To Dig or Not to Dig: Optimizing Peanut Digging Decisions in the Presence of Leaf Spot Defoliation

To Dig or Not to Dig: Optimizing Peanut Digging Decisions in the Presence of Leaf Spot Defoliation

Dan Anco & Kendall Kirk, Clemson, Ian Small, & David Wright, UF/IFAS

digging peanuts

Figure 1. 2018 Peanut digging underway. Photo credit: David Wright

When it comes time to dig peanuts at the end of the growing season, many things influence how many pods make it into the basket. Research by Dan Anco and collaborators has documented two things which can decrease yield, over maturity and disease. Though slightly different, both have the potential to weaken pegs and increase pod loss, and both can be influenced by late season rains and delayed field access. In the past, Virginia type peanuts have characteristically exhibited more of a tendency for pod loss due to over maturity than runner varieties.  The same appears to be the case when looking at losses due to late or early leaf spot diseases. While late and early leaf spot have some differences, they both cause lesions and can defoliate canopies.

peanut defloation series

Figure 2. Leaf spot defoliation. Credit: Ian Small, UF/IFAS

To reevaluate the role of leaf spot diseases and yield loss, researchers at the University of Florida teamed up with scientists across the southeast and in the Virginia-Carolina regions to pool together data and conditions from many years to look at two common questions: How much loss occurs with different amounts of leaf spot infection?, and Is there a disease threshold where we might consider digging a field early?

Each situation can be somewhat unique, but based on their research, the team was able to develop some rough rules of thumb.  Mature runner type losses became significant after approximately 30% of the canopy was defoliated due to disease, whereas mature Virginia type losses became significant when 25% or more of the canopy was shed.  For the second question, if a field is not yet at optimal maturity, it appears that when Virginia types pass 40% defoliation, they generally tend to increase losses (due to defoliation) faster than maturity is improving or yield is increasing in an otherwise healthy field. While it doesn’t look pretty, runner types appear to be able to sustain up to 50% defoliation while waiting on optimal maturity before losses increase more than the yield gains from additional maturity. In other words, if the crop is not mature there is a critical threshold (40% for Virginia types and 50% for runner types) where yield losses due to defoliation will outweigh any further improvement in maturity.

As a reminder, if you are thinking about making a fungicide application to prevent end of season defoliation, and to help maintain the integrity of stems and pegs, be sure to check the preharvest interval (PHI) on the label of any fungicide you are considering to apply.  Do not apply the fungicide if you are not able to wait until after the PHI has passed to harvest.

Digger operation and setup is important during every harvest, but is particularly important if field conditions include sizeable leaf spot defoliation or over maturity. In another set of studies, we have seen above ground digging losses to be significantly impacted by conveyor speed. To assist with digger conveyor speed setup, a calculator is available at the link below.

Peanut Digger Conveyor Speed Calculator


List of the key collaborators from the Southeast and Virginia-Carolina regions that were involved in this project:

Dan Anco1, James Thomas1, Barbara Shew2, David Jordan3, Albert Culbreath4, Walter Monfort5, Hillary Mehl6, Nicholas Dufault7, Barry Tillman8, David Wright9, Ian Small9, Austin Hagan10, Howard Campbell10

1Clemson University, Department of Plant and Environmental Sciences, Edisto Research and Education Center, 64 Research Road, Blackville, SC 29817, USA; 2North Carolina State University, Department of Plant Pathology, 112 Derieux Place, Raleigh, NC 27695, USA; 3North Carolina State University, 100 Derieux Place, Department of Crop Science, Raleigh, NC 27695, USA; 4University of Georgia, Department of Plant Pathology, 2360 Rainwater Road, Tifton, GA 31793, USA; 5University of Georgia, Department of Crop & Soil Sciences, 2360 Rainwater Road, Tifton, GA 31793, USA; 6Virginia Tech, Tidewater Agricultural Research and Extension Center, 6321 Holland Road, Suffolk, VA 23437, USA; 7University of Florida, Department of Plant Pathology, 2550 Hull Road, Gainesville, FL 32611, USA; 8University of Florida, North Florida Research and Education Center, 3925 Highway 71, Marianna, FL 32446, USA; 9University of Florida, North Florida Research and Education Center, 155 Research Road, Quincy, FL 32351, USA; 10Auburn University, Department of Entomology and Plant Pathology, 149 ALFA Building, Auburn Univ, AL 36849, USA

Scientists Share Latest Research and Production Tips at Carinata Field Days Across the Southeast

Scientists Share Latest Research and Production Tips at Carinata Field Days Across the Southeast

Ian Small, UF/IFAS Plant Pathologist, discussed disease management and advanced scouting tools at the Carinata Field Day in Quincy, FL.

Authors: Dan Geller, Ben Christ, Wendy-Lin Bartels, Bill Hubbard, Sheeja George, Ian Small, David Wright

This Spring, both farmers and researchers in the Southeast United States are at work. Inside the farm gate, producers are taking advantage of every opportunity to be out with their crops, putting in extra time to ensure their production goals for the season will be met. At the same time, researchers participating in the Southeastern Partnership for Advanced Renewables from Carinata (SPARC), a USDA NIFA CAP funded grant project, are putting in long hours in the field, greenhouses, and laboratories to develop new varieties of carinata, an emerging oilseed crop in the Southeastern US.

Carinata is grown in the cool-season to provide a second cash crop that can be used to produce high-grade jet fuel, diesel, gasoline and animal feed, as well as provide cover crop benefits. SPARC scientists are working on best management practices for production, and post-harvest uses of the seed to help producers by increasing yields and profitability of carinata. Maintaining the connection between scientists and producers is imperative. Early in its formation, SPARC leadership foresaw the need for a strong and diverse extension team that would serve as a bridge between scientists, producers, and regional extension agents.

David Wright, UF/IFAS Agronomist, discussed carinata production best management practices at the Carinata Field Day in Tifton, GA.

The SPARC team hosted carinata field days in Jay, and Quincy, Florida, Milstead, Alabama, and Tifton, Georgia this spring. The SPARC events in Jay, FL (February) and Quincy, FL (March) attracted over 50 interested farmers, extension agents, academics, and agency representatives who came to learn more about carinata production from SPARC experts and collaborators. SPARC members presented topics on carinata production including weed, pest, disease and fertility management. The team also discussed planting and harvesting techniques as well as timing of planting and harvest to fit into common crop rotations in the Southeast. An overview of carinata contracts and crop insurance was also provided to attendees of these events. The field days provided the opportunity to observe carinata in the field and discussion included details of SPARC experiments at each site.

Some of the key points addressed at the field days were:

  1. Carinata genotype multi-location trials are underway to evaluate advanced breeding lines under diverse environmental conditions. Crop improvement efforts continue to target enhanced cold tolerance, early maturity, high oil and seed yield in carinata
  2. Carinata’s “fit” as a winter cash crop in Southeast cropping systems was emphasized
  3. Best management practices for carinata production were discussed – timely planting is key (early to mid-November for North Florida). For more details on row spacing, nutrient management, pest management, harvest management, seed depth, tillage requirements refer to the production manual and other resources on;
  4. Crop insurance stipulations for carinata were discussed. For more details on production contracts and insurance contact a representative from Agrisoma
  5. The importance of a life cycle analysis (LCA) to understand the overall impact of carinata production in the southeast was presented. Ongoing research is focused on increasing value to stakeholders in the carinata supply chain – from seed supplier to producer, handler, processor, fuel and coproduct end-user

Austin Hagan, Auburn Plant Pathologist, discussed disease management and variety evaluations at the Alabama Carinata Field Day.

One of the team’s primary objectives is to understand the farmers’ expectations and what they would need to effectively grow the crop during the winter months. Dr. Wendy-Lin Bartels and Benjamin Christ, both from the University of Florida’s School of Forest Resources and Conservation, are social scientists leading SPARC’s understanding of the barriers and opportunities that may exist for producers in the Southeast to adopt carinata. They began with broad questions directed to the many stakeholders involved with SPARC and have since directed their focus to regional agents and producers. Through surveys at Carinata Field Days and phone interviews, Wendy-Lin and Ben have constructed a model of the barriers and opportunities relevant to producers in the Southeast. This information is directed back to SPARC and serves as the producers’ collective voice as researchers continue their work to develop better, regionally appropriate varieties of carinata.

Agrisoma representatives discussed production and marketing options at the Carinata Field Day in Jay, FL.

As carinata harvest approaches and field studies wind down for the year, the extension team will begin to work with SPARC researchers to develop tools to provide farmers the most up-to-date publications. The extension team has already started a working relationship with the feedstock team, which is expected to result in several critical publications to be published by extension in Florida, Alabama and Georgia. The team will soon begin work on the first of the SPARC e-Learning courses to be developed during the program which will utilize expertise from all the SPARC research teams to provide continuing education to extension agents, crop advisers, and other key stakeholders in the carinata supply chain.


Carinata SPARCs Interest as a Winter Crop for the Southeast U.S.

Carinata SPARCs Interest as a Winter Crop for the Southeast U.S.

Ian Small, Ramdeo Seepaul, Mike Mulvaney and David Wright, UF/IFAS Researchers

This week a Qantas jet flew from the United States to Australia using biofuel generated from Brassica carinata (carinata). This event was just one of several exciting developments involving carinata that have happened over the past year. Strong markets exist for the fuel, co-products and meal that can be produced from carinata seed.  This is creating an opportunity to establish carinata as a winter crop for producers here in the Southeastern U.S. To accelerate the establishment of commercial carinata production in the southeastern US, a consortium known as the Southeastern Partnership for Advanced Renewables from Carinata (SPARC), will work to address barriers to production, and reduce risk along the supply chain. The SPARC team is comprised of scientists from several Southeastern universities, government agencies, industry (Agrisoma Biosciences Inc., and Applied Research Associates Inc.), and a consortium representing the commercial aviation industry. The establishment of this team was made possible with support from the U.S. Department of Agriculture’s (USDA) National Institute of Food and Agriculture (NIFA).

Our goal is to commercialize Carinata to produce jet fuel and feed for livestock while mitigating risks along the entire supply chain,” says David Wright, project lead and an agronomy professor at the University of Florida.

In this article, two key objectives of the SPARC feedstock development team are highlighted:  to assist with the selection of varieties suited to the Southeastern U.S., and to optimize the cropping systems fit of carinata with traditional crop rotations.

Testing Advanced Carinata Varieties Across the Southeast

Over the past 5 years, scientists at the University of Florida and Agrisoma have been screening advanced carinata varieties to identify high yielding, early maturing, cold hardy, and disease tolerant varieties, with high oil content, and desirable fatty acid composition. As a result, several varieties have been identified that provide opportunities to increase carinata seed yield by 40%, and increase oil yield by 2%, over existing commercial varieties. After benefiting from several years of selection and testing in the region, Agrisoma’s breeding pipeline of varieties promise even higher yielding, earlier maturing varieties, that would complement prevalent summer crop rotation systems in the US Southeast. Successful commercialization of carinata based renewables will depend on reliable and sustainable year round availability of feedstock; therefore expansion of carinata production across the Southeastern U.S., as determined by adaptability, will strengthen the supply chain.

To establish the suitability of locations in the Southeast for carinata production, SPARC cooperators planted 16 advanced carinata breeding lines that have potential for near future commercial deployment at 15 locations in Alabama, Florida, Georgia, Mississippi, North Carolina and South Carolina. This multi-site regional testing approach will assess the yield potential, determine production sensitivity to resource management and climate variables, and identify productive regions for commercialization and supply chain development.

Figure 1. Carinata yield trials at the North Florida Research and Education Center, Quincy, FL. Photo credit: Ian Small

This regional study is already yielding useful information about these advanced lines. The cold weather at the start of the 2018 year provided a major test of the resilience of the varieties against cold damage. This information will be key to selecting the next commercial varieties for the Southeastern U.S.

Testing Sustainable Crop Rotations with Winter Carinata in the Southeast

As commercial carinata acreage expands from the Panhandle of Florida to more northern states in the Southeast, it is important to determine the latitudinal limits of winter production, and quantify cultural practices that enhance cold tolerance. Tillage practices are expected to play an important role in the degree of frost tolerance of carinata due to the maintenance of crop residue on the soil surface which may protect the crop from freeze damage, and due to differences in soil temperature during establishment. Integration of fertility management is important on the characteristic sandy soils of the Southeast in order to meet crop demand as well as limit nutrient movement to water bodies and groundwater. Fitting carinata into current crop rotations will provide growers with additional income, but rotations that are economically and agronomically feasible are still being investigated. Existing common cropping systems in the Southeast include corn, cotton, peanut, soybean, and sorghum. The selection of regionally appropriate cropping systems for double cropping carinata is currently limited by the planting and harvest window of summer cash crops.

Figure 2. Carinata production field in Central Georgia. Photo credit: Christine Bliss

Research on early maturing carinata lines, combined with harvest management practices ideal for the Southeast, will help overcome that limitation. Integration of tillage, fertility, and rotations for sustainable carinata production may provide enhanced ecosystem services for water quality, carbon sequestration, and integrated weed management. The effects of previous summer crops on carinata production, as well as the effects of carinata production on subsequent summer crops, will be determined in two long-term cropping systems studies in Jay and Quincy, Florida. Researchers will determine regions suitable for sustainable carinata production in the Southeast, and identify those rotations that are both economically and agronomically viable. Tillage effects on frost tolerance of carinata will be quantified, and recommendations will be developed and extended to growers and industry professionals through field days and workshops.

For more information, consider attending of the upcoming Carinata Summit or one of the regional field days:

For more information on carinata production and recent projects with the biofuel made from carinata, use the following links:
General background
Sotheastern Partnership for Advanced Renewables from Carinata
UF/IFAS Carinata Research
Carinata Production Recommendations for the Southeastern United States
Agrisoma Carinata Production website
Agrisoma Renewable Energy website
Press release: Canadian Bio Fuel Company Announces Significant Collaboration with University of Florida
Applied Research Associates (ARA)
Press release: ARA partners with the University of Florida to commercialize sustainable fuels and co-products from carinata
Recent developments
Biofuels Digest article:  SPARC in the Engine: Florida aims to be an alternative jet fuels hub as new public/private project debuts
Biofuels Digest article: Farm to flight – Carinata crop commercialization takes off
Biofuels Digest article: Qantas, Agrisoma, Honeywell, AltAir, WFS partner in historic first Pacific jet biofuels flight
Australian Aviation article: Qantas flight QF96 to feature biofuel blend

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) 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) 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).


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)


Save a Penny, Lose a Dollar – The Importance of Spray Nozzle Selection and Maintenance

Save a Penny, Lose a Dollar – The Importance of Spray Nozzle Selection and Maintenance

Over time spray nozzles wear with use, resulting in rate and application changes that can increase your spray costs. Photo Credit: Ian Small

Ian Small, UF/IFAS Plant Pathologist, NFREC Quincy, and Jeff Clack, Hypro Pentair Flow Technologies

There is no shortage of new technologies being marketed to improve the efficiency of farming operations.  The most cost effective place to start is with the basics, or in other words, start with the parts of your operation that improve efficiency for the least effort and cost! As a colleague of mine likes to say, “Consider the pain for the gain.”  As we approach the 2017 growing season, it is essential to keep in mind one of the fundamentals of pesticide application – sprayer nozzle selection. Proper selection of nozzle type and size is essential for correct pesticide application.

There are several types of nozzles available on the market (flat fan, extended range, high flow, low drift, etc) that have been developed for specific applications. It is important to select the appropriate nozzle type and size for each type of application you intend to make. Consider the type of spraying you are planning to do: broadcast, banded/directed, boomless, or boom extender. For example, if you are broadcast spraying you will need to consider your nozzle tip spacing, speed during application, target application rate, solution density, and target droplet size when selecting a nozzle type. After installation of new nozzles be sure to calibrate your sprayer to verify that all nozzles are functioning correctly and that the target application rate is being achieved. For a step-by-step guide to calibration utilize the link to this publication: Calibration of Pesticide Applicators: Boom Sprayers.

There are several online nozzle selection tools to help ensure that you are selecting the appropriate nozzle for your application. Here are two examples of these tools:

Although these tools are freely available, it is still your responsibility to verify that you will be able to adhere to label precautions, or state and federal laws relating to appropriate nozzle type and associated application pressures. In certain applications, drift reduction is very important! See the following guide to spray drift reduction Managing Pesticide Drift and the recent article on managing dicamba drift Managing Dicamba Drift when using New Dicamba Resistant Cotton Varieties.

Nozzles do wear with use, resulting in incorrect flow rates and application patterns. If your flow rate and application pattern are incorrect this will result in less effective sprays, as well as increased spray costs. Certain nozzle materials will wear faster than others and applying certain abrasive pesticide formulations will accelerate this process.

To detect nozzle wear:

  • Check the flow rate. To check the flow rate of your current nozzles, conduct a boom sprayer nozzle performance test Boom Sprayer Nozzle Performance Test.
  • Visually check the spray pattern.
  • Check the spray coverage. Nozzle wear or poor alignment will reduce the uniformity of coverage.
  • Inspect the spray pressure and volume. If using centrifugal pumps, monitor for increases in liquid volume sprayed. If using positive displacement pumps, monitor for pressure decreases.

Poor sprayer calibration is an often-overlooked culprit behind misapplication. Simply checking each nozzle to ensure that proper flow rate is being attained can help identify problems. If using nozzles with screens, routine cleaning of screens associated with each nozzle can often solve flow rate problems on nozzles that are not worn.  A spray nozzle can be considered out of calibration tolerance if its flow rate is 10% greater than its rated flow. All agricultural nozzles are rated for flow at 40 PSI and color coded as such. A red nozzle for example represents an “04” size. This equates to 0.4 GPM at 40 PSI. If the nozzle is calibrated and its flow rate is 0.44 GPM or greater it should be replaced.

Boom section management is also an area that deserves attention. Many growers express concern that certain nozzles on their booms do not shut off immediately when deactivated. This is often due to air in the booms and hoses. If pressure is applied to a system that contains air in the liquid line, the air then becomes compressed. When the boom is shut off, the air decompresses and holds the check valves open and the nozzles continue to spray or drip until the air is depressurized. The addition of aspirators to the boom will eliminate this problem, and enable a more rapid response to boom controls.

Lastly, be sure to clean all spray equipment after use. Sprayer hygiene is of utmost importance. Regardless of sprayer type, the proper sanitation of the unit greatly reduces unintended injury to targeted and neighboring fields. Commercial rinsing and cleaning formulations are available to help neutralize residual chemicals, and enhance sanitation when going from one crop to the other using materials that can damage the next crop if not properly rinsed.

By selecting and maintaining the correct nozzles, calibrating and cleaning your sprayer, and adhering to appropriate application techniques you can help ensure the sustainability of your farming operation, and prevent unintended consequences from poor application techniques.


Additional information on this topic is available utilizing the following links:

  1. Calibration of Chemical Applicators Used in Vegetables

  2. Managing Pesticide Drift

  3. Boom Sprayer Nozzle Performance Test

  4. Broadcast Boom Sprayer Calibration

  5. Calibration of Herbicide Applicators

  6. Five Tips to Reduce Pesticide Spray Drift

  7. Calibration of Pesticide Applicators: Boom Sprayers

  8. Teejet Tips for Nozzle Maintenance

  9. Machine Finder Guide to John Deere Sprayer Nozzles