plants to wilt and eventually die.  Corn is most susceptible in the seedling stage when plant growth is slow and conditions are dry.  Seed treatments and soil insecticides will typically give an 18 day window of protection after emergence.  Once plants have surpassed the most susceptible stage, chinch bug damage becomes less of an issue.

Adult and Immature Chinch Bugs
Photo Courtesy of Bart Drees TAMU Agrilife

If plant growth is slow and chinch bug numbers have reached 5 or more on 20% of plants 6 inches tall or less, a foliar rescue treatment should be applied to stop injury.

When using ground equipment, a high volume, high pressure sprayer delivering a minimum of 20 gpa should be used.  Aerial applications should only be used if ground equipment cannot make it across a  field.

If an application is deemed necessary, bifenthrin would be the product of choice for ground and air.

 

Western Flower Thrips Photo courtesy of UC IPM and Jack Kelly Clark

Early Season Thrips Management Strategies in Cotton

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By Sebe Brown, Dr. David Kerns, Dr. Rogers Leonard – LSU AgCenter Entomologists

Thrips are annual pests of cotton in Louisiana. Damage by these insects cause stunted growth, delayed plant maturity and plant death under heavy infestations.  Cotton is most susceptible to thrips from emergence to the 4 true leaf stage.  Once cotton has reached the 4 true leaf stage, root differentiation has increased, terminal bud growth is accelerated and plants become less susceptible to injury.

The most common thrips found in Louisiana cotton are tobacco thrips, eastern flower thrips, onion thrips and western flower thrips.  These insects overwinter on a variety of weed hosts.  Planting seasons with windy conditions can have considerable influence on the severity of thrips populations in early cotton.  Thrips are typically weak flyers and wind helps to distribute infestations across fields.

Cotton seedlings that experience cool, wet soils develop very slowly and remain susceptible to thrips injury much longer than cotton planted in a warmer, more optimum, environment.  This year has been very warm and wet with considerable alternate hosts around cotton fields to produce sources of thrips infestations.  With the loss of Temik for the 2012 growing season, insecticide seed treatments (ISTs) and over-sprays will be critically important for controlling thrips on seedling cotton.

Cotton seed comes with a variety of seed treatment options that may either be purchased through a seed company or applied by a dealer downstream.  Outlined below are a few of my thoughts with regards to insecticide seed treatment packages on cotton seed.

Dow’s Phytogen seed comes with a base package of thiamethoxam (Cruiser), with Avicta Complete Cotton available upon request.  Avicta Complete Cotton includes Cruiser for the IST, multiple fungicides and abamectin for nematode control.  Information on Phytogen seed treatment options can be found here.

http://www.dowagro.com/phytogen/varieties/seed_treatments.htm

Monsanto’s Deltapine cotton seed comes with a combination of products that fall within the Acceleron treatment umbrella. The base package in cotton includes imidacloprid (Gaucho) and several fungicides.  However there are several options within the Accereleron brand.  Be sure that your seed is treated with what was ordered.  These options are upgrades to Avicta Duo Cotton with Cruiser for insect control, several fungicides for disease control and abamectin for nematodes.  Beware: the Acceleron seed treatment label in other crops may contain other products.  More information on Acceleron seed treatment options can be found here.

https://www.acceleronsts.com/Cotton/Pages/Cotton.aspx

Bayer’s Stoneville/Fibermax cotton seed comes with a base package that includes Gaucho for insect control and thiodicarb for nematodes that falls under the Aeris treatment umbrella.  Producers also have the option to upgrade to Poncho/Votivo with clothianidin (Poncho) for insects and Bacillus firmus (Votivo) for nematodes. More information on Aeris seed treatment options can be found here.

http://www.bayercropscience.us/products/seed-treatments/aeris/

Western Flower Thrips Photo courtesy of UC IPM and Jack Kelly Clark
Western Flower Thrips Photo courtesy of UC IPM and Jack Kelly Clark

Another option is to buy the minimum insecticide treatment available, and have a dealer apply additional insecticides downstream after the seed is purchased.

IST’s offer limited early season protection from thrips. Effective residual efficacy usually offers 10-14 days of control after plants emerge. Unsatisfactory residual control can occur with these treatments and cotton should be frequently scouted for thrips until the four leaf stage and when cotton plants are actively growing.

During 2011, western flower thrips were a problem in many Louisiana cotton fields. Western flower thrips can be difficult to control with standard applications of acephate, dimethoate, bidrin, etc.  Producers also risk flaring spider mites and cotton aphids with repeated applications of broad-spectrum insecticides. Recent research conducted by the LSU AgCenter demonstrated satisfactory control of a complex of species including western flower thrips with Tracer and Radiant at 2 and 7 days after treatment.

The use of a nonionic surfactant with these insecticides can help increase efficacy against thrips. Rescue applications of foliar insecticides should be applied early in cotton development with applications at the 1-2 true leaf stage yielding significantly greater lint per acre than treatments applied at the 3-4 true leaf stage.  Do not wait for thrips treatment in an attempt to time an overtop herbicide application.

Insecticide seed treatment options get producers off to a good start when it comes to insect pest management in cotton. However, these treatments should not be relied upon for sole control of all early season pests. IST’s are one of the best management practices (BMP’s) recommended by the LSU AgCenter for cotton IPM.

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

Thrips-injured cotton. Photo: LSU AgCenter
Thrips-injured cotton. Photo: LSU AgCenter
Cotton without thrips injury. Photo: LSU AgCenter
Cotton without thrips injury. Photo: LSU AgCenterThrips-injured cotton. Photo: LSU AgCenter

Wheat Insect Update

Wheat Insect Update published on No Comments on Wheat Insect Update

by Sebe Brown, Extension Entomologist

All, I have been seeing more instances of true armyworms infesting wheat in the North Louisiana.  These include wheat plots at St. Joe and Winnsboro at various stages of growth.  Our threshold for armyworms is 5 worms per square foot with foliage loss occurring. If armyworms reach the flag leaf and the wheat has not headed an application should be made.  I have also encountered varying levels of stink bugs (primarily rice stink bug) in wheat. Populations of stink bugs have to be high for damage to occur and our threshold is 10% infested wheat heads in the milk stage and 25% infested heads in the soft dough stage.  Stink bug numbers  will usually be higher around the edges of a field with numbers falling off as you walk further toward the middle. This means you may reach threshold around the edges of a field, but may also be well below threshold 100 feet in.  Applications of pyrethroids can control both of these pests.

Rice stink bug  photo courtesy of Gus Lorenz

Armyworm larvae on wheat heads photo courtesy of Robert Bellm, University of Illinois Extension

 

 

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