Crops Blog

Agronomic Crops > Crops Blog

​On June 12, the EPA granted an exemption for the use of  flupyradifurone (Sivanto Prime) insecticide for use on Alabama sweet sorghum for the 2017 growing season, under the provisions of Section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act.  This will provide sweet sorghum producers with a much needed tool to control sugarcane aphid, Melanaphis sacchari.  Growers need to study the full Sivanto label, the  Section 18 label, and the EPA authorization letter to make sure they are using the product correctly.   The exemption expires on November 15, 2017.

Authorization lette

Sivanto label from CDMS 

Alabama Section 18 Exemption 


Kathy Flanders

flandkl@auburn.edu


Retaining bolls is important to cotton productionThe 2017 growing season is thus far a decidedly wet one. Rainfall throughout the state was a welcome change from the previous dry spell, but excessive amounts have delayed cotton plantings or caused isolated replants. For cotton that is established and approaching squaring, the next critical management activity is application of PGRs.

Heavy rainfall years will require a change in PGR strategies, especially for dryland producers. No matter the strategy though, it is critical to get the first application out early – prior to 1st bloom or even early if excessive growth is present. This is crucial to managing growth later in the season. Growers cannot rely on late season applications alone. A lone high rate application late in the growing season may achieve early cutout, but will have missed the objective of early season boll retention and growth reduction.

There are several misconceptions of what PGR accomplish in the cotton plant. They do not: stimulate Flowering, boll production, or have any significant effect themselves on yield. The do: Improve boll retention especially in the lower canopy, manage excess canopy growth and there by allows better pesticide penetration, can reduce boll rot incidence, and reduce lodging. It is all of these things combined that contribute to the likelihood of increased yields.

The name of the game is Boll Retention, especially early in the lower canopy. Retaining first position bolls boosts yield potential substantially. High square loss (25% or greater) trigger the plant to compensate with increased node production, greatly adding to excess vegetative growth. This growth is hard to control later in the season. In larger plants, it is difficult to get a high enough PGR concentration to have the desired effect of reducing growth. Early season PGR applications are extremely critical in wet years. The challenge is compounded by fewer chances to get the sprayer in the field. Therefore, it is imperative for growers to track and understand their cotton growth so timely applications are made (see image below - click image for full view). Below are some tips on monitoring cotton and strategies to consider.

Cotton morphology

DD60 = ((Max temp + Min temp)/2) - 60

Knowing the DD60 accumulation in a given field is important to effective plant growth monitoring. The table above gives a basic summary of DD60's required to reach flowing stage in cotton. During these critical stages measuring Height to Node Ratio (HNR), which is total plant height dived by the number of nodes present, can give a grower a good clue as to the type of growth the crop is having. If measurements are in the vegetative range, an aggressive PGR strategy would be advisable. Below are some recommendations on application strategies based on a moderate vs aggressive approach - click the image for a easy reading.

PGR application strategies1.jpg

For some basic take home points, PGR Application is Justified When…

  • Height: Cotton plant is 25-30 inches tall or greater during the 1st week of bloom.
  • Nodes Above White Flower (NAWF): Plant has greater than 9-10 nodes above first white flower during 1st week of bloom, and optimum growing conditions look to continue
  • Square/Fruit Retention: Square retention is low (50-75% or less) at first bloom and soil moisture is high.
  • Internode Distance: Is 3-5 inches between 4th and 5th node from terminal.

Trey Cutts, Extension Specialist/Assistant Professor

Cotton Cropping Systens Agronomist


In the last several weeks since the start of May, we had too much rainfall (>15 inches in many areas) during crop planting. I have received several inquiries regarding herbicide damage on cotton and peanut, mostly related to Reflex, Valor and Dual Magnum. I have summarized these questions below.

1. I have pigweed problem and I use Reflex behind the planter. However, it rained over 5 inches since I planted and my cotton seedlings is showing bad Reflex burn on cotyledons. What should I do? Should I replant?

The answer is check your crop stand first. If you do not have enough stand, then a replant is definitely needed. If the stand is acceptable and seedling burn is the only issue, wait to see if these seedlings will start to put on first true leaves (see Picture 1). As long as they start growing, it will be a matter of time for them to recover and usually no visible injury can be seen on true leaves. Varieties with high seed vigor (e.g. Phytogen 444) may get a better stand and grow out of initial injury sooner.

 

2. Will I lose yield because of soil herbicide injury caused by excessive rainfall?

No significant cotton and peanut yield reduction caused by soil herbicides has been observed in my research trials in the last two years, if these herbicides are sprayed within label rates. Herbicide injured cotton and peanut can usually grow out of initial injury and stunting in 3-4 weeks under normal growing conditions. However, if these crops suffer further stress such as prolong water- logging, thrips, snails, rhizoctonia, fusarium and other pests, yield loss may be possible. Therefore, managing other pests and stress will be important to secure yield.

 

3. Can Valor sprayed behind planter hurt my peanut if it rained too much?

In our Valor trial this year, I have observed some stand reduction in Valor 3 oz/A and Valor 3 oz + Strongarm 0.45 oz/A plots that were caused by excessive rainfall as compared to non-treated checks (see Picture 2). But nothing makes me very concerned and this stand reduction did not happen often in our trials. The Headland trial showed a little more stand reduction than Fairhope trial. One thing I have to mention specifically is if you plant old seed or low quality, low vigor peanut seeds, you may see Valor injury more often because those seeds may barely get you an acceptable stand even though you do not spray anything behind the planter. Seed quality and vigor are very important to overcome initial herbicide injury and stunting.

 

For more details about this article and images, please download Herbicide damage under excessive rainfall (2).pdf.

 

Steve Li,

Extension Weed Science Specialists


Below is a brief discussion of the seasonal activity of thrips and some major caterpillar pests based on moth catches from sticky wing pheromone traps that have also been summarized in the graphs. For detailed peanut insect pest scouting and control recommendations, please refer to the Alabama Peanut IPM Guide.

Thrips as an early season peanut pest is a common issue throughout Alabama. In the research plots in Headland have been severely affected by thrips with damage ratings in untreated check plots nearly 80% loss of terminal leaves in the three-week old plants. Peanuts with soil treatments such as Thimet, Admire Pro, Velum, and Orthene in single rows looked remarkably healthier compared to the untreated check (see picture below). Foliar treatments for thrips include Radiant (spinetoram), Besiege (premix), and Orthene (acephate). Check your plant condition and thrips pressure before using foliar treatments as they can also wipe out beneficial insects.

thrips damage 6-16-17.jpg

Lesser cornstalk borer (LCB):  This year we have found plenty of lesser cornstalk borer in Headland before the rains. On June 8, we counted nearly 11 LCB larva from 40 samples during the dry spell. Moth numbers were 109 during the week. On June 15, LCB moth counts reduced to 94 and only three caterpillars collected from the plot survey after the prolonged rain. LCB really like dry sandy soil, so watch those peanuts by pulling them out across several locations and watch for larvae and/or webbing.

Armyworm update:  Beet armyworm (BAW) moths are definitely on the move to peanuts and other crops in South Alabama. Moth numbers are around 28 to 34 moths per week for the past two weeks. You may start seeing caterpillars emerging from egg masses deposited by females on the lower surface of leaves (see picture below). Look at the terminal leaves while scouting for thrips and other insects as many insects lay eggs on those soft leaves. Fall armyworm (FAW) moth numbers near peanut fields has been low at this point; they could mainly infesting hay and pasture fields. July and August are typical times when we see migration of several different species of armyworms to peanuts.

BAW egg cluster1.jpg

Image courtesy: Kansas State University Extension

Last but not the least, watch for corn earworms and tobacco budworms. Corn earworms appear to be more active compared to the budworms and it is important to correctly identify the species. If your peanuts are small and insect pressure is low, then it is wise to ease up on foliar treatments so that you have control options when you really need them. Spraying with quick knockdown chemicals hurts the natural enemies (e.g., ground beetles, assassin bugs) that may be providing you good control of small caterpillars.

For any further information about peanut insects, check out the Alabama Peanut IPM website or call 251-331-8416. Stay in touch with your agronomic crop regional extension agent for immediate assistance.

Ayanava Majumdar, Extension Entomologist, 251-331-8416

Kris Balkcom, Research Agronomist

Peanut IPM:  www.aces.edu/peanutipm

Facebook page:  Alabama Peanut IPM    


facebook event stored grain.jpg

A series of workshops in Alabama will provide farmers with practical advice for managing stored grain pests.  The workshops are hosted by the Alabama Cooperative Extension System and sponsored by the Alabama Wheat and Feed Grain Producers.  On-farm grain storage facilities help farmers to keep their combines running and to get the best prices for their grain.  However poor storage conditions can reduce grain quality resulting in price discounts that offset potential gains from grain storage.  Participants will learn by observing actual grain storage systems, by hands on demonstrations, and by interacting with stored grain experts from Auburn University, the University of Georgia, Oklahoma State University, and industry.  Topics include stored grain pest biology, moisture management, temperature management, bin monitoring systems, sanitation, and chemical control.  The one-day workshop will be conducted near Headland (July 17), and then repeated in Atmore (July 18), Marion Junction (July 19), and Madison (July 20).  Pesticide Recertification and Certified Crop Adviser CEU's available.

Workshop Agendas

Southeast Alabama Stored Grain Workshop.pdf, July 17

Southwest Alabama Stored Grain Workshop.pdf, July 18

West Central Alabama Stored Grain Workshop.pdf, July 19

North Alabama Stored Grain Workshop.pdf, July 20

Posted by Kathy Flanders, flandkl@auburn.edu


​Southern rust (Puccinia polysora) poses a significant threat to corn in the southern third of Alabama and this disease has already been diagnosed in corn in Baldwin Co.  Yield gains from fungicide inputs have exceeded 80 bu/A under severe rust pressure in late-planted irrigated corn at the Gulf Coast Research and Extension Center (GCREC) in Fairhope, AL.   Destructive southern rust outbreaks occur every three to four years in Southwest AL, with disease onset typically occurring at tasseling or silking in outbreak years.  The relatively early diagnosis of this disease suggests that 2017 may be a bad rust year in Southwest Alabama, especially with the scattered shower forecast statewide for the next 10 days.  The risk of damaging rust outbreaks in corn declines with increasing distance from the Gulf of Mexico.  In addition to southern rust, Northern and Southern corn leaf blight along with gray leaf spot have also been diagnosed in corn at AAES outlying research units.  With the elevated risk from rust along with grey leaf spot, Northern and Southern corn leaf blight, fungicides are a possible disease control option.  It is recommended that corn producers only use fungicides as needed because yield gains in healthy corn from fungicide inputs is minimal.  The best yield gains from fungicides inputs typically occur in fields with a yield potential in excess of 175 to 200 bu/A.  Corn should be scouted weekly beginning at tasseling or silking for diseases.  The impact of diseases is greatest between tasseling (GS VT) and the soft dough (GS R4).  Over a three year study period, the least effective fungicides in terms of rust control and yield gains were Muscle 3.6F (generic tebuconazole) and Tilt 3.6E (propiconazole).  Rust severity and yields for the latter fungicides sometimes did not differ from the non-fungicide treated control.  In contrast, Quilt Xcel and Priaxor provided superior rust control, which often translated into the greatest yield grains.  Other fungicides that significantly reduced rust damage along with increased yield above that of the non-treated control were Fortix and combination of Aproach/Aproach Prima.


Spider mites (specially the two-spotted spider mite, Tetranychus urticae) is a regular occurrence in many row crops of Alabama. The 2016 drought really provided the perfect conditions for spider mites in peanuts, especially those treated with synthetic pyrethroids for managing mid-season insects like caterpillars. Once you get spider mites in peanuts, there is only one registered chemical class. The recent US Drought Monitor has started to show some areas of abnormal dryness – so stay alert and watch the drought monitor (picture below).

us drought monitor map 5-23-17.jpg

This article summarizes our first-year spider mite research in peanuts where we deliberately used a synthetic pyrethroid to flare up the pest. This research was done under a high tunnel in Clanton in order to exclude rainfall (rains have ruined many of our studies in the past). Peanuts were treated with bifenthrin on August 1 and 15 at 6 oz per acre; these chemical treatments killed beneficial mites and aggravated the two-spotted spider mite to invade the crop. After about 10 days post-treatment, we had a terrible outbreak of spider mites that was shocking to the eye. Within 15 days post-treatment, spider mites started to aggregate in large numbers on the leaf terminals and the plants were severely webbed (picture below).

 spider mite species1.jpg

Interestingly, another species of spider mites, Tetranychus tumidellus, was found at Brewton last year. T. tumidellus has red body and flared up in one area of the field, but never did as much damage as T. urticae. So, if producers see anything interesting like this, then please take a picture as best as you can and contact a regional extension agent so we can document cases. In 2016, we tested two unregistered miticides, Agri-Mek and Portal, with the hope that the industry may be interested to register them in peanuts in future (there is a IR-4 proposal in the making). Comite was the registered miticide for comparing effectiveness of spider mite control. Split or single application of Portal and Agri-Mek significantly reduced two-spotted spider mites compared to the untreated check; the products also had good persistence in controlling mites (picture below).

 miticide results1.jpg

When seen under a microscope, dead spider mites are visible as shriveled bodies compared to mite samples from untreated plots. Overall, we were able to show from this study that spider mites alone can cause 29% yield loss in peanuts under stressful environmental conditions.

 peanut plot pic1.jpg

In conclusion, peanut producers should pay very close attention to insecticide rotation and use some of the new softer or more selective insecticides for caterpillar control to prevent spider mite outbreak. Selective insecticides are also safer to beneficial insects that feed on caterpillars and other pest species. Irrigation in peanuts is also helpful to reduce some foliar and soil insect pests. There are many choices for pest management when insects/mites are detected early and treated timely; call a regional extension agent or go online for the Peanut IPM Guide for developing an IPM plan suitable for your farm. For contacting the author (Dr. A), call or text 251-331-8416. The Alabama Peanut IPM program also has a mobile-friendly website and sends additional pest alerts via Facebook.      

Ayanava Majumdar, Extension Entomologist 

Kris Balkcom, Extension Agronomist


With all of the rain that we have gotten lately, many people had already burned down their fields but then were unable to plant. They are now in the situation where they have 2-4 inch weeds, wet fields, and won't be able to plant for another week. Rain is predicted for next week, so what is the best option. ​Obviously, since you are using a burndown, we are talking about a no-till situation so tillage is not an option. Even though it is late for planting, you are still able to plant soybeans and cotton but you don't want to use a burndown that has a plantback time. The best option at this point would be to apply another burndown of Gramoxone. The best time to apply Gramoxone is either early in the morning or right before the sun goes down. We ( Larry Steckle, Garrett Montgomery (The University of Tennessee) and I conducted a study for two years on the time of day effect on different herbicides. We determined that gramoxone controlled horseweed 85% when sprayed at sunrise, 59% when applied at noon, and 92% when applied at sunset. There was no difference between the sunrise and sunset applications but we deterimined that when the gramoxone is applied during the middle of the day it is burning the plant so quickly that it doesn't have time to kill the plant. With this option, you don't have to worry about waiting for a plantback time or for the weeds to die. They will die within 24-36 hours and you will be ready to plant as long as you can get in the field.


Some Areas of Central Alabama experienced extremely heavy rainfall, as seen in the graphic below, over this past Saturday night (May 20-21st) and heavy rain is forecasted for the next 2 days. This may cause the need for some localized replanting. Cotton seedlings are extremely sensitive to heavy rainfall or flooding. If producers have a failed stand, there is still time in Alabama to replant cotton versus switching to an alternative crop. Cotton can be planted through the 1st week of June without excessive risk.

Making a replant decision is not clear-cut. Cotton has the capacity to recover from poor conditions early in the season, so consider the points below in making that decision:

  • If there is any doubt about whether to replant, it is best not to replant.
  • Although an optimum cotton stand is 2 to 4 plants per foot, 1 to 2 plants per foot with a uniform stand can still bring acceptable yields.
  • Research has shown that excessive skips, such as a dozen 3-foot skips in 80 row feet, can justify a replant.
  • Only make the decision after the crop has had a few days of good growing conditions.
  • If replanting in early June, utilize an early maturing variety and manage accordingly.
  • Be sure to terminate the old stand with a burn-down herbicide application.
  • Only spot plant portions of a field within 14 days of original planting to avoid later management problems.

Alabama Rainfall Totals 20 May, 2017 - National Weather Service
(Click on map to enlarge.)


The effectiveness of Velum Total alone or in combination with a pegging-time application of Propulse was compared with AgLogic aldicarb 15G for managing peanut root-knot nematode juvenile populations, leaf spot and white mold suppression, and yield of the peanut variety Georgia-06G on an irrigated site with an established peanut root-knot population at the Wiregrass Research and Extension Center in Headland, AL. Peanut was cropped behind cotton in 2013, peanut in 2014 and 2016, and sunn hemp in 2015.  At-plant nematicide treatments included Velum Total at 18 fl oz/A applied with a single nozzle centered over the open seed furrow in 5 gal/A spray volume, AgLogic aldicarb 15G (aldicarb) at 7 lb/A applied in-furrow.  A non-treated control was also included.  To simulate a through-the-line application, Propulse at 13.7 fl oz/A was broadcast to Velum Total-treated peanuts at-pegging with a tractor-mounted boom sprayer with three TX-8 nozzles per row calibrated to deliver 15 gal/A of spray volume at 45 psi and immediately watered in with 0.2 inch delivered via a lateral irrigation system. Planting date in all study years was in early June.  The study was irrigated as needed in all study years. Leaf spot and white mold were controlled with a calendar fungicide program that included multiple application of Provost 433SC alone or alternated with Abound 2SC along with additional applications of Bravo WeatherStik and/or Absolute for a total of 7 total fungicide applications per year. Vigor ratings were recorded approximately 30 days after planting. Leaf spot intensity and stem rot incidence were recorded immediately before and after inversion, respectively. Root-knot damage to the roots and pods was rated immediately after plot inversion. Seedling vigor differed by nematicide treatment but not by study year. Greater vigor ratings were obtained with Velum Total alone or with Propulse at-peg compared with the non-treated control, while the vigor rating for AgLogic aldicarb was intermediate.  Leaf spot intensity differed by year with the greatest disease ratings recorded in 2013, while minimal leaf spotting and premature defoliation observed in 2014 and 2016. While Velum Total fb Propulse at-peg had lower leaf spot ratings than Velum Total alone along with AgLogic aldicarb and the non-treated control in 2013, similar leaf spot ratings were observed for all nematicide treatments and non-treated control in 2014, 2015, and 2016. White mold incidence was also lower for Velum Total fb Propulse at-peg program in 2013 and 2016 when compared with the non-treated control, however, no differences in disease incidence were noted in any study year between the former nematicide program and Velum Total alone. Greater stem rot indices were reported in 2013 and 2014 for AgLogic aldicarb than the non-treated control. Final root-knot juvenile populations differed by study years with the greatest numbers reported in 2014, while equally low counts were noted in 2015 and 2016.  Yields differed by study year and nematicide treatment with 2015 having the greatest, and 2014 and 2016 having equally low yields, when peanut followed peanut. Yield response with the Velum Total alone and Velum Total fb Propulse at-peg but not the aldicarb programs was significantly higher than the non-treated control. Yields for Velum Total alone and aldicarb products were similar.


1 - 10Next