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

Tropical Storm Gordon’s Impact on Cotton and Peanuts in Escambia and Santa Rosa Counties

Tropical Storm Gordon’s Impact on Cotton and Peanuts in Escambia and Santa Rosa Counties

Cotton laid down in the field by Tropical Storm Gordon.

For most row crop growers in Florida, Tropical Storm Gordon had minimal impact.  However, in the westernmost part of the state, much of the cotton suffered significant damage.  Though the winds were not extremely strong, the combination of saturated soils and winds wreaked havoc on what had looked like a stellar cotton crop.

The western Panhandle had been blessed with ample rains throughout the summer.  Prior to T.S. Gordon making landfall on September 3, many farmers were excited about the prospective yields for their 2018 cotton crop.  In northern Escambia County, farmers reported rainfall ranging from 7-11 inches.  Though the area did not receive a long period of high winds,  the combination of waterlogged soils and wind caused a great deal of lodging in cotton that was nearing full maturity almost ready to be defoliated.  Canopies heavy with loaded bolls and wet leaves laid down on damp soil and have not since righted their position.  The bolls touching wet ground have rotted off the plant.  The plants are matted throughout the field.   Many farmers have shared their concerns with the difficulty of defoliating a field that has cotton laying across the row middles.

Though the winds from T.S. Gordon died down within 24 hours, the rains continued.  It has continued to rain regularly since September 3rd.  Not only is the cotton worse for wear, but peanut harvest has been steadily delayed by the rains.  Greg Phillips, manager of Birdsong Peanuts-McCullough, said “Peanut harvest in the area has been greatly slowed by the rain.”  He estimates that around 7% of the entire crop has been harvested, whereas if the weather conditions had been favorable, 15% of the year’s crop would been harvested by this time.  He does report good grades so far, but he is concerned that further delays might cause a decline in both yield and grades.

The  Agroclimate image below shows the total rainfall in inches from August 13th to September 25th.  It is evident that the western Panhandle and Lower Alabama have received ample amounts of rain, but the story that it doesn’t tell is that all of this rainfall is coming at a time of year when conditions are generally starting to dry out for harvesting.

The image below from Agroclimate provides a good comparison of rainfall totals from the past 45 days to September 25.  The map of the southeast on the left shows the historical average rainfall for this time of year  The more colorful map of the southeast on the right shows the deviation from “normal” rainfall amounts.  In the case of late summer 2018, T.S. Gordon brought in much higher than average rainfall in the areas shaded in blue and purple.

It will take some time to know the full extent of the impact from T.S. Gordon.  Crop damage appears significant, but the full effects will not be known until after the completion of the 2018 crop harvest.

Help Feed the Hungry – The UF/IFAS Extension Peanut Butter Challenge is Underway!

Help Feed the Hungry – The UF/IFAS Extension Peanut Butter Challenge is Underway!

Donate jars of unopened peanut butter to your County Extension Office for delivery to local food pantries. Paul Davis, 4-H youth development agent, and Julie McConnell, horticulture agent, both with UF/IFAS Extension Bay County, stand next to their 2016 peanut butter donations.

If you want to help feeding hungry people in Florida’s Panhandle this year, you can donate peanut butter during the annual Peanut Butter Challenge, coordinated by UF/IFAS Extension.

Thanks to a partnership of UF/IFAS Extension and the Florida Peanut Producers Association, food pantries from Pensacola to Monticello will receive thousands of jars of donated peanut butter this December.

From October 1 through November 21, you can donate unopened jars of peanut butter to your local UF/IFAS Extension county office, and other drop off points in each participating county.

Since 2012, the volunteers and UF/IFAS Extension faculty have collected jars of peanut butter from residents, volunteer groups, and businesses in 16 northwest Florida counties. “Last year, UF/IFAS Extension county offices received 6,222 jars of peanut butter,” said Libbie Johnson, agricultural agent for UF/IFAS Extension Escambia County and co-organizer of the Challenge.

In addition to these donations, the Florida Peanut Producers Association also contributes, supplying more than 3,000 jars each Challenge,” Johnson said.

The Peanut Butter Challenge not only raises awareness about the important contribution of North Florida’s peanut growers to the state’s peanut industry, but also helps provide a healthy, locally produced product to food-insecure families in Northwest Florida,” Johnson said.

Check out the YouTube video produced to share the importance of this nutritious food for local food pantries.


Friday Feature:  America’s Peanut Farmers

Friday Feature: America’s Peanut Farmers

Peanut FarmerWith peanut harvest in full swing in the Panhandle (between showers that is), I thought this would be the perfect week to share a video produced by American Farm Bureau to teach students about agricultural careers.  The video, called “America’s Peanut Farmers: Sustainability,” is part of the My American Farm website with resources for school teachers. Use the link below to view the video:

America’s Peanut Farmers


If you enjoyed this video, you might want to check out the featured videos from previous weeks:  Friday Features

If you come across an interesting or humorous video, or a new product innovation related to agriculture, please send in a link, so we can share it with our readers. Send video links to:  Doug Mayo

Rapid Response Team Deployed to Investigate Peanut Collapse

Rapid Response Team Deployed to Investigate Peanut Collapse

Research plots in 2017 affected by peanut collapse

Figure 1: Research plots in 2017 affected by peanut collapse. Photo by B. Tillman

Shannon McAmis, De Broughton, Nick Dufault, Ian Small, Zane Grabau, Barry Tillman, and Diane Rowland, UF/IFAS Extension

In 2017, peanut growers of the Panhandle and North Central regions in Florida, and many areas in Georgia faced a number of issues. In addition to high disease, insect pests, nematodes, and Hurricane Irma’s aftermath, growers were faced with a new problem: peanut collapse or decline. University scientists hypothesized that abnormal weather patterns, including low solar radiation and decreased night-time temperatures during an important part of plant development, may have contributed to the collapse. Late in the season, growers noticed yellowing or necrosis of leaf margins, premature defoliation, plant stunting and weak pegs, all adding up to digging losses and reduced yield. This phenomenon was named peanut collapse or peanut decline by many growers and researchers (Figure 1: Peanut collapse). An estimated 25,000 acres fell victim to peanut collapse and experienced yield reduction of more than 1,000 pounds per acre. (retrieved from:  Peanut Season has Begun in North Florida). UF/IFAS Extension Agents and researchers teamed up with University of Georgia and regional producers and scrambled to find the cause, but no main culprit was found.

 A region-wide tour of peanut collapse took place

Figure 2: A region-wide tour of peanut collapse took place with researchers, extension agents, and producers present.

In 2018, a team of Extension Agents and scientists are hoping to uncover more of this mystery and begin to gather the data needed to predict problems for harvest this year and into future years. They are using the help of a mobile app combined with drone flights. Researchers are using FieldX, an iOS app that is available through FieldX, Inc. that allows users to map field borders and upload geolocated pictures and notes conveniently on one platform.

creenshot of the desktop app FieldX Dashboard

Figure 3: Screenshot of the desktop app FieldX Dashboard.

FieldX is able to map and display multiple farms and fields at one time while individually tracking the geolocation of pictures and notes taken in the field. The app can track the exact path taken while scouting the field as well as record the specific location where pictures or soil and plant samples are taken.

Screenshot of the mobile app FieldX GeoNotes

Figure 4: Screenshot of the mobile app FieldX GeoNotes.

The FieldX app will allow for any incident of peanut collapse to be mapped, photographed, and described all on one convenient platform that can be shared with other users. This will help the team visualize the effect of peanut collapse for the entire region, and allow researchers to collect data about what happened when and where.

Recording the occurrence and progression of peanut collapse (and other diseases) will allow researchers to begin tracking symptom progression and begin to formulate models to assess risk in the future. Researchers will also combine drone or Unmanned Aerial Systems (UAS) images from identified fields to help develop early warning signals for the possible onset of collapse.  Although the main focus of this work is to better understand peanut collapse, this technology can also be used to record and document other issues that may come up in the field, to better identify and predict risks to peanut production in the future.

The Peanut Decline Research Team encourages growers to report appearance of possible decline.  If you suspect peanut decline may be an issue in one or more of your fields, contact your local county agent or De Broughton, Suwannee County Extension, who is coordinating this effort in Florida.

Friday Feature:  Highlights from the 2018 UF/IFAS Peanut Field Day

Friday Feature: Highlights from the 2018 UF/IFAS Peanut Field Day

This week’s featured video was produced by the Panhandle Ag Extension Team to share the most important points made by the six speakers at the 2018 Peanut Field Day.  The event was held August 23, 2018 near Marianna at the North Florida Research and Education Center.  Topics discussed at the Field Day included: new peanut varieties, managing insects, fungal diseases, and weeds in peanut fields, the fertilizer value of peanut vines for the ensuing cover crop, and the Wildfire and Hurricane Indemnity Program being offered to farmers by USDA’s Farm Service Agency.


If you enjoyed this video, you might want to check out the featured videos from previous weeks:  Friday Features

If you come across an interesting or humorous video, or a new product innovation related to agriculture, please send in a link, so we can share it with our readers. Send video links to:  Doug Mayo