I Spot a Leaf Spot

by Sierra Mayle, Animal Sciences major

In the wake of summer, many gardeners and agricultural developers will definitely see what is called leaf spot. Everywhere and common, this is often caused by pathogenic fungi that infect  the leaf and once there, grows and grows until leaf tissue is destroyed.

Depending on the severity the leaf can have smaller dots to the entire leaf being enclosed in this fungi. Now, it is important to note that even though these may be  common but not necessarily fatal diseases, plants and trees that were already under a lot of stress or not healthy to begin with are much more susceptible.

The fungi will cause degeneration  of plant tissues and have the potential to seriously injure if the fungus is not under control. It is difficult to treat once leaf spot have become prominent because with using chemicals on the trees comes the risk of further injuring and lessening the tree’s strength.  More information on control can be found on this website: www.ladybug.uconn.edu/FactSheets/leaf-spot-disease-of-trees-and-shrubs.php

Some trees commonly susceptible are maple, oak, walnut, ash, hickory, and horse chestnut. There are a few different fungi that cause this problem, including anthracnose and leaf blister (affecting oak trees). Anthracnose deals with multiple clusters of this species producing the black or brown spots on the leaves. Leaf blister most commonly affects oak trees in cooler spring weather.

We should always watch for leaf spot.  There are many varieties of plant, trees, and crops this can affect and through hortweek.com, agriculturalists have been warned to watch for this leaf spot fungi on cauliflower, pink or black lesions appearing on the heads.

Even though this fungus may not be severe on any scale it has the potential to weaken and destroy plant tissue, leaving the unknown possibility for anything to happen . . . maybe even a resistance mutation over time with the repeated use of fungicides trying to fight them?


UConn > Leaf Spot Diseases of Trees and Shrubs

Hortweek.com > www.hortweek.com/alert-high-risk-leaf-spot-predicted-2017/fresh-produce/article/1420948


Sierra Mayle is a third year student at The Ohio State University, exploring animal sciences and plant pathology. In her spare time she enjoys reading and playing with her three dogs and ferret.

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.


The End of Cigars?

Virus mosaic symptoms

Virus mosaic symptoms. Wikimedia commons

by Ryan Jeon, Biological Engineering

Tobacco Mosaic Virus (TMV) is an RNA virus that infects plants among the Solanaceous family, such as tobacco, peppers, and tomatoes. The most telltale symptom of the disease is mosaic discoloration of the leaves, an aesthetic discoloration that is deadly to the plants. The TMV virus is spread so easily just by physical contact, unlike a lot of other plant pathogens. While the virus does not kill humans, the virus is still a problem, at least to me. Humans working in a greenhouse can easily pass the virus from plant to plant if they are not careful. Farmers using a tobacco plant carrying the TMV virus can find the virus still viable in the finished tobacco products, such as Swisher Sweets.

The TMV virus made its mark in Europe in the 1800’s. Even though the tobacco plant hails from South America, it is thought that a Columbian leaf infected with the TMV virus was sent to Germany, not as a plant, but in the form of a cigar. Remember that the virus can spread by physical contact, and is still found in finished tobacco products. This is what may have caused the TMV outbreak in Europe. It was even recorded in Colonial America. The pilgrims had imported the plant as a cash crop but planted them as a monoculture. Unfortunately for them, they did not know the agricultural problems of that, and thus never rotated crops. The tobacco plant had heavy nutritional needs, and drained the soil void, where its constant nutritional deficits contributed to its susceptibility to disease.

If the virus is found in a plant, there is no fixing it. It must be disposed of immediately. This means the whole plant must be removed, which means losses in yields. While one might turn to a pesticide to stop the spread, one must remember that it is a virus, which means that regular pesticides won’t work. The virus is notably hardy, and is tolerant to desiccation. It is very important to be wary of biosecurity and to always take extra precautions to isolate and secure the disease. This is the best way to keep other plants safe. While the virus may not cause any extinction of any plants yet, maintaining biosecurity is the best way to prevent spread of the virus.



I love animals so much that I decided to dual minor in Animal Sciences and Veterinary Medicine. After these long 6 years I have learnt that there are many parallels between infectious disease in the veterinary field and those in the plant pathology field. One major similarity is that the general theme of biosecurity is central and core to our learning. Anything from insects to dirty towels, and even our own boots can spread deadly pathogens.


Penn State University fact sheet- Tobacco Mosaid Virus in Greenhouses

American Phytopathological Society – Tobacco Mosaic Virus: The Beginning of Plant Virology

Tobacco Mosaic Virus: Notes on Tobacco Mosaic Virus (TMV)

Michigan State University Extension – Common Questions and Answers about Tobacco Mosaic Virus

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.



by Emily Hayes, Sustainable Plant Systems major

Even with various scientific studies and extensive research based on the safety of GMOs, a large majority of the population is strongly opposed to genetically modified organisms. Ironically, most of the opposers do not actually know what the anagram GMO even stands for. On youtube.com, one can access a video clip from Jimmy Kimmel Live ( a comedy program) where the host asks several random people what their opinions are on GMOs. He also asked if they knew what it stood for. Not surprisingly, everyone he asked said they avoid eating GMO food products because GMOs are “bad”, however, only about 5% of those people actually knew what GMO stands for. Something is clearly wrong with this picture.  How can a person shape such a strong opinion of something with such little knowledge or understanding of it? Also, it is a pretty bold statement to say “ I don’t eat GMOs” when a lot of processed food (especially with corn or soybean ingredients) contained genetically engineered products.  A very large portion of food today is genetically modified.

On the other hand, how trustworthy are the studies that “prove” that genetically modified food is totally safe; especially when the studies are being done by the companies that produce and manufacture GMO seeds and GE crops? Monsanto is one of those companies. Monsanto is also publically very vocal about the safety of GMOs and GE crops. This could be seen as a biased viewpoint and it is a well known fact that experiments can be designed and set up to produce the desired results. Even if those studies are unbiased and set up properly, has enough time really passed to determine the actual safety of ingesting GMOs? It is important to consider the different kinds of GMOs and GE crops. Yes, humans have been genetically modifying plants for centuries, however, it was all done by cross pollination and selective breeding. To insert actual DNA into a plant tissue or seed is entirely different. It is important to understand the different methods of how organisms are modified.

A large portion of the population is strongly opposed to GMOs, while most scientists have embraced GMOs with open arms. The public perception almost implies that large corporations, such as Monsanto, are trying to poison people and give everyone cancer. In reality, Monsanto is most likely trying to improve plant genetics to produce higher yields and potentially end world hunger. The truth always finds a way out. Time will tell if GMO/GE seeds/crops are safe or not, but it’s too early to know for sure.

My name is Emily Hayes. I am a senior at The Ohio State University majoring in Sustainable Plant Systems with a specialty in Horticulture and minoring in Soil Science. I expect to graduate with my BS in Agriculture in December 2017 and continue my education with attending graduate school.

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.

“The Plant That Ate the South”


Kudzu domination of a Mississippi ecosystem
Peggy Greb, K9674-2. USDA.

by Kori Goldberg, Master of Environment and Natural Resources student


Over the past few years I have taken more than a dozen road trips south, and, although each trip is different, unfortunately one thing always remains the same: the kudzu domination of the forests. Kudzu is a perennial vine that has overtaken ecosystems across the southeast U.S. The success and aggressiveness of kudzu has prompted the nickname “the plant that ate the south” (Knebusch, 2014). This is a major plant health issue, not for kudzu itself, but for the thousands of native U.S. species that are outcompeted by it.


The history of kudzu in the U.S. begins in 1876 when the plant, native to Asia, was brought to Philadelphia for the Centennial Exposition of 1876 (Forseth and Innis, 2010). Following its introduction, the plant became a popular choice for ornamental decoration and was encouraged for use as erosion control by the Soil Conservation Service (The Nature Conservancy, 2017). More than 100 years later the plant was placed on the Federal Obnoxious Weed List in 1997 (Forseth and Innis, 2010).


The rapid growth of kudzu (it grows as fast as one foot per day), has serious implications for the plant diversity of the U.S. (The Nature Conservancy, 2017). Kudzu spreads over the tops of trees and shrubs, reducing the amount of light they receive and out-competing them for water and important nutrients.

Kudzu grows far faster in conditions of higher carbon dioxide concentrations and prefers warmer temperatures (Forseth and Innis, 2010). These characteristics are particularly concerning because global atmospheric pollution and temperature are expected to increase in coming years, thus creating even more favorable conditions. Kudzu may even utilize a “novel weapon” by releasing biochemicals that affect the microorganism community of the soil, making the growing environment less conducive to native plants (Callaway and Ridenour, 2004).

Future Work

Kudzu is rapidly advancing northward into Indiana, Ohio, and other U.S. states. Researchers are exploring the reasons for kudzu’s success to help inform future management decisions. Ongoing initiatives work to educate the public about kudzu, prevent its spread, and manage it where it has already taken hold. Possible management options include cattle and goats who rapidly consume kudzu, continuous mowing, and limited herbicide options.

You can help stop the spread of kudzu in Ohio by reporting sightings of the plant on the Great Lakes Early Detection Network, which you can find more information about here: cfaes.osu.edu/news/articles/plant-ate-the-south-is-here-poster-tells-public-watch-out-for-kudzu.

Works Cited

Callaway, Ragan M., and Wendy M. Ridenour. “Novel Weapons: Invasive Success and the Evolution of Increased Competitive Ability.” Frontiers in Ecology and the Environment 2.8 (2004): 436. Web.

Fig. 1. Greb, Peggy. Image Number K9674-2. Digital image. USDA. United States Department of Agriculture, 16 July 2009. Web. 1 June 2017.

Forseth, Irwin N., and Anne F. Innis. “Kudzu (Pueraria montana): History, Physiology, and Ecology Combine to Make a Major Ecosystem Threat.” Critical Reviews in Plant Sciences 23.5 (2004): 401-13. Web.

“Journey with Nature: Kudzu.” The Nature Conservancy. The Nature Conservancy, 2017. Web. 30 May 2017.Knebusch, Kurt. “News: ‘Plant That Ate the South’ Is Here: Poster Tells Public to Watch Out for Kudzu.” OSU.edu. N.p., 8 Apr. 2014. Web. 30 May 2017.

Kori Goldberg is a student at The Ohio State University pursuing her Master’s in Environment and Natural Resources. In her free time she loves to be outside, whether climbing, kayaking, or enjoying green spaces in Columbus.

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.

Beware the GYPSY MOTH: Cascading Devastation in the Northeast May Be Headed Your Way

by Abigail Newburger, Jewish Studies

aerial gypsy moth damage

National Weather Service Boston

A French astronomer living near Boston in the 1860’s imported European gypsy moths (Lymantria dispar) for an experiment.  He was interested in evaluating them as an alternative to silkworms for textiles.

From an unintended gust of wind on his windowsill in Massachusetts in the late 1860’s to defoliation able to be seen from space, gypsy moth damage continues.

With no natural predators, the gypsy moth population rapidly increased.  Also, most North American birds and insect eaters cannot tolerate the irritating spines on the insects.

The gypsy moth caterpillars are defoliating millions of acres of forest.  This is not only unsightly, but leads to a catastrophic cascade of events.

Repeated defoliation harms trees. Within a couple of years they are robbed of their nutrients which can lead to their decline. They are more susceptible to other insects and disease.   This may lead to susceptibility to fires.  This economically impacts the timber industry.  This in turn adversely affects states that rely on income from the lumber industry.  Defoliated areas are also unsightly and can reduce campers coming to that area.  This can economically impact parks that rely on camping income.

The defoliated trees no longer provide a canopy for wildlife such as birds and their offspring.   More light reaches the forest floor.  This increased light harms the plants that need shade and maybe allow invasive species to grow faster.

One of the moth’s favorite food is the oak (Guarino). Many wildlife species depend on acorns for food.  Deer especially rely on acorns.  The health of various wildlife depends on the availability of food.  Some of these animals are used for human food as well.

Some people have had their homes turn black from all the gypsy moth poo, also called frass  (Guarino). Much scientific research has gone into studying the effects of all that Nitrogen from the moth frass on oak forest floors (Christenson, Lovett, Mitchell, Groffman).

The moths themselves have caused numerous issues with one of them being delayed flights.  A flight was delayed at Boston’s Logan International Airport while the pilots waited for the insects to clear. (Guarino).

A skin rash from the caterpillars is happening to many people.  You do not need to have contact with the gypsy moth caterpillar to be affected.  If sweeping up caterpillar poo wasn’t bad enough, their hairs travel in the breeze and land on drying clothing or your skin.  These allergic rashes have landed many people in the doctor’s office.  Some have described the rash as being worse than poison ivy (Freyer > Boston Globe News story with photo of rash)

Scientists have been searching for methods to decrease the population.   One fungus has been nicknamed the “caterpillar killer” by Cornell University’s mushroom blog: Entomophaga maimaga.  Although by consuming this fungus from Japan the caterpillars would die, the fungus cannot take root in very dry Spring seasons. Since the last few Springs have been unseasonably dry, there is not a very positive outlook for the summer.


Abigail Newburger is a fifth-year undergraduate student at The Ohio State University. Originally from Potomac, Maryland she is hoping to move back to the Greater Washington D.C. area to work in the nonprofit sector.



Christenson, L.M., Lovett, G.M., Mitchell, M.J. et al. Oecologia (2002) 131: 444. doi:10.1007/s00442-002-0887-7

Freyer, Felice J. “Gypsy moths have found yet another way to annoy people.” Boston Globe. N.p., 24 May 2017. Web. 3 June 2017.

Guarino, Ben. “Northeast battles gypsy moths, an insect plague stripping trees bare and delaying airplanes.” The Washington Post. N.p., 7 July 2016. Web. 3 June 2017.

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.





Corn Smut – Delicacy or Disaster?

Corn smut artwork

by Megan Baisden

Depending on who you ask, you will hear different answers. Caused by the pathogenic fungus Ustilago maydis, it is a plant disease that causes smut on corn.

The actual fungus infects the host plant by infesting the ovaries of the plant. This makes the kernels swell up like tumors.

They have similar textures and developmental patterns as mushrooms and affects all species of above-ground corn. This hasn’t stopped it from being a delicacy in Mexico, known there as huitlacoche or corn truffle. It is commonly eaten in soup and quesadillas among other tortilla based foods. Seeing it as a delicacy goes all the way back to the time when Aztec culture was flourishing.

You can read more about it here, including preparation instructions www.gourmetsleuth.com/articles/detail/huitlacoche

This is an interesting question to ask because how different do two cultures have to be so that one views something as a delicacy while the other has negative view of the disease? This is the biggest reason I find the concept of corn truffle so interesting. Was it originally an attempt to make a negative thing better? Or was it viewed as a gift from the gods?

This disease is managed in the U.S. – it tends to occur after periods of heavy rain or high moisture, so that is the biggest contributing factor to its delicacy status. It tends to be cooked with ingredients that have strong tastes such as garlic or chili. As it is cooked, it turns into a liquid that resembles ink and adds a strong earthy taste to whatever dish it accompanies. What do you think? Would you give it a try? Part of experiencing other cultures is to give their interesting foods a shot.

More details about the preparation and history of corn truffle

About the Author:

I am an OSU employee who is taking time to figure out my true calling. My true interests involve water conservation and the plants and animals that are part of the different aquatic ecosystems. I spend my free time raising an 8-week old puppy and trying to get the cat to give him a chance.

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.



Precision Ag

by Dakota Jones, Sustainable Plant Systems major

Agriculture has always had many advancements over the years to get us where we are today. From when the first plow was made in 1837 to today, where we have huge tractors plowing the ground, the way we farm has changed.

Today we use machines and technology to help guide our tractors through the field. Most recently, we are utilizing numerous technologies have greatly increased our farming.  One of these is GPS, or global positioning system. GPS allows us to precisely drive our machines and plant very accurately, which reduces driver fatigue and leads to increased yields.

Another popular practice is variable rate fertilizer application, as well as variable rate seed application. This technology allows us to have control where we place seed and fertilizer, reducing seeds and fertilizer where they are not needed. This helps the farmer save thousands of dollars. This can also help reduce algal blooms due to not having fertilizer leach because too much was applied.

More practices are starting to catch more popularity. UAV’s, and irrigation techniques are catching the market by storm. Irrigation is mostly used in places that have to conserve their water, because they have a limited source. UAV’s are used to scout fields in a fast and very effective way.

Jones, Dakota. (2017) Precision Ag: A growing trend. Unpublished. The Ohio State University.

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.

Genetic Engineering

By Taylor Broerman, Sustainable Plant Systems major

Genetic engineering has gotten a bad rap over the years for being something unnatural or wrong. However, genetic engineering is not entirely a bad thing. There are a few reasons for this including herbicide resistance in crops, insecticide resistance in crops, and some positive effects on the environment.

Having herbicide resistant crop allows us to spray certain chemicals on those plants to protect them and keep weeds down. This allows for a successful production year for the crop and consistent food security. Insect resistance is another important aspect for a good production year and food security. Bt crops are the most common type of genetically engineered insect resistance. Bt is a bacteria that is harmful to certain insects that ingest plant material modified with the Bt strain. Genetically  modified crops can also can have a beneficial impact on the environment by reducing the amount of tillage farmers need to do, which in turn, decreases runoff of fertilizers and chemicals into lakes and streams.

Each of these positive reasons for genetic engineering have some push-back, mostly from media, however genetic engineering is going to be a big part of the future of agriculture, whether or not it is completely accepted by everyone.

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.