Not fresh, from concentrate . . .

orange juice

Photo credit: USDA ARS, Scott Bauer

by Christian Young, Plant Health Management major

Although not as well-known as late blight of potato or ergot of rye, citrus greening, a vector transmitted plant pathogen, is threatening the continued existence of Florida’s citrus industry.

As goes Florida’s citrus industry, so goes the jobs of nearly 76,000 individuals.

Valued at well over $10 billion, the citrus industry is currently held in limbo as various plant scientists and geneticists work to acquire a permanent solution to the disease.

Citrus greening, or huanglongbing (HLB), is a bacterial disease that spreads through the Asian psyllid, a tiny insect that consumes sap from leaves, meanwhile transmitting the bacterium. Originally found in Asia and eventually South America, the disease has been infecting thousands of acres in Florida for nearly a decade.

While various treatments and methods have been attempted, there has yet to be a completely effective eradicator or preventative measure. Fortunately, in late 2015 researchers at the University of Florida released information regarding the development of a genetically engineered orange tree that initially appears to be resistant to the disease.

Unfortunately for Florida’s number one fruit crop and most of their employees, it may be as long as multiple years before a GM orange tree is available for commercial cultivation. In the meantime, we all may need to prepare to harken back to the 1950’s and ‘60’s, when OJ came from a can in the freezer and you added water to it.

Consider it nostalgia.

Sources
How Long Can Florida’s Citrus Industry Survive? by Greg Allen (NPR)

UF creates trees with enhanced resistance to greening, University of Florida news release

About the author: Christian Young is a Plant Health Management major in his junior year. Upon graduation he plans to take advantage of entrepreneurial opportunities within industry, striving to develop highly-profitable, less-invasive methods of agricultural production and resource extraction.

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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.

Golf Course vs “Dollar Spot”

Photo credit: Paul Vincelli

Photo credit: Paul Vincelli

by Olivia Huang, Professional Golf Management major

Some golf course managers have gotten severe headaches from a visible “coin” located on golf greens.

Unfortunately, those “coins” are worth nothing, instead, they are dead turfgrass causing by disease. Because the dead turf size is about the size of a silver dollar, we call it Dollar Spot, as shown in the photo.

Dollar spot is a foliar disease of furfgrass caused by a pathogen classified as Sclerotinia homeocarpa. Affected grasses will show symptoms as “white to straw-colored lesion that progress downward from the leaf tip or laterally across leaf blade,” (Tom W. Allen, Alfredo Martinez, and Lee L. Burpee). Individual leaf blades can be damaged in many forms: 1, many small lesions,2, one large lesion, or 3, the whole leaf bale can be blighted. If a small part of the grass has been affected, it might “coalesce into large straw-colored areas of blighted turf measuring 15cm -3 meters in diameter” (Tom W. Allen ). Turfgrasses that are affected by dollar spot disease often have thinned foliage and may be intruded by weed species, and golf course managers will be worried if that happens (especially on putting greens).

The environmental effects of dollar spot disease are: 1) it is toxic for the root of plants and hard to cure, 2) it will widely spread out as it develops, 3) the fungus can be easily carried by equipment (eg: golf clubs), water, living species, and wind aids.

But don’t worry, scientists have figured out some ways to manage this type of disease:
1.    Maintaining soil moisture (low soil moisture helps developing dollar spot)
2.    Keep monitoring fertility (low nitrogen fertility is beneficial to infection from the disease)
3.    Fungicides such as benzimidazole and nitriles are effective
4.    Biological control
(Remember: “Perhaps too much of everything is as bad as too little” –Edna Ferber)

The golf course is a territory where managers need to deal with turf every single day, and if they don’t, the diseases like “dollar spot” might invade the whole course and decrease the quality of the course.  Therefore, it is important to be able to forecast and prevent turfgrass diseases.

References:

Allen, Tom W., Alfredo Martinez, and Lee L. Burpee. “Dollar Spot of Turfgrass.” www.apsnet.org. N.p., 2005. Web.

“Dollar Spot (Center for Turfgrass Science).” Center for Turfgrass Science (Penn State University). N.p., n.d. Web. 22 Jan. 2016.

Photo credit: P. Vincelli

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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.

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.