Management Practices Archives - Department of Soil and Crop Sciences

Sorghum producers see less damage by sugarcane aphids

7Aug

By: Adam Russell

Grain sorghum producers are reporting sugarcane aphids in the High Plains, but the pest has made little impact on the Texas crop during 2020, according to Texas A&M AgriLife Extension Service experts.

But forage sorghum, an increasingly popular silage option, has experienced more significant losses, as producers and Texas A&M AgriLife scientists and specialists search for effective and efficient treatment methods. Those fields bound for forage production were not hard hit so far this year.

Pat Porter, Ph.D., AgriLife Extension entomologist, Lubbock, said sugarcane aphids have not been “as big a deal as they were years ago” due to creation of resistant hybrid sorghum varieties and vigilant monitoring and spray applications keeping their numbers in check as they migrate.

Sugarcane aphid nymphs and an adult on a grain sorghum leaf. (Texas A&M AgriLife Extension Service photo by Pat Porter)

Sugarcane aphids devastated sorghum fields after their 2013 emergence in fields around Beaumont. They made their way to the Texas Plains by 2015, and the results were catastrophic for sorghum producers.

Producers in the Rio Grande Valley alone lost $31 million to the pest in 2015, according to an AgriLife Extension study that also showed producers who utilized recommended scouting and spraying regimens once the pest neared thresholds avoided $35 million in potential losses.

Since then, sugarcane aphids effect on Texas’ sorghum production has waned, and Porter said this season has shown numbers continue to decline.

“There’s so many fewer aphids coming up from South Texas,” he said. “The resistant hybrids are the No. 1 factor, and then you have producers in South and Central Texas who are on top of their numbers and really decreasing the migratory populations.”

Porter said some producers along the Gulf Coast sprayed their fields, but he suspects sugarcane aphids may be manageable in the High Plains without applications if beneficial insect populations are well-established.

Forage sorghum

Forage sorghum, however, continues to be impacted by sugarcane aphids because there are very few aphid-tolerant forage sorghum hybrids. It is also planted more densely and grows taller than grain fields. Those factors make spray applications less effective and forage fields more susceptible to significant infestations.

Jourdan Bell, Ph. D., AgriLife Extension agronomist, Amarillo, said forage sorghum has become an increasingly important silage option for beef cattle and dairy producers in the region. It’s a drought-tolerant alternative to corn silage and can withstand intermittent periods of in-season drought stress without losing quality as quickly as corn.

Bell said Texas A&M AgriLife Research efforts are showing that sugarcane aphid effects on forage yields and quality can be mitigated with actions that reduce their impact on grain fields – timely identification and management.

Untreated test plots experienced 33%-44% yield losses and reduction in quality as a forage, she said. Data showed relative feed quality was reduced by as much as 50% under heavy sugarcane aphid infestations.

“With the arrival of sugarcane aphids on the Texas High Plains, we have seen many forage sorghum fields lost to sugarcane aphid feeding as well as yield and quality reductions,” she said. “It is important that producers and consultants are scouting their forage sorghum fields and applying timely insecticide application to maintain yield and quality.”

Texas cotton farmers adjusting in wake of court ruling on dicamba

23Jun

ByL Kay Ledbetter

The Texas A&M AgriLife Extension Service stands ready to advise producers on agronomic alternatives and options in the wake of a June 3 ruling from the U.S Court of Appeals for the Ninth Circuit to immediately vacate the registrations of three dicamba products, Xtendimax, FeXapan and Engenia.

Cotton producers across the nation are having to rethink their management after a recent court ruling on dicamba herbicide products. (Texas A&M AgriLife photo)

Approximately 80% of the state’s cotton has been planted, and an estimated 60-80% is XtendFlex cotton – a dicamba-tolerant cotton that would have allowed the application of available registered dicamba herbicide products for weed control.

Producers are working to determine their next moves, which are somewhat complicated by the different actions being taken by the U.S. Environmental Protection Agency, EPA, and the Texas Department of Agriculture, TDA, as well as those pesticide registrants involved in the litigation.

Dan Hale, Ph.D., AgriLife Extension associate director, College Station, suggests producers comply with the EPA existing stocks provisions by making allowable applications of products according to the specific product labels.

AgriLife Extension cotton specialists and county agents also suggest producers consider selecting alternative seed options with other herbicide technologies such as 2,4-D, if they have not planted their 2020 cotton crops.

Background

In 2016, EPA granted conditional, two-year registrations for these three products. When this conditional registration was set to expire in late 2018, EPA approved another conditional two-year registration for the products, with additional restrictions on use, said Scott Nolte, Ph.D., AgriLife Extension state weed specialist.

In addition to being federally restricted-use pesticides, these dicamba products were “state-limited-use” pesticides in Texas, requiring specific applicator training annually prior to use, Nolte said. AgriLife Extension has offered this training to more than 7,000 producers in 2018, 4,500 in 2019 and 3,200 this year.

Status of the cotton crop across Texas

Reports from Texas A&M AgriLife Extension Service agronomists from around the state provided these estimates:

In the South Plains, an estimated 80% of the producers use the dicamba technology and at least 80% of that seed is already in the ground, said Murilo Maeda, Ph.D., Lubbock.
In the Coastal Bend region, roughly 50% of the already-planted cotton crop is using those technologies, said Josh McGinty, Ph.D., Corpus Christi.
In West Central Texas, approximately 60% of the cotton has been planted, with primarily dryland left to plant. About 70% of the producers utilize these technologies, and have already purchased seed, fungicide and some herbicides, said Reagan Noland, Ph.D., San Angelo.
In the Rolling Plains region, about 80% of the producers incorporated the technology into this year’s crop, which is 70% planted, said Emi Kimura, Ph.D., Vernon.
In the High Plains, all cotton acres are planted, as the last date to plant was May 31, and at least 50% or more of the producers use these technologies, said Jourdan Bell, Ph.D., Amarillo.

Moving forward without the dicamba technologies

So, what are cotton producers to do now? They have a few options.

Nolte and Peter Dotray, Ph.D., Texas A&M AgriLife Research weed scientist, Lubbock, suggest affected producers consider some alternative weed control options to address management problems considering this new development.

Preplant and at-plant soil residual herbicides were used by most growers, and it will be critical to use additional soil residual herbicides such as Dual, Warrant and Outlook early or mid- postemergence, regardless of what postemergence herbicide is used, they said.

“Based on the EPA’s order, we expect growers to continue to rely on dicamba until July 31,” Dotray said. “When dicamba is limited or not available, glyphosate and/or glufosinate may be used at one or both of the postemergence application timings. We may see more cultivation and hooded sprayers used to manage weeds.”

Producers can access the latest version of the AgriLife Extension cotton weed management guide for more information.

Additionally, Syngenta’s Tavium Plus Vapor Grip, which was registered separately in 2019, was not included in this litigation. Its registration, which allows application to Roundup Ready 2 Xtend Soybeans and Bollgard II XtendFlex cotton, remains in place. It has label restrictions that must be followed. In cotton, a single postemergence application may be made until the 6-leaf cotton stage or 60 days after planting, whichever comes first.

Federal and state reactions to court ruling

While the court ruling was made on June 3 and effective on that date, on June 8, the EPA issued an order providing guidance on the sale, distribution and use of existing stocks of the three affected dicamba products. The EPA order stated in part:

Distribution or sale by any person is generally prohibited except for ensuring proper disposal or return to the registrant. Keep in mind that “distribution” is broadly defined as including “distributing, selling, offering for sale, holding for sale, shipping, holding for shipment, delivering for shipment, or receiving and (having so received) delivering or offering to deliver, or releasing for shipment to any person in any state.”
Commercial applicators may distribute or sell existing stocks that are in their possession. Existing stocks are defined as the products “which were packaged, labeled, and released for shipment prior to the time of the order on June 3, 2020.”
Growers may use any existing stocks, as defined above, consistent with the product’s previously approved label and may not continue after July 31.
Texas Agriculture Commissioner Sid Miller has said he will formally request a Section 18 exemption from the EPA to allow the continued use of dicamba in Texas under emergency conditions.

The Texas cotton crop is already growing or going in the ground right now, and “our cotton growers must have certainty,” Miller said.

An Emergency Exemption under Section 18 of the Federal Insecticide, Fungicide and Rodenticide Act, FIFRA, would authorize EPA to allow limited use of the pesticide in defined geographic areas for a finite period once the EPA confirms that the situation meets the statutory definition of an “emergency condition.”

New app development could aid crop irrigation management

25Feb

By: Kay Ledbetter

Texas A&M AgriLife is developing an inexpensive and easy-to-use mobile app and irrigation management system to help agricultural producers increase water-use efficiency and continue producing cotton.

The new project is funded by the Texas A&M Water Seed Grant Initiative and is titled “A Novel Sensor- and Crop-Model-Based Decision Support Tool for Efficient Irrigation Management.”

linear irrigation system with sprinkler heads close to ground

Increasing water-use efficiency in cotton will be the focus of a new study at the Texas A&M AgriLife Research and Extension Center at Vernon. (Texas A&M AgriLife photo by Kay Ledbetter)

The app is being developed in the Texas Rolling Plains region, which produces about 13% of the state’s cotton, said Srinivasulu Ale, Ph.D., Texas A&M AgriLife Research geospatial hydrologist and lead investigator on the project in Vernon.

Yet that cotton production faces challenges from recurring droughts and declining groundwater levels in the Seymour Aquifer. Furthermore, projected warmer and drier weather in the future will require larger groundwater withdrawals to meet crop water demands, Ale said.

To sustain cotton production in this region, he said, producers must adopt water-use efficient irrigation strategies.

Design & Development of Mobile App

Joining Ale on the project will be Curtis Adams, Ph.D., AgriLife Research crop physiologist; Emi Kimura, Ph.D., Texas A&M AgriLife Extension Service agronomist; and Yubing Fan, Ph.D., AgriLife Research postdoctoral research associate, all in Vernon. Also, Jim Wall, Ph.D., executive director, and Keith Biggers, Ph.D., director of computing and information technology, both at the Texas A&M Center for Applied Technology, College Station, will provide expertise.

The project is partnering with the Gateway Groundwater Conservation District, Quanah, and the Rolling Plains Cotton Growers Inc., Stamford.

Weather data collected in the field over the growing season will be used to help identify the proper irrigation management strategy. (Texas A&M AgriLife photo by Kay Ledbetter)

“Our goal is to deliver a product to cotton producers that can greatly improve their irrigation management, but is simple and accessible,” Adams said.

Most irrigation support tools have limitations that make them less useful to producers in some way, he said, and this project’s goal is to improve upon existing technologies using a novel approach.

“Our app will collect crop information from sensors mounted on center pivot systems, use weather data from online sources, and provide a number of potential combinations of real-time updated deficit- or full-irrigation schedules and economic outcomes,” Biggers said. “Producers can choose an irrigation strategy that best suits their well capacities and expected returns.”

This field information will be used in conjunction with the historic and projected short-term future weather data over the growing season in crop and economic models to estimate projected cotton yield, irrigation levels and net returns under different irrigation management strategies.

Considering short- and long-term weather forecasts

“To our knowledge, none of the existing apps use projected short-term weather forecasts in generating real-time irrigation schedules, and our proposed app does that,” Ale said.

Once validated using data from a field experiment, the proposed system will be further evaluated by selected producers under different crop conditions, soils, irrigation capacities and weather.

Wall said their plan is to have the app developed by the end of this year, test it in producers’ fields in 2021 summer, and release it in fall 2021.

Kimura estimates if producers adopt the tool on 200,000 acres of irrigated land in the Rolling Plains, it could potentially save millions of gallons of groundwater and extend the economic life of the Seymour Aquifer.

“But we don’t think its viability will be limited to the Rolling Plains,” Ale said. “We expect the proposed system to allow modifications to include other row crops and for use in other crop production regions of Texas and beyond.”

Glyphosate myths, facts addressed

24Feb

By: Kay Ledbetter
Contact: Scott Nolte – scott.nolte@tamu.edu

Whether on social media or in farming circles, many questions linger about glyphosate, better known as Roundup, and a link to cancer.

“It’s hard to know what to believe, but it’s important to make sure the information you receive is based on good science,” said Scott Nolte, Ph.D., Texas A&M AgriLife Extension Service state weed specialist, College Station.

Nolte addressed the issue during the Panhandle Farm Management Symposium in Amarillo recently, providing insight into the “myths and truths” surrounding the issue.

The controversy began with a ruling in 2015 by the International Agency for Research on Cancer, IARC, a subgroup of the World Health Organization tasked with determining the potential of a product to be carcinogenic. IARC indicated there was limited evidence glyphosate is carcinogenic in humans and sufficient evidence in animals.

However, because risk assessment and certain key studies were not considered by this organization, this year the U.S. Environmental Protection Agency released a statement Aug. 8 saying it would no longer approve product labels claiming glyphosate is known to cause cancer. The Agency said it is a false claim that does not meet the labeling requirements of the Federal Insecticide, Fungicide and Rodenticide Act.

Glyphosate use and regulation

Nolte said glyphosate has been in use since the mid-1970s and is the most studied chemical ever.

“Glyphosate, or Roundup, is a very effective herbicide that works on grasses and broadleaf weeds,” he said. “It works by inhibiting an enzyme that prevents plants from making three key amino acids needed to grow. This enzyme is not found in humans or animals, so it does not hurt them.”

Pesticides such as glyphosate are regulated by the EPA; the Food and Drug Administration, FDA; and the U.S. Department of Agriculture, USDA. These regulatory agencies determine safe residue levels and regulate tolerances.

They determine exposure risk through residue in food, water, residential use and occupational use, Nolte said. Two criteria they use are lowest observable adverse effect level and no observable adverse effect level. They set the chronic reference dose, which is an estimate of a daily oral exposure for a chronic duration to the human population that is likely to be without an appreciable risk of deleterious effects during a lifetime.

“Studies are conducted to get an observable effect and then they cut it back 100-fold to ensure if you are exposed on a daily basis to a chemical, chronic duration, it is without appreciable risk of effects during a lifetime,” he said.

How do we know Roundup is safe?

“Nothing is guaranteed to be 100% safe,” Nolte said. “But glyphosate is the most studied chemical in use today. None of the scientific studies have been able to definitively tie glyphosate to the cancer risks it’s been tied to.”

He said studies show the relative toxicity of glyphosate is just slightly higher than Vitamin B2 and far lower than Vitamin D3.

“Just about everything can be toxic in sufficient quantity – water, salt, organic pesticides, aspirin, caffeine, even sunscreen approved for babies – so it’s all relative,” he said. “Every day we weigh the risk with the benefits, whether it is driving to work or flying on an airplane.”

“You are responsible for good stewardship and following the label of all chemicals used,” he said. “So, handle it properly.”

Each chemical is required to have a signal word on it to determine its toxicity:
– “Danger, poison” indicates the product is highly toxic by any route into the body.
– “Danger” means it can cause severe eye damage or skin irritation.
– “Warning” indicates it is moderately toxic orally, dermally or through inhalation. Moderate eye or skin irritation.
– “Caution” means the product is slightly toxic orally, dermally or through inhalation. Slight eye or skin irritation.

“In this ranking system, only the word ‘caution’ is used on Roundup. You have to read and follow the label.”

What does science tell us about Roundup?

When IARC came out with their ruling on glyphosate in 2015, they knew about some additional data that would have been useful in making their decision. However, since it was not printed yet, they did not take it into consideration.

“It’s extremely challenging to talk in absolutes,” Nolte said. “There are too many things at play. But based on scientific evidence at this point, statistically, there is no tie between glyphosate and cancer. It’s usually never one thing that is involved in causing cancer, so that doesn’t mean in an individual situation where someone was predisposed to cancer that the chemical didn’t play a role.”

The piece of missing information was the Agricultural Health Study, funded by the National Cancer Institute and the National Institute of Environmental Health Sciences in collaboration with EPA.

Considered one of the largest human health studies done, it has been following people for 20 years who are chemical applicators using glyphosate or their spouses. The conclusion of this large, prospective cohort study was “no association was apparent between glyphosate and any solid tumors or lymphoid malignancies overall.”

“You can decide if it is right for you to use or not,” Nolte said. “Genetic probability likely has as much or more to do with someone getting cancer as the environment. And science tells us if we use these things properly, the risk is extremely low. The label is the law. Follow it.”

Genes from wild wheat relative to aid in battle against trio of pests

19Jun

Writer: Kay Ledbetter
Contact: Dr. Shuyu Liu, sliu@ag.tamu.edu

Wheat curl mite, greenbug and Hessian fly have long been troublemaker pests for Texas wheat, but a team of Texas A&M AgriLife Research scientists is ready to go high tech to help control them.

Dr. Shuyu Liu, AgriLife Research wheat geneticist in Amarillo, will lead a team to develop hard winter wheat germplasm with resistance to these pests using genes from a wild wheat relative. The research is funded by a U.S. Department of Agriculture National Institute of Food and Agriculture grant.

Dr. Shuyu Liu makes a cross between TAM 114 and a wild wheat relative at the Texas A&M AgriLife Research greenhouse near Bushland. (Texas A&M AgriLife photo)

Joining Liu on the study are AgriLife Research scientists from Amarillo: Dr. Jackie Rudd, wheat breeder; Dr. Chenggen Chu, wheat genetics scientist; Dr. Ada Szczepaniec, entomologist; and Dr. Qingwu Xue, crop stress physiologist. Joining from College Station are Dr. Amir Ibrahim, wheat breeder, and Dr. Shichen Wang, bioinformatics scientist.

Wheat production in Texas is limited by the harsh and variable environment and a multitude of diseases, insects and other pests, Rudd said.

“We are now looking to the past, to wheat’s wild relatives, to find solutions to these stresses, which can reduce yield and end-use quality,” he said.

The specific goal of this project is to explore synthetic hexaploid wheat to find new resistance genes to defend against these three pests, Liu said.

“Currently, TAM 204 is the only commercial cultivar with this level of resistance,” he said. “It is critical we continue to diversify and find different sources of resistance to these pests.”

The synthetic wheat lines were developed by the International Maize and Wheat Improvement Center, known as CIMMYT, from artificial interspecific crosses between durum wheat and Aegilops tauschii, a progenitor species of wheat, Rudd said.

The synthetic lines are reservoirs of resistance genes not found in modern wheat varieties, he said.

“A lot of work has been done worldwide to bring genes from synthetics into spring wheat,” Rudd said. “But so far, little has been done to incorporate these into winter wheat, like we grow in the Great Plains of the U.S.”

Liu said by combining the resistance found in the synthetics with existing bread wheat germplasm, “we can broaden the genetic base for more durable resistance.”

Processes such as exome capture will help geneticists find markers that are tightly linked or even part of the gene, Chu said. The markers can then be used in an accelerated breeding process facilitated by doubled haploids to merge these genes into existing TAM varieties.

Dr. Chenggen Chu dissects the young embryo from wheat seeds to make a doubled-haploid plant. (Texas A&M AgriLife photo by Kay Ledbetter)

Liu said because pests evolve with host-resistance genes and biotypes of insects continually change, single major resistance genes may only be effective for a few years.

“This situation pushes researchers to keep searching for new sources of resistance and new genes in currently available sources of wheat or its relatives,” he said.

In recent years, progress in wheat genetic and genomic research has accelerated due to improved techniques and knowledge, Liu said. With improved understanding of the wheat genome and new molecular techniques, the whole process of developing superior germplasm lines and adapted cultivars can be sped up.

“Research in the molecular lab, growth chamber and greenhouse, along with field experiments, will be conducted to identify and validate diagnostic genic markers linked to target genes controlling important traits,” he said.

“This project will provide a greater understanding of the pest-resistance mechanisms,” Liu said. “The genetic markers linked to them can aid in selection efficiency by breeders, who will use the superior germplasm to develop future cultivars with these resistances for farmers.”

Importance of Preplant Incorporated and Preemergence Herbicides in Peanut Production

11Apr

Written by: Emi Kimura, James Grichar, Pete Dotray and Josh McGinty
Contact: Dr. Emi Kimura, Emi.Kimura@ag.tamu.edu

Best Management Practices (BMPs) for peanut production include effective season-long weed management. Below are four weed management principles in peanut production.

Start clean
Use residual herbicides
Timely postemergence applications
Know your weeds

Early season weed management is most important, which means weed control later in the season should be easier. Yield losses are minimized when peanuts are free of weed competition for the first 4-6 weeks after planting.

There are five critical herbicide application timings in peanut production: preplant burndown (PP), preplant incorporated (PPI), preemergence (PRE), early postemergence (EPOST) 10-20 days after planting, and postemnergence (POST) 30-45 days after planting.

Timing of herbicides is critical, as yield losses are minimized when peanuts are free of weed competition for the first 4-6 weeks after planting.

The use of PP, PPI, and PRE herbicides are critically important for minimizing weed competition during the early season. April is a good time for planning/applying PP and PPI herbicides in your peanut fields while PRE herbicide applications are made at-planting.

Preplant burndown

Early emerging weeds such as Russian-thistle and kochia can be controlled by tillage or use of burndown herbicides. One of the strengths of paraquat (Gramoxone) is Russian-thistle, and glyphosate (Roundup PowerMax and other generics) is effective on a broadspectrum of annual and perennial grass and broadleaf weeds.

Preplant incorporated

Preplant incorporated herbicides labeled for peanut include ethalfluralin (e.g., Sonalan 3EC and generics), pendimethalin (e.g., Prowl H2O and generics), and trifluralin (e.g., Treflan and generics). These dinitroaniline herbicides (also known as yellow herbicides) are effective on annual grasses and small-seeded broadleaf weeds such as Palmer amaranth (carelessweed or pigweed), Russian thistle (tumble weed), and kochia (iron weed).

They are ineffective at controlling large-seeded broadleaf weeds such as cocklebur, sunflowers, and sedges (yellow and purple). Use of a PRE herbicide will enhance control of some of these weeds. Please read the label carefully for recommendations regarding effective incorporation methods for these PPI herbicides. If the incorporation is too deep, and peanuts are planted shallow, peanut roots from planted seed have to go through treated soil which can result in stunting.

Preemergent herbicides

The use of a PRE herbicide can be effective at controlling annual broadleaf and sedge weeds. There are several options for PRE herbicides in peanut including flumioxazin (e.g., Valor, Panther, Rowel, and other generics), S-metolachlor (e.g., Dual Magnum and generics), dimethenamid (e.g., Outlook and generics), acetochlor (Warrant), and imazethapyr (e.g., Pursuit and generics).

PRE must be applied and activated before weed emergence and some must be applied prior to peanut emergence to avoid crop injury. Please read labels carefully for incorporation methods (irrigation, mechanical, etc.), application rates, application timing, and grazing or feeding restrictions.

Flumioxazin should be applied prior to planting and up to 2 days after planting and before peanut emergence. It provides 4-6 weeks of residual activity for controlling Palmar amaranth, golden crownbeard, morningglory species and other weeds. Crop injury can occur if flumioxazin is applied 3 days after planting. Severe stunting can occur with flumioxazin if applied alone or in combination with S-metolachlor under cold, wet soils or water logged conditions and peanuts may never recover during the growing season. Acetochlor and dimethenamid provide good residual control of grass weeds and small-seeded broadleaf weeds, and can control ALS-resistant Palmer amaranth.

It is important to read the label carefully, especially on application rates based on your soil types, feeding restrictions, rain-free periods, rotation restrictions, herbicide groups, and other issues.