Beef Brunch Educational Webinar Series

This online educational webinar series was developed specifically for beef cattle producers. The goal of this series is to bring timely educational information to our beef cattle producers across the state. More information on upcoming webinars can be found online at Beef Brunch Educational Series page.

October Webinar - Estrus Synchronization Webinar

This next Beef Brunch Webinar Series, Estrus Synchronization, is scheduled for Tuesday, October 13, 2020 at 10:30 am.

This webinar will be hosted through Microsoft TEAMS. An internet connection is required but a microphone and webcam are not necessary. The TEAMS application may be downloaded by smartphone or tablet and is a free software application.

Participants may join by accessing the webinar online at Beef Brunch page..

For more information on the Beef Brunch Webinar Series, please contact Ashley Edwards at 512-818-5476 or akedwards@agcenter.lsu.edu.

Central Region Horticulture Hints

Our Regional Horticulture Agents and specialists put together the Horticulture Hints for the Central Region in Louisiana. Check out the Fall 2020 Central Region Horticulture Hints. These are done quarterly and have great information on timely issues happening across our region. Great resource and information for any homeowner or commercial horticulturalist.

Fusarium Head Blight of Wheat (Scab) in Louisiana

Steve Harrison, Trey Price, and Boyd Padgett - LSU AgCenter scientists, Kelly Arceneaux and Allyson Harding, LSU AgCenter research associates

Introduction

Fusarium head blight (FHB, commonly referred to as scab) is primarily caused by Fusarium graminearum. The fungus causes shriveled and poorly filled seed that result in reduced yield and test weight. The pathogen also produces the mycotoxin, deoxynivalenol (DON), which is toxic to animals and humans and can cause grain rejection at the elevator. Scab has been a major problem in Louisiana wheat over the past several years and is a major factor in the decline of Louisiana wheat acreage. Management of FHB is difficult because there are no highly effective single management practices (varieties or fungicides) and an integrated approach is required.

Epidemiology and Symptoms

Scab management begins with an understanding of the conditions favoring infection and disease development. The fungus infects corn and wheat and fields planted to corn the previous year, are at higher risk of developing scab than those planted after soybeans. Infested corn debris (also wheat straw and other hosts) can harbor the pathogen and serve as initial inoculum sources. Fungal spores produced on this debris are dispersed by rain splash or wind to nearby wheat plants. Other inoculum can be introduced into the field via windblown spores. Other hosts include 14 genera of Poaceae, two genera of Fabaceae, and one genus of Cucurbitaceae. Once an epidemic begins, plant to plant spread is likely to occur. Infection normally occurs during flowering but can occur from head emergence though early grain fill. Prolonged periods of rainfall during flowering and temperatures from 75-85^oF are conducive to scab development. Symptoms usually appear 10 to 14 days after flowering as bleached sections of heads, which will be evident from the turn row (Figure 1). This symptom is often mistaken with the appearance of maturing wheat. Upon closer inspection, affected fields will usually have infected heads showing the characteristic bleached appearance of sections (florets) with pinkish/salmon/light orange coloration along the glumes (Figure 2). This coloration is caused by millions of microscopic spores (reproductive structures) of the pathogen. There are usually healthy kernels along with the diseased kernels on the same head (Figure 2). In extreme cases, however, the entire head may be infected. At harvest, infected seed will be shriveled, off-color, much lighter than healthy kernels, and are referred to as “tombstones” (Figure 3) or Fusarium Damaged Kernels (FDK).

Figure 1. FHB infected field showing bleaching of heads.

Figure 2. Wheat head showing infected and healthy sections and salmon-coloration along glumes.

Figure 3. Scabby kernels showing shriveling and discoloration versus healthy kernels.

DON

The advisory levels for DON are as follows:

1. One ppm DON on finished wheat products such as flour, bran, and germ, for human consumption.
2. 10 ppm DON on grains and grain by-products and 30 ppm in distillers grains, brewers grains, and gluten feeds with limits on daily intake.
3. 5 ppm DON on grains and grain by-products destined for swine with the added recommendation that these ingredients do not exceed 20% of their diet.
4. 5 ppm DON on grains and grain by-products destined for all other animals with the added recommendation that these ingredients do not exceed 40% of their diet.

This guidance has been prepared by the Division of Plant and Dairy Food Safety in the Center for Food Safety and Applied Nutrition and the Office of Surveillance and Compliance in the Center for Veterinary Medicine at the Food and Drug Administration (FDA).

Additional information on DON can be found at: Guidance for Industry and FDA: Advisory Levels for Deoxynivalenol (DON) in Finished Wheat Products for Human Consumption and Grains and Grain By-Products used for Animal Feed

Management

While there is no single effective management practice, combining a moderately resistant variety with a timely fungicide application for suppression of FHB can significantly reduce damage from this disease. It is important to have a management plan in place before planting. Each year LSU AgCenter scientists evaluate scab severity in variety trials, and in inoculated, misted nurseries at several locations. This information can be used to help a grower choose varieties with moderate levels of FHB resistance along with good yield and agronomic characteristics.

Other management practices that may aid in management include crop rotation with non-host crops, tillage, mowing/shredding, or staggered planting/varietal maturity. At harvest, combine fan speed may be increased to blow out infected seed, which is lighter than healthy seed. This practice can lower FDK and DON, an increase test weight of harvested grain. Additionally, seed cleaning equipment may help remove affected seed but may not be cost effective. These cultural practices alone will not completely manage FHB. An integrated approach is required to lessen the impact of FHB.

• If possible, plant moderately resistant, locally adapted varieties.
• Avoid following corn and start with a clean seedbed if possible.
• Apply a suppressive fungicide in a timely manner. Triazole fungicides are suppressive on FHB, and some are more effective than others (Table 1). Generally, applications of Prosaro, Proline, or Caramba at flowering will reduce scab severity and DON while preserving yield.
• More recently, an SDHI/triazole premix marketed as Miravis Ace, has been shown to be competitive with the best triazoles (Table 1).
• DO NOT APPLY a QoI (strobilurin) fungicide after flag leaf emergence. These fungicides can increase DON.

Timing is critical. There is a very short window during flowering to make an effective fungicide application for FHB control. The biggest problem is that ideal conditions (wet weather) for FHB infection are not conducive to making fungicide applications by ground. Head coverage also is critical. Sprayers should be calibrated to deliver maximum water volume (minimum 15 GPA by ground, 5 GPA by air) and optimal droplet size (300 to 350 microns).For ground sprayers, nozzles angled at 30° to the horizontal will maximize head coverage. Some research has shown that dual nozzles angled in opposite directions will also increase head coverage.

It is common to see several years of scab epidemics followed by a year with little to no disease. In Louisiana, scab epidemics have occurred in 5 of the last 6 seasons. There are disease forecasting tools that predict the likelihood of a scab epidemic based on weather pattern, variety susceptibility, and crop growth stage. The ScabSmart Fusarium Risk Assessment Tool that is based on temperature and relative humidity is available online, and has regional commentary that will help you to determine scab risk at your given location. This is the only practical way to determine the need to spray since scab symptoms may not show up for a week or more after infection occurs. For more information, please see the following resources:

www.scabsmart.org

www.scabusa.org

Table 1. Fungicide efficacy for control of wheat Fusarium head blight (scab).

¹Application of products containing strobilurin fungicides may result in elevated levels of the mycotoxin Deoxynivalenol

(DON) in grain damaged by head scab. P = poor, F = fair, G = good, NL = not labeled, NR = not recommended.

²Multiple generic products containing the same active ingredients also may be labeled in some states.

³Based on application timing at the beginning of anthesis (Feekes 10.5.1).

Varietal Resistance to Fusarium Head Blight Disease

Over the past 10 years a very high priority has been placed on development of FHB resistant wheat varieties by the SunGrains breeders, particularly the LSU AgCenter wheat breeding program. Our goal is to develop high-yielding FHB-resistant wheat varieties adapted to the unique environment of the Gulf Coast region and to present information to growers to help them deal effectively with FHB. To accomplish this, misted nurseries inoculated with scabby corn are grown at Alexandria, Baton Rouge, and Winnsboro to characterize FHB reaction of LSU breeding lines and entries in the state variety trials and regional nurseries. Molecular markers and genomic selection methods are also used to enable ‘stacking’ of several FHB resistance genes in the same variety. This is important because there are no single genes that provide a high level of resistance, but genes can be stacked in a variety to provide a higher level of resistance.

When evaluating FHB ratings keep in mind that scab is greatly influenced by rainfall and temperature during heading. When comparing FHB, FDK, and DON of varieties in the yield trials, it is important to compare varieties that head within a few days of each other. Very early or late-heading varieties may escape disease by virtue of flowering at a time when weather was not conducive for infection. The use of misted and inoculated nurseries (Figure 4) ensures heavy disease pressure during flowering and avoids confounding of genetic resistance with maturity differences. Determination of genetic resistance should be based on several locations and years when scab was present. AgCenter researchers collaborate with other scientists across the nation as a part of the U.S. Wheat and Barley Scab Initiative , and this is an excellent source of information on scab. Efforts from this multi-state initiative are directed toward developing and identifying varieties and management practices that minimize the impact of this disease on growers. In addition, new and existing fungicides are evaluated for their ability to reduce infection and spread of scab.

Figure 4. Misted and inoculated nursery used to evaluate FHB reaction of wheat varieties.

The complete wheat performance report and data tables can be found at the wheat and oat variety trials website or AgCenter's Small Grain Breeding and Performance Trial Data .

Table 2 gives a Fusarium reaction type and FHB traits data based on at least two years of data in the disease nurseries. (Click here for sortable Table 2 in Excel format. ) Keep in mind that this data is from a misted and inoculated nursery and that disease pressure is intense in order to separate varieties. Normal yield plots and grower fields are very unlikely to have disease levels this high. Table 3 contains yield and agronomic performance of varieties tested in the past two years in Winnsboro, LA. (Click here for sortable Table 3 in Excel format.) Varieties are classified as Resistant (R), Moderately Resistant (MR), Moderately Susceptible (MS), or Susceptible (S) based on FDK and DON data for at least two years. There are big differences in FHB reaction of the varieties. If possible, growers should choose a MR or R variety that has good grain yield and agronomic characteristics.

Acknowledgements

The authors appreciate and acknowledge support for this research provided by the Louisiana Soybean and Grain Research and Promotion Board.

DON analysis was conducted by the USDA Mycotoxin Diagnostic Laboratory in the Department of Plant Pathology Department at the University of Minnesota under the direction of Dr. Yanhong Dong.

This research is also supported by the U.S. Department of Agriculture, under Agreement

No. 59-0206-8-206. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative.

Table 2. Fusarium Headblight Reaction and Ratings from Winnsboro Disease Nursery for Two Years.

Contains data for entries tested in past two years in misted nurseries at Winnsboro in 2018, 2019 and 2020.

^aFHB Reaction is observed reaction based on FDK and DON for two or more years. Reaction Types are: Resistant (R), Moderately Resistant (MR), Moderately Susceptible (MS), and Susceptible (S).

^bFHB rating is a 0-9 score of head symptoms, where a 0 indicates no symptoms and a 9 indicates complete head coverage

^cFDK is percent Fusarium Damaged Kernels.

^dDON is parts per million of Deoxynivalenol toxin. DON data from 2020 is not complete.

Table 3. Performance in normal wheat variety trial across North Louisiana for two years.

Data from Alexandria and Winnsboro in 2019 and 2020.

^aBold 'Brand/variety' indicates the entry is commercially available, others are non-released breeding lines.

^bFHB is Fusarium Headblight Reaction Type based on at least two years of data from a misted and inoculated nursery. Resistant (R), Moderately Resistant (MR), Moderately Susceptible (MS), and Susceptible (S).

^cGrain Yield is bushels per acre at 13% moisture.

^dTest Weight is pounds per bushel.

^eHead Day is day of year for 50% heading.

^fStripe rust is relative score with 0 = none and 9 = severe infection and dieback.

^gLeaf Rust is percent tissue of upper three leaves affected by leaf rust.

^hNS indicates that variety mean difference were not statistically significant.

Get Your Lawn Ready for the Fall & Winter

With our fingers crossed and the hope of cooler weather, we need to think about how to it will affect the growth of warm-season grasses like St. Augustine, centipede, Bermuda, and zoysia. Typically, the cooler weather means that these grasses will begin to slow down. With this slowdown in growth, it is not a good idea to do anything that would disrupt or damage the turf such as filling, aerating, or dethatching. Even though we should not have to mow as often, it is still important to mow regularly to maintain proper height and make sure that mower blades are still sharp.

Photo 1. Warm season grass growth chart.

According to LSU AgCenter Specialists, most warm-season grasses will be completely or partially dormant by mid- to late November or December. The only exception may be with St. Augustine, which may not go completely dormant during mild South Louisiana winters. This dormant period is how the turf in your yard can survive the potential freezes during the winter months.

The LSU AgCenter does not recommend applying fertilizers high in nitrogen (the first of the three numbers on the bag) this late in the summer as it will stimulate fall growth. This stimulated growth this late in the summer makes the grass more susceptible to cold injury this winter by not allowing it to go dormant and in the case of St. Augustine grass, attack from the fungus disease called brown or large patch during the mild fall months.

Photo 2. Brown patch damage. Photo by Dan Gill.

This time of year, we begin to see and hear about a good time to winterize your lawn. According to Ron Strahan, LSU AgCenter Turf Specialist, winterize is a term, when used with warm-season grass lawn care, is simply stated as slow down growth, and increasing the levels of nutrient potassium (the third number on the bag), which is an attempt to toughen plant tissues for the winter freezes. Be careful with winterizers that contain high levels of nitrogen. The first number in the analysis of these fertilizers, which is the percentage of nitrogen, should be zero or very small. The third number, which is the percentage of potassium or potash in the fertilizer, should be the highest, as in 0-0-60, for instance. We recommend you do not purchase winterizers with substantial amounts of nitrogen.

If you are having a problem with late-summer broadleaf weeds you can spray lawn weed killers now. There are many formulations available that kill a wide range of weeds with a single product. As always check to label to make sure it is suitable for the type of grass you have in your lawn. Just remember, since it is too late to fertilize, stay away from using weed-and-feed herbicide and fertilizer this late in the summer.

It is also the time of year to begin to think about preventative weed control for cool-season annuals like burweed (sticker-grass), chickweed, henbit, and annual bluegrass. These preemergence herbicides kill weeds as they germinate and before they emerge from the ground. Timely applications of these herbicides are critical for success and should be applied by early October. Preemergent herbicides prevent weed growth for several months and usually last through the spring. There are several preemergence herbicides available to homeowners in easy to spread granules and are less likely to damage your lawn if used as directed. LSU AgCenter recommends products like Greenlight Crabgrass Preventer, Hi-Yield Dimension, Scott’s Halt, and Greenlight Portrait. However, if you plan to overseed your lawn with rye, do not use these preemergent herbicides.

Insects and disease problems also occur later in the year. A common disease that is seen, especially in St. Augustine, during cooler, wetter months is brown patch. The areas of grass scan have yellowish or orange cast that turns tan or brown color (See Photo 1). Spread can be rapid and your grass will recover in the spring. If you decide to treat, fungicides labeled to control lawn diseases are available.

Another pest that can be active if the hot, dry weather lingers into the later months of the year, is the chinch bug. These ant-sized insects feed by sucking the sap from the grass, causing it to dry out and die. To spot this damage look closely at the blades of grass in the affected dead areas and see if they look rolled up lengthwise (See Photo 2). Since chinch bugs kill the grass, we recommend prompt treatment to minimize damage. There are a variety of lawn insecticides to control chinch bugs and are available wherever garden pesticides are sold.

Photo 3. Chinch bug damage. Photo by Dan Gill.

As the weather begins to cool, and the mowing of our lawns decreases, homeowners will enjoy a little lawncare relief. However, do not let this keep you from making sure your lawn is ready and protected from the winter months ahead. A little time in the lawn in the fall can payoff for a healthy, green lawn next Spring.

For more information on fall lawncare or other related topics, visit the LSU AgCenter website or call Mark Carriere, Pointe Coupee Parish County Agent, at the Pointe Coupee Parish Extension Office at (225) 638-5533 or via email at mcarriere@agcenter.lsu.edu.

Paraquat and Pre-Certification Training

Kim Pope Brown, LSU AgCenter Pesticide Safety Coordinator

It is that time of year when producers are starting to desiccate soybeans to aid in harvesting. The product that many producers use is paraquat. As many of you should be aware, in the fall of 2019, paraquat received a new label requirement. Anyone who handles paraquat products must be a certified applicator and must successfully complete the new paraquat training course. Below are a few reminders for producers and applicators who are using or plan to use paraquat:

• Product may only be mixed, loaded, or applied by certified applicators who have successfully completed the paraquat-specific training before use.
• Uncertified applicators can no longer use paraquat under the direct supervision of a certified applicator.
• Training can be accessed online through the “How to Safely Use and Handle Paraquat-Containing Pesticides” paraquat training module.
• Once completed, the training is good for three years.
• The training must be completed by the individual, and the individual must receive a 100% on the final assessment upon completion of the training. Multiple attempts can be made to score 100%.
• A certificate will be generated upon completion. Be sure to maintain this documentation for inspection.

With the changes to some of our product labels, farm crew members that have previously been able to work under the direct supervision of a certified applicator can no longer do so, depending on label requirements. The LSU AgCenter Pesticide Safety Education Program has put together a few opportunities to assist in test prep or pre-certification training for applicators who need a little assistance prior to taking the exam. Currently, we are offering virtual pre-certification training. Please see the dates and times in Table 1.

Table 1. Virtual Pre-Certification training dates and times.

People who wish to participate must pre-register at the LSU AgCenter online store by 4 p.m. the business day prior to the selected event. Once you have registered, you will be provided a link via email that you will use to connect to the training event on both days of your selected event. This training will be in two parts to help ease the amount of time in front of a computer.

The training will take a total of four hours to complete. The cost of the training is $45. This is the link for registration.

If there is something more specific that you need in your area, please feel to contact Kim Brown or Bryan Gueltig with the LSU AgCenter Pesticide Safety Education Program for more information at kbrown@agcenter.lsu.edu or bgueltig@agcenter.lsu.edu.

Winter Cover Crops: Benefits and Planning Strategies for Cover Crop Success

Josh Copes, Rasel Parvej, James Hendrix, Lisa Fultz, Syam Dodla and Naveen Adusumilli, LSU AgCenter scientists

Corn harvest is winding down across Louisiana, soybean harvest is in full swing and cotton harvest has begun in a few areas. As we move into the fall months, now is the time to begin planning your winter cover crop management strategy.

Cover crops are the most effective and efficient tool in improving soil fertility. Cover crops add organic materials to the soils that improve soil physical, chemical, and biological properties. They can improve soil organic matter content, cation exchange capacity (CEC), water and nutrient holding capacities, water infiltration, water use efficiency, soil structure, bulk density (a measure of soil compaction), microbial biomass and nutrient cycling. Cover crops ensure year-round ground cover that reduces soil runoff and erosion potentials, decreases weed pressure and herbicide needs, scavenges nutrients left over from the previous crop and prevents leaching loss of nutrients into groundwater.

Cover crop selection will depend on the goals a producer would like to accomplish. For example, a cover crop that produces a deep tap root, such as the tillage radish, should be selected for compacted or no-till soils.

Having a clear objective will also aid in cover crop management. For example, cereal rye can be a good choice for increasing soil organic matter, minimizing soil erosion, and suppressing weeds. The fibrous root system of cereal rye and other cereals helps prevent soil erosion and scavenge nutrients. In contrast, a tap-rooted cover crop — such as forage or tillage radishes, wooly pod vetch and red clover — is better suited for deep nutrient scavenging and potentially aids in loosening a soil compaction layer or preventing one. Mixes of cereal and legume covers can reduce early-season N fixation issues in corn. Legume cover crops such as crimson clover and hairy vetch can be a good source of nitrogen fertilizer for the subsequent corn or cotton crop, which could reduce fertilizer need and cost. Preliminary data collected by AgCenter scientists have shown that in soybeans, legume cover crops can supply N for early growth needs until nodules develop.

Other important considerations when selecting a winter cover crop includes the cash crop to be grown and winter cover crop termination. Be sure to plant only quality seed, which will help eliminate weed seed contamination issues. When planting legumes, make sure the rhizobium inoculant strain is correct for the legume species that will be planted, and always inoculate. If planting pre-inoculated legume seed, get pure live seed per pound and adjust seeding rates accordingly; some pre-inoculated seed is larger and therefore has less pure live seed per pound. Seeding rates of cover crops will depend on seeding method, date of sowing and whether the farm is enrolled in a CSP or EQIP program. For cereals, avoid low seeding rates and/or establishment methods that could lead to spotty emergence. Spotty emergence could cause the cereal to “bunch” (a single plant with multiple tillers and a large root system), which could lead to main crop establishment issues, such as skips and variations in seed placement depth and seedling emergence. Also, avoid planting a cover crop drill into the top and middle of the seed bed. This will prevent planting the cash crop into the cover crop drill, which could lead to stand establishment issues.

Cover crops should be planted as soon as possible following the main crop harvest. When planted earlier in the fall, nutrient scavenging will be increased and growth/biomass production will be maximized prior to cold weather, which will slow the growth and development of the cover crop. Planting your cover crop soon after harvest is especially important if corn will be planted. Early cover crop termination, when planting corn, combined with late planting of a cover crop (November) will reduce overall biomass production, therefore minimizing the benefits of the cover crop. Legumes are generally slow growing if planted late (November), and biomass production will be minimal prior to the onset of cold weather. If fields are enrolled in an NRCS conservation program requiring cover crops, be sure to follow the NRCS cover crop guidelines. Below is a link (hyperlink No. 1) that contains NRCS seeding rates and planting dates for common cover crops grown in Louisiana. In cooperation with the NRCS, data provided by LSU AgCenter research resulted in a reduction in cereal rye seeding rate from 90 to 120 lb/a to the current rate of 45 to 120 lb/a.

The planting window for most winter cover crops is Oct. 1 to mid-November. Ranges for average first frost dates for Monroe, Shreveport, Alexandria and Baton Rouge are November 15, 18, 19 and 29, respectively (Average Frost date by state). Hyperlinks No. 2 and 3 below are some useful tools that may aid in further refinement of accomplishing the intended goals for your farm. NRCS payments for cover crops change from year to year. Updated numbers are included in the decision tool (hyperlink No. 4) in estimating overall costs of cover crops implementation. If you have any questions or concerns, please feel free to contact your local AgCenter agent or one of us.

NRCS planting dates and seeding rates for common cover crops grown in Louisiana: Louisiana Seeding Rate Tables

Cover Crop and Tillage Scenarios (Potential Scenarios and their implications on incentives payments.)

Q & A of Conservation Policy and Crop Insurance Surrounding Cover Crops

Cover Crop Economics Decision Tool

Contact information:

Josh Copes
Cell: 318-334-0401
Office: 318-766-4607
jcopes@agcenter.lsu.edu

Rasel Parvej
Cell: 497-387-2988
Office: 318-435-2157
mrparvej@agcenter.lsu.edu

James Hendrix
Cell: 318-235-7198
Office: 318-766-4607
jhendrix@agcenter.lsu.edu

Lisa Fultz
Cell: 225-366-8863
Office: 225-578-1344
lfultz@agcenter.lsu.edu

Syam Dodla
Cell: 225-505-7064
Office: 318-741-7430
sdodla@agcenter.lsu.edu

Naveen Adusumilli
Cell: 318-884-0514
Office: 225-578-2727
nadusumilli@agcenter.lsu.edu

Soil Sampling and Testing

Rasel Parvej, Brenda Tubana, and Jim Wang, LSU AgCenter soil scientists

Soil Sampling:

• Soil should be tested at least once in every two to four years, or once in a complete crop rotation.
• Soil sample should be taken at the same time of each sampling year and at a constant depth of 0 to 6 inches with a soil probe or auger.
• At least one sample should be taken for every 10 acres of land for zone sampling and 2.5 acres of land for grid sampling. Both zone and grid sizes depend on spatial variability of the field. More soil samples are needed per unit area for highly variable fields. Therefore, soil type and color, past management, and yield map should be considered to determine the actual zone and grid sizes.
• Each soil sample should consist of 15 to 20 subsamples (i.e. two to three subsamples per acre for zone sampling and six to eight subsamples per acre for grid sampling). However, more subsamples are needed for fields that received fertilizer banding and/or manure spreading in the past. Subsamples should be taken in a zigzag pattern within each zone or grid.
• Scrape the thin layer of soil surface before inserting the soil probe or auger. When furrow irrigation is used, samples should be taken from the shoulder of the bed. However, for any field, samples should not be taken from fertilizer bands, manure or lime stockpiles, wet spots, fence rows and areas that are too small to manage separately. All subsamples should be mixed thoroughly in a clean plastic bucket. Remove stones, roots, stems, trash, and other debris from the mixed soil samples.
• Each soil sample should be placed in a separate plastic bag with clear labelling that includes farm name and location, sampling date and depth, previous crop, and expected crop to be grown and sent immediately to the soil testing lab for routine soil analysis.

Soil Testing:

• Soil samples should be tested in a certified soil lab, such as the LSU AgCenter Soil Testing and Plant Analysis Lab in Baton Rouge, that uses appropriate soil extraction methods. Soil-test-based fertilizer recommendations in Louisiana are based on Mehlich-3 soil exaction method.
• Soil samples should be analyzed in the same lab each year to create a historical record.

Soil Test Interpretation and Fertilizer Recommendations:

• Soil test results should be interpreted based on the critical soil test nutrient concentration. The critical concentration is defined as the soil test nutrient concentration below which crop response to added fertilizer is expected and above which is unlikely. Critical nutrient concentration varies with crops, soil types and U.S. state. Therefore, soil test results should be interpreted with crop, soil type and state-specific critical nutrient concentrations that are derived from correlation and calibration research. Usually, soil scientists from every land-grant university develop their own critical soil test nutrient concentrations for each crop of that state. So, it is best to analyze soil samples in the state soil testing lab.
• Fertilizer recommendations should be based on critical soil test nutrient concentration and fertilization philosophies. There are three main fertilization philosophies: sufficiency, buildup and maintenance, and cation saturation ratio. In the sufficiency approach — used by most land-grant universities, including the LSU AgCenter — fertilization is only recommended if the soil test nutrient level is at or below the critical level and the fertilizer rate is determined based on expected crop yield increase. This approach is called “fertilize the crop.”
  • In the buildup and maintenance approach, also known as “fertilize the soil,” fertilization is almost always recommended unless the soil test level is very high. The buildup part of this approach is used for soils with nutrient concentration below the critical level and the fertilizer rate is determined based on sufficiency rate plus some extra fertilizer to raise the soil test nutrient concentration above the critical level. The maintenance part is used for soils with nutrient concentration above the critical level and the fertilizer rate is determined based on the expected nutrient removal rate by the crop to maintain soil test nutrient concentration at the same level.
  • The cation saturation ratio is not very accurate or economic for fertilizer recommends. In this approach, fertilizer is recommended based on the cation ratio of mainly calcium (Ca), magnesium (Mg) and potassium (K) on the cation exchange site. The most used ratio is 65% Ca, 10% Mg, 5% K and 20% others.
• Care should be taken using the buildup and maintenance philosophy for K fertilization in coarse-textured soils with low cation exchange capacity (CEC <10) such as loamy sand and silt loam soils. Potassium is highly prone to leach down in the soil profile with excessive rainfall in low CEC soils. Building up the soil test K level in coarse-textured, low-CEC soils may not be feasible or economical. Please visit the LSU AgCenter website for detailed soil-test-based fertilizer recommendations for each crop.

Fertilizer Application:

• Fertilizer recommendations based on soil tests mainly include phosphorus (P) and K, which can be applied in the fall, especially for fine-textured soils with a high CEC (>20). For coarse-textured, low-CEC soils, it is better to apply all fertilizers in the spring or at planting. There is a misconception about spring application of P (triple super phosphate) and K (potash) that both fertilizers require a long time to dissolve and become available for plant uptake. Many studies have shown that a spring application of both fertilizers is better than a fall application in increasing crop yield, especially for soils that are highly prone to nutrient loss via leaching, runoff, and erosion.
• Because both P and K are highly immobile in soils, both fertilizers should be placed near the root zone (on the top of the bed for furrow irrigation systems) and incorporated with shallow tillage for tilth fields. Banding of P fertilizer is very effective for both acidic (pH <5.5) and alkaline (pH >7.5) soils because P availability is greatly affected by soil pH.

Soil pH and Liming:

• Soil pH is the most important soil quality component that greatly influences soil nutrient availability. Most nutrients are highly available at a soil pH of 6.5. Therefore, soil pH needs to be adjusted to the target pH either by applying lime for low pH (<6.0) soils or by elemental sulfur for high pH (>7.5) soils. Increasing soil pH by liming is a more common practice than decreasing soil pH with elemental sulfur.
• The rate of lime depends on the initial and target soil pH and the buffering capacity of the soil (buffer pH, ability of a soil to resist the change of pH). If the soil buffering capacity and the difference between initial and target soil pH are low, lime rate would be low. However, for soils with high buffering capacity (low buffer pH), lime rate would be high even for a small change of soil pH. Clay soils have higher buffering capacity and require a greater amount of lime for each unit increase of soil pH than silt loam soils. Note that LSU AgCenter Soil Testing and Plant Analysis Lab does not run buffer pH but does indicate the unit change of soil pH with the addition of maximum 3 tons of lime, thus allowing farmers decide how much they would like to spend, assuming higher than 3 tons lime may be too expensive.
• The target soil pH should be determined based on the crop to be grown. For example, soybeans are more sensitive to low soil pH than corn and cotton. The target soil pH should be set at 6.3 for soybeans and 6.0 for corn and cotton. Lime is required if the target soil pH is 0.2 unit more than actual soil pH.
• Lime takes at least six to nine months, depending on liming materials, to react with the soils and raise soil pH. Therefore, lime should be applied uniformly and incorporated by tillage in the fall.

Liming Materials:

• The quality of liming materials is very important to raise soil pH. There are two qualities of liming materials: purity and particle size. The purity of a liming material is determined in relation to pure calcium carbonate (CaCO₃), Calcitic limestone, which is rated as 100% (molecular weight of pure calcium carbonate is 100) and this rating is called calcium carbonate equivalent (CCE). The rate of lime recommended by soil testing labs is based on pure Calcitic limestone with 100% CCE. So, the actual lime application rate should be adjusted based on the CCE of the liming materials. For example, if the CCE of the liming material is 80% and the recommendation is 2 tons of lime per acre, 2.5 tons of lime (2 tons/0.80) per acre should be applied.
• Particle size is the fineness factor of liming material and is expressed as the percentage of liming material passes through various sized screens. The higher the percentage of liming material passes through the larger size screen (i.e. smaller hole), the greater the fineness factor would be. Finer particles are more efficient in neutralizing soil acidity (increasing soil pH) by reacting quickly with soils due to greater surface area or soil contact. However, the liming materials should have a good distribution of particle sizes with both smaller and larger particles so that smaller particles can raise the soil pH quickly and larger particles can have a long-term control in neutralizing soil acidity. According to current Louisiana recommendations for ground lime, 90% of liming materials should pass through a 10-mesh sieve, 50% should pass through a 60-mesh sieve, and 20% should pass through a 100-mesh sieve.
• Both purity (CCE) and particle size (fineness factor) of the liming material are expressed together as effective CCE (ECCE) or effective neutralizing value (ENV). The higher the ECCE or EVN of the liming material the more efficient it is in increasing soil pH. Like CCE, the actual lime rate also needs to be adjusted with the ENV of the liming material if the recommendations are based on ENV. For example, if the ENV of the liming material is 60%, but the recommended lime rate is based on standard calcium carbonate with 90% ENV, 1.5 tons (0.9/0.6) of lime should be applied for every 1 ton of lime recommended. Note that the lime recommendations from LSU AgCenter Soil Testing and Plant Analysis Lab is based on 50% ECCE or ENV.

Glyphosate-resistant Italian ryegrass management: Now is the time!

Daniel Stephenson and Josh Copes, LSU AgCenter specialists

Glyphosate-resistant Italian ryegrass has been an issue in the mid-South for the past 10 to 15 years. In Louisiana, growers have been battling this pest for five to 10 years, and the problem is spreading each year. Louisiana does not have ryegrass issues like Mississippi, but if control strategies are not implemented, Louisiana will.

Mississippi State University developed herbicide programs for glyphosate-resistant management, and the LSU AgCenter has adopted those programs for dissemination to Louisiana producers. The Mississippi program is divided into fall, winter and spring treatments for corn, cotton, soybean, and rice.

The fall program — the best strategy for glyphosate-resistant Italian ryegrass management — begins with residual herbicides that are applied mid-October to mid-November. Residual herbicide choices are S-metolachlor at 1.27 to 1.6 lb/A of active ingredient, Boundary at 2 pt/A, Zidua WG at 2.5 oz/A,trifluralin at 1.5 lb/A of active ingredient and Command at 2 pint/A. The crop to be planted dictateswhich residual herbicide should be used. S-metolachlor should be used for corn, cotton, and soybeans; Boundary for corn and soybeans; Zidua for corn and soybeans; trifluralin for cotton and soybeans; and Command for rice. Regardless of which residual herbicide is applied, tank-mixing with paraquat at 0.5 to0.75 lb/A of active ingredient is a must to control any emerged ryegrass at application.

If a fall cover crop will be planted, many of the residual herbicides listed above should not be applied before planting. However, research has shown that applying S-metolachlor or Zidua one to three weeks after emergence of cereal rye, clover and Austrian winter peas will cause little to no injury of the cover crop and will provide residual control of many winter weeds.

Winter programs, meaning mid-January to mid-February, are limited. Research shows that clethodim at 0.094 to 0.125 lb/A of active ingredient is the only choice; however, ryegrass must be no more than 4 to 6 inches tall at application. Remember that clethodim must be applied at least 30 days before planting corn or rice. Also, whether clethodim is applied alone or tank-mixed with another herbicide, always apply clethodim with a high-quality crop oil concentrate rather than non-ionic surfactant or methylated seed oil. In addition, spray-grade ammonium sulfate should be added.

More than likely, the clethodim application in the winter will be tank-mixed with other herbicides for burndown. If clethodim is tank-mixed with any auxin herbicide like 2,4-D, then 0.125 lb/A of clethodim must be used. Auxin herbicides can antagonize the activity of clethodim on Italian ryegrass, thus reducing control, but applying 0.125 lb/A is enough clethodim to overcome the antagonism. However, one major point is often overlooked. Italian ryegrass must be no more than 4 to 6 inches tall at this application if control is to be achieved. I have observed numerous claims of clethodim “failures” on ryegrass, then determined that the rate was less than 0.125 lb/A when tank-mixed with an auxin herbicide, was applied with an airplane so coverage was inadequate and/or ryegrass was much larger than 6 inches in height. Incorrect herbicide rate, poor coverage and large weed size are consistent reasons for herbicide failures regardless of the weed targeted or time of the year. Yes, clethodim-resistant Italian ryegrass has been documented in Mississippi. Louisiana has some highly suspicious sites that are under evaluation, but I believe resistance begins when clethodim is applied incorrectly. Please take the time to do it right.

Imagine it is March 10, corn will be planted in a few days and 12- to 36-inch, multi-tillered glyphosate-resistant Italian ryegrass is present in the field. Based on data, paraquat is the only option available in the spring program. Unfortunately, paraquat is not a great option. In this situation, applying paraquat at 0.75 to 1 lb/A plus atrazine at 1 qt/A followed by another paraquat application at similar rate 10 to 14 days later is required. An identical plan is required where cotton and soybeans will be planted, except tank-mix diuron at 1.5 pt/A of active ingredient for cotton or metribuzin 75 DF at 4 oz/A for soybeans. Understand that these paraquat applications are not going to “melt” the ryegrass or make it disappear. It will die, hopefully, but its carcass could hamper planting and/or compete with seedling crops.

Earlier this year I wrote an article entitled “Italian ryegrass is everywhere! Do not forget about it this fall” where I asked farmers, consultants and dealers to not forget about the ryegrass issue. Now is the time to take the plan discussed above and implement it. If we do not, then we cannot expect a different situation next spring.

Feel free to contact Daniel Stephenson at 318-308-7225 or Josh Copes at 318-334-0401 with questions. Have a great day.

Start Planning for Your Fall Garden

As summer’s end approaches, it is time to start thinking of your fall garden. That is right, as soon as your spring/summer vegetables start to finish their production cycle it is time to get an early jump on your fall/winter garden.

Photo 1. Start your seeds in a tray approximately this size. You can always put them into a larger size once they establish a healthy root system.

Unfortunately, we have past the time to start your seeds of broccoli, Brussels sprouts, cauliflower, Chinese cabbage, cabbage, cucumbers, squash, mustard greens, and shallot sets for an early fall garden start in September. However, remember you would want to begin to start those seeds for transplants at the end of July or early August.

Remember, start these seeds in trays on a table outdoors under the shade. It is important to keep the soil moist, not wet. If the soil stays too wet, it could cause your seeds to rot. Also, remember to not plant the seed too deep into the seed trays as this will cause for the seed to not emerge from the soil surface causing it to appear as if it never germinated. As the plant grows and the root system increases in size, you can begin to water them more and eventually you may even need to move them into a larger size pot (approximately 4” in diameter) prior to transplanting.

I usually recommend waiting until mid-to late September to transplant your fall crops. If you plant too early the remaining summer heat and worms tend to wreak havoc on them causing you undue stress. By the end of September, it is also a good time to direct-seed beets, bush beans, lettuce, and carrots.

So, plan ahead and prepare for your upcoming fall garden right now. Get those seeds ordered or pick them up at a local retailer to get them started soon. If you have any questions about when to plant, and how to plan your garden year-round, the LSU AgCenter Vegetable Planting Guide is a great resource. It lets you know the perfect time to plant your fall and spring garden vegetables, and the perfect rotation so you have a steady vegetable source from your garden all year long.

Photo 2. Louisiana Vegetable Planting Guide is a great resource to gardeners across the state.

For more information on preparing your home garden or about other resources from the LSU AgCenter, contact Mark Carriere, Pointe Coupee County Agent, by calling (225) 638-5533 or by emailing him directly at mcarriere@agcenter.lsu.edu.