plant pathology

What’s breakfast without a glass of orange juice?

by Andrzej Czarniecki, Sustainable Plant Systems major

Photo Credit: Tim R. Gottwald and Steve M. Garnsey - USDA, ARS, U.S. Horticultural Research Laboratory, Florida

Photo Credit: Tim R. Gottwald and Steve M. Garnsey – USDA, ARS, U.S. Horticultural Research Laboratory, Florida

Orange juice may soon be a thing of the past. International researchers along with University of Florida and Florida State University researchers have received a 4 million dollar grant from the USDA in order combat Candidatus Liberibacter spp.  a devastating bacterial disease also known as Citrus Greening, or huanglongbing (HLB), or yellow dragon disease, which is known all around the world, affecting many other citrus growing countries and with no cure known. It is slowly killing off large orange production fields of Florida with up to 162,000 acres, as far as 50% of production has been cut in the last 4 years due with a $7.8 billion in revenue lost since 2007.

The disease enters the tree through a sap-sucking insect known as Diaphorina citri, the Asian Citrus Psyllid which feeds on the foliage of the plant allowing the bacteria to enter into the vascular system via the phloem and causing it to clog up. This causes the tree to starve itself from supplying proper nutrients resulting in fruit that is inferior in size, green, bitter which doesn’t allow for sales in the fruit market. There have been limitations such as not being able to culture the bacteria to send the bacteria to other researchers slowing down the process of finding a cure, therefore; scientists are trying a number of alternative different paths, such as; using  a bacteria similar in their study trials or by genetically modifying citrus trees with resistant genes from a spinach plant.

Reference
Researchers share $4 million USDA grant to attack citrus greening

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This blog post was an assignment for Societal Issues: Pesticides, Alternatives and the Environment (PLNTPTH 4597). The views expressed are those of the author and do not necessarily reflect the views of the class, Department of Plant Pathology or the instructor.

Panama Disease is Driving Scientists ‘Bananas’

Banana2by Elizabeth Callow, Sustainable Plant Systems: Agronomy

Chances are, if you ate a fruit this morning, it was likely a banana. Bananas are one of the most readily available fruits in the word, boasting high vitamin and nutrient contents. Since the 1950’s, only one variety of banana has been readily available on the global market. This banana is commonly called the Cavendish banana, named after the family who first propagated it in the United Kingdom.

Tropical Race 4 of Panama disease has been known to exist for nearly 50 years. However, it hasn’t been until recently that this has posed a major problem for banana suppliers. Panama disease is a type of Fusarium wilt, and once it is present in a location it is nearly impossible to eradicate. Tropical Race 4 is related to Tropical Race 1, which completely wiped out the Gros Michel banana (the predecessor to the Cavendish banana) in the 1950s. Unless a resistant variety is found, banana production could be severely altered in the coming months and years.

These issues are largely a result of excluding diversity in the banana population. Bananas are propagated as clones, so there is virtually no genetic diversity in the banana population. This creation of a monoculture has been observed in several prominent historical events. Examples of such events include the Irish Potato Famine and Dutch Elm Disease. While the loss of the banana will not lead to a worldwide food shortage, it is imperative to learn from our mistakes and ensure that diversity is a top priority to maintain good health in our crops.

Links for Further Exploration
Our Favorite Banana May Be Doomed; Can New Varieties Replace It? NPR
Bye Bye Bananas – The Washington Post
The Most Popular Eating Banana Might Soon Go Extinct

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This blog post was an assignment for Societal Issues: Pesticides, Alternatives and the Environment (PLNTPTH 4597). The views expressed are those of the author and do not necessarily reflect the views of the class, Department of Plant Pathology or the instructor.

Sudden Oak Death Kills More Than Oaks

Photo: U.S. Forest Service

Sudden oak death is a disease of oaks and over 100 other trees, shrubs and ornamentals. Photo: U.S. Forest Service

It’s a bit misleading. Sudden oak death is indeed a serious disease of several oak species, but the disease also impacts over 100 trees, shrubs and ornamentals, making it a concern for our forests, landscapes and the ornamental and nursery industries > More info

Sudden oak is an invasive disease spreading in Northern California forests (and a small portion of Oregon), causing widespread death of infected trees.  Because the pathogen, Phytophthora ramorum, infects several ornamental species, nursery stock in California, Oregon and Washington are subject to regulations for dissemination and sale.

It’s not hard to imagine the consequences if sudden oak death were to spread acroo\ss the U.S.  There are very few management or treatment options that are environmentally safe, practical and effective in forest situations.  Ohio State scientists are studying how to determine how many and which trees are likely to survive in a given areas, based on genetic markers.

The work is being conducted by Pierluigi Bonello, professor in the Department of Plant Pathology at Ohio State, Anna Conrad, graduate student, and their colleagues.  Their work was recently published in Forest Ecology and Management (312:154-160).

Read more about their work in a recent CFAES news release > Will It Live or Die?

Norman Borlaug Statue in the U.S. Capitol

Norman Borlaug, plant pathologist, Father of the Green Revolution and Nobel Peace Prize Laureate, was honored with a statue in the National Statuary Hall in the U.S. Capitol.  He’s also known as “the man who fed the world” for the development of high-yielding, disease-resistant wheat that vastly improved wheat production in Mexico, India and the U.S.

The statue of Borlaug, an Iowa native, was unveiled on March 25, 2014, what would have been his 100th birthday. The right side of the statue’s pedestal reads, “The Man Who Saved A Billion Lives.”

His legacy continues through several foundations that continue to provide education and research on crop improvement.

Read More
Biography > National Statuary

 

Where there are plants, there are plant diseases

diseaseheadlines2

Plant diseases impact all countries on all continents, including Antarctica.  For the Celebration of Nations event in the College of Food, Agricultural, and Environmental Sciences, I placed several news headlines on a world map to convey the global scope of plant pathology.

Scanning the headlines, many people were surprised – and concerned. Even plant pathologists were impacted by all of the headlines in one place, on one world map.  And this is a very short list.

We were honored to receive the “Most Educational Display” award at the event for this display.  My colleagues suggested that this is a good visual way to get the message out about the importance of plant pathology, and so I choose this blog post as a way to start.  Yes! Coffee, chocolate, bananas, oranges . . .  wheat, rice, corn and more – they are all on the list.

Read more
Tackle Fungal Forces to Save Crops, Forests and Endangered Animals > Science Daily
American Phytopathological Society on Twitter > News

 

Do Plants Feel Pain?

. . .  When a tree is pruned, does it suffer?

This was the question posted in the NY Times Science Q&A on Dec. 23.

My quick answer: no . . . plants don’t have nerves or a central nervous system associated with what we think of as “pain”.

As Amy Litt pointed out in the NY Times article, however, plants do mount a response to injury (e.g. pruning of a limb), insect attack or pathogen infection.  This is an important and active area of research that’s important to plant pathologists in the development stress-tolerant, disease and pest-resistant crops.

> Read the full Q&A

Related video > Can Plants Think?

Noticing the Brown-Tipped Evergreens

diplodia tip blight

Wallis et al. Ohioline Fact Sheet Diplodia Tip Blight

Winter is really the season for the evergreen trees.  There’s nothing like the beauty of snow-covered pines, spruces, firs – they are the stuff of winter landscape!

This brings me to a common disease of pines – Diplodia tip blight, caused by the fungus, Diplodia pinea. Austrian pines are particularly suspectible.  If you’ve seen an Austrian pine tree, you’ve probably seen clumps of brown needles – that’s likely the work of the fungus.  Austrian pines are often planted as street trees in this part of the country because they are tolerant to the road salt used for winter ice/snow control.

PhD candidate Patrick Sherwood and Professor Enrico Bonello in the Department of Plant Pathology are using the Diplodia-pine system as a model to study plant defense against pathogens.  They are delving down to the biochemical and molecular levels to study the complex, intriguing interactions between plant and fungus.

Many students are surprised to discover that plants indeed mount a defense response against pathogens. It’s not the same as the immune system of humans and animals, but there are key similarities as well as differences.

The use of disease resistant plants or crops is a cost-effective, environmentally sound management strategy.  An ounce of prevention is worth a pound of cure – that’s especially true for plants.

Related article:
Diplodia tip blight > Ohioline Fact Sheet