Purdue University - Extension - Forestry and Natural Resources
Six pieces of data to collect from deer you harvest this year
Deer season is upon us in Indiana! If you are a serious hunter and deer manager, here are some things you should consider collecting from deer you harvest. This data provides valuable insights to the deer herd condition, and when combined with hunter observation data and habitat data, like browse transects, you can get a clear picture of the deer herd and habitat quality on your property. However, one year of harvest data is unlikely to be much of value, but collecting data over multiple years can help you track trends in the herd and habitat quality.
What to collect
When you harvest a deer on your property you should consider collecting the following pieces of biological information:
*Each deer you harvest should be assigned a unique ID number to be sure all the following data is assigned to the right deer.
Sex and Age
Collecting deer sex and age (based on tooth replacement and wear) can help you divide the rest of the data you collect into sex and age classes. Find out how to determine age by viewing Age Determination in White-Tailed Deer video. You do not
necessarily have to age a deer to the exact year, but you should separate ages into at least 3 age classes; fawns, yearlings, and >= 2.5 years old. This can be important for tracking changes to the average weight per age class or average antler measurements per age class over time.
Weight
You can collect either live weights or dressed weights, but you should pick one or the other and collect all weights consistently. Be sure to test your scales for accuracy before weighing deer. Tracking changes to the average weight per age class can provide
information about the nutritional status of the herd.
Lactation Status
Lactation status of does is often used as an index of fawn recruitment and can help determine if a doe had a fawn the summer preceding the hunting season. Lactation status for does harvested early in the season can be checked by squeezing the teats to produce milk you may need to cut into the mammary gland on does harvested later in the season to check lactation status.
Antler measurements
Antler measurements should be collected from bucks harvested on your property, including yearlings. Find out how to measure the antlers by viewing How to Score Your White-Tailed Deer video. At a minimum, you should collect the number of points on each antler and the basal circumference of the main beams. You may also consider collecting the inside spread of the antlers and the main beam lengths. Additionally, you can collect the gross Boone & Crockett Score.
Rumen contents
This piece of data can be helpful from a scouting and hunting aspect. Looking into the rumen of a deer can help you determine what deer may be eating during the portion of the year the deer was harvested. You may find green material (which can be hard to identify), corn, acorns, or whatever else deer may be consuming.
Things you need to collect harvest data
Here is a list of items you might need to collect data from harvested deer.
Putting all of this data together can give you a picture into the condition of the deer herd on your property. Collecting this data only takes a small amount of time and effort and the information you gather is well worth it! For more information of how to collect biological data from harvested deer, check out this video from Purdue Extension.
Help the Indiana Department of Natural Resources (IDNR) collect biological data from harvested deer
Most of the data we discussed in this blog post and that is covered in the White-Tailed Deer Post Harvest Collection video, are data the Indiana DNR is collecting through an online post-harvest survey. This is a great opportunity for hunters to help the DNR collect data that will be used to manage the deer herd throughout the state. More information about the after the hunt survey can be found by visiting the Indiana DNR Deer After Hunt Survey page. If you are successful in harvesting a deer in Indiana this year, be sure to check your email for a link to the survey.
Additional Resources:
Age Determination in White-Tailed Deer video, Purdue Extension – FNR YouTube Playlist
How to Score Your White-Tailed Deer video, Purdue Extension – FNR YouTube Playlist
White-Tailed Deer Post Harvest Collection video, Purdue Extension – FNR YouTube Playlist
White-Tailed Deer Harvest Log (pdf), Purdue Extension-FNR
Indiana Deer Hunting, Biology and Management, Indiana Department of Natural Resources (IDNR)
Indiana Hunting and Trapping Guide, Indiana Department of Natural Resources (IDNR)
Managing White-Tailed Deer: Collecting Data from Harvested Deer, Alabama Cooperative Extension System
Jarred Brooke, Wildlife Extension Specialist
Department of Forestry & Natural Resource, Purdue University
Purdue Landscape Report: Just as sure as you try to predict the weather, it is likely to change. But going out on a limb, I predict that we will have a bit of a dud for fall color display this year. Not a very risky prediction, considering that many plants already are starting to turn color and/or drop leaves in some areas of the state.

Nyssa sylvatica (black gum) showing early fall color due to drought stress. Source
So why would the colors be early and/or a bit duller than usual? Certainly, some of the reason why plants display fall colors has to do with the genetic makeup of the plant. That doesn’t change from year to year. But the timing and intensity of fall colors do vary, depending on factors such as availability of soil moisture and plant nutrients, as well as environmental signals such as temperature, sunlight, length of day, and cool nighttime temperatures.
The droughty conditions experienced during much of the second half of summer are likely to have decreased the amount of fall color pigment. Southern Indiana has been particularly parched. Despite recent rains in some areas, much of the state remains designated as abnormally dry to moderate drought. You can check your area’s conditions at the US Drought Monitor for Indiana. Additional maps and data is available at the Midwest Regional Climate Center.
Growing conditions throughout the season affect fall color as does current weather. Colors such as orange and yellow, which we see in the fall, are actually present in the leaf all summer. However, those colors are masked by the presence of chlorophyll, the substance responsible for green color in plants during the summer. Chlorophyll allows the plant to use sunlight and carbon dioxide from the air to produce carbohydrates (sugars and starch). Trees continually replenish their supply of chlorophyll during the growing season.
As the days grow shorter and (usually) temperatures cooler, the trees use chlorophyll faster than they can replace it. The green color fades as the level of chlorophyll decreases, allowing the other colored pigments to show through. Plants that are under stress–from conditions like prolonged dry spells–often will display early fall color because they are unable to produce as much chlorophyll.
Yellow, brown and orange colors, common to such trees as birch, some maples, hickory and aspen, come from pigments called carotenoids, the same pigments that are responsible for the color of carrots, corn and bananas.
Red and purple colors common to sweet gum, dogwoods and some maples and oaks are produced by another type of pigment called anthocyanin, the pigment responsible for the color of cherries, grapes, apples and blueberries. Unlike chlorophyll and carotenoids, anthocyanins are not always present in the leaf but are produced in late summer when environmental signals occur. Anthocyanins also combine with carotenoids to produce the fiery red, orange, and bronze colors found in sumac, oaks, and dogwoods.
Red colors tend to be most intense when days are warm and sunny, but nights are cool–below 45º F. The color intensifies because more sugars are produced during warm, sunny days; cool night temperatures cause the sugars to remain in the leaves. Pigments are formed from these sugars, so the more sugar in the leaf, the more pigment, and, thus, more intense colors. Warm, rainy fall weather decreases the amount of sugar and pigment production. Warm nights cause what sugars that are made to move out of the leaves, so that leaf colors are muted.
Leaf color also can vary from tree to tree and even from one side of a tree to another. Leaves that are more exposed to the sun tend to show more red coloration while those in the shade turn yellow. Stress such as drought, poor fertility, disease or insects may cause fall color to come on earlier, but usually results in less intense coloration, too. And stress or an abrupt hard freeze can cause leaves to drop before they have a chance to change color.
So far, weather conditions lead me to think this will be one of those not so showy fall color years. I hope I am proven wrong!
Resources
Fifty Common Trees of Indiana
An Introduction to Trees of Indiana
Native Trees of the Midwest, Purdue University Press
Why Leaves Change Color, USDA Forest Service, Northeastern Area
B. Rosie Lerner, Retired Extension Consumer Horticulturist
Purdue Horticulture and Landscape Architecture
Cities and towns in the U.S. contain more than 130 million acres of forests. These forests vary extensively in size and locale. An urban forest can describe an urban park such as Central Park in New York City, NY, street trees, nature preserves, extensive gardens, or any trees collectively growing within a suburb, city, or town. Urban forestry is the name given to the care and maintenance of those ecosystem areas that remain after urbanization. Data from the 2010 census indicated more than 80% of Americans live in urban centers with a population increase greater than 12%. The population of Indiana represents only 2.1% of the nation. In the last 8 years, IN has had an influx of 200,000 people which represents a population increase of 3.0%!
Urban forests, which help filter air and water, control storm water runoff, help conserve energy and provide shade and animal habitat must be maintained. As our nation becomes more urbanized, appreciate those urban foresters working to ensure we have save urban forest spaces to enjoy. These precious resources add more than curb appeal and economic value, they improve our quality of life.
What does an urban forester do? Here’s a quick answer:
References:
Purdue Urban Forestry & Arboriculture, Purdue Forestry and Natural Resources
USDA Forest Service Urban Forests, United States Department of Agriculture
US Census Bureau, United States Census Bureau
Interested in Purdue Urban Forestry? Contact:
Lindsey Purcell, Chapter Executive Director
Indiana Arborist Association
Ben McCallister, Urban Forestry Specialist
Forestry and Natural Resources
Resources:
Tree Support Systems, The Education Store, Purdue Extension Resource Center
Corrective Pruning for Deciduous Trees, The Education Store
Tree Installation: Process and Practices, The Education Store
What plants can I landscape with in area that floods with hard rain?, Got Nature? Blog, Purdue University Forestry and Natural Resources Extension

Deer that die from EHD are often found around water. This deer was found in August 2019 in Crawford County and was likely killed by EHD. Photo courtesy of Brody Wade.
Be on the watch for deer with EHD in Indiana
Recently, a white-tailed deer in Clarke County Indiana tested positive for Epizootic Hemorrhagic Disease (EHD), and potential EHD cases have been reported in 26 other Indiana counties. Here are a few things you should know about how EHD, how to spot it, and how to report it.
What is EHD and BTV?
Epizootic hemorrhagic disease (EHD) and bluetongue virus (BTV) are viral diseases, collectively called hemorrhagic diseases (HD), and are common in white-tailed deer. Both diseases are transmitted by biting midges often called “no-see-ums” or gnats. Neither disease is a human health issue, but they can cause significant mortality in white-tailed deer. Outbreaks of HD tend to impact deer populations locally, meaning an outbreak may occur in one part of a county but not in other parts.
When do EHD outbreaks occur?
EHD and BTV outbreaks often occur in late summer and early fall (August-September), especially in years with drought-like conditions. Drought causes water sources to shrink, which creates warm, shallow, and stagnant pockets of water creating ideal breeding habitat for the midges that transmit EHD. Deer also congregate in these areas to find water, which helps the midges pass the disease between infected and healthy deer. EHD outbreaks can last until a frost that kills the midges.
What are the signs of a deer with EHD?
Deer with EHD often appear weak, lethargic, and disoriented. Other signs of EHD in deer are ulcers in the mouth or on the tongue, swollen face, neck, or eyelids, and a bluish color to the tongue. Deer with EHD often search for water to combat the fever caused by the disease. EHD can be confirmed by testing blood and tissue (i.e., spleen) samples, but samples must be collected shortly after death.
Where am I likely to find a deer with EHD?
Because deer with EHD often seek out water to combat the resulting fever, deer killed by EHD are commonly found around water. If you have a stream, creek, river, or other source of water on your property, looking in the vicinity of those areas can help you locate deer that have succumb to EHD.
What do I do if I find a deer I think has EHD?
If you come across a sick or dead deer that you think has EHD you can report it through an online reporting system run by the Indiana DNR. Here is a link to the reporting system: Report a Dead or Sick Deer.
Can deer survive an EHD outbreak?
Yes, some deer will survive EHD. While up to 90% of deer that contract EHD may die from the disease, the deer that survive build up antibodies to EHD, which may make them immune to future outbreaks. Additionally, does may pass the antibodies and immunity to their offspring.

Sloughing or splitting hooves on two or more feet of a deer taken during the fall hunting season are typical of chronic HD. Photo courtesy of the Southeastern Cooperative Wildlife Disease Study.
How can I tell if a deer I killed during hunting season has survived EHD?
If you kill a deer during the hunting season this year, pay attention to the hooves. Deer that survive an EHD outbreak often have indentions or cracks on their hooves (see picture).
Sloughing or splitting hooves on two or more feet of a deer taken during the fall hunting season are typical of chronic HD. Photo used courtesy of the Southeastern Cooperative Wildlife Disease Study.
Are deer that have survived EHD safe to eat?
Yes, deer that have survived EHD are safe to eat.
For updated information on EHD in Indiana check out the Indiana DNR – Epizootic Hemorrhagic Disease web page.
Resources:
Report a Sick or Dead Deer, Indiana Department of Natural Resources (IN-DNR)
EHD Virus in Deer: How to Detect and Report video, Quality Deer Management Association
Epizootic Hemorrhagic Disease, Cornell University
How to Score Your White-Tailed Deer video, Purdue Extension – FNR YouTube Playlist
Deer Harvest Data Collection, Purdue FNR Got Nature? blog
Jarred Brooke, Wildlife Extension Specialist
Purdue Forestry and Natural Resources
One of the most dangerous pests to trees is a human, especially with equipment.
Injuries to trees caused by a lawn mower or weed trimmer can seriously threaten a tree’s health.
Additionally, damage to the bark layer of trees causes a long-term liability by creating a wound which leads to a defect, becoming an unsafe tree.
The site of injury is usually the root flare area, where the tree meets the turf and gets in the path of the mower or trimmer. The bark on a tree acts to protect a very important transport system called the cambium layer.

This is where specialized tubes are located which move nutrients and water between the roots and the leaves. Bark layers can vary in thickness on different tree species. It can be more than an inch in thickness or less than 1/16 of an inch on young, smooth-barked trees such as maples and birch trees. This isn’t much protection against string trimmers and mowing equipment, especially the young trees.
Any type of damage or removal of the bark and the transport system can result in long-term damage. Damage, which extends completely around the base of the tree called girdling, will result in ultimate death in a short time.

Tree wounds are serious when it comes to tree health. The wounded area is an opportunity for other insects and diseases to enter the tree that causes further damage. Trees can be completely killed from an attack following injuries. Fungi becomes active on the wound surface, causing structural defects from the decay. This weakens the tree or it eventually dies, creating a risk tree to people around it.
Newly planted, young trees need all the help we can provide to become established in the landscape and these trees are often the most commonly and seriously affected by maintenance equipment. However, injury can be avoided easily and at very low cost with these suggestions.
The removal of turf or prevention of grass and weeds from growing at the base of the tree are low-tech solutions to eliminate a serious problem. Spraying herbicides to eliminate vegetation around the base of the tree can decrease mowing maintenance costs. Be sure to use care when applying herbicides around trees.Trees are a major asset to your property and important to our environment. Protect our trees and preserve these valuable assets by staying away from tree trunks with any mowing or weed trimming equipment. The damage lasts and it cannot be repaired and often results in losing your tree.
Purdue University Landscape Report Article
Resources
Corrective Pruning for Deciduous Trees, The Education Store – Purdue Extension resource center
What plants can I landscape with in areas that floods with hard rain?, Purdue Got Nature? Blog
Tree support systems, The Education Store
Tree Installation: Process and Practices, The Education Store
Lindsey Purcell, Urban Forest Specialist
Forestry and Natural Resources
United States Department of Agriculture Animal and Plant Health Inspection Service Bulletin: USDA declares August Tree Check Month and urges public to look for Asian longhorned beetle.
WASHINGTON, July 23, 2019 — August is the height of summer, and it is also the best time to spot the Asian longhorned beetle (ALB) as it starts to emerge from trees. The U.S. Department of Agriculture (USDA) is asking the public to take five minutes to step outside and report any signs of this invasive pest. Checking trees for the beetle will help residents protect their own trees and better direct USDA’s efforts to eradicate this beetle from the United States.
“It’s important to look for signs of the beetle now, because it’s slow to spread during the early stages of an infestation,” said Josie Ryan, APHIS’ National Operations Manager for the ALB Eradication Program. “With the public’s help, we can target new areas where it has spread and provide a better chance of quickly containing it.”
The Asian longhorned beetle feeds on a wide variety of popular hardwood trees, including maple, birch, elm, willow, ash and poplar. It has already led to the loss of more than 180,000 trees. Active infestations are being fought in three areas of the country: Worcester County, MA, Long Island, NY (Nassau and Suffolk Counties), and Clermont County, Ohio.
“Homeowners need to know that infested trees do not recover and will eventually die, becoming safety hazards,” warned Ryan. “USDA removes infested trees as soon as possible because they can drop branches and even fall, especially during storms, and this keeps the pest from spreading to nearby healthy trees.”
The Asian longhorned beetle has distinctive markings that are easy to recognize:
After seeing signs of the beetle:
It is possible to eliminate this pest and USDA has been successfully doing so in several areas. Most recently, the agency declared Stonelick and Batavia Townships in Ohio to be free of the Asian longhorned beetle. We also eradicated the beetle from Illinois, New Jersey, Boston, MA, and parts of New York. The New York City boroughs of Brooklyn and Queens are in the final stages of eradication.
For more information about the Asian longhorned beetle, other ways to keep it from spreading—such as not moving firewood—and eradication program activities, visit USDA Animal and Plant Health Inspection Service. For local inquiries or to speak to your State Plant Health Director, call 1-866-702-9938.
Other Resources:
Report Invasive Species, Purdue Agriculture & Indiana Invasive Species Council
Great Lakes Early Detection Network, Bugwood Apps
New Hope for Fighting Ash Borer, Got Nature? Blog
Mile-a-Minute Invasive Vine Found Indiana, Got Nature? Blog
Sericea Lespedeza: Plague on the Prairie, Got Nature? Blog
Invasive Plants: Impact on Environment and People, The Education Store, Purdue Extension
Invasive Plant Species in Hardwood Tree Plantations, The Education Store
Invasive Plant Species: Callery Pear, Purdue Extension The Education Store
United States Department of Agriculture Animal and Plant Health Inspection Service
Purdue Landscape Report: When was the last time you really looked at your trees? It’s all too easy to just
enjoy their cool shade and the sound of their leaves, but if you don’t know what to look for you could miss deadly diseases or dastardly demons lurking in their leaves and branches. A quick check can help you stop a problem before it kills your tree or your local forest!
National Tree Check Month is the perfect time to make sure your tree is in tip-top shape! Our checklist will help you spot early warning signs of native pests and pathogens and invasive pests like Asian longhorned beetle, spotted lanternfly, and sudden oak death. You can stop invasive pests in their tracks by reporting them if you see them.
Is your tree healthy and normal?
Start by making sure you know the type of tree you have. Is it a deciduous tree like an oak or maple? Or is it an evergreen that like a spruce or a pine? Don’t worry about exactly what species it is. It’s enough for you to have a general sense of what the tree should look like when it’s healthy.
Check the leaves
Check the trunk and branches
Now what? If you answered YES to any of the questions above, there’s a good chance something is wrong. To decide if and how you should treat or report the problem, you’ll need to have a tentative diagnosis. Luckily, there are many ways to get one!
Know the tree species? Use the Purdue Tree Doctor to get a diagnosis and a recommendation on whether treating or reporting is needed. This app allows you to flip through photos of problem plagued leaves, branches and trunks to help you rapidly identify the problem. If you have an invasive pest, it will guide you how to report it.
Don’t know the tree species and still need help? Reach out to local experts. We’re happy to help!
Confused but think something is TERRIBLY WRONG? Contact Purdue’s Exotic Forest Pest Educator, report online, or call 1-866-NOEXOTIC.
Resources:
Trees and Storms: Understanding Damage, Risk and Recovery – Got Nature? Blog, Purdue Extension – FNR
Why Is My Tree Dying? – Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Caring for storm-damaged trees/How to Acidify Soil in the Yard, In the Grow, Purdue Extension
Tree Risk Management, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store
Tree Installation: Process and Practices, The Education Store
Tree Planting Part 1 & Tree Planting Part 2, videos, The Education Store
With all of the recent rain we have had throughout the state,
I have received several inquiries about effects on wildlife and what we can expect. While some flooding is natural in low areas and wildlife are adapted to respond, extreme flooding can impact wildlife. Flood waters can wash away nests or drown developing or very young animals for those living in low-lying areas. For example, heavy spring rains can reduce nest success of wild turkeys.
In many cases, wildlife will adapt by simply moving to higher ground. I tend to get an increase in inquiries about snakes after flooding. They begin showing up in neighborhood homes when they have never been observed in years past. Certainly our environment changes over time and wildlife can and do respond to these changes. However, sudden changes are likely due to a response of snakes moving to drier ground. The good news is this and other similar displacement of wildlife is usually temporary.
What can we do? I’m afraid not much for our currently flooded friends. However, in the long-term, times like this reinforce the need to create and enhance quality wildlife habitat. Providing wildlife with quality habitat that contains the necessary food, cover and water resources gives them a fighting chance to deal with issues that inevitably arise. In addition, wetlands that landowners build and restore on their properties not only enhance wildlife habitat, but also help retain moderate flood waters and recharge groundwater supplies.
If some unwanted wildlife has overstayed their welcome in and around your home, check out the Purdue Education Store publication, Considerations for Trapping Nuisance Wildlife with Box Traps. If you think you have found a sick or injured animal, you can find a list of licensed Wild Animal Rehabilitators in your area on the DNR Division of Fish and Wildlife’s Orphaned and Injured webpage. In Indiana, wildlife rehabilitators have necessary state and federal permits to house and care for sick or injured wild animals.
Additional Resources
Preventing Wildlife Damage – Do You Need a Permit? The Education Store, Purdue Extension
The Basics of Managing Wildlife on Agricultural Lands, The Education Store, Purdue Extension
Brian J. MacGowan, Extension Wildlife Specialist
Department of Forestry and Natural Resources, Purdue University

A “weedy” field like this may seem unsightly to some, but to wildlife, it provides invaluable food and cover. Just by leaving this field unmowed, you can improve habitat on your farm.

Mowing just to clean up the farm, or Recreational Mowing Syndrome (RMS), eliminates habitat for countless wildlife species.
Do you have a sudden urge to jump in the tractor and mow your fields, field borders or road ditches?
You might have RMS.
Do you enjoy spending your weekend in the cab of the tractor with a mower in tow in search of places to mow across your property?
You might have RMS.
Do you get queasy at the sight of a “weedy” unkempt field?
You might have RMS.
What is RMS you ask? RMS stands for Recreational Mowing Syndrome, a condition that afflicts many rural landowners during the summer months. And if you answered yes to any or all of the questions above, then you have RMS.
What is it?
RMS is the sudden urge many landowners get to ‘clean’ up their property by mowing the ideal fields, field borders, and road ditches around the farm during the summer months. While a mowed field may look attractive in the eyes of a landowner, in the eyes of wildlife, this is a serious problem.
These prime mowing spots provide habitat for a suite of birds, mammals, herpetofauna, and pollinating insects that inhabit our rural landscapes. Many of these species are actively nesting or raising young in these areas during peak mowing season – April through September. And the weeds coming up in these fields like common milkweed, tall ironweed, common ragweed, and many others provide food and cover for wildlife.
How to treat it?
The easiest way to treat RMS is by going cold-turkey – park the tractor for the summer. If you are not ready to give up mowing all together, then restrict your mowing to just the lanes around the fields, instead of the whole field. If you are ready to give up mowing, but still want to enjoy time in the tractor, try these options.
Instead of hooking up the mower, hook up the sprayer and go control some invasive species on the property, like bush honeysuckle, autumn olive, or sericea lespedeza. Or try hooking up the disk and disking around the field to prepare firebreaks for a late summer or fall prescribed fire.
You can still spend time on the tractor during the summer months without eliminating wildlife habitat through mowing. In fact, you can improve it!
Next time you look at your window and see a “weedy” field, don’t cringe and give into the urge to mow it. Instead, just smile and listen to all the quail whistling, songbirds singing, and bees buzzing in the habitat you improved by not mowing.
Resources
Renovating native warm-season grass stands for wildlife: A Land Manager’s Guide, The Education Store, Purdue Extension Resource Center
Effective Firebreaks for Safe Use of Prescribed Fire, Got Nature?, Purdue Extension – FNR
Sericea Lespedeza: Plague on the Prairie, Got Nature?, Purdue Extension – FNR
Jarred Brooke, Wildlife Extension Specialist
Purdue Forestry and Natural Resources
Sudden oak death, as the name suggests, is a disease that is capable of rapidly killing certain species of oaks. It was first identified in California, in 1995. Two years earlier it was identified in Germany and the Netherlands, killing rhododendron. Because the pathogen originally infected and killed tanoaks, an undesirable, understory scrub tree, it generated little interest until other, more desirable oaks species began dying. However, by this point, the disease was well established and eradication no longer an option, with millions of oak trees killed by the disease. Currently, over 120 hosts in addition to oaks have been identified, and more continue to be added to this list. What is most unusual about sudden oak death is the severity of disease symptoms coupled with the broad host range of the pathogen. This leads to difficulty in diagnosing and managing this disease.
What causes this disease?
The pathogen that causes SOD is Phytophthora ramorum (pronounced Fī-toff-thor-ă ră-mor-ǔm). This pathogen belongs to a group of organisms in the Kingdom Chromista, and has characteristics similar to fungi, plants and animals. It spreads throughout the plant by hyphal threads (like fungi), produces spores (like fungi) that have flagella and swim through water (like animals), but its cell wall is made up of cellulose (like plants). When conditions dry up, Phytophthora can produce thick walled sexual spores called oospores, or asexual chlamydospores. Because P. ramorum is not a ‘true’ fungus, many fungicides labeled for control of other fungal diseases are not effective against it.
With such a broad range of plant hosts, it is important to stress that P. ramorum affects different species in different ways. Identification must be confirmed in the laboratory and cannot be identified on field symptoms alone. Many common landscape shrubs are also infected by other endemic Phytophthora species, and symptoms look similar. Boring insects and other root rots may be mistaken for this disease. For this reason, all Phytophthora infections should be screened by the Purdue Plant and Pest Diagnostic Laboratory.
What are the symptoms of SOD?
To understand this disease, it is important to recognize that there are two categories of hosts: bark canker hosts and foliar hosts. Further complicating this is the fact that oaks are divided into three subgroups, and only the red oak group are susceptible to this pathogen. Of our 17 oak species in Indiana, half are potentially, or known to be susceptible, and include black, blackjack, cherrybark, Northern pin, pin, red, scarlet, and Shumard oaks. Diagnostic symptoms of infected red oaks include oozing sap and red-brown cankers that often leading to death.
Our concern right now is on ‘the other’ hosts. Despite its name, sudden oak death primarily spreads through foliar hosts that are sold throughout the United States. Foliar hosts include rhododendrons, azalea, viburnum, lilac, and periwinkle (Vinca minor).
These hosts (and many others) are infected via the leaves and small branches. These infections rarely cause death, and can be mistaken for sunscald, twig canker, and dieback caused by other pathogens, including native Phytophthora species. Although symptoms from these infections are not severe, and are rarely fatal, the infections produce enormous numbers of spores that can infect neighboring, susceptible oaks—and other plant species. For this reason, we are asking people to examine any rhododendrons (or other co-mingled hosts like azalea, viburnum and lilac) purchased this spring from Walmart and Rural King, while the disease may still be controlled and the pathogen contained. Although this disease doesn’t look like much on rhododendron or lilac, its ability to spread to oaks and kill them is what makes it so devastating. These shrubs play a key role in the spread of P. ramorum, acting as a breeding ground for spores (inoculum) that can spread through water, wind-driven rain, plant material, or human activity. Oaks are considered terminal hosts, since the pathogen does not readily spread from intact bark cankers; they become infected only when exposed to spores produced on the leaves and twigs of neighboring plants.
For full article and photos view: Purdue Landscape Report
Other resources:
Sudden Oak Death, California Oak Mortality Task Force
Sudden Oak Death, Indiana Department of Natural Resources
White Oak, The Education Store, Purdue Extension resource center
Planting Forest Trees and Shrubs in Indiana, The Education Store
Successful Oak and Hickory Regeneration, The Hardwood Ecosystem Experiment: 2006-2016, The Education Store
Find a Certified Arborist, International Society of Arboriculture
Janna Beckerman, Professor
Purdue Botany and Plant Pathology