Category Archives: Botany and Plant Pathology

Searching for viruses that make plants sick

Ripening sweet cherries in Mosier, Oregon. Photo credit: Lauri Lutes

When plants get sick, they can’t be treated or cured in the same way as people who receive medicine for an illness.  Plants require specialized care by scientists who are uniquely equipped to study and treat their diseases.  As a graduate student in the lab of Dr. Jay Pscheidt in the Department of Botany and Plant Pathology, Lauri Lutes is a plant doctor looking for viruses that infect sweet cherry trees in Oregon. She is able to identify an infected sweet cherry tree by looking at symptoms, including yellow rings or discolored mottling on the leaves, or fruit that is smaller than normal. To pinpoint the identity of the virus, further tests in the lab are performed.

Mottling and ringspot symptoms on sweet cherry, Prunus avium, in Umpqua Valley, Oregon. Photo Credit: Jay W. Pscheidt

Sweet cherries are one of Oregon’s top commodities, with 12,300 acres of sweet cherry production near the Dalles and Hood River, and 3,200 acres in the Willamette valley. There are a few viruses that the Oregon Department of Agriculture looks for each year, including Plum pox virus, a quarantine pathogen in the United States. However, if sweet cherry trees are infected with something other than the most common or most damaging viruses, they may never receive a diagnosis! Lauri works with the Oregon Sweet Cherry Commission to determine where diseased sweet cherry trees are located in Oregon. During her time at OSU, Lauri has discovered a virus infecting sweet cherry trees in the Dalles region that had never been reported in Oregon!

Lauri Lutes collecting leaf samples from sweet cherry trees in The Dalles, Oregon. Photo credit: Lauri Lutes

As an undergraduate student majoring in biology at Indiana University South Bend, Lauri discovered her passion for plant biology after taking a plant systematics course. Her undergraduate research consisted of studying fungal pathogens in a native waterleaf plant that grows in the forest floor of Indiana. Lauri attributes her positive experiences in undergraduate classes and research to female professors who provided encouragement and strong mentoring. After the birth of her daughter during her senior year of college, Lauri’s path toward attending grad school diverged, and she began working at a plant pathogen diagnostics company, Agdia, Inc. There, she used magnetic particles to purify viruses from plant material and co-developed a Technical Support Department. Curiosity driven, she found that she still wanted a deeper foundation in plant pathology, which led her to pursue graduate work at OSU.

View of Mount Hood from sweet cherry orchard in Parkdale, Oregon. Photo credit: Lauri Lutes

In addition to her work with sweet cherry tree viruses, Lauri is enrolled in the Graduate Certificate in College and University Teaching (GCCUT) program, and is active in science communication, having recently been selected to attend ComSciCon-PNW (Communicating Science Conference) in Seattle. After grad school, Lauri is considering teaching at the university level and continuing her involvement in science communication. As the first person in her family to complete an advanced degree, she hopes to inspire and expose her daughter to educational opportunities she might not have had otherwise.

Please join us this Sunday, April 2nd on KBVR Corvallis 88.7FM at 7 pm PST, to hear much more about Lauri’s journey through grad school, and her research about sweet cherry tree viruses. 

You can also stream this episode live at

View from a sweet cherry orchard in the Hood River, Oregon. Photo credit: Lauri Lutes

A very Hungry Caterpillar, a very Tenacious Scientist

Tyria jacobaeae (cinnabar moth) caterpillars chowing down on Senecio triangularis at Marys Peak summer 2014

Tyria jacobaeae (cinnabar moth) adult Photographer: Eric Coombs










Our guest this week is Madison Rodman who recently finished her Master’s degree in Botany and Plant Pathology. Growing up as the daughter of crime lab scientist and an ecologist in North Dakota, Madison told us that there was not a singular moment when she knew she wanted to do science; she always loved the outdoors. It is no surprise that Madison is a go-getter and a very organized scientist herself, but her science story is less than typical. Madison’s first research experience involved hiking through the jungles of Thailand surveying for tigers! While wildly adventurous, this trip taught Madison that field work is not all rainbows and tiger stripes, but that there are venomous snakes in the jungle and tigers are good at hiding. What drew Madison to this field trip was the opportunity to see the organism in its habitat, but she also realized that all the lovely jungle plants were hiding in plain sight and waiting to be surveyed as well.

Madison Rodman poses with her research organism Senecio triangularis summer 2016

Upon returning to Minneapolis to continue her undergraduate studies at the University of Minnesota, Madison focused on Plant Biology and realized that plant-insect interactions were something that interested her. She applied for a Research Experience for Undergraduates (REU) at the University of Michigan, and spent the summer investigating the impact of atmospheric CO2 levels on plant chemistry and how changes in leaf defense chemistry affects herbivores. This was the pièce de résistance of a science project combining: whole organism science, plant-insect interactions, and climate change biology. Things were really coming together for Madison, and she knew she wanted to go on to graduate school and continue studying plant-insect interactions.

Manipulative experiment in action near Big Lake summer 2015


She did just that, and much much more, at Oregon State. Madison defended her Master’s thesis this winter, through which she studied the risk of a biocontrol agent, the cinnabar moth, on a native plant, Senecio triangularis, or arrow-leaf groundsel. These biocontrol caterpillars, will chomp the European tansy ragwort, an invasive weed, to the ground and look pretty cute doing it, but in some parts of Oregon they have recently switched to feeding on the native arrow-leaf groundsel. The good news: the tansy buffet is in low supply; the bad news: arrow-leaf groundsel is on the menu. How risky is the annual feeding of cinnabar moth caterpillars on arrow-leaf groundsel populations? Can caterpillar feeding have negative effects on the reproduction and survival of arrow-leaf groundsel? Both the arrow-leaf groundsel and the cinnabar moth are here to stay, but this native plant might be in trouble as annual temperatures continue to rise. You’ll have to tune in to hear more about the cinnabar moth and Madison’s field work in the high Cascades and Coast Range of Oregon. We promise it is all rainbows and moths…

Madison in her native habitat near Mount Hood summer 2016

Also at Oregon State, Madison has also been able to practice and boost her teaching skills through the Graduate Certificate in College and University Teaching (GCCUT) program. She has always loved communicating science, from being an undergraduate teaching assistant at U of MN to intern at Wind Cave National Park. Madison hopes to stay involved in teaching and community outreach after grad school when she relocates to Minnesota. We’re so excited to present her perspective on graduate school and share her science story.

Tune in to KBVR Corvallis 88.7FM this Sunday February, 5 at 7 pm PST to hear Madison’s story and learn about plant-insect interactions. You will not want to miss her take on graduate school, biocontrol, and beyond.

Not a local listener? Don’t fret, you can stream this episode live at

Inspiration Dissemination is happy to announce its addition to the KBVR archive as a podcast! Listen to this episode whenever and where ever you have internet access. Link TBA.

Magical Mushrooms, Mischievous Molds

Panorama of the whitebark pine seedling at the Dorena Genetic Resource Center (USFS)

Did you know that whitebark pine is the highest elevation tree here in the Pacific Northwest? If you have driven the Rim Road of Crater Lake National Park, you may have noticed a huge gnarly tree lovingly known by few as the “Grandmother” whitebark pine. These trees withstand harsh winds and cold temperatures, giving them a krummholz or “crooked wood” appearance. Some grow nearly horizontal.

Zolton’s favorite whitebark pine at the rim of Crater Lake

As one of the few tree species that grow at high elevations, whitebark pine acts as an ecosystem foundation species, making it possible for other plants, fungi, and animals to utilize higher elevation environments. Growing together, a population of whitebark pines form ecological islands and promote biodiversity in subalpine areas. For example, the Clark’s Nutcracker and whitebark pine have been coevolving for eons. The Clark’s Nutcracker is the only bird that can break open the pine cones of whitebark pine. While the bird eats some of the seeds, it also cashes them and can disperse the seeds many miles away. Other species such as rodents and bears eat the seeds as well.

Much more research is needed to fully understand the ecological importance of whitebark pine in its characteristic ecosystem. However, recently whitebark pine research is focused on another interaction, that of whitebark pine with an invasive plant pathogen, white pine blister rust. Since the 1900s, this pathogen has dramatically reduced populations of whitebark pine and other 5-needle pines of North America. This means that whitebark pine populations and the biodiversity islands it forms at high elevations are in trouble.

Zolton with his experimental seedlings at Dorena.

Fortunately, some populations show natural resistance to the pathogen, and our guest, Zolton Bair from the department of Botany and Plant Pathology, is comparing the transcriptomes, the collection of genes expressed as RNA, of resistant and susceptible trees to understand tree defense against white pine blister rust. Be on the lookout for his dissertation defense this year!

As a teenager, Zolton loved collecting and identifying mushrooms. Through a class called magical mushrooms, mischievous molds he realized that fungi are very important to humans as food, medicine, and can be problematic for farmers. He became interested in plant pathology after conducting undergraduate research in a mycology lab that focused on the spread of fungal spores between agricultural fields.

Experimental plot: Keep off!

You do not want to miss this week’s episode of Inspiration Dissemination with our guest Zolton Bair. Tune into KBVR Corvallis 88.7 FM this Sunday January, 22 at 7 pm to hear about Zolton’s journey from barefoot mushroom hunting in Virginia to studying plant pathology here at Oregon State, and we promise you won’t be disappointed to learn more about the awesome tree story of whitebark pine.

Not a local listener? Follow this link to stream the show live.

Mosquito soup in the Brazilian rainforest

Fieldwork in the Brazilian Amazonia meant continuously trying to outsmart their savviest opponents…ants!

Fieldwork in the Brazilian Amazonia meant continuously trying to outsmart their savviest opponents…ants!

Deforestation in Brazil due to cultivation of monoculture crops, such as soybean, has profoundly impacted wildlife populations. In the lab of Taal Levi in the Department of Fisheries and Wildlife, wildlife biologist Aimee Massey has adopted a quantitative approach to studying this impact. During her first and second year of graduate school, Aimee traveled to Brazil for fieldwork and data collection, collaborating with researchers from Brazil and the UK. During this trip, she collected 70,000 biting flies, including mosquitoes and sandflies, by engineering 200 fly traps constructed from 2-liter soda bottles, netting, and rotting beef. Aimee installed biting traps throughout 40 individual forest patches, which are regions delineated by their physical characteristics, ranging approximately in size from the OSU campus to the state of Rhode Island.

Who knew fieldwork could be such a balancing act?!…especially when trying to avoid poisonous insects and thorns. Let’s hope the next branch Aimee reaches for is not of the slithering snake kind!

Who knew fieldwork could be such a balancing act?!…especially when trying to avoid poisonous insects and thorns. Let’s hope the next branch Aimee reaches for is not of the slithering snake kind!

Subsequent DNA analysis on biting flies provides a relatively unbiased source of wildlife tracking, since mosquitoes serve as a repository of DNA for the wildlife they have feasted upon. DNA analysis also provides information regarding diseases that may be present in a particular patch, based on the bacterial and viral profile. For example, sandflies are carriers of protozoa such as leishmania, which cause the disease leishmaniasis. To analyze DNA, Aimee uses bioinformatics and metabarcoding, which is a technique for assessing biodiversity from an environmental sample containing DNA. Different species of animals possess characteristic DNA sequences that can be compared to a known sequence in an online database. By elucidating the source of the DNA, it is possible to determine the type of wildlife that predominates in a specific patch, and whether that animal may be found preferentially in patches featuring deforestation or pristine, primary rain forest.

Learning about human/wildlife interactions while drinking tea with camel’s milk in Laikipia, Kenya.

Learning about human/wildlife interactions while drinking tea with camel’s milk in Laikipia, Kenya.

Aimee completed her undergraduate studies at University of Maine, where she quickly discovered she wanted to study biology and chemistry in greater depth. She planned to attend med school, and was even accepted to a school in her junior year; however, an introductory fieldwork course in Panama spent exploring, doing fieldwork, and trekking made a deep impression on her, so she decided to apply to graduate school instead. Aimee completed a Masters degree in environmental studies at the University of Michigan, during which time she spent 4 months at the Mpala Research Centre in the middle of the Kenyan plateau, just north of the Masai Mara. Following completion of her Masters degree, Aimee spent a year as a research assistant at the University of New Hampshire working with small mammals. Before beginning her PhD studies at OSU, Aimee spent two months in Haines, Alaska doing fieldwork with her future PI, Taal Levi. After she finishes her PhD, Aimee plans to focus on conservation work in New England where she is originally from.

Having fun after fieldwork; Aimee’s eulachon fish catch of the day in Haines, Alaska. One is better than none!

Having fun after fieldwork; Aimee’s eulachon fish catch of the day in Haines, Alaska. One is better than none!

Tune in on October 23rd, 2016 at 7PM on the radio at 88.7FM KBVR, or stream live, to hear more about Aimee’s adventures in Brazil, and why her graduate work is shaping our understanding of how deforestation impacts biodiversity.


We Answer to the Nucleotide Chain Gang

This week on Inspiration Dissemination our featured guest is our very own Zhian Kamvar aka DJ CATGAG the co-host and co-founder of our weekly broadcast. Before his radio and phytopathological fame, Zhian was an eager biologist and a DJ by a different name! All will unfold during this week’s episode, but I will supply some teasers to get the oospore rolling.

Zhian got interested in biology while in high school in California where he wanted to become a mortician…yes we all were very surprised (but not really) to learn this. Like any aspiring mortician, Zhian used the internet to find out how he should focus his studies and achieve his goal. Anatomy and Physiology were high on the list. Zhian was fascinated with many aspects of human biology particularly respiration and circulatory processes that “just happen.” For example, the human heart pump blood throughout the body 80 times per minute with no conscious intention of the individual. That was only the tip of the iceberg and his enthusiasm continued to grow while in his first genetics course in college at Truman State University in Kirksville, Missouri. This is when everything changed for Zhian and he decided to forgo his dream of becoming a mortician and focus on genetics. After a rough start at scaling the learning curve, Zhian aced Advanced Genetics and began an undergraduate research project investigating the that genes are responsible for making cultivars of corn grow and develop differently. A pivotal and proud moment for Zhian was presenting a poster at a national conference; this was only one of the many conferences that would follow.

Zhian seems very normal and boring, but wait!

Zhian poses with a petri dish containing a cultured specimen of the plant destroyer Phytophthora syringae. (Photo Credit: Lindsey Thiessen)

During his time at Truman State University, Zhian stumbled upon and promptly crashed into a gig as a radio DJ for the Truman State College Radio Station-KTRM “The Edge”. Zhian’s shows hosted the metal, vinyl, and classical genres. One of Zhian’s shows was a morning show called “Up Late with a Vampire,” a classical music hour for your morning commute in nowhere Missouri. Thus began our own DJ CATGAG’s life as a radio DJ subjecting us to his diverse musical taste. Zhian is not only a music connoisseur, from the common to the obscure, but also Zhian made and produced some of his own music, OH YES we have samples to play this Sunday! First, Zhian mixed electronic tunes as…wait for it…DJ Poopslice! Then his sound truly took form as Not Jeremy Jones where he explored harsh noise and “poplematic” (problematic pop) music.

Also, worth mentioning that after graduating from Truman State Zhian took a solo trip to Daegu, South Korean where he taught English for 3 years. In South Korea, Zhian did a lot of reading in his free time and decided he really missed participating science and research. He decided it was then time to apply to graduate school.

Zhian demonstrating functionalities of his software package, poppr, to a workshop at the American Phytopathological Society meeting in 2015 (Photo Credit: Sydney Everhart) (From twitter:

Zhian demonstrating functionalities of his software package, poppr, to a workshop at the American Phytopathological Society meeting in 2015 (Photo Credit: Sydney Everhart) (From twitter)

Lucky for us, (and I mean that sincerely) he was accepted to Oregon State University Department of Botany and Plant Pathology. Zhian is part of the lab of Nik Grünwald where he studies the population genetics of plant destroyers in the genus Phytophthora, specifically Phytophthora syringae and Phytophthora ramorum (this one is the pathogen responsible for Sudden Oak Death). These organisms are fungi-like and usually reproduce asexually, but they do have sex when conditions are good. His dissertation focuses on diversity of Phytophthora populations. Basically, if a population is very diversified than the effect of the pathogen on the plants involved is going to be harder to manage; whereas a population of clones may be taken out uniformly. In addition to interpreting population genetics, Zhian has been working to develop software tools that will help others to analyze data to study the genetics of other organisms. His R package called poppr allows users to analyze and visualize the distribution of genetic diversity in a population. Zhian does very great work, and we are sad to know that soon he will finish his dissertation and leave the Inspiration Dissemination team.

This is an episode you will not want to miss. Tune in at 7 pm on Sunday, August 14 to KBVR Corvallis 88.7FM or stream the show live.

CSI-Cultivated Squash Investigator: Murder in the Pumpkin Patch

Hannah Rivedal, PhD student in Botany and Plant Pathology, started working with plants before college in her neighborhood greenhouse and plant nursery. She loved growing and caring for plants that were destined to brighten her neighbors’ yards. Hannah believes, “You can’t be in a bad mood when you are holding a bunch of Petunias!” College-decision time neared and as a well-mannered Wisconsin go-getter, Hannah began college at University of Wisconsin, Madison seeking a degree in Genetics with a minor in Japanese which would lead nicely into medical school. All the while, she would travel back to her hometown on holidays and school breaks to work at the greenhouse where she first fell in love with Botany.

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Hannah preparing an experiment in the greenhouses at OSU.

Mid-college Hannah has a revelation after taking a Horticulture class and doing a little volunteer work at the hospital that Pre-med is not the path for her. In total “Hannah-fashion” she takes the reins and sets up informational interviews with eleven academic advisors at UW Madison to try and figure out what she was going to do, and she knows three things: 1) she LOVES plants, 2) she enjoys the challenge of diagnostics, and 3) she loves the reward of getting her hands dirty and working toward a solution. She decided to switch her major to Plant Pathology because it had all of these elements and more! She loves that Plant Path allows her to work directly with growers.

Hannah got her feet wet in “the biz” through undergraduate research in many different labs in the Plant Pathology department, and completed a senior capstone project in a plant disease tolerance lab focused on potatoes. When her college career was nearing an end, Hannah knew that to become a fully-grown Plant Pathologist she would need to continue with a graduate degree.

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Hannah in her natural habitat among her squash seedlings.

Hannah is currently working on many angles of this case under the supervision and guidance of her major advisor, Ken Johnson. Hannah hopes that her research with in Plant Pathology will lead to a position as a Plant Pathologist at an extension station working with growers and conducting research that is tailored to their unique situation.

That brings us to this breaking report: We have a Squash Killer on the loose! Willamette Valley growers want to know what is killing their Winter Squash. Plant Pathogens beware: Hannah Rivedal- CSI (Cultivated Squash Investigator) is on the case!

Victim: Cucurbit species, specifically Winter Squash (Cucurbita maxima), important pumpkin relative responsible for supplying the Willamette Valley and the surrounding region with ‘pumpkin’ soup, seeds, and pie filling. Did you know good’ole Jack-o-lantern pumpkin seeds are not the ones you find in the store? Those are most-likely Winter Squash seeds!

Symptoms: Wilting, crown rot, and root rot. Could cause a 100% yield loss.

Suspects: a soil borne disease that could be Fusarium oxysporum (Wilt pathogen), Fusarium solani (Rot pathogen), Plectosphaerella cucumerina (General wilt pathogen), or a combination.

Here all about it, this weekend on Inspiration Dissemination!


Hannah posing with some big beautiful Winter Squash Summer 2015.

Tune in on Sunday, March 13 at 7 pm to hear more from our own OSU Squash Sleuth, Hannah Rivedal, or stream the show live at

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Winter squash collected and awaiting diagnosis!

American Agriculture is Getting Rusty

In the year 2000, a disease called Wheat Stripe Rust occurred in more than 20 American states. This was the largest incidence in US history. While fungicide can reduce losses, the disease no doubt hurt farmers across the United States. Wheat Stripe Rust continues to be widespread around the United States, and is particularly threatening in the Pacific Northwest, west of the Cascades, where annual temperatures are cool and humidity is high. The weather in the Willamette Valley provides ideal growing conditions for the fungus, which looks like golden striations on the leaves of healthy wheat.

from, "PhD students fight Wheat Strip Rust", 2014.

from, “PhD students fight Wheat Strip Rust”, 2014.

Joining us on the show Sunday, February 14th is Daniel Farber. Daniel is a PhD student in Botany and Plant Pathology here are Oregon State University, where he studies the disperal of a fungus called Puccinia striiformis triticina that is the causal agent for the disease Wheat Strip Rust. Dispersal from a single infection of this fungus can spread the disease over a single generation, and spores can travel through the air and remain viable up to 500 kilometers away from the source of infection!

Researchers in the past have looked at these large scale patterns of spread, but they may have missed the trees for the forest, since no one has done detailed studies of how such a process occurs at the level of a single spore. By examining the shape of dispersal gradients in local, isolated infections, Daniel hopes to understand the root of this phenomena by asking how airborne infection dispersal occur from one leaf to another, at the smallest observable level. Using modelling to predict disperal patterns, Daniel hopes that this deeper understanding might lead to a more sustainable agricultural practice that is less dependent on excessive fungicide use, and that the understanding of how to model airborne pathogen spread in this way might also be applied to human health issues ranging from bird flu to the current Zika virus epidemic.

To learn more about Daniel and his work, tune in Sunday night at 7PM PST or stream the show live!

Fighting Fire with Flora

It has been a record breaking year for wildfires, with over 900,000 acres burned in Washington alone. This past summer in the Pacific Northwest families went to sleep wondering very seriously if they would need to evacuate before morning. Not all of their prayers were answered. Some abandoned land and possessions. In towns like Wenatchee, WA and John Day, OR people lost their homes and in the dense forests of the Cascades some firefighters lost their lives. Each year the damage done by wildfires grows in this country, and if climate models prove correct, this danger will only increase in the future.

Today the question of what to do with burned over land is deeply divisive in the state of Oregon. The damage wrought by wildfires is especially concerning because it affects both commercial timber stands and protected, often old growth, forest land.

Studying the question of what to do with burned over lands far from Corvallis, Lea Condon get her hands dirty in the deserts of Nevada. In an area called The Great Basin, Lea studies soil crusts, communities of organisms that live right on top of the soil which are important for ecosystem health among the cheat grass and native plant communities of The Great Basin.

Dinner in the works in eastern Nevada

Dinner in the works in eastern Nevada

Mosses and lichens under survey

Mosses and lichens under survey










In the field sites were Lea works, raising grazing animals is crucial to local economies. The increasing frequency of destructive wildfires, and the wear and tear on soil crusts caused by large animals grazing, has a disruptive effect on mosses and lichens that are important for maintaining optimal ecosystem health. A graduate student in Oregon State’s Botanty and Plant Pathology department, Lea studies under David Pyke, hoping to discover how these mosses and lichens can be restored after damanging events like wildfires occur.

Lea, moss growth experiment

Lea, moss growth experiment

To learn more about Lea’s story and research, tune in tonight at 7PM PST to 88.7 FM, or stream the show live here!

Pathogens Ruining Your Pinot: Grape Powdery Mildew and Willamette Valley Vineyards

Cracked berries: Grape powdery mildew on chardonnay berries with cracking of berries being a result of heavy infestation.

Cracked berries: Grape powdery mildew on chardonnay berries with cracking of berries being a result of heavy infestation.

In the 1960s and 70s Oregon wine makers did something incredible. They began growing pinot grapes in the cold, wet climate of the Pacific Northwest, where it was previously believed they could not be produced. Since then, the Willamette Valley has come to prominence as one of the United States’ premier growing regions, with vineyards harvesting grapes for every kind of wine you can imagine.

However, there are serious challenges to the wine industry in Oregon. A fungus known commonly as grape powdery mildew, which plagues vineyards across the United States, is one of the main culprits. Unlike other places in the United States, the growing season for grapes is completely different in the climate of the the Pacific Northwest. In this environment, traditional strategies for protecting grape harvests from outbreaks of these fungal spores are not as effective.

This is where Lindsey Thiessen comes in. A PhD candidate in Walt Mahaffe’s Botany and Plant Pathology lab, Lindsey studies plant and fungal pathosystems. Pathosystems are the relationships between the disease causing agent (in this case, a fungus) and the host (in this case, the grapes). In order to protect the Oregon wine industry, Lindsey is learning about the ecology of grape powder mildew fungus and grape plants during ‘overwintering’, when the grape buds and fungus go dormant. Lindsey helped devise a spore trapping device for use in the growing season to provide valuable information on fungal threats. This device, along with her own models for potential disease outbreak, should aid vineyard management in developing treatment strategies for their grapes.

Join us tonight at 7PM PST to find out more! You can tune in to 88.7 KBVR or stream the show live online at!

Cleistothecia on leaf: Fungal fruiting bodies (cleistothecia, approximately 130 µm diameter) of Erysiphe necator (causal agent of grape powdery mildew) under 20x magnification. Brown/black cleistothecia are mature enough for overwintering, whereas white and yellow fruiting structures are presently being formed.

Cleistothecia on leaf: Fungal fruiting bodies (cleistothecia, approximately 130 µm diameter) of Erysiphe necator (causal agent of grape powdery mildew) under 20x magnification. Brown/black cleistothecia are mature enough for overwintering, whereas white and yellow fruiting structures are presently being formed.

Sieving: L.T. sieving cleistothecia being collected from leaves in cement mixer-ice water bath.

Sieving: L.T. sieving cleistothecia being collected from leaves in cement mixer-ice water bath.


All photos courtesy of Lindsey Thiessen

Forestry Forensics 101

Look out tropical tree thieves! Beware, Pacific pine pilferers! Kristen Finch is on the case!

Sunday April 26, Kristen joined the hosts of Inspiration Dissemination to discuss her study of wood chemistry in Douglas Fir. Kristen’s love of leafy things began in 7th grade when she realized that polyploid strawberries with more than two sets of chromosomes are really big and juicy. This amazed her, because whereas the strawberries benefit from this genetic disposition, a human being would probably die from it!


Kristen’s admiration of the plant kingdom led her to study Ponderosa Pines with her undergraduate mentor and OSU alum, Dr. Ann Willyard. After completing her degree in biology at Hendrix College in Arkansas, Kristen took some time to find out what kind of research she wanted to do in botany by interning at Fairchild Tropical Botanical Garden. Extracting DNA from Caribbean Mahogany, a process that can take up to ten days, gave her a sense of appreciation for other potential methods of analysis.

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