Volume 9, Issue 2 - March 2019

Daniel Fromme, Davis, Jeff A., Stephenson, Daniel O., Brown, Sebe, Price, III, Paul P, Padgett, Guy B., Brown, Kimberly Pope, Deliberto, Michael

Louisiana Crops Newsletter Volume 9 Issue 2 March 2019 banner.jpg thumbnail

Corn growth and development depend on temperature

By Dan Fromme

Corn growth and development are closely related to temperature. Warmer temperatures mean faster corn growth, and cooler temperatures mean slower corn development.

Temperatures are used to calculate growing degree days (GDD). Some people call them heat units (HU). Several formulas exist to calculate GDD, but the one used most often is the modified 86/50 cutoff method (MGDD).

MGDD for any given day is calculated by subtracting 50 from the average daily temperature. To calculate the average daily temperature, add the daily high and the daily low temperatures, then divide by 2.

GDD = max temp + min temp - 50 F

There are two rules for calculating MGDD. First, if the daily high was greater than 86 F, then 86 F is used to calculate the average. Second, if the daily low was less than 50 F, then 50 F is used to calculate the average. These upper and lower temperature thresholds, or limits, define the boundaries beyond which corn develops very slowly, if at all.

Throughout the years, we have talked about MGDD accumulation when silking or physiological maturity (black layer) occurs. For example, a particular hybrid will silk at 1,365 MGDD or reach physiological maturity at 2,800 MGDD.

Another useful purpose for following MGDD accumulation is to track the rate of leaf development prior to pollination. From V1 to V10, new leaves (defined by the appearance of leaf collars) emerge at a rate of about 85 MGDD per leaf. This is equivalent to about one leaf every five to six days in early April. From V10 to the final leaf, leaves emerge at a rate of about 50 MGDD per leaf.

Practical uses of this information include estimating how far along the corn crop should be for any given location if we know the planting date and the MGDD accumulations since the planting date.

It is especially important to know the emergence date, but if this is not available, we can use 125 MGDD from planting to emergence.

For instance, corn should reach the V6 growth stage by the time 635 MGDD have accumulated since planting. This is calculated by using 125 MGDD from planting to emergence, then figuring 510 MGDD (6 x 85) from emergence to V6.

Corn seed germination

By Dan Fromme

The radicle, or primary root, elongates first from the seed followed by the coleoptile, or shoot, growing in the opposite direction (Figure 1). Under good conditions, elongation of the coleoptile begins within a day of the emergence of the radicle. The coleoptile grows approximately 3/4 inch upward to the soil surface followed by differential mesocotyl growth. The mesocotyl is white internode tissue located between the seed and the coleoptile node, and elongates to push the coleoptile to the soil surface. Mesocotyl elongation continues until it perceives light near the soil surface.

corn germinationjpg

Figure 1. Corn germination with the radicle and coleoptile elongating from the seed. The blue color is from a pesticide for protection from insect feeding and disease infection.

Corn has two root systems: seminal and nodal

By Dan Fromme

The radicle is the first to elongate from the seed followed by the coleoptile (shoot). Soon after the appearance of the radicle and coleoptile, three to four additional seminal roots will elongate from the seed. Together, the radicle and seminal roots comprise the seminal root system, which helps establish the young seedling by absorbing water and nutrients from the soil.

Two distinct roots systems exist in corn: seminal and nodal. Nodal roots begin to develop at the coleoptile node, the junction of the coleoptile and mesocotyl (Figure 1). Nodal roots are consistently located 0.5 to 0.75 inches below the soil surface unless the seed was planted shallow. The placement of this root system is related to the perception of incident of light by the mesocotyl. The length of the mesocotyl varies, therefore, due to seedling depth and is less for shallow-planted and more for deeper-planted corn. The recommended seeding depth for corn is 1.5 inches or deeper to ensure the root system develops properly and anchors the plant sufficiently.

Seminal root system growth slows following emergence of the coleoptile above the soil surface with maximum size reached at approximately V2. The nodal root system is visible at approximately V2 and represents half of the root mass by V3. It becomes the dominant root system by V6 and for the remainder of the plant’s life. The seminal roots are still distinguishable after V6 and can serve as a diagnostic tool later in the season to identify the original seeding depth, initial root health or presence of compaction zones.

Nodal roots will originate from each stalk node below the soil surface and can be identified. Nodal roots that originate from stalk nodes above the soil surface are commonly referred to as “brace roots” since they angle downward to help brace the plant from wind, although they function similar to other roots once they enter the soil. Brace roots may be visible by V9. Their presence varies among plants and fields due to environmental conditions. One to three sets of brace roots typically form on plants in commercial corn fields and are usually located at the nodes closest to the soil surface: nodes 6, 7 and 8. Node 6 brace roots are visible first and will be flush with or parallel to the soil surface while brace roots 7 and 8 will angle downward. Brace roots located at node 8 will typically not reach the soil surface. Approximately 70 nodal roots will originate from the stalk (below and above ground) over the course of the season, beginning with the first nodal roots to the upper brace roots. §

Source: Corn Growth and Development, Iowa State University, PMR 1009, March 2011


Figure 1. Seminal and nodal root development.

Methods to control corn prior to replanting

By Daniel Stephenson

I have begun to receive calls about termination of a corn crop where a poor stand was achieved. If cotton or soybeans will be planted rather than corn, clethodim is a good option. There are 1, 2 and 3 lb ai/gal formulations currently available, and 0.125 to 0.25 lb ai/A of clethodim will provide control.

If corn will be replanted, clethodim can be used to kill first-plant corn, but only 0.0469 lb clethodim/acre is allowed. Using a 1 lb/gal formulation, the rate is 6 oz of product/acre. A 2 lb/gal formulation is 3 oz of product/acre, and a 3 lb/gal formulation is 2 oz of product/acre.

Regardless of the formulation used, there is a six-day replant restriction before corn can be replanted. Please understand that if more than the labeled rate of clethodim/acre is applied, the replant restriction for corn increases to 30 days. Also be aware that clethodim can have residual soil activity, thus killing the replanted corn, if more than the labeled rate of clethodim is used and/or corn is replanted in less than six days.

Other options are paraquat at 0.625 lb ai/acre (i.e. Gramoxone SL at 40 oz/acre) plus metribuzin at 3 oz/acre or diuron at 1 pt/acre or atrazine at 1 pt/acre. Corn can be replanted immediately after this application. However, good coverage is essential, and even then, the grower may not realize complete control. Probably the best option, but not the most popular, is tillage — actually busting the corn seed or plant off the top of the bed.

Please call with questions. My mobile number is 318-308-7225.

Replanting corn? Consider the following.

By Dan Fromme

Replanting often is needed due to cold soils, flooding, frost, seedling disease, insect damage, hail and planting seed having poor vigor. This results in reduced plant stands and non-uniform emergence.

  • Determine the stand density.
  • Measure 1/1,000 of an acre (see Table 1).
  • Count the number of plants in the measured area.
  • Count the width of the planter (eight rows for eight-row planter, 12 rows for a 12-row planter, etc.) in at least six representative locations in the field.
  • Do not intentionally avoid areas in rows with gaps.
  • Multiply the average number of plants by 1,000 to obtain the final plant population per acre.

2. Determine yield potential of the current stand.

  • See Table 2.

3. In addition to not having an adequate plant stand, developmental or leaf stages may differ as a result of non-uniform emergence.

  • With a two-leaf delay on 33 percent of the plants, yield loss is 10 percent. At 16.5 percent delayed, loss is 5 percent. At 8.25 percent delayed, yield drops to 2.5 percent. And with just a 4.125 percent of delayed plants, loss is 1.25 percent.
  • With a four-leaf delay, yield losses are even greater. At a 33 percent delayed population, yield loss is 23 percent. That drops to 11.5 percent with 16.5 percent of the plants delayed, to 5.75 percent at 8.25 percent of plants delayed and 2.88 percent at 4.125 percent delayed plants.

4. Consider planting date when replanting. In Louisiana, yields drop by about 3 percent for each week that corn is not planted in April.

5. Estimate replanting costs, including tillage, seed, fuel (for tillage and planting), additional pesticides, labor, etc. §

Table 1. Feet of row representing 1/1,000 of an acre at different row widths.

Row width (inches)Length of single row to equal 1/1000 of an acre
3017 feet, 5 inches
3614 feet, 6 inches
3813 feet, 9 inches
4013 feet, 1 inch

Table 2. Relative yield potential of corn by population.

Final plant population (plants per acre)Percent maximum yield

Note: Values are based on preliminary LSU AgCenter research. 100-percent yield potential is estimated to occur with a plant population of 31,000 and early planting.

Corn Planting 3007 059jpg

New crop prices and spring planting decisions

By Michael Deliberto

Several factors influence a producer’s decision as to which crops they will plant this spring. Factors such as market conditions, price expectations, weather and rotation strategy play a pivotal role in the decision-making process. Some of these factors can be somewhat predictable based on agronomic and economic intelligence gathering, but Louisiana weather is the proverbial wildcard. Also, ongoing trade tensions between the United States and China only serve to exacerbate uncertainty surrounding spring acreage planting intentions and is a sentiment corroborated by many market observers.

Decreased exports for cotton and, in particular, soybeans created burdensome ending stocks that the markets cannot clear, and hence, that amount of unsold production is carried over into the next marketing year. It appears that for cotton, a smaller-than-expected 2018 crop will limit the amount of ending stocks carried over into the 2019 crop year. However, given acreage projections from the National Cotton Council and the USDA, new crop acreage appears to be in the neighborhood of 14.5 million acres for 2019.

Another important piece of market information is that many analysts are citing a wetter-than-normal spring. This will benefit the cotton-producing areas of West Texas in providing much-needed soil moisture. Recall that in 2018, abandonment rates in Texas were high, hence contributing to a shorter crop. With a smaller abandonment rate coupled with an expected 20 million bales cotton crop in 2019, cotton prices remain in a narrow price range, with new crop futures in the $0.72 to $0.77 (optimistic) per pound range. The larger crop continues to weigh on prices. Opportunity exists for the market to improve when this trade dispute is finally ended. In the meantime, December futures are in the range of $0.725 to $0.748 per pound as a larger U.S. harvest and trade uncertainty act to limit a major advancement in price.

From 2015-16 to 2018-19, there has been a year-over-year increase in the soybean supply advanced by expanded acreage and favorable production conditions. For 2019, U.S. planted acreage is expected to decline and range between 84 million and 86 million acres. This would be a 3-million- to 5-million-acre decline from the previous year. It is expected that soybean acreage will shift into cotton in the Midsouth region and into corn in the Southeast region of the U.S. At the time of writing, new-crop November futures for soybeans closed at $9.40 per bushel. Currently, futures prices are ranging from $9.25 to $9.59 per bushel. Ending stocks and reduced export sales to the U.S.’s main market (i.e. China) has suppressed price to the $8.60 per bushel mark for 2018, a decline from $9.33 per bushel received a year earlier. Sales to other markets have improved to a degree so as to keep the price afloat, but the volume of lost sales to China cannot be reallocated among smaller, albeit important, U.S. export customers. A resolution to the trade dispute is difficult to predict, but the recent announcement of Chinese sales is promising for a market trying to move surplus domestic stock.

Nevertheless, what are some factors producers should consider when evaluating the relative net return of cotton vs. that of soybeans? The LSU AgCenter Department of Agricultural Economics and Agribusiness has a Corn, Cotton and Soybean Net Returns Comparison Tool that evaluates relative returns of competing enterprises subject to production costs, expected yields, expected prices and land rent mechanism type as specified by the producer. The Microsoft Excel farm management tool can be accessed at https://www.lsuagcenter.com/articles/page1546614079640. The tool calculates net returns above variable costs and land rent for each crop and shows the difference, if any, between those two net returns in the table. Therefore, values shown in the table can be interpreted as the advantage in net returns per acre for one crop as compared to the other. As values for variable cost, yield and rent are changed, the corresponding net return differences will change accordingly.

The information provided in Figure 1 indicates the price points at which the net returns of cotton (yield of 1,050 pounds of lint per acre) exceeds the net return of soybeans (with a yield of 50 bushels per acre). At a cotton lint price of $0.73 per pound and a soybean price of $9.50 per bushel, the net returns to cotton are $98 more per acre than soybeans under the production cost and share rental percentage parameters contained in the decision tool. This scenario is producer-specific, as changes to one or multiple parameters will change the results in the net return comparison table.

Although it is difficult to predict what effect a resolution to the U.S.-China trade dispute may have on soybean prices, information from Figure 2 can provide insight into the price point soybeans can favorably compete with cotton when yield parameters are isolated for observation. In Figure 2, yields for cotton and soybeans were raised based on potential site productivity factors. Assuming that the cotton lint price remains at $0.73 per pound, once soybean prices move between $10.50 and $10.75 per bushel, soybeans then possess a net return advantage over cotton. However, as the price of cotton moves above $0.75 per pound, the net returns from cotton are greater than those for soybeans across all imposed price levels.

This farm management tool can assist producers in identifying the more profitable enterprise that should be included in a whole-farm management plan. Market conditions remain fluid, and the sensitivity of a change in the price of one crop alternative may have implications on the relative return difference between two competing enterprises. As such, production cost volatility, management intensity and rental rate can also impact net returns of an enterprise.


Figure 1. Cotton net return advantage compared to soybean net returns, scenario No. 1.


Figure 2. Cotton net return advantage compared to soybean net returns, scenario No. 2.

Monitor temps to decide when to plant cotton

By Dan Fromme

Cotton planting is just around the corner in Louisiana, and now is a good time to review a few key practices to help everyone get off to a great start in 2019. It is always best to plant according to soil temperature and not the calendar. If a field is planted too early, your cotton crop may suffer a stand loss and cold temperature stress, which reduces yield potential.

Germination can begin when mean daily temperature is 60 F at seeding depths, but growth will be slow at these temperatures. A soil temperature of 65 F at depth of 4 inches for three consecutive days and a favorable five-day forecast following planting are best. Also, nighttime minimum temperatures should be forecast to be above 50 F for the following five days. During the critical germination period, soil temperatures below 50 F can cause chilling injury to germinating cotton. Emergence will generally occur after accumulation of 50 to 80 DD60s, or heat units, after planting. Planting should be delayed if the five-day forecast predicts the accumulation of less than 25 heat units after planting. The minimum plant population in the final plant stand should be no fewer than two healthy plants per foot.

Creating a pest-free seedbed is critical to avoid problems from cutworms and spider mites. Pre-plant, burndown herbicide applications should be made at least four weeks prior to planting to ensure no green vegetation is in the field for these pests to survive. It is equally important to eliminate weedy host plants on field borders to reduce insect pest problems later on that might move into adjacent cotton fields.

For more information, see our publication at https://www.lsuagcenter.com/profiles/bneely/articles/page1545324682192

Soybean seed treatment decisions

Insecticide Seed Treatments

BY Sebe Brown and Jeff Davis

One of the most important decisions producers must make when planting soybeans in Louisiana is planting date. Soybeans can be planted from early March to late June. This wide variation in planting dates potentially exposes seedling soybeans to a multitude of insect pests that affect both above- and below-ground plant structures.

Optimal seeding dates for each maturity group planted in Louisiana are:

  • Group III: April 15 to May 10
  • Group IV: April 15 to May 10
  • Group V: March 25 to May 5
  • Group VI: March 25 to April 30

Soybean seedlings possess an exceptional amount of vigor and can tolerate a substantial amount of insect injury during the seedling stage. However, early-planted soybeans may also encounter greater environmental fluctuations that affect air and soil temperature. Cool conditions can negatively affect vigor and, under the right conditions, stall plant growth and development. The addition of insect injury to the aforementioned environmental conditions increases stress the plant encounters, resulting in loss of stand and yield potential. Therefore, the inclusion of an insecticide seed treatment (IST) provides growers a risk management tool when soybeans are planted early. The primary insect pests of early-planted soybeans are bean leaf beetles, three-cornered alfalfa hopper, wireworms, grape colaspis and thrips.

On the opposite end of the spectrum are soybeans planted late (i.e. behind wheat or are late due to unforeseen circumstances such as inadequate or excessive soil moisture.) These beans are more at risk for insect injury due to the potential for large insect populations to build in neighboring fields and generally more insects present in the environment. As a general rule with all agronomic crops, the later the crop, the more insect pressure that will be encountered throughout the season. This is particularly evident when soybeans are planted into wheat stubble. Wheat stubble is favorable for the development of three-cornered alfalfa hoppers. Thus, an IST is a sound investment when soybeans are planted late.

However, soybeans planted in a timely manner, within the recommended planting window, under optimal soil conditions and low pest densities often will not benefit from the addition of an IST. Insecticide seed treatments typically produce the most benefits when environmental conditions are suboptimal. With the current economic climate and many agricultural professionals looking at areas to cut inputs, it is difficult to justify the use of ISTs on soybeans when planted under optimal conditions. Saving the cost of an IST can go to making a stink bug application later in the season, which may provide a greater economic return.

Outside of early- or late-planted soybeans are situations where ISTs are justifiable. These include weedy fields with incomplete burndown applications, reduced-tillage field arrangements, fields with historically problematic early insect pests (wireworms and three-cornered alfalfa hoppers) and the use of a cover crop. Each field is unique, and the use of ISTs as a blanket treatment over every acre may not be justifiable with $8 soybeans.

Soybean Fungicide Seed Treatments

By Trey Price and Boyd Padgett

Early-season disease concerns can include Pythium or Phytophthora species, causing seed rot, damping off or root rot in areas that are not well drained. Group 4 seed treatment fungicides provide some protection against these species. If soils are well-drained and planting conditions are optimal, disease caused by these pathogens is unlikely.

Pre-emergence seedling disease or post-emergence damping off caused by Rhizoctonia solani is the most common seedling disease in soybeans in Louisiana (Figures 1 and 2). Plants surviving the seedling stage may develop root rot, resulting in delayed development and stunting. Cold weather, nematode and insect infestation and herbicide damage may exacerbate Rhizoctonia damping off.

In recent years, less-than-ideal planting conditions have caused significant stand losses in Louisiana. Seed treatments containing a strobilurin (Group 11) or SDHI (Group 7) compound are very effective at reducing incidence and severity of Rhizoctonia damping off. The pathogen population, which is soil-borne, may be reduced in long periods of flooding, when soil temperatures are high and in fallow fields. Potential for disease is greater in lighter soils, and optimal conditions for disease development are 75 to 90 degrees with 30 to 60 percent soil moisture, although the pathogen is capable of causing disease at lower temperatures and in any soil type.

“Base” fungicide seed treatments — usually metalaxyl or mefenoxam plus at least one broad spectrum fungicide — have become more common. In most cases, base treatments adequately protect seedlings under the adverse growing conditions often encountered early in the planting window.

Results from many years of research trials indicate seed treatments will result in increased stand under moderate to severe disease pressure. However, realizing significant yield preservation and economic benefit in soybeans is the exception, not the rule.

If your seed company does not offer a choice of seed treatments, the base offering likely will be sufficient. It is unnecessary to over-treat base fungicides with additional fungicides unless targeting a specific problem. Also, know which fungicides come on the seed, as it is redundant to over-treat with a fungicide having the same mode of action.

If seed companies offer “naked” seed, soybeans may be planted without a fungicide seed treatment as long as you have no history of seedling disease issues, plant in the recommended window, achieve appropriate soil temperature and soil moisture, and schedule planting when the long-term weather forecast is ideal for soybean development. If you prefer to plant fungicide-treated seed, significant cost savings may be attainable by allowing distributors to over-treat or treating naked soybean seed yourself.

Harvest conditions in 2018 have limited the soybean seed supply and quality for 2019. Because soybeans may not be available for replanting, growers may want to treat seed to help ensure stand establishment. There are conflicting reports of fungicide seed treatments increasing soybean germination. Fungicides will not resurrect dead seed, but they may increase seedling vigor (i.e. a seed that is infected with a pathogen, but still alive) and should be considered if planting low-germ or low-quality seed.

Soybean Figure 1JPG

Figure 1. Thin soybean stand as a result of Rhizoctonia solani.

Soybean Figure 2JPG

Figure 2. Soybean seedling infected by Rhizoctonia solani.

Cotton seed treatment considerations

Insecticide Treatments
By Sebe Brown

In Louisiana and the cotton belt, thrips are considered the No. 1 early-season pest of seedling cotton. Tobacco thrips compose the primary species infesting Louisiana cotton while western flower thrips are often present at lower numbers. With the absence of Aldicarb (although we now have a commercially available Aldicarb replacement named AgLogic) insecticide seed treatments now dominate the early-season cotton insect pest management landscape.

As of 2019, there are only two seed treatment options: acephate and neonicotinoids. Imidacloprid and thiamethoxam are the two most commonly used neonicotinoids and these treatments are offered alone or in combination with nematicides. Based on bioassay data generated in the past seven years, the LSU AgCenter does not recommend thiamethoxam alone as a seed treatment for cotton. This is due to the formation of resistance by tobacco thrips. However, imidacloprid is still effective and when used in conjunction with the insecticide/nematicide thiodicarb (Aeris) provides very good control of thrips. If Aeris is not an option, imidacloprid over-treated with acephate (6.4 oz/cwt) is another viable option. Acephate alone will control thrips; however, acephate has a significantly shorter residual than imidacloprid and the probability of returning with a foliar application is very high. Also, if you elect to overtreat cotton seed with acephate, the seed cannot be returned.

In-furrow applications of imidacloprid also work very well controlling thrips. Four-pound imidacloprid at 9.2 oz/acre or 2 lb material at 19.0 oz/acre provides excellent control of thrips. AgLogic, the generic replacement for Temik, has demonstrated satisfactory control of thrips at the 3.3 and 4 lb/acre rates.

Lastly, foliar rescue treatments are also an option. Foliar treatments should be made when immature thrips are present and/or when large numbers of adults are present and damage is occurring. Seedling cotton will typically always have a few adult thrips, but the treatment trigger is the presence of immatures. The presence of immature thrips often signifies that the insecticide seed treatment has lost is efficacy and reproduction is occurring. Avoid spraying solely based on plant injury since the damage has already occurred. Be aware that residual herbicides and sand blasting injury can mirror thrips injury. Also, there are no currently labelled insecticides allowed to be tank mixed with dicamba or 2,4-D.

Some considerations when deciding what foliar insecticide to use follow on the next page.

Insecticide choice depends on a number of factors such as cost, impact on secondary pests and spectrum of thrips species present. If a foliar thrips treatment is justified, do not wait for a herbicide application, and only spray when necessary to avoid flaring spider mites and aphids.

Considerations when picking foliar insecticides


  • Pro: Relatively inexpensive, decent efficacy at high rates, less likely than acephate to flare spider mites and aphids.
  • Con: Less effective on western flower thrips, less effective than acephate or bidrin when applied at lower rates.


  • Pro: Relatively inexpensive, effective towards western flower and tobacco thrips.
  • Con: May flare spider mites and aphids if present.


  • Pro: Effective, less likely than acephate to flare spider mites and aphids.
  • Con: More expensive, less flexibility with applications early season.


  • Pro: Effective, least likely to flare spider mites and aphids.
  • Con: More expensive, requires adjuvant, more effective on westerns than tobacco thrips.

Intrepid Edge

  • Pro: Effective, unlikely to flare spider mites and aphids. Intrepid Edge is a mix of Radiant and Intrepid. Activity is similar to Radiant.
  • Con: Requires the application of two modes of action, but only gets the benefit of one.

Cotton Fungicide Seed Treatments

By Trey Price and Boyd Padgett

Many soil-borne fungi, including multiple species of Fusarium and Pythium, Rhizoctonia solani and Thielaviopsis basicola, cause seedling diseases of cotton under optimal environmental conditions (Figure 1). Cool, wet conditions encountered during planting and the early parts of the season immediately after seedling emergence often drive an increased incidence of seedling disease, which usually manifests as a complex of multiple pathogens. Seedling diseases may result in plant death, delay early season vegetative growth, delay maturity and ultimately reduce yield.

Seed companies usually offer base fungicide treatments containing one to four modes of action from Groups 3, 4, 7, 11 and/or 12, which in most cases are adequate for control. However, if adverse conditions are expected at planting, over-treatment of base seed treatments may be an option. Prior to ordering seed, or prior to over-treating, it is advisable to determine exactly which fungicides are included in base treatments since pricing, options and availability may vary with company. There are also potential redundancies when over-treating; that is, treating seed with two different fungicides from the same FRAC group (same mode of action) likely will not improve efficacy. Some seed companies offer flexibility with seed treatment options, which may provide an opportunity to reduce input costs. In cases where seedling disease pressure is high, even the best seed treatment products (regardless of active ingredients) may fail; therefore, using integrated disease management techniques in conjunction with fungicide seed treatments is recommended.

Finally, fungicide seed treatments and in-furrow fungicide products should be considered beneficial for seedling disease management within two to three weeks after planting.

For more information, contact your local agent, specialist or research station. Also, the resources below might prove useful.

Seed Treatments in Field Crops


Label databases



Cotton Figure 1JPG

Figure 1. Cotton planted without a fungicide seed treatment.

Paraquat and dicamba training requirements

By Kim Brown

In the past few months, there have been a few changes to the regulations pertaining to some of the commonly used pesticides in agriculture. As many of you are aware, the products Engenia, XtendiMax and FeXapan now only allow for certified pesticide applicators to apply these products. Non-certified individuals are no longer allowed to apply these herbicides under the direct supervision of a certified applicator. Please make sure that anyone applying these products gets their pesticide certification. Most applicators will need to become a certified private pesticide applicator when working on a farm and applying any of the pesticide products mentioned in this article. If an individual works for a custom pesticide applicator, then they will need to become certified as a commercial pesticide applicator. Please contact the LSU AgCenter Pesticide Safety Education Program using the contact information found at the bottom of this article.

On March 8, 2019, the Environmental Protection Agency (EPA) announced the availability of a required training module for certified applicators using paraquat dichloride, also known as paraquat. This training was developed by paraquat manufacturers as part of EPA’s 2016 risk mitigation requirements and has been approved by the EPA. This training covers paraquat toxicity, new label requirements and restriction, consequences of misuse and other important information.

Companies are required to have the newly labeled product on the market after Nov. 14, 2019; some may produce and sell newly labeled product before that date.

Paraquat is a restricted use pesticide for use only by a certified applicator. This new restriction applies to mixing, loading and applying paraquat as well as other pesticide-handling activities.

Applicators will most likely start seeing changes to paraquat labels sometime this year. One of the main changes to paraquat labels will be requirements similar to the aforementioned herbicides. Under the new label, applicators using this product will be required to be a certified pesticide applicator and take an EPA-approved training course. In addition to this training, applicators will be required to take a 15-question exam and make score 100 percent. This product-specific training will be good for three years once an applicator has completed this training and passed the exam.

When purchasing the newly labeled product:

1. Product may only be mixed, loaded and applied by a certified applicator who has successfully completed the paraquat-specific training before use.

2. Training must be repeated every three years. This requirement for training is only one of several actions EPA has taken to prevent poisonings with new label changes including:

3. Restricting the use of all paraquat products to certified applicators only.

  • Certified Applicator Statement (for mixers, loaders and applicators)
  • “Danger — one sip can kill.”
  • Skull and crossbones symbol on the container.

4. Clarifying toxicity in English and Spanish.

5. New graphics and statement on the label.

6. A “product package safety requirements sticker” affixed to the container.

7. A “counter card” reiterating the same important warning information to be distributed with every container.

8. Plans for closed system packaging for containers less than 120 gallons.

It is also important to note that the EPA is allowing the sale of paraquat that is already in the channels of trade, so some paraquat sold this growing season may not have the new training requirement on the label. If the new training requirement is listed on the label of the product purchased, they must complete the training. Growers that currently have paraquat without the new labeling listing the required training are not required to complete the training.

Additional information can be found at https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators. Please 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.

LSU AgCenter Specialists

SpecialtyCrop Responsibilities NamePhone
Corn, cotton, grain sorghum Agronomic Dan Fromme 318-880-8079
Cotton Agronomic Dan Fromme 318-880-8079
Grain sorghum Agronomic Dan Fromme 318-880-8079
Soybeans Agronomic Boyd Padgett 318-614-4354
Wheat Agronomic Boyd Padgett 318-614-4354
Pathology Cotton, grain sorghum, soybeans Boyd Padgett 318-614-4354
Pathology Corn, cotton, grain sorghum, soybeans, wheat Trey Price 318-235-9805
Entomology Corn, cotton, grain sorghum, soybeans, wheat Sebe Brown 318-498-1283
Weed science Corn, cotton, grain sorghum, soybeans Daniel Stephenson 318-308-7225
Nematodes Agronomic Charlie Overstreet 225-578-2186
Irrigation Corn, cotton, grain sorghum, soybeans Stacia Davis Conger 904-891-1103
Ag economics Cotton, feed grains, soybeans
Kurt Guidry 225-578-3282

Distribution of the Louisiana Crops newsletter is coordinated by
Dan Fromme

Dean Lee Research and Extension Center
8105 Tom Bowman Drive
Alexandria, LA 71302
Phone: 318-473-6522
Fax: 318-473-6503

We’re on the web.

William B. Richardson, LSU Vice President for Agriculture
Louisiana State University Agricultural Center
Louisiana Agricultural Experiment Station
Louisiana Cooperative Extension Service
LSU College of Agriculture

The LSU AgCenter and LSU provide equal opportunities in programs and employment.

Photos appearing in this newsletter were taken by LSU AgCenter personnel unless otherwise noted.

4/1/2019 7:53:55 PM
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The LSU AgCenter and the LSU College of Agriculture