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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UD researchers share weed science, crop trial info at annual Weed Day in Georgetown

June 27, 2011 under CANR News

Growers and those serving in the agricultural industry toured research plots at the Carvel Research and Education Center in Georgetown as part of Weed Day, an annual agriculture tradition at UD’s experimental station whose goal is to deliver the latest research findings from studies conducted throughout the year on trials involving key agronomic crops, such as corn, soybean, lima beans and watermelon, to evaluate their effectiveness of weed management.

Those attending were welcomed by Mark Isaacs, director of the Carvel Research and Education Center, Mark VanGessel, University of Delaware extension specialist and professor in the Department of Plant and Soil Sciences, and Barbara Scott and Quintin Johnson, members of VanGessel’s team of weed science researchers.

After the welcome, Weed Day began inside Carvel’s meeting rooms with a brief overview of UD’s trials, what methods or herbicides have shown promising results, and weeds that remains challenging, such as morning glory, speedwell, annual ryegrass, herbicide-resistant pigweed and Palmer-aramanth.

Later in the morning, visitors were chauffeured on haystacks for a firsthand look at several field trials, with VanGessel introducing the tour group to a trial on organic production of corn, soybean and winter wheat.

Keeping local growers up to date on field trials is a very important part of Weed Day, as communication to the industry is a key component in Delaware’s continued agronomic success and is part of Cooperative Extension’s outreach mission.

To read more about Weed Day, visit the Carvel and Research Education Center News Website

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For the love of limas

May 5, 2011 under CANR News, Cooperative Extension

Pole lima beans are a Delaware staple.

April 20 was National Lima Bean Respect Day but in Ronald Dodd’s eyes, limas deserve kudos every day of the year.

The Georgetown septuagenarian has been growing pole limas since he was a boy and says that his father and grandfather grew them before he did. Dodd’s 55- by 147-foot garden, on land he owns one block off Georgetown’s Circle, features 42 to 45 hills of pole limas each season.

Come harvest time, he’ll enjoy pole limas in succotash accompanied by baking powder biscuits, just like scores of other native Delawareans.

But head a couple hundred miles from the First State, or talk to new state residents, and you may get puzzled looks at the mention of pole limas. “At conferences, I’ve met people in the agricultural industry who have never heard of pole limas,” says Emmalea Ernest, aUniversity of Delaware Cooperative Extension associate who specializes in lima bean research. “But there is a long tradition of growing pole limas here; there is a real lima bean culture in Delaware.

“As a plant breeder, the most interesting thing to me about pole lima beans is that it is still possible to find people in Delaware who are growing local landrace varieties that they have selected themselves or that have been passed down in their families.  For other vegetables, even though there are lots of people out there growing heirloom varieties, they got the seed from Burpee, not their grandmother.”

Lima beans are a big business in Delaware. Limas are grown on more acres in the state than any other vegetable crop. However, the commercial market is made up almost entirely of baby limas and Fordhooks, not pole limas. These baby limas and Fordhooks are grown for processing, which, nowadays, means flash-frozen, not canned.

If you want to eat fresh lima beans this summer, you’ll need to be on the look-out for pole limas at farmers’ markets, particularly markets in Sussex or Kent counties. Or, better yet, you can grow them yourself, suggests Ernest.

She knows, though, that some folks may need convincing that it’s worth the effort to grow limas, pole or otherwise. Maybe they weren’t paying attention on National Lima Bean Respect Day. Or, more likely, they still have vivid memories from childhood of mushy, over-cooked canned limas heaped high on dinner plates or school lunch trays.

There’s nothing worse than a soggy canned lima but these days, flash-frozen baby and Fordhook limas are tasty and have a nice, firm texture, says Ernest.

And there’s absolutely nothing better than a fresh-picked pole lima, she says. “The taste of a pole lima is delicious and the pole lima isn’t starchy, unless you leave it on the vine too long. My four-year-old daughter, Irene, just gobbles them up.”

As an added bonus, pole limas – and limas in general – are nutritional powerhouses. They’re rich in fiber, potassium, iron, copper and manganese.

In her own Ellendale garden, Ernest doesn’t bother growing baby limas or Fordhooks – “I am able to get enough of them at work,” she says. But she has devoted 400 feet of trellis to pole limas.

If you want to grow pole limas this summer, now’s the time to prepare. Pole limas have a long growing season and should be planted between mid-May and early June. Pole limas can be grown on teepees but Ernest prefers trellises because teepees can blow over in windy conditions. Pole limas can tolerate New Castle County’s heavy, clay soils as well as Sussex’s sandy conditions.

Ernest starts her pole lima plants from seed. You can buy seeds online; pole lima plants are available at some independent nurseries and farmers markets. One of the most popular varieties is Dr. Martin, an heirloom that features 16- to 20-foot-long vines bearing large, flat pods. Big Mama and King of the Garden are other local favorites. For something different, try the Christmas Lima, sporting a red and white speckled bean that has a butter-like texture and a subtle chestnut-like flavor.

Pole limas need a lot of room and should be planted four to six feet apart. To keep your pole limas happy, Ernest says to go heavy on the watering and light on the fertilizing. Keep an eye out for spider mites and stink bugs; the two most common lima pests. Pod development should start occurring in mid- to late-August, with mature beans ready to pick about three weeks later. Pods will continue to develop into September.

If you have a bumper crop of pole limas you can freeze them or, like Ronald Dodd, you can give the excess to friends and neighbors. “I have plenty of ‘customers’ who like to get some of my pole limas,” says Dodd. “But last year was not a great season; I didn’t have any extra to give away.”

Plenty of native Delawareans – and Delawareans in the know – will be hoping for better pole lima yields this growing season.

Article by Margo McDonough

Photo by Danielle Quigley

This article can also be viewed on UDaily by clicking here.

 

 

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CANR researchers team up to combat lima bean disease

February 3, 2011 under CANR News, Cooperative Extension

When battling downy mildew, a potentially devastating disease that strikes lima beans (Phaseolus lunatus), one of Delaware’s most important vegetable crops, assembling a team of experts to attack the problem from all angles is a must. That’s why a diverse group of plant scientists in the University of Delaware’s College of Agriculture and Natural Resources has joined together to battle this important plant disease.

Tom Evans, professor of plant pathology in the Department of Plant and Soil Sciences, and many graduate students have studied downy mildew over the past 15 years.

Evans said lima beans are vital to agriculture in Delaware and are “the cornerstone of the state’s processing vegetable industry.” Approximately 6,000 hectares of baby lima beans are grown annually, with a farm value of over $6 million. If lima bean cannot be grown profitably in the state, then many other processing vegetables would not be grown due to the economics of processing.

Downy mildew, caused by the fungus-like organism Phytophthora phaseoli, is prevalent in Delaware because it thrives in humid conditions, and lima beans are grown on small, dense acreage. Evans said that most lima bean growers are concentrated in close proximity from Dover to Georgetown and from the Delaware Bay west into Maryland, so wind-driven rain makes it easier for the pathogen’s sporangia to move from one lima bean field to another.

That was the case in 2000, when downy mildew caused $3 million damage in what Evans called “the largest downy mildew of lima bean epidemic ever recorded.” Two factors contributing to this epidemic were the emergence of a new race of the pathogen, Race F, which overcame the genetic resistance of lima cultivars being grown, and frequent wind-driven rain that spread the pathogen’s sporangia.

With the emergence of Race F, growers could no longer rely on downy mildew resistant lima bean cultivars to prevent the disease, as they had in the past. New cultivars with resistance to Race F need to be developed and in the meantime growers have relied upon fungicides to manage the disease.

Bob Mulrooney, extension specialist in plant pathology, has tested fungicides for effectiveness against downy mildew for a number of years and has identified new more environmentally-friendly chemicals which offer good control. Mulrooney’s research results are the basis for growers’ current downy mildew management practices.

Evans and his group have been responsible for studying the biology of the pathogen, monitoring the evolution of new races of the pathogen and the epidemiology of the disease.

Extension associate Nancy Gregory diagnoses the disease on samples sent in by growers, maintains the pathogen in culture for field and greenhouse experiments, and determines their races.

Emmalea Ernest, an extension associate at the Carvel Research and Education Center in Georgetown, Del., breeds lima bean for desirable traits, such as disease and drought resistance, and is developing cultivars for Delaware farmers. Ernest and Evans work together screening lima bean germplasm from around the world for resistance to races E and F of P. phaseoli. Ernest has conducted experiments to determine how the resistance genes are inherited. After making crosses between resistant parents followed by several years of field screening, Evans and Ernest are testing lima bean lines with resistance to both races this summer.

Nicole Donofrio, assistant professor of plant and soil sciences, is responsible for the pathogen side of the study, trying to understand the pathogen’s virulence mechanisms, and how it evolves to attack certain aspects of the plant. Donofrio said, “In order to fight the disease, you have to know your enemy, and the more you know your enemy, the more equipped you are to tackle it when things like a new race emerge.”

Knowing exactly how to fight against the disease from a pathogen standpoint is difficult. Donofrio points out that P. phaseoli has over 500 effector genes, molecules that bind to a protein altering its activity and enabling infection. To study effectors, Donofrio and doctoral student Sridhara Kunjeti took a two-pronged approach. First, they took what they knew about P. infestans, the pathogen responsible for the Irish potato famine and a close relative of P. phaseoli, and searched for similar genes in P. phaseoli to determine if it used similar mechanisms in its attack on lima bean.

Next, they looked at lima beans that had been infected for three and six days to see which effectors were active during those time-points of infection. Donofrio said this could lead to a breakthrough because if they are able to characterize the effector genes, they can look for traits that could be a countermeasure to pathogen attack and thereby block pathogenesis.

Randy Wisser, assistant professor of plant and soil sciences, works on aspects of quantitative genetics and plant breeding and Blake Meyers, Edward F. and Elizabeth Goodman Rosenberg Professor and chair of the Department of Plant and Soil Sciences, works on genomics of lima bean-downy mildew interactions.

In various combinations, the research team has received over $200,000 from various CANR seed grants and Delaware state grants to more fully explore P. phaseoli and downy mildew.

Article by Adam Thomas

This article can also be viewed online on UDaily by clicking here.

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