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Jaisi laboratory tracks chemicals in water, farmland throughout Mid-Atlantic

February 27, 2013 under CANR News

Deb Jaisi studies phosphorus in his labUniversity of Delaware researcher Deb Jaisi is using his newly established stable isotope facility in the Environmental Biogeochemistry Laboratory (EBL) to find the fingerprints of isotopes in chemical elements — specifically phosphorus — in order to track sources of nutrients in the environmentally-sensitive Chesapeake Bay, other bodies of water and farmland throughout the Mid-Atlantic.

Jaisi, assistant professor in the Department of Plant and Soil Sciences in the College of Agriculture and Natural Resources, explained that he and his research team are currently working on many projects in the EBL, including two that are funded through seed grants, one focusing on terrestrial phosphorus sources and the other on marine phosphorus sources in the Chesapeake. One of those grants is from the UD Research Foundation (UDRF) and is titled “Role of Non-terrestrial Phosphorus Sources in Eutrophication in the Chesapeake Bay.”

For the project, Jaisi and his team of graduate students and post-doctoral researchers are looking at different sources of phosphorus in the Chesapeake Bay over time. Working with Old Dominion University, the team has been provided sediment core samples taken from bay that spans several decades of sediment accumulation and is extracting the phosphorus from those sediments and measuring the isotopic composition of phosphate.

Jaisi explained that they do this in order to identify the sources of phosphorus and see how those specific sources have changed over time in the bay, which could be important information in seeking to understand their impact on the water quality in the bay.

Jaisi said that it is important to study phosphorus because it “is one of the most important nutrients for any living being. In most cases, this is a limiting nutrient and what that means is that it controls the growth or how much life you can have out of that nutrient.”

Jaisi continued, saying, “DNA and RNA are made of phosphorus backbone — so our bones are made of phosphorus, our teeth are made of phosphorus. You can name every part of the body and it has phosphorus, and the same is true for any other living being.”

While phosphorus is important to life, too much phosphorus — particularly in bodies of water — can cause serious ecological problems, leading to algae blooms and oxygen deficiency.

 

 

Jaisi’s group also has a U.S. Department of Agriculture (USDA) grant to compare the phosphorus plants take up to the phosphorus that is present in fertilizers, while also tracking any excess fertilizer that is used by growers to see where that fertilizer goes.

For farmers or homeowners applying phosphorus-rich fertilizer, Jaisi said it is not clear how much phosphorus from fertilizer is being taken up by plants. “We don’t explicitly understand how much phosphorus is needed or where the phosphorus ends up,” he said, adding that a phosphate oxygen isotope fingerprint tool can provide a more detailed picture. “We hope to provide a better resolution of phosphorus fate – that this phosphorus fraction leaked out of the soil and went to the ground or surface water, and this fraction is taken up by plants.”

The researchers are also looking at how rivers carry phosphorus and how far they can trace certain sources of phosphorus in a river. This research is being done in Maryland, and Jaisi explained that the group is looking at how phosphorus is leached out of soil and carried into creeks and rivers. “We are taking samples along a creek and in sediments to see how far the phosphorus can go. Does it retain somewhere in the river, or is it exported to the Chesapeake Bay?”

Isotope fingerprinting

To find the fingerprints of isotopes, Jaisi uses a machine known as a stable Isotope-Ratio Mass Spectrometer (IRMS).

Jaisi said that because “different sources may have different isotopic composition,” if he and his research team can figure out an element’s isotopic composition, they can identify how that element has impacted the environment.

“For example, if the phosphate is originating from a wastewater plant, that is one isotopic composition or one type of fingerprint. Then, compare that fingerprint to what comes out of the fertilizers, and to what comes out of soil erosion from the geological processes — that kind of phosphate has other isotopic compositions.”

The currently installed IRMS has three different components, each capable of measuring a specialized element. One is used for phosphate oxygen isotopes, one for carbon and nitrogen isotopes and one for water and carbonates. The three machines feed into the mass spectrometer via a synchronizing unit called ConFlow.

Jaisi said that such machines used to measure phosphate oxygen isotopes are not very common, with only a handful worldwide.

Although his group mainly focuses on phosphorus, the EBL and the equipment is available to other researchers at the University and outside, and can be used to measure for stable isotopes of nitrogen, carbon, sulfur and other light elements.

For more information on Jaisi’s lab, visit the website.

Article by Adam Thomas

Photos by Danielle Quigley

Video by Adam Thomas and Danielle Quigley

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UD awarded $1.5 million USDA grant to study lima beans

January 11, 2013 under CANR News, Cooperative Extension

Researchers from UD study lima beansDelaware is currently the number two producer of lima beans in the United States, second only to California and with the possibility of becoming number one in the future.

Because of this, it is imperative to study the many aspects of various diseases affecting the crop in Delaware and throughout the mid-Atlantic region.

Such work requires a collaborative effort and a team has been assembled thanks to a five-year, $1.5 million U.S. Department of Agriculture (USDA) Specialty Crop Research Initiative grant.

The grant awarded to the University of Delaware includes researchers from UD, Delaware State University, the University of Maryland, Ohio State University, Cornell University and the University of California Davis (UC Davis) who will begin studying the various effects of plant disease on lima beans in the First State.

The many aspects of this grant will include studies that are being conducted for the first time in history.

There are six components to the grant, each with various researchers studying different parts of the problem. They are conducting research on downy mildew, pod blight, white mold, root knot nematodes and germplasm resources and developing an economic analysis.

Downy mildew

Downy mildew is a fungal-like disease of the lima bean caused by Phytophthora phaseoliand the goal of the research team is to improve disease forecasting and look at genetic diversity of the population of the pathogen. In this way, researchers will be able to inform farmers of their risk of occurrence of the disease and have a better understanding of the genetics of the pathogen.

Tom Evans and Nicole Donofrio, professors of plant pathology in the Department of Plant and Soil Sciences in UD’s College of Agriculture and Natural Resources, and Nancy Gregory, plant diagnostician for UD, will work together on this part of the project.

Pod blight

Pod blight is caused by the pathogen known as P. capsici and Gordon Johnson, assistant professor of plant and soil sciences at UD, will work on this part of the study with Evans and Gregory.

Unlike downy mildew, which is a disease that generally affects only lima beans, P. capsicihas a very wide host range. Once it strikes a particular crop, it is very difficult to get rid of, with pathogen’s spores lasting up to 10 years in the soil. Because of this, pod blight is an increasing problem for growers. The disease occurs in low-lying areas of fields and is more frequent in wet years. Therefore, this part of the project has three goals: to look for a fungicide to deal with the disease, to monitor the disease, and to look for alternative or organic non-pesticide driven strategies for control.

The study is also looking at risk management strategies, including information for growers in the state about the best time to spray for disease control and consideration of alternate control strategies.

Gregory, who diagnoses field samples collected by the research team and growers, maintains cultures of the pathogens and produces  the inoculum for the studies, said that the researchers are eager to “learn more about the epidemiology and the spread of pod blight and downy mildew, that will enable us to do a little bit better job on forecasting.”

She also noted how great is to have so many expert researchers involved, noting that she is looking forward to making significant progress on problems that have plagued the region for years. “To pull together a strong team of researchers like this and many new graduate students is really going to pull a lot of this research together and we’ll really come up with some great results.”

White mold

Kate Everts, an adjunct associate professor of plant and soil sciences at UD and a Cooperative Extension specialist with both UD and the University of Maryland, is leading research on alternative ways to control white mold, another disease that is very difficult to eliminate.

With an even broader host range than P. capsici, and an even longer life — persisting in soils for 20-30 years — finding out as much about the disease as possible, as well as possible ways to control it, is imperative.

Everts will look not just at lima beans but other crops, as well, as she tests biological control strategies and alternative control strategies for dealing with the white mold.

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University of Delaware Poultry Career Seminar series

December 11, 2012 under CANR News

Poultry career seminar seriesThe University of Delaware held its first Poultry Career Seminar series this fall with funding provided by a grant from the United States Poultry Foundation and additional funds from the UD Career Services. The series of four seminars were held on October 3, 8, 16 and November 1.

Connie Parvis, director of education and consumer information from Delmarva Poultry Industry, Inc., spoke at the Oct. 3 seminar. She started the program giving an overview of the industry and discussed career and scholarship opportunities. She was joined by Byron C. Friend from the United States Department of Agriculture (USDA) Agricultural Marketing Service who spoke about how his service facilitates the marketing of poultry, poultry products and eggs.

The second seminar included Bernie Murphy, a UD alumni who earned his doctorate from Iowa State University and serves as President of the Jones Hamilton Co., a leader in producing, packaging and distributing chemicals and compounds for a variety of customers since 1951.

Perdue Farms also presented during the second seminar, with Todd Baker, breeders operations manager, Katelyn MacCann, UD alumna and breeders farm manager, and Chris DelCastillo, Milford associate relations representative, speaking about career and internship opportunities at Perdue Farms, a family-owned company producing the Perdue brand of premium fresh chicken based in Salisbury, Maryland.

The third seminar included Pat Townsend, director of human resources at Mountaire Farms, who described their year long management training program, as well as internship and career opportunities. Mountaire Farms is a diverse poultry and agricultural business that partners with local farming communities to raise chickens and grains to feed them.

He was followed by Bill Brown, UD alumni and UD poultry extension specialist, and Carissa Wickens, assistant professsor and equine extension specialist. Brown described the purpose of Cooperative Extension and the many career opportunities it affords, while Wickens discussed the CANR Cooperative Extension Summer Scholars Internship Program and brought along her summer scholar, Rebecca Frost, a sophmore studying in the Department of Animal and Food Sciences (ANFS).

Chuck Snipes, Mid-Atlantic sales representative of Cobb-Vantress, Inc., gave an overview of his company’s research, development and production of broiler breeding stock and the company’s internship and career opportunities. The final speaker in the seminar series was Nannette Olmeda-Geniec, poultry technical consultant for Elanco, an international company that develops products and services that enhance animal health, wellness and performance. Olmeda-Geniec is a veterinarian who earned her doctorate at UD in ANFS and presented an overview of this international company and the opportunities for internships and careers within her company.

A total of 81 students attended the seminars, with seven students attending all four. The seminars were also used to promote the United States Poultry Foundation’s College Student Career Program to be held in Atlanta, Georgia in January 2013. The program will allow students opportunities to interview with 25 regional, national and international poultry and agribusiness companies and organizations while having the opportunity to network with over 970 companies.

A goal of ANFS is to increase the number of students participating in the United States Poultry Foundation’s College Student Career Program. This year the ANFS Department will increase the number of undergraduate and graduate students participating in the expo from 4 to 11.

Photo by Danielle Quigley

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Trees can help cities better prepare for severe weather events

November 21, 2012 under CANR News, Cooperative Extension

In the aftermath of Hurricane Sandy, many cities are taking a look at how they can better prepare for severe weather events. A low-tech – but effective – solution is to plant trees, says Sue Barton, ornamental horticultural specialist for the University of Delaware.

“A single mature tree can intercept several thousands of gallons of stormwater. Plant more trees in the right places and you can mitigate the impact of storm events,” says Barton.

She points to the research of David Nowak, a forester at the U.S. Department of Agriculture’s Northern Research Station in Syracuse, N.Y., who has analyzed the role that “urban forests” play in controlling runoff and flooding, reducing the costs of stormwater management facilities, and decreasing water pollution.

An “urban forest” doesn’t necessarily mean a tree-filled area the size of Central Park. Instead, researchers like Nowak look at the overall tree coverage in a community. The average urban tree canopy in the U.S. is 23 percent. But the tree canopy in the New Castle County metro area is estimated to be just 19 percent, and the city of Wilmington’s tree canopy is 16 percent.

“Philadelphia and Wilmington have experienced water overflow situations after decent-sized rains, not just storm events like Hurricane Sandy,” says Barton, a Cooperative Extension specialist and associate professor in the Department of Plant and Soil Sciences. “The stormwater management systems in these cities were engineered many years ago and they can’t handle the water flow after a big rain – which means raw sewage and other organic material bypasses the treatment plants and go directly into streams.”

Fixing antiquated stormwater systems isn’t cheap. “One of Nowak’s greatest contributions may be his research into the economic benefits of trees,” says Barton. “He came up with a way to put a dollar cost on how much trees can save a community. He looks at the cost of trees and tree maintenance relative to the costs of updating aging stormwater systems.”

In Wilmington, the Delaware Center for Horticulture (DCH) has been a driving force behind stormwater mitigation efforts that include planting trees and shrubs, establishing rain gardens and installing underground holding tanks. All three of these elements were included in a stormwater project at the Trolley Square Acme that was completed in June 2011.

The 9,000-square-foot project filters, slows and absorbs rain that falls on the roof of the Acme and its 1.42 acre parking lot. Comprised of 19 shade trees, more than 2,800 shrubs and smaller perennial plants, a rain garden, and underground holding tanks, the project captures an estimated 70 percent of the site’s annual rainfall, providing relief to the city’s combined stormwater and sewer system.

Gary Schwetz is a senior project analyst at DCH and was instrumental in the development and execution of the Acme project. His advice to those who want to use trees to intercept stormwater: “Think big.”

Schwetz doesn’t mean you need to plan a big project – like the 2,819 or so living things planted at the Acme — but that you need to include big trees.

“Large trees are better at absorbing rainwater and mitigating air pollution,” says Schwetz.  “A 20-foot tree will have eight times the environmental benefits of a 10-foot tree.”

Of course, it can be tough to grow a big tree in the narrow space between a city sidewalk and the street, or in a city backyard. It can even be tough for big trees to do well in public spaces like Rodney Square, which little by little has seen its grassy area reduced and covered by pavers and other impervious surfaces.

Schwetz and fellow DCH staffers worked on an innovative landscape project that will help big trees flourish at Rodney Square. Other partners were the city of Wilmington and the Delaware Department of Transportation.

What makes the project different, says Schwetz, is the use of a new structural cell technology as the planting medium. These milk-crate-like structural cells can support sidewalks and hold a high volume of good quality soil, creating conditions in which large trees should be able to thrive.

Rodney Square isn’t the only place the city of Wilmington has been planting trees lately. Some 250 trees were planted by the city in the last year and a half. And, one year ago, the city hired Mandy Tolino has its first-ever urban forest administrator.

“Trees and the green infrastructure improve water quality by helping slow water down during a storm, as well as by reducing erosion,” notes Tolino.

Recently, she has been involved in a pilot tree trench installation at Brown Burton Winchester Park, at 23rd and Locust streets. On the surface, this tree trench looks like an ordinary row of trees. But underground, the trench is lined with a permeable fabric and filled with gravel. During a rainstorm, water flows through a storm drain to the trench, where it’s stored in the empty spaces between the stones before slowly infiltrating into the soil below.

There will be a public dedication of the Rodney Square landscape project on Nov. 27 at noon. For more information, call the Delaware Center for Horticulture at 658-6262.

Article by Margo McDonough

Photo by Danielle Quigley

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UD alum Westenbroek works as agricultural adviser in Afghanistan

November 7, 2012 under CANR News, Cooperative Extension

Patricia Westenbroek said that when she was young, her mother instilled in her a desire to help others. While her agricultural education at the University of Delaware helped lead her to a role in the Cooperative Extension Service, it is that desire to help that brought her to Afghanistan, working as an agricultural adviser for the U.S. Department of Agriculture (USDA) Foreign Agricultural Service.

Westenbroek — a UD alumna who graduated in 1997 with a bachelor of science degree in animal science with a pre-veterinary concentration and minors in agricultural economics and chemistry and went on to earn a master’s degree in agricultural development at the University of Aberdeen in Scotland — said that her job entails working with extension specialists in the Directorate of Agriculture, Irrigation and Livestock (DAIL). She said that she works on “a variety of agriculture projects, including animal husbandry, animal nutrition, beekeeping, and planting perennial trees at the district and provincial level.”

DAIL works closely with United States and coalition forces, the Department of State, the U.S. Agency for International Development (USAID) and local organizations as a team to “strengthen the capacity of the Afghan government, improve farm management and rebuild markets,” said Westenbroek.

One part of her job that she finds especially enjoyable is working with the female extension agents employed by DAIL in the province. “In them is so much promise,” said Westenbroek. “Public roles for women have been limited in Afghanistan and that has been changing. These women take the risk to help their people improve their lives by providing social, agricultural and education services.”

While some might have reservations about moving to Afghanistan, Westenbroek said that the decision for her was fairly easy. “I’ve wanted to be able to do this type of work for a long time,” said Westenbroek. “It was natural to say yes to an opportunity to help farmers and extension agents.”

Although she does admit that there was initially a bit of trepidation about going to Afghanistan, Westenbroek said, “The opportunity to work with Afghans as they rebuild their country outweighed my concerns.”

Though her day-to-day routine is varied — one day she may be out on a mission with military colleagues to meet villagers while the next she may be meeting with government officials or extension agent — she always has a daily Dari lesson to help her learn the local language.

The other thing that remains constant is what she enjoys most about her job: the people.

Westenbroek said that she meets all sorts of people ranging from “DAIL representatives who truly want what is best for their province or district to help the farmers to make positive changes; a young boy who is extremely proud of his goats because they are healthy; a little girl excited to see two women with the military team walking with me around the village and telling me about her day at school; the kindness of everyone as I learn Dari — teaching and laughing with me.

“I have been overwhelmed by the warm welcome from a young Afghan woman who embraced me with tears of joy, thanking me and all Americans for coming to Afghanistan to help her country.”

Article by Adam Thomas

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UD’s Wommack part of $25 million USDA food supply safety study

February 21, 2012 under CANR News

K. Eric Wommack, professor of environmental microbiology in the Department of Plant and Soil Sciences at the University of Delaware, is part of a five-year, $25 million U.S. Department of Agriculture (USDA) study aimed at preventing potentially fatal illnesses linked to Shiga toxin-producing E. coli bacteria (STEC) in the nation’s food supply.

STEC poses a serious threat to the food supply, resulting in more than 265,000 infections in the United States each year.

The coast-to-coast study includes a team of 48 investigators from multiple universities and government agencies, with the University of Nebraska and Kansas State University as the lead institutions.

Wommack became involved with the project after serving on a USDA grant review panel with Jim Keen, the lead project director from the University of Nebraska, who had been studying STEC for a number of years and was putting together the project proposal.  “It was really just good fortune on my part to be lucky enough to be involved with the group,” said Wommack, adding that he has not previously worked with STEC but can potentially bring a new angle to the research through his experience in microbial ecology.

As a microbial ecologist, Wommack said he is “interested in all the microbes that make up communities of microbes.” He equated this to an environmental ecologist, only instead of looking at “all the plant species within the make-up of the forest or the grassland, I look at all the microbes that comprise a microbial community.”

For this study, Wommack will examine the microbial communities that form around STEC to see if there is a pattern that scientists can pinpoint. This would allow the researchers to trace non-toxic levels of STEC by determining the kinds of microbial communities where it is most likely to occur.

“It is difficult to detect STEC when it is at the non-poisonous levels, but it is still there and so my work may show that there are other microbes that just happen to occur alongside STEC but are a whole lot easier to find. It is not like (STEC) is the only bacteria in a cow, so we are interested in looking at the larger communities that surround the pathogenic organisms.”

Wommack also will try to understand the ecology of STEC on a fundamental level.  “Although it is an organism that is an awful pathogen and kills people,” Wommack explained, “it is also a microbe that is out there and it has to live in whatever environment it is found in, and so most everything we know about STEC is when it is making people sick. We don’t really know much about it other than that — meaning its place in the ecology of microbial communities.”

Wommack said he is excited to get started on this research project, anticipating that he may begin work as soon as March. “It is hard to argue against knowing more,” he said. “Knowing and understanding more about the biology and the ecology of the organism will ultimately help us to control its incidence in the food supply.”

About Prof. Wommack

K. Eric Wommack is a professor in UD’s Department of Plant and Soil Sciences in the College of Agriculture and Natural Resources.

He also has appointments in the Department of Biological Sciences in the College of Arts and Sciences and in the marine biology and biochemistry program in the College of Earth, Ocean, and Environment. His laboratory is based in the Delaware Biotechnology Institute.

Wommack received a doctorate in marine estuarine environmental sciences from the University of Maryland, a master’s degree in physiology from the University of St. Andrews in Scotland and a bachelor’s degree in economics from Emory University in Atlanta.

He is a member of the American Society for Microbiology, the American Society of Limnology and Oceanography and the International Society for Microbial Ecology.

Article by Adam Thomas

Photo by Evan Krape

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UD researchers identify novel regulatory network within legumes

January 26, 2012 under CANR News

Three collaborating laboratories in the Department of Plant and Soil Sciences at the University of Delaware — those of professors Blake Meyers, Janine Sherrier and Pamela J. Green — recently identified a novel regulatory network within legumes, including in alfalfa and soybean plants.

The work was performed predominantly by Jixian Zhai, a doctoral student in the department and was published in the December issue of the prestigious journal Genes & Development, one of the top journals in molecular biology and genetics. The genomics project was funded by a grant from the U.S. Department of Agriculture.

Conducting their research at the Delaware Biotechnology Institute (DBI), the investigators set out to get a comprehensive view of how small RNAs function in legumes and how they might be important to these plant species. They focused their work on the chromosomal sequences (genome) of Medicago, a legume genus that includes both the crop plant alfalfa and the species that was recently sequenced, Medicago truncatula.

The researchers sequenced libraries containing millions of small RNAs, important gene regulatory molecules, as well as the genes targeted by these small RNAs. Using advanced computational techniques to categorize the RNA sequences, they identified a novel function for a handful of “microRNAs” — special small RNAs that direct the targeted destruction of specific protein-coding messenger RNAs.

Among these plant microRNAs, the team determined that many target genes encode NBS-LRRs, or “guard proteins” that function in defense against pathogenic microbe infiltration. These NBS-LRRs function as an immune system to battle pathogens but presumably must be suppressed to allow the interactions with beneficial microbes for which legumes are particularly well known. The result of this microRNA targeting is a complex network of co-regulated small RNAs that Zhai characterized using a set of computational and statistical algorithms and analyses.

“The NBS-LRRs keep pathogens out, but these plant cells are still allowing beneficial microbes to enter,” says Sherrier. “The regulation of genes encoding NBS-LRR proteins has been largely unknown until now.”

Over time, these mechanisms have evolved into a more elaborate system in legumes to take advantage of this defense-suppressing system and facilitate the development of nodules, the specialized root structures of legumes in which the beneficial plant-microbe interactions take place.

“We may have found the ‘switch’ that recognizes good versus bad microbes,” adds Meyers, Edward F. and Elizabeth Goodman Rosenberg Professor and chair of the Department of Plant and Soil Sciences. “These guard proteins usually trigger cell death when a pathogen is recognized, but the plant cell is triggering cell death when it encounters a ‘good’ microbe. The circuit we identified may play a role in preventing cell death when the microbe is a friend.”

This discovery could ultimately prove important to the improvement of plant-microbe interactions in other crop plants by allowing plants to become healthier by letting in the good microbes, but keeping the pathogens out.

“We didn’t expect to find something as exciting as this,” says Sherrier. “It’s exciting because no one knows about this kind of gene control and also because it is showing us the diverse interaction between plants and bacterium as well as plants and fungi that could help us develop better mechanisms in other plants, like Arabidopsis.”

“Beyond the applied significance, the finding that NBS-LRR genes are key targets opens up a new frontier for basic research,” says Green, Crawford H. Greenewalt Professor of Plant and Soil Sciences.

If this diverse regulation of beneficial microbes could be added to other crop plants, it could mean scientists could program the plants to grow stronger and taller with less water, and even fertilize themselves.

Article by Blake Meyers and Laura Crozier

Photos by Evan Krape and Kathy F. Atkinson

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University’s Kniel, Everts join study of produce safety

December 9, 2011 under CANR News, Cooperative Extension

Researchers at the University of Delaware are participating in a project that is focused on increasing produce safety and delivering more trustworthy salad fixings.

Total funding for the University of Maryland-led project amounts to $9 million, with $5.4 million in contributions coming from the U.S. Department of Agriculture’s National Institute of Food and Agriculture and substantial industry funds.

The three-year study promises to be one of the most comprehensive studies of fresh produce safety ever conducted.

Produce safety has been a hot topic ever since 2006, when a deadly batch of spinach killed three people and sickened hundreds of Americans. The project will involve extensive testing and data collection by industry, supplemented by field experiments involving eight other university and federal laboratories around the country.

Kali Kniel, associate professor in UD’s Department of Animal and Food Sciences, and Kathryne Everts, professor and Cooperative Extension specialist in plant pathology at Maryland with a joint appointment at UD, are part of the University of Delaware team.

“Since the large outbreak of E. coli in 2006 which was traced back to spinach grown in the Salinas Valley of California, produce commodities have been under great scrutiny,” Kniel said of the project. “As we all know fresh fruits and vegetables are grown outside, which puts them at great risk for coming in contact with biological hazards like pathogenic bacteria and viruses. There are some processes that growers and packers can do to reduce the risk but the science is still not there to completely understand what those are. This project will help to resolve that for very important and ‘high-risk’ products, including leafy greens and tomatoes.”

Kniel explained the role that she and Everts will play in the study, saying, “Dr. Everts and I will be working with the farmers and packers to both develop metrics and to disseminate the science-based results of the project.  I am particularly looking forward to working with regional growers and packers to help them deal with the food safety challenges including increased biological testing and best practices for safe compost and water use.”

Robert Buchanan, a University of Maryland professor and director of its Center for Food Safety and Security Systems, is heading the research initiative.

In addition to UD and Maryland, other universities involved include Ohio State University, Rutgers University, the University of California Davis, the University of Florida and the University of Maryland Eastern Shore. The USDA and the Food and Drug Administration (FDA) will be involved in the research as well.

The initiative’s industry partners — representing more than 90 percent of the leafy greens and tomato production in the United States — will conduct about 200,000 separate tests during the project to measure the presence of pathogens.

“This project is very unique in that it has the support of the industry on a significant scale. We have a great team of scientists and great industry support,” Kniel said.

The research aims to create the scientific basis for detailed safe, hygienic practices in farming, packing, transporting and storing fresh produce.

The idea is to prevent water, air or ground sources of pathogen contamination by setting standards or benchmarks that can be applied in a variety of growing regions and countries.

The study will examine questions such as how far apart do you need to keep a lettuce patch from pigs or other farm animals to prevent bacterial contamination and what kinds of barriers are needed to prevent contaminated water from reaching crops?

Members of the research team said they believe the project will give regulators, farmers, packers and others along the supply chain the scientific and technological knowledge needed to develop and defend produce safety protocols, or “metrics” as the industry calls them.

At the production stage, the research will focus on air, water and other environmental factors related to potential contamination by pathogens; risks during harvesting, packing, and processing; as well as temperature and other handling concerns as produce moves to market.

Photos by Ambre Alexander

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UD’s Wisser receives USDA grant to study genetic barriers in corn

November 15, 2011 under CANR News

When it comes to crops in the U.S., corn is king. Just because it is king, however, does not mean that breeders and in turn growers are using corn to its fullest potential.

With this in mind, the University of Delaware’s Randall Wisser and a group of six fellow researchers have received a five-year $4.2 million grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture (USDA-NIFA) to study the genetics of adaptation and crop improvement.

Wisser, assistant professor in the Department of Plant and Soil Sciences, said that “there is a great deal of diversity in corn, or maize, particularly in the tropics, which has generally been underutilized in the U.S.” This is because tropical sources of maize are unadapted to North American environments.

Wisser added, “It is virtually impossible to realize the potential breeding value of maladapted materials; finding ways to efficiently adapt crops to new environments is a frontier of agricultural genetics research.”

Populations that lack genetic diversity can fall prey to climate change or other stressors by not having an array of genes on which to draw from. Breeding-based solutions to addressing abiotic and biotic challenges require access to genetic diversity. “If you’re drawing from a limited sample of diversity, the likelihood that you’ve got the necessary genes is less,” Wisser said.

Through its research, the team aims to help plant breeders increase breeding efficiency and access more genetic diversity, increasing their capability of responding to current and future challenges in food production.

Wide-ranging study

The research team is conducting a range of studies that combine field and controlled environment testing with genome sequence analysis and analytics.

In one avenue of research, they are working to better understand the genetics underlying how environment variables such as temperature and day lengths influence plant maturity, a primary barrier to adaptation.

When tropical maize is grown in a North American environment, like Delaware, where summer day lengths can reach up to 15 hours (compared to 10-12 hour days in the tropics), the plants are not receiving the appropriate signals that tell them to flower. They just keep growing, getting very tall and producing lots of leaves, flowering very late or not at all. The plants are out of synch with the growing season and get damaged by frosts or produce no seeds.

Maize that now grows in the U.S. has been adapted over hundreds of years with increasing selection intensities. Through many generations of breeding, an elite pool of maize plants have been developed for North American farmers that are insensitive to long days and flourish in these climates.

“In the process of intense selection, there’s been a big loss in potentially valuable genetic diversity,” Wisser said. “We are thinking about ways to recoup some of what has been lost to help deal with the complex problems of the future”

In another study of the project, the team will test if there are common regions in which the corn genome is associated with broad environmental adaptation or in which genetic barriers are created.

The group will track the flow of genes across generations of selection in the same tropical population adapted to a broad range of environments from Wisconsin to Puerto Rico.

“If adaptation is achieved through one or a few genetic tracks, then existing methods can be used to more quickly adapt tropical maize to different environments,” Wisser said. “If, on the other hand, there are multiple independent genetic tracks to adaptation then a different set of solutions will be needed.”

Wisser said he is hopeful that by studying the adaptation process researchers can pinpoint the barriers that limit use of tropical genetic diversity for North American maize improvement and “open the flood gates” for accessing maize diversity.

The research team

Other investigators in the study are Sherry Flint-Garcia from the USDA-Agricultural Research Services (ARS) and University of Missouri; James B. Holland from the USDA-ARS and North Carolina State University; Nick Lauter from the USDA-ARS and Iowa State University; Natalia deLeon from the University of Wisconsin-Madison; and Seth Murray and Wenwei Xu from Texas A&M University.

Further information about the Maize ATLAS (Adaptation Through Latitudinal Artificial Selection) project can be found at this website.

The study is funded by the USDA Climate Change Mitigation and Adaptation in Agriculture program, which also funded research by Carl Schmidt, associate professor of animal and food sciences and biological sciences at the University of Delaware, concerning heat stress in poultry. For more on that story, see the earlier UDaily article.

Article by Adam Thomas

Photo by Danielle Quigley

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Stink Bug Season

October 3, 2011 under CANR News, Cooperative Extension

Pull up the welcome mat; they’re back. It’s early fall in Delaware, which means pumpkins on the vine, apples on the trees and stink bugs in the house.

“Last year, I got a flood of calls about stink bugs during the last week of September,” said Brian Kunkel, an entomologist with the University of Delaware’s Cooperative Extension. “Sure enough, this past week, Extension has been hearing from homeowners trying to get rid of stink bugs.”

“As the days grow shorter and the evening temperatures cooler, Delawareans are discovering these uninvited houseguests in their garages, porches and decks, as well as inside the house,” Kunkel said. “The brown marmorated stink bug becomes a nuisance pest when it heads inside to find overwintering sites.”

While merely an annoyance to most homeowners, the brown marmorated stink bug (BMSB) poses an economic threat to Delaware agriculture. Fruit crops seem to be at greatest risk, especially peaches and apples. About 18 percent of the mid-Atlantic apple crop had stink bug damage last year, according to the U.S. Apple Association.

“West Virginia apple orchards experienced significant crop loss last season because of the BMSB,” Kunkel said. “Here at UD, we’re doing everything we can to make sure that we don’t see the kind of crop loss that West Virginia had.”

Several of Kunkel’s colleagues in Extension and UD’s College of Agriculture and Nature Resources are researching BSMBs in soybean, lima bean, sweet corn, field corn and sweet pepper fields.

Two of the most active researchers are Joanne Whalen, the Extension’s integrated pest management specialist, and Bill Cissel, an Extension associate who is investigating stink bugs as part of his graduate studies.

Cissel and Whalen, assisted by two interns, are examining stink bugs in conditions similar to home yards and gardens, too. In UD’s Garden for the Community, a one-third-acre plot on the Newark campus, the duo surveyed stink bug nymphs, adults and egg masses on plants commonly grown in home gardens — tomatoes, zucchini, yellow squash, cucumbers, eggplant, sunflowers and bell peppers. Plus, they’re studying a plot of ornamental plants to see which plants stink bugs use as hosts.

Rutgers University, Virginia Tech, the University of Maryland and the Delaware Soybean Board are some of the partners on one or more of these projects.

Although Delaware has several native stink bugs, BMSBs originates in Asia and were accidentally introduced to the United States. First collected in Allentown, Pa., in 1998, BMSBs have been spreading across the eastern half of the U.S. ever since.

Kunkel said spiders and birds have been known to eat BMSBs (he’s heard reports of house cats eating them, too) but the pest has no recognized natural predator here.

The USDA Beneficial Insects Introduction Research Lab, housed on UD’s campus, is investigating biocontrol measures. Biocontrol introduces natural predators into an environment to control, if not eradicate, the pest problem. But the rigorous research process and government approvals needed for biocontrol measures can take years, even decades.

Delaware’s farmers are asking for help now. So the focus of Whalen and Cissel’s research is on monitoring to determine when to control stink bugs, as well as which insecticides provide the best control.

Field observations in 2010 indicated that stink bug infestations usually start on the perimeters of fields, Cissel noted. “We’re studying whether perimeter applications of insecticides will prevent stink bugs from penetrating the interior parts of soybean fields,” he said.

“In our corn research, we are trying to determine how much damage stink bugs are causing and when the plant is most sensitive to damage — is it when it’s silking, during grain fill or closer to harvest?”

Insect research projects typically run for two to three seasons, and most of the UD studies are in their first year. So it’s too early to discuss preliminary results, Cissel said, especially since the BMSBs weren’t as active this summer as previously.

“We had a really large outbreak last year,” Kunkel said, “but we’re not seeing those kinds of numbers this year.”

Tell that to Kathy Fichter, a resident of Chadds Ford, Pa.

“It’s just as bad as last year and it’s only the beginning of stink bug season here,” said Fichter, who always has a tissue at hand, ready to scoop up stink bugs. “My two sons won’t go near them, and these are boys who like bugs,” she said.

“Our neighborhood seems to be a ‘vacation destination’ for stink bugs. They come here by the hundreds, maybe even thousands,” she added. “My neighbors are in the same predicament. Yet, a few miles away, they aren’t such a nuisance.”

Kunkel isn’t surprised by Fichter’s stink bug woes, even though regional conditions are generally better. “Stink bug outbreaks — and insect outbreaks in general — tend to be localized,” he said. “We often hear of one neighborhood getting slammed while another neighborhood a half-mile away will have very few bugs.”

If the BMSB already has arrived at your house — or you want to make sure it doesn’t — take control measures now. The best thing you can do, Kunkel said, is to seal all cracks around windows, doors, siding, utility pipes and chimneys. Often overlooked, he said, are the cracks that can appear around dryer vents and gaps around window air-conditioning units.

“Try to look on the bright side,” Kunkel said. “Stink bugs that get inside are helping you to winterize your house. Wherever they got in today is where the cold winter winds will, later this year.”

Article by Margo McDonough

This post also appears on UDaily.

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