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Climate change provides good conditions for fungus in soybeans

Published July 9, 2014
Charcoal rot experiment in greenhouse
Greenhouse study showing drought-stressed soybean with different levels of resistance to charcoal rot.

URBANA, Ill. – With over 100 diseases that can attack soybean crops, why would charcoal rot rise to the top of the most wanted list? University of Illinois scientists cite the earth’s changing climate as one reason that more research is needed on the fungus that causes charcoal rot.

Fungi may often be associated with cool, damp growing conditions but Macrophomina phaseolina, the fungus that causes charcoal rot, prefers hot and dry drought conditions.

“As the climate continues to change and we see more extremes in the weather, including hotter, drier summers, this fungus will have more favorable conditions to gain a foothold in soybean and other crops,” said Osman Radwan, a U of I molecular biologist. “If we look at diseases of soybean, we find that soybean cyst nematode (SCN) is at the top, but in the past decade or so, charcoal rot has become one of the top 10 diseases that affect soybean yield.”

In examining previous studies on charcoal rot, Radwan and his team noticed that worsening weather conditions associated with climate change, such as higher heat and drought, brought an increase in the incidence of charcoal rot in soybean.  He suggests that a research strategy be created to develop a high-yielding soybean that is both resistant to charcoal rot and drought tolerant.

“Right now we are screening lines of soybean to charcoal rot and drought stress, in collaboration with Glen Hartman, a USDA-ARS and U of I plant pathologist,” Radwan said. “His team is screening for charcoal rot resistance, and I am screening for drought tolerance,” Radwan said. “Our ultimate goal is to identify the line that shows resistance to both charcoal rot and drought stress and in this way improve soybean tolerance to both the pathogen and the extreme weather conditions.”

The review of research on the subject has been written along with Hartman and Schuyler Korban from U of I.  Radwan said that this background for what’s already been done on the topic will help them to develop a strategy for the next step.

Radwan emphasized that it’s not just soybean crops at risk. The fungus  causes charcoal rot in about 500 other host plants, including corn, sorghum, sunflower, and other important crops. This fungus also grows in high concentrations of salt, which isn’t much of a problem to growers in the United States, but it is for farmers in developing countries where salinity is considered an issue. Consequently, the plant must be able to tolerate drought, salt, and resist this fungus at the same time.

One intriguing direction Radwan described that shows promise is that there may be interactions between M. phaseolina and other soil pathogens such as soybean cyst nematode (SCN) and sudden death syndrome (SDS).

“We have some assumptions about whether SCN can increase or decrease the incidence of charcoal rot as resistance to both pathogens might be controlled by two different pathways,” Radwan said. He explained that biotrophic pathogens such as SCN need plant tissue to survive, but the fungus that causes charcoal rot is necrotrophic, meaning that it kills the plant tissue, then lives on the dead plant cells.

“We need to understand at the molecular level how these two pathogens interact when they are present in soybean fields. Understanding the mechanisms of molecular interactions between SCN and M. phaseolina will help molecular biologists and breeders to design an effective method to control both diseases and to breed soybean for resistance to both pathogens,” he said.

Although no plants have complete immunity from the fungus, some soybean lines have been shown to have partial resistance to it. Hartman’s group has already begun screening many lines in soybean for resistance to charcoal rot.

In controlled greenhouse conditions, Radwan grows a variety of soybean cultivars in sandy soil and then stops watering the plants to simulate drought. The susceptible ones wilt and, even after adding water, don’t recover. Those that are tolerant to drought survive.

“If we screen for drought stress, we hope to find some cultivars that are charcoal rot resistant and others that are drought tolerant so that we can cross them,” Radwan said. “Of course, they also must have good agronomic traits, such as having a high yield potential, in order to be acceptable to farmers.”

Genetic Mechanisms of Host-Pathogen Interactions for Charcoal Rot in Soybean was published in an issue of Plant Molecular Biology Reporter. Laura V. Rouhana, Glen L. Hartman, and Schuyler S. Korban contributed to the research.

 

Additional Images:

Ten videos for vegetable gardeners

Published July 8, 2014

URBANA, Ill.  – Gardeners can find more than 400 useful videos on the University of Illinois Extension YouTube channel, according to U of I Extension horticulture educator Ron Wolford.

The following are 10 videos that will help a new vegetable gardener get off to a good start.

Read labels at the garden center http://bit.ly/readlabel - Learn why you should take the time to read plant labels before you buy the plant. Lots of good information is found on the label.

Taking a soil sample for a soil test http://bit.ly/soilsample - Learn how to take a soil sample for a soil test. A soil test is one of the most important first steps in starting a vegetable garden.

Fertilizer 101 http://bit.ly/fertilizer101 - Learn the basics of fertilization to ensure healthy, sturdy vegetables that will be better able to withstand insects and disease.

Marking seed rows with sand http://bit.ly/seedrows - Learn how to use sand to mark your rows in the garden.

Space-saving ideas for vegetables http://bit.ly/spacesavin - Learn some space-saving techniques for gardens with limited space.

Using weed barrier cloth in a vegetable garden http://bit.ly/weedbarrier - Learn why you should think about using a weed barrier cloth in your vegetable garden.

Cool- and warm-season veggies http://bit.ly/coolnwarm - Learn how cool and warm season vegetables prefer different soil and air temperatures.

Tip for vegetable transplants: Pinch off flowers http://bit.ly/pinchflowers - Learn why you should pinch off the flowers of your tomato transplants.

Succession planting tips http://bit.ly/successionplanting - Learn how to extend your harvest season by using succession planting in your garden.

Extending your vegetable garden season http://bit.ly/extendseason - Learn how you can extend your vegetable garden season in the spring and fall.

“All of these are only a mouse click away,” said Wolford.

News Source:

Ron Wolford, 773-233-2900

News Writer:

University of Illinois Extension

Damage assessment of runaway barges at Marseilles lock and dam

Published July 8, 2014

URBANA, Ill. - It takes a synchronized lock and dam system—operating like a motorized flight of stairs on the Illinois River, using gravity to move the water—to maintain a minimum depth for boat traffic. A disastrous domino effect occurred on April 19, 2013, when heavy rain and runoff, strong winds, and river currents resulted in seven unmoored barges crashing into the dam at Marseilles. University of Illinois soil scientist Ken Olson studied the extensive repercussions of the incident.

“Four of the seven barges partially sank, blocking the southernmost submersible spillway gates that maintain the 9-foot navigation channel,” Olson said. “The other three barges blocked the water flow, which backed it up for many miles and flooded adjacent Illinois River bottomlands, including the town of Marseilles.”

On the human level, Olson said that approximately 1,500 residents had to be evacuated from the low-lying areas, more than 3 feet of floodwater surrounded 200 buildings, and at least 24 homes were destroyed.

“The greatest agricultural impact was that, because this important waterway transportation system was out of commission, shipments of fertilizers and grains were delayed,” Olson said.

The U.S. Army Corps of Engineers (USACE) created a temporary rock dike dam after the accident to permit repairs to the three most severely damaged gates. The temporary dike was able to hold enough water to elevate the navigation pool, but it was not until May 15, four weeks later, that boat traffic was restored.

“The northern stretch of the Illinois River is a main artery for shipping bulk commodities to terminals at the Gulf of Mexico,” Olson said. “The interruption affected delivery of shipments of agricultural inputs, such as fertilizer and lime material, and outputs, including grain. The torrential rains that moved through the upper Midwest in April and May of 2013 resulted in the Coast Guard declaring the Illinois River to be unnavigable; any transport required Coast Guard permission.”

Olson said that a safety zone was created in order to protect salvage operations from impediment by the vessel traffic above the damaged Marseilles Dam. It extended between the Marseilles Lock and Dam and Seneca, Ill.

“An additional section between Alton, Illinois, and Brendon Road lock at Joliet remained closed for weeks due to high water and excessive river debris,” Olson said. “Heavy rains in late May extended the shipping restrictions.”

According to Olson, the system of locks and dams on the Illinois River managed by USACE is vulnerable to changing climate and weather extremes. These more frequent and unpredictable conditions can cause shipping accidents, damage to lock and dam systems, streambank erosion, shipping accidents, and local flooding.

“Runaway barges damage Marseilles Lock and Dam during 2013 flood on the Illinois river” was published in the July-August 2014 issue of the Journal of Soil and Water Conservation. Lois Wright Morton co-authored the paper. Olson is a researcher in the Department of Natural Resources and Environmental Sciences in the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.

The full paper is available at http://www.jswconline.org/content/69/4/104A.full.pdf.

 

 

 

Additional Images:
  • 7 sunken barges
  • Temporary dike

Pork: USDA reports help brighten outlook

Published July 7, 2014

URBANA, Ill. – According to Purdue University Extension economist Chris Hurt, pork producers might want to say thank you for the recent USDA reports that have sharply brightened their profit outlook. The June 27 Hogs and Pigs report indicated that breeding herd expansion had not yet started and that baby pig death losses from the PED virus continued to be high last spring. The second report of beneficial numbers came in the June 30 Grain Stocks and Acreage reports, which were contributors to rapidly falling corn and soybean meal prices.

“In the week following the reports, higher anticipated hog prices and lower anticipated feed prices have increased profitability prospects about $18 per head for the period that represents use of the 2014 crops,” Hurt said. “Lean hog futures rose on average about $6 per hundredweight and corn prices fell by about 40 cents per bushel with soybean meal declining around $30 per ton.

“Prior to the hog inventory report, there was an expectation that the nation’s breeding herd was already in expansion, with spring farrowing intentions up 2 percent,” Hurt continued. “However, on June 1, the breeding herd was down fractionally and actual spring farrowings were also down modestly. The PED virus apparently continued to inflict higher death losses in the spring than had been anticipated. While USDA does not specifically ask producers to report death losses from PEDv, they do report the number of pigs per litter. By comparing the reported number of pigs per litter this year to the five-year trend provides a proxy of how PEDv has affected baby pig survival.”

Hurt said that this analysis suggests that baby pig death losses began to show up in the national data last October, with 2 percent losses. That expanded to 3 percent in November, 6 percent in December, and peaked near 8 percent death losses in the coldest weather months of January, February, and March. Losses appeared to be moderating somewhat with warmer weather, but were still 7 percent in April and 5 percent in May. The death losses from PEDv will likely continue to trend lower this summer, but current information suggests that the disease is far from controlled.

“The number of hogs coming to market this fall and winter will be smaller than had been expected due to smaller spring farrowings and higher-than-expected PEDv death losses,” Hurt said. “This is the basis for the sharply higher lean hog futures this fall and winter. Producers have been selling their surviving hogs at higher weights. The number of hogs marketed in the first half of 2014 was down about 4 percent, but weights were up over 3 percent. As a result, pork supplies were surprisingly down less than 1 percent as weights substantially compensated for PEDv death losses. This means that high hog prices are being partially driven by smaller pork supplies, but more important by strong pork demand. The two most important components of strong pork demand are related to the currently tiny supply of beef and to strong pork export demand.

“Record-high retail beef prices have some consumers looking around the meat case for alternatives,” Hurt added. “In May, USDA estimated the average grocery store price of beef cuts to be $5.91 per pound. The average cut of pork on the other hand was $4.10 per pound. Even though this was also a record pork price, it was $1.81 per pound lower than beef. This large price difference seems to be causing a number of consumers to shift toward pork.  Foreign consumers have been strong competitors for limited world supplies of pork as well. Losses from PEDv have been highly publicized since February and this has seemingly contributed to aggressive foreign buying of pork in an attempt to avoid the summer pork shortages resulting from peak baby pig death losses last winter.”

Hurt said that as a result, hog prices in the first half of 2014 averaged a record of about $80 per hundredweight on a live basis. This was nearly 25 percent higher than in the same period the previous year. The full impact of smaller pork supplies will be felt this summer with new record-high hog and pork prices. Live hog prices are expected to average in the mid $90s in the third quarter before moderating in September and moving down to the mid-to-higher $70s for the final quarter of 2014.

“Producer profits were record high in the second quarter this year, near $70 per head,” Hurt said. “Continued record hog prices and now lower feed prices mean that record will fall this summer as third quarter profits are expected to be over $100 per head. These extremely high profits are clear signals for producers to increase pork production. The USDA report did reveal that producers have received this signal and they intend to increase farrowings by 4 percent this fall. If they start the expansion, and if PEDv is better controlled, pork supplies can begin to grow by the spring of 2015, and could total 4 to 6 percent higher in the last three quarters of 2015.

“No relief for consumers is expected this summer as retail pork prices keep moving up to new records,” Hurt concluded. “Retail pork prices are expected to level off in the fall and then move somewhat lower into the winter. More relief from record-high retail pork prices can be expected in the second half of 2015 as pork supplies build.”

 

Jul30

Palmer Amaranth Field Research Tour

9:00 AM - 1:00 PM
Palmer Amaranth Research Site, Union Hill, Ill.

The tour will begin at 9 a.m. and conclude with a catered lunch around noon. Advanced registration is available at bayerrespecttherotation.com. There is no fee to attend and credits for certified crop advisers will be available. The research site is located approximately ½ mile east of the intersection of county roads 14000 west and 3000 north near the community of Union Hill, Ill.

Palmer amaranth field research tour set for July 30

Published July 2, 2014

URBANA, Ill. - The University of Illinois weed science program will hold a field tour and discussions on July 30 at the Palmer amaranth research site, located approximately ½ mile east of the intersection of county roads 14000 west and 3000 north near the community of Union Hill, Ill.

The tour will provide an opportunity for farmers, input suppliers, members of the media, and others to have a first-hand encounter with a Palmer amaranth population thriving just a few miles south of Chicago. The tour will feature four presentations by weed scientists that highlight the identification, biology, and management of Palmer amaranth, and will also provide ample opportunity to view the numerous research plots. 

Participants will receive a complimentary tour booklet that contains field research protocols and maps to help guide them through the research plots. The tour will begin at 9 a.m. and conclude with a catered lunch around noon.  Advanced registration is available at bayerrespecttherotation.com. There is no fee to attend and credits for certified crop advisers will be available.

Tour presentations will include:

  • Larry Steckel, Extension weed scientist, University of Tennessee, will provide tips on Palmer amaranth identification and also share his vast experience in managing this invasive and extremely competitive weed species in Tennessee.
  • Pat Tranel, professor of molecular weed science, U of I, will discuss the current status of herbicide resistance among waterhemp and Palmer amaranth populations in Illinois, and also offer insights into how to best employ future technologies to manage these dioecious pigweeds.
  • Aaron Hager, Extension weed scientist, U of I, will discuss recommendations to manage Palmer amaranth in Illinois agronomic crops, including how to best utilize soil-residual herbicides in combination with intense crop scouting, timely applications of foliar-applied herbicides, and other mechanical and cultural methods.
  • A representative of Bayer CropScience will also provide an update on new Bayer traits and technologies under development to help manage Palmer amaranth and other troublesome weeds.

“Our Palmer amaranth field research activities and tour are in collaboration with scientists and researchers from Bayer CropScience.  We thank Bayer CropScience and all our research partners for providing the research support necessary to better understand and manage Palmer amaranth in Illinois, said Hager.

Remember the European corn borer?

Published July 2, 2014

URBANA, Ill. - The European corn borer, once regarded as a major and consistent insect pest, is now only rarely observed in most commercial cornfields across the Corn Belt, said a University of Illinois entomologist.

Mike Gray said that in 1939, European corn borers were first reported in Illinois and by 1942 the pest could be found in all counties within the state. “William ‘Bill’ Luckmann, a longtime retired and well-known entomologist, once mentioned that he had only observed two cornfields totally destroyed by insects—once by chinch bugs and once by European corn borers,” Gray said.

Since the introduction of Bt hybrids in 1996, the use of transgenic corn has risen sharply. Gray said that according to the USDA Economic Research Service, Bt hybrids were planted on 76 percent of the U.S. corn acres in 2013. In 2013, transgenic corn hybrids (including Bt hybrids, stacked hybrids [Bt and herbicide tolerant], and herbicide tolerant only) were used on 90 percent of corn acres. The widespread use of highly effective Bt hybrids on lepidopterous insect pests such as the European corn borer has had a significant areawide population suppression effect on this once prominent species.

“In evening drives around the state of Illinois the past few years, the first or second flights of European corn borers have been barely noticeable,” Gray said. “Many will recall what these spring and summer evening drives did to our windshields.”

Depending on the accumulation of heat units, the first flight of European corn borers generally lasts from mid-May through mid-June. Moths emerge from corn residue and seek out areas of dense vegetation found in ditch banks, fence rows, and grass waterways. Gray explained that females emit a sex pheromone in these “action sites” very late in the evening that attracts males and mating ensues. Females depart action sites after sundown and begin laying egg masses in nearby cornfields, typically two egg masses per night for upwards of 10 days.

From June 13 to 26, a Department of Crop Sciences research team led by Ron Estes, principal research specialist in agriculture, and Nicholas Tinsley, postdoctoral research associate, conducted surveys of action sites in the following 12 counties: Champaign (June 13, 5 action sites), Clinton (June 24, 3 action sites), Douglas (June 13, 5 action sites), Fayette (June 24, 4 action sites), Jefferson (June 24, 3 action sites), Kankakee (June 26, 5 action sites), Kendall (June 26, 5 action sites), Knox (June 17, 5 action sites), McLean (June 17, 5 action sites), Pike (June 18, 3 action sites), Sangamon (June 18, 3 action sites), and Whiteside (June 25, 5 action sites).

Within each action site, 100 sweeps were taken and very few moths (9 total) were collected: Champaign County (1), Douglas County (3 - one in each of 3 sites), Kankakee County (1), Kendall County (1), Knox County (1), McLean County (1), and Sangamon County (1). During these surveys, 51 action sites (100 sweeps/site) were sampled across 12 counties resulting in 5,100 sweeps that yielded 9 moths, or 0.0018 moths per sweep.

“Based upon these results, I believe the following questions are worthy of consideration. Are too few survivors emerging from Bt fields to sustain the continuing efficacy of Bt hybrids against European corn borers? So far, no field-selected Bt-resistant strains of European corn borers have been documented,” Gray said.

Gray questioned if the smaller (5 percent) seed-blend refuges will result in even fewer European corn borer survivors in the landscape and further increase the selection pressure for resistance development. “Recall that structured 20-percent refuges were the norm for Bt corn hybrids for many years. In addition, the structured refuge was a preferred resistance management approach along with the use of high-dose Bt hybrids for European corn borers,” he added.

Gray explained that early on, concern over larval movement from plant to plant by European corn borer larvae resulted in scientists favoring a structured refuge versus a seed blend for this insect pest. “Is the added cost of Bt hybrids worth the investment for this insect pest in light of very low densities of the European corn borer and the less than favorable current and projected commodity prices?

“If the use of Bt hybrids declined, would producers have sufficient time to scout large commercial cornfields, utilize economic thresholds, and apply rescue treatments as needed? Time will tell if this once very significant insect pest will return as a consistent threat,” he said.

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