Tag Archive: Rust

Soybean Rust Detected in Jackson County

Soybean Rust Detected in Jackson County

Figure 1. Soybean rust was detected on soybean in a soybean sentinel plot in Jackson County, Florida on June 26, 2017. The map above shows scouted and confirmed locations through July 18, 2017 as reported on the USDA IPM PIPE website.

Ian Small, Kelly O’Brien, and David Wright, UF/IFAS NFREC Quincy, and Ethan Carter , UF/IFAS Regional Crop IPM Agent

Soybean rust was confirmed in early-planted soybean sentinel plots on June 26, 2017 at the UF/IFAS Extension Office in Marianna Florida. Ethan Carter, Regional Crop IPM Agent cooperating with Ian Small, and Kelly O’Brien on the monitoring of the sentinel plot, submitted the leaf samples that were analyzed and found to be positive for soybean rust.  Sentinel plots are planted very early, so they are more mature with a more developed canopy than most soybean production fields to serve as an early-warning system for farmers.

Figure 2. Soybean rust on upper (A) and lower (B) leaf surface (Photo credit: Ian Small).

With the unseasonably wet start to summer, conditions have been suitable for soybean rust to produce spores for dispersal.

Figure 3. Map showing rainfall for the previous 45 days (June 1 – July 15) http://agroclimate.org/. Frequent rainfall has resulted in favorable conditions for soybean rust and many other plant diseases.

Figure 4. Map showing deviation from historical rainfall averages for the southeast US for the past 45 days (June 1 – July 15) http://agroclimate.org/. Many parts of Alabama, Florida, and Georgia have experienced greater than 14 inches above historical average rainfall.

It will be important for growers to scout for disease and stay on top of their fungicide application programs this year.  Follow updates from USDA Pest Information Platform for Extension and Education (ipmPIPE) to monitor soybean rust distribution in your area.  Several fungicides are available that provide very good control of soybean rust:  UT Fungicide Efficacy for Control of Foliar Soybean Diseases. Be sure to rotate fungicides from different classes to prevent resistance.  Before selecting your fungicide for control, consider other diseases such as Cercospora leaf blight that may also be an issue in your fields.

Each year the rust epidemic typically begins in the Gulf Coast area and spreads north. Monitoring of sentinel plots in Florida plays an important role in providing information to soybean producing states. This sentinel plot monitoring effort was made possible through funding from the Eastern Region Soybean Board (ERSB).

Resources:

UT Fungicide Efficacy for Control of Foliar Soybean Diseases

USDA site for tracking soybean rust

A farmer’s guide to soybean diseases

Using foliar fungicides to manage soybean rust (updated)

 

PG

Author: Ian Small – ismall@ufl.edu

Ian Small

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2017/07/21/soybean-rust-detected-in-jackson-county/

Soybean Rust Confirmed in Quincy Soybeans

Soybean Rust Confirmed in Quincy Soybeans

Soybean rust (SBR) was found in a soybean sentinel plot in Gadsden County, Florida on June 2. This is the first discovery of SBR on soybeans in Florida this year. SBR was also found on kudzu in Miller, Baker, Grady and Brook’s counties in southwestern Georgia.

Soybean rust (SBR) was found in a soybean sentinel plot in Gadsden County, Florida on June 2. This is the first discovery of SBR on soybeans in Florida this year. SBR was also found on kudzu in Miller, Baker, Grady and Brook’s counties in southwestern Georgia.  The map above shows scouted and confirmed locations through June 10, 2016.

 Brown-red lesions caused by Phakopsora pachyrhizi on the upper soybean leaf surface. (Photo courtesy of U. S. Department of Agriculture

Soybean Rust – brown-red lesions on the upper soybean leaf surface. Photo courtesy of U. S. Department of Agriculture

Soybean rust appeared early this year.  The mild, wet winter has resulted in a higher incidence and severity of soybean rust found on kudzu than in recent years.  Soybean rust was confirmed in early planted soybean sentinel plots on June 2, at University of Florida, Quincy, NFREC.  This is very early for discovery of the disease on soybean and with tropical storm Colin coming up through Florida into Georgia and the Carolina’s, it is advised to keep a close eye on soybeans that were planted in May in those areas.

Infection normally takes about 10 days to present itself, so scouting closely in mid-June is advisable along the tropical storm track.  A timely fungicide application should be made when infection is first seen, as the disease can spread quickly resulting in severe yield loss as the disease progresses.

 

Soybeans infected and not infected with Asian soybean rust, caused by Phakopsora pachyrhizi, in a fungicide trial in Attapulgus, GA, 2006. (Photo by R. C. Kemerait, Jr.)

Soybeans infected and not infected with Asian soybean rust in a fungicide trial in Attapulgus, GA, 2006. Photo by R. C. Kemerait, Jr.

More information on Soybean rust identification and management:

2016 UGA Soybean Foliar Disease Control Guide

American Phytopathological Society – Soybean Rust

The USDA Soybean Rust Public Website – monitoring the annual spread of soybean rust 

 

PG

Author: David Wright – wright@ufl.edu


http://nfrec.ifas.ufl.edu

David Wright

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2016/06/11/soybean-rust-confirmed-in-quincy-soybeans/

Soybean Rust found in Jackson County Sentinel Plot

Soybean Rust found in Jackson County Sentinel Plot

Soybean rust (SBR) has been found on the sentinel plot in Jackson County at the Extension Office.  Because these plots are scouted for SBR on a regular basis, the SBR was confirmed very early.  SBR has now been confirmed in Florida, Louisiana, Mississippi and Texas in 2015.

Soybean growers should consider a fungicide application, if weather conditions stay as they are.  Slightly cooler weather favors the spread of SBR, but it likes high humidity and rain showers.

Scouting for Soybean Rust

 Brown-red lesions caused by Phakopsora pachyrhizi on the upper soybean leaf surface. (Photo courtesy of U. S. Department of Agriculture

Brown-red lesions caused by Phakopsora pachyrhizi on the upper soybean leaf surface. Photo courtesy of U. S. Department of Agriculture

The first symptoms of soybean rust caused by Phakopsora pachyrhizi begin as very small brown or brick-red spots on leaves (Figure 2). Symptoms caused by P. meibomiae are similar to those of P. pachyrhizi, but this lesson will focus on P. pachyrhizi because most of the research and observations have been made with this species. In the field, these spots usually begin in the lower canopy at or after flowering, although seedlings can be infected under certain circumstances. Often the first lesions appear toward the base of the leaflet near the petiole and leaf veins. This part of the leaflet probably retains dew longer, making conditions more favorable for infection. Lesions remain small (2-5 mm in diameter), but increase in number as the disease progresses.
American Phytopathological Society

More details on scouting for the disease are available in the publication  Asian Soybean Rust

Fungicide Options for SBR

Soybeans infected and not infected with Asian soybean rust, caused by Phakopsora pachyrhizi, in a fungicide trial in Attapulgus, GA, 2006. (Photo by R. C. Kemerait, Jr.)

Soybeans infected and not infected with Asian soybean rust, caused by Phakopsora pachyrhizi, in a fungicide trial in Attapulgus, GA, 2006. Photo by R. C. Kemerait, Jr.

Dr. Kemerait, UGA Extension pathologist, shared the photo above from a fungicide trial he conducted on soybean rust back in 2006.  With heavy disease pressure, fungicide treatment is dramatic.  For the past eight years, SBR has not been a major problem in the Southeast, but conditions have been more favorable this year for disease development.  I recommend using a triazole, if soybean rust is already present in a field. If it is not present, use a strobilurin (Headline, Stratego, etc.) to control a wider variety of diseases. Spray if you find rust in your soybeans, or when soybeans start into the reproductive stage (R1 to R3).  Below are Dr. Kemerait’s bottom-line management tips for soybean rust.

Kemerait’s Asian soybean rust management tips:

  1. Asian soybean rust can (and does) limit yields in some soybean fields in Georgia most
    years.
  2. Asian soybean rust has occurred in every county in the state at some time or another over
    the past 10 years. Soybean rust is most likely to be found on soybeans and kudzu.
  3. Soybean producers are advised to protect their crop with a fungicide IF a) the crop has
    reached reproductive growth, b) Asian soybean rust has been detected locally or is likely
    to be found locally, c) environmental conditions are favorable for development and
    spread of rust, e.g. adequate rainfall or storms, and d) the grower’s crop has the potential
    to make a satisfactory crop.
  4. Asian soybean rust is less likely to be a problem in a field with poor growth and plants
    stunted by drought or other factor than in a field with good growth, heavy foliage, and a
    closed canopy of foliage.
  5. Some growers plan to apply fungicides to their soybean crop automatically as the crop
    reaches the R3/pod formation growth stage. They reason that since they will already be
    applying Dimilin and boron during this time period and because the crop is susceptible to
    rust, it just makes sense to tank-mix the fungicide for good timing and to save a trip
    across the field later. This is a good strategy, especially when other diseases may occur
    during this time as well. However, if soybean rust does not develop until much later, the
    R3 fungicide application may not have been needed.
  6. In some studies, a single, well-timed application of an effective fungicide may be all that
    is needed to adequately protect a grower’s crop from soybean rust. However, depending
    upon the timing of arrival of the soybean rust pathogen (earlier versus later) and the
    impact of weather, e.g. tropical storms, it may be necessary (and profitable) to make a
    second fungicide application 2-4 weeks after the first application.

To get all of Dr. Kemeraits recommendations for soybean disease control, download:

2015 Georgia Soybean Disease Guide

 

PG

Author: David Wright – wright@ufl.edu


http://nfrec.ifas.ufl.edu

David Wright

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2015/08/22/soybean-rust-found-in-jackson-county-sentinel-plot/

Crown Rust Outbreak in North Florida Oats

Crown Rust Outbreak in North Florida Oats

Crown rust on Oats

Crown rust on Oats

Crown rust (Puccinia coranata) was found in over 3000 acres of oats in Levy, Suwannee and Madison counties in the last week. The most notable characteristic of the fungus is small pustules which contain orange-yellow spores. Rubbing the leaf with your fingers or a towel will leave a fine orange powder.

These pustules block sunlight from reaching the leaf and inhibit photosynthesis. Severe cases can be fatal to the plant; lesser infestations still seriously reduce forage yields. The disease thrives in warm (50-80 degrees F), moist conditions and is considered one of the most serious diseases of oats. Spores are distributed by wind and can move long distances easily. The spores overwinter in warmer southern climes and move back on the wind to northern states in the summer.

This particular strain of crown rust is affecting all varieties of southeastern oats, so regular scouting of oats for this disease is recommended. Early diagnosis is key. If identified or suspected, contact the local UF/IFAS County Extension agent to confirm the diagnosis.

Heavy grazing pressure can reduce the amount of fungal inoculant on the oat crop. The spores will not affect the grazing livestock. Excessive grazing itself can kill or stunt oat cropss, so monitor grazing to ensure the treatment is not as bad as the disease.

There are fungicides labeled for control of crown rust, however, they should only be used with confirmed infection. Several fungicides are limited to only one or two applications per season.  Also, with a fungicide cost of at least $ 10 per acre, plus the application cost of at least $ 5/acre, it is critical to be sure fields are actually infected and do require treatment.  Follow the label directions, each of the fungicides have at least a seven day grazing withdrawal period, based on recommendations from NCERA-184, the North Central Regional Committee on Management of Small Grain Diseases.

No matter how crown rust is managed, winter feeding programs will be disrupted. Consider using commodity feeds or over-seeding ryegrass to supply the critical needs of the herd. Failure to maintain animal performance will continue the economic impact of crown rust long after warm season pastures return.

Further information about crown rust is available at the USDA Crown Rust website, or by contacting your County Extension Agent.

Fungicides for crown rust control-based on recommendations from NCERA-184, the North Central Regional Committee on Management of Small Grain Diseases

Wheat Fungicides listed above are also effective for crown rust control in oats. Source: NCERA-184, the North Central Regional Committee on Management of Small Grain Diseases.

PG

Author: Jed Dillard – dillardjed@ufl.edu

Jefferson County Livestock and Natural Resources Agent with a commercial cow/calf background. My degree is in animal breeding, but I do more work wth forage systems. Long time clover/legume booster for both livestock and wildlife

Jed Dillard

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2013/12/13/crown-rust-outbreak-in-north-florida-oats/

Triple-Threat in One Soybean Field: Grasshopper Damage, Asian Soybean Rust and Palmer Amaranth

Example of a soybean plant being eaten by grasshoppers

Example of a soybean plant being eaten by grasshoppers

September generally signals the start of peanut and cotton harvests, but in many counties of northwest Florida late planted soybeans still need continued scouting for disease, insect, and weed pests.  Unfortunately, one producer here in the western Florida panhandle is dealing with all three.

The producer initially called our office to determine whether grasshopper damage in the field was enough to warrant a control measure.  Grasshoppers are generally not a deal breaker in bean production, but after examination of the beans that were planted in wheat stubble, it was determined there were enough grasshoppers of varying life stages doing enough damage to necessitate control.

Small grasshoppers (1 inch or less) are easier to control than larger ones.

Small grasshoppers (1 inch or less) are easier to control than larger ones.

According to the Alabama Cooperative Extension Soybean Production Guide, grasshoppers should be controlled to prevent greater than 20-percent leaf loss from pod set until maturity.  Auburn research has shown that grasshoppers have emerged as a pest of soybeans in recent years, primarily in conservation tillage systems. After plants reach the reproductive stage, they will no longer set new leaves.  High leaf loss from pests at this point can reduce yields.

The table below listing grasshopper control recommendations is found in the publication referenced above.

Grasshoppers

Insecticide   and Formulation

Amount of Formulation on per Acre

Lb Active Ingredient per Acre

Minimum Day Last Application Harvest

Acephate
     Orthene 97

0.5 lb

0.485

14

      Orthene 90s

0.56

0.5

14

Beta-cyfluthrin   (Baythroid)

2.0-2.8 oz

0.017-.02

45

Bifenthrin   (Brigade 2EC)

2.1-6.4 oz

0.033-.01

18

Bifenthris   (Discipline 2EC)

2.1-6.4 oz

0.033-0.01

18

Carbaryl
      Sevin 4F, XLR

1 quart

1

21

      Sevin 80S

0.63 lb

1

21

Gamma-cyhalothrin   (Prolex 1.25)

1.28-1.54 fl.oz.

0.0125-0.015

30

Lamba-cyhalorthin(Karate   Z 2.08 CS)

1.6-1.92 oz

0.025-0.03

30

Methyl   Parathion 4EC

1.5 pint

0.75

20

Penncap-M   2 FM

2-3 pint

0.5-0.75

20

Zeta   cypermethrin (Mustang   Max 0.8EC)

3.2-4 oz

0.02-0.025

21

 

 

 

 

 

 

 

 

 

 

 

 

Soybean loopers, velvetbean caterpillars, and armyworms were also being scouted while surveying the grasshopper damage, but were not found.  Instead, however, soybean rust was discovered.  This field had not yet been sprayed to protect from rust.  Preliminary diagnosis of the soybean rust was confirmed by Dr. Ed Sikora, Auburn plant pathologist.

Soybean rust prior to sporulating

Soybean rust prior to sporulating

Dr. Sikora preaches “Spray or Pay” when it comes to soybean rust, meaning all soybean producers should be actively managing soybean rust in order to prevent diminished yields.  According to the University of Florida EDIS publication,  Asian Soybean Rust, control options include applications of strobilurins (pyraclostrobin, azoxystrobin, trifloxystrobin), triazoles (tebuconazole, propiconazole), and tank mixes of strobilurins and triazole compounds. Yield increases of 20 bu/A have been noted with fungicides as compared to non-treated  plots.  Dr. David Wright, UF/IFAS Agronomy Specialist, suggested that the grower tank mix a triazole product or Topguard with the insecticide used to treat the grasshoppers.  For a list of different control options based on crop stage and disease incidence, see Auburn’s Fungicide Use Strategies for Asian Soybean Rust.

Finally, the producer was already aware he had herbicide resistant palmer amaranth and has been taking control measures.  There are many methods to help reduce and eliminate palmer amaranth in a given field, but herbicide treatments vary between crops and cropping systems.  If you have questions concerning managing herbicide resistant palmer on your farm, contact your local county extension agent directly.  If you see palmer amaranth at this point in your field, roguing the plants and disposing of them properly is a good option, though it is very time consuming and tiring.  Additional palmer amaranth control information can be found in the following UF publication: Control of Palmer Amaranth in Agronomic Crops

Herbicide resistant palmer amaranth

Herbicide resistant palmer amaranth

 

 

PG

Author: Libbie Johnson – libbiej@ufl.edu

Agriculture agent at UF IFAS Escambia County Extension.
http://escambia.ifas.ufl.edu/

Libbie Johnson

Permanent link to this article: http://franklin.ifas.ufl.edu/newsletters/2013/09/13/triple-threat-in-one-soybean-field-grasshopper-damage-asian-soybean-rust-and-palmer-amaranth/