Got Nature? Blog

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

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
Why do leaves change color and why do leaves fall off in autumn?, Got Nature? Blog
Why Leaves Change Color, The Education Store, Purdue Extension
Fifty Trees of the Midwest App for the iPhone, The Education Store
Native Trees of the Midwest, The Education Store
Why Leaves Change Color, USDA Forest Service, Northeastern Area
It’s Fall, but why are the leaves still green? article and video, WLFI.com

B. Rosie Lerner, 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, 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

Shaneka Lawson, USDA Forest Service/HTIRC Research Plant Physiologist/Adjunct Assistant Professor
Purdue University Department of Forestry and Natural Resources


Purdue Landscape Report: When was the last time you really looked at your trees?  It’s all too easy to just trees, grasslandsenjoy 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 beetlespotted 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

  • Are the leaves yellow, red or brown?
  • Are they spotted or discolored?
  • Do the leaves look distorted or disfigured?
  • Is there a sticky liquid on the leaves?
  • Do the leaves appear wet, or give off a foul odor?
  • Are leaves missing?
  • Are parts of the leaves chewed?

Check the trunk and branches

  • Are there holes or splits in the trunk or branches?
  • Is the bark peeling from a tree that shouldn’t shed its bark?
  • Are there tunnels or unusual patterns under the bark?
  • Is there sawdust on or under the tree?
  • Is there sap oozing down the tree?
  • Does the sap have a bad odor?
  • Do sticky drops fall on you when you stand under the tree? You might have spotted lanternfly. Please report it right away!

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 Educatorreport online, or call 1-866-NOEXOTIC.

Resources:
Trees and Storms, The Education Store, Purdue Extension Resource Center
Why Is My Tree Dying?, The Education Store
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

Cliff Sadof, Professor & Coordinator of Extension
Purdue University, Department of Entomology

Elizabeth Barnes, Exotic Forest Pest Educator
Purdue University, Department of Entomology


man standing in tall grass

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.

man mowing tall grass

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, herpetofuana, 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


Storm damage, trees downSafety first! Stay clear and look for dangerous hanging limbs, broken branches and other failures before beginning cleanup or inspections. Keep others clear of the areas beneath and around damaged trees. Be alert for power lines that could be involved with damaged trees. All utility lines should be considered energized and dangerous.

Lindsey Purcell, Purdue urban forestry specialist, shares, “in my experience, during storm cleanup, many tree owners are faced with the decision of what to do with their trees relative to restoration or removal”.  There are several types of tree damage that occur from violent weather. Each has its own specific assessment considerations. All parts of the tree should be inspected during a post-storm assessment. This requires the expertise of trained, professional arborists to assist with the decision making regarding the best course of action. Unfortunately, there are those who take advantage of the situation and overcharge or provide poor advice when it comes to the best decision on their trees. Don’t make any hasty decisions and be sure you are hiring an International Society of Arboriculture (ISA) Certified Arborist, ask for references and proof of insurance in the process.

View publication Trees and Storms located in The Education Store, Purdue Extension’s resource center, for more information.

Resources:
Trees and Storms – The Education Store, Purdue Education Resource Center
Caring for storm-damaged trees/How to Acidify Soil in the Yard – In the Grow, Purdue Extension
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Why Is My Tree Dying? – The Education Store
Tree Risk Management – The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


Dying oak leaves, phytophthora ramorum-Sudden Oak DeathSudden 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: a million trees gone and counting, North Central Pest Management Center
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


Question: I have noticed that a lot of very mature (> 80 ft) sycamore trees look ill. They don’t seem to have as many leaves, or as large as they usually get and some have already turned brown and died. There are at least 2 in my 5 acres of woods and have noticed the same with other sycamores while driving from Mooresville to Indianapolis. Is there a certain blight/cancker/pest that is damaging sycamores this year?

Answer: I have also noticed that many sycamores appear relatively bare and may have brown or wilted leaves on the stems and littering the ground around the trees. The culprit is sycamore anthracnose, a fungal disease that causes damage and death of leaves as well as stem cankers. Sycamore anthracnose symptoms can be severe when we have cool, moist spring weather at the time of bud-break and leaf emergence , but healthy trees generally recover and put on new leaf area once the environmental conditions that favor the disease change to the warmer, drier conditions of late spring and summer.

Normally, the best management practices for sycamore anthracnose are patience and maintaining good tree health. The disease cycle is dependent on cool, moist spring weather, so it will run its course by late spring or summer when the average temperatures rise. Trees that are repeatedly defoliated could be reduced in vigor and be more susceptible to other problems, so steps to promote good tree health can be used as a preventative measure.

Resources:
Fertilizing Woody Plants – The Education Store, Purdue Extension Resource Center
Diseases of Landscape Plants (leaf diseases) – The Education Store
Sycamore – The Education Store
Hardwood Lumber and Veneer Series – The Education Store
Anthracnose of Shade Trees – Purdue Plant and Pest Diagnostic Laboratory
Purdue Plant Doctor App- Purdue Extension

Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources


Tick INsiders

Scientists from Purdue’s Tick INsiders program, Lauren Hagen (left) and Maria Muriga (right), drag and check tick cloths at Tippecanoe River State Park in 2018. The program is looking for high school students and citizen scientists interested in helping with tick collections this year. (Tick INsiders photo)

Purdue University’s Tick INsiders program is looking for Indiana high school students and other Indiana residents willing to roll down their sleeves to get involved in a citizen science project.

Cate Hill, a Purdue professor of entomology, leads this effort to analyze the bacteria and viruses in Indiana’s ticks to build an understanding of what they are carrying and how that might impact human health. To do that, she needs volunteers to collect ticks from all over the state.

This year the Tick INsiders program will provide training for up to 50 students. Citizen scientists are also now welcome to collect and send ticks to Hill’s lab.

“It’s really important work. The Centers for Disease Control and Prevention reports that human cases of tick-borne diseases doubled from 2004 to 2016. If we’re going to get a handle on that and develop strategies for reducing tick bites and treating patients, we need to know where our ticks are and what our ticks are carrying around inside them,” Hill said. “That means we need a lot of ticks, and we need help collecting them.”

Three species of ticks – the blacklegged or deer tick, the lone star tick and the American dog tick – are found in Indiana. These ticks can transmit multiple pathogens, nine of which are known to cause human illnesses, though not all have been identified in Indiana. The Indiana State Department of Health reports more than 100 cases of Lyme disease each year and dozens of cases of Ehrlichiosis, anaplasmosis and Rocky Mountain spotted fever.

Research suggests that ticks can carry a cocktail of microbes – bacteria and viruses – that can sicken bite victims and may work in concert to affect the severity of an illness and human immune response.

“Not all tick bites are the same. We don’t know what is passed from a tick to a human each time someone is bitten, which means that health care professionals may need to consider multiple tick-borne pathogens in a person who has been bitten by a tick,” Hill said. “This program improves our knowledge so that we can improve our outcomes.”

Indiana residents interested in participating can collect ticks and send them to Hill’s lab for analysis. Videos on safe and proper collection techniques, as well as how to send ticks will be at Tick INsiders.

For full article, see Purdue Agriculture News.

Resources

Ticks 101: A Quick Start Guide to Indiana Tick Vectors, The Education Store – Extension Resource
The Biology and Medical Importance of Ticks in Indiana, The Education Store
Mosquitoes, Purdue Extension Entomology
One Small Bite: One Large Problem, Got Nature?, Purdue Extension-Forestry and Natural Resources
Mosquitoes and ticks – little pests carry big risks, Got Nature?

Catherine A Hill, Professor of Entomology/Vector Biology
Purdue University Department of Entomology


Kristol from Tippecanoe County, IN, sent in question to the Purdue Extension-Forestry and Natural Resources experts (Ask an ExpertGarden) asking what resources are available to help with landscaping for a front yard and sidewalk area that accumulates water after a hard rain. She also asked for resources to improve drainage.

Purdue Extension has several articles and resources to help with this type of situation.

The resources in our Rainscaping and Master Gardeners Program shares several neat options:
Rain Gardens Go with the Flow, Indiana Yard and Garden, Purdue Horticulture
Rainscaping Program
Master Gardeners Program

Don’t miss the publications located in the Purdue Extension resource center, The Education Store, relating to the topic:
Tree Installation: Process and Practices
Planting Forest Trees and Shrubs in Indiana
Climate Change: How will you manage stormwater runoff?

For Midwest Landscapes, have a look at the Purdue Landscape Report:
Purdue Landscape Report

Try this app developed by experts at Purdue University to with tree identification and tree problems caused by a variety of factors:
Tree Doctor, Purdue Extension-The Education Store

Check out upcoming workshops available for land and woodland owners, to talk with an expert:
Purdue Extension-Forestry and Natural Resources Calendar

Check out our Got Nature? posts as well, as this is always a great resource for new information:
Got Nature?, Forestry and Natural Resources-Purdue Extension

These resources give you lots of options that match what your looking for along with experts in the field to contact if needed.

We always appreciate the questions coming in, so keep them coming. Our experts will respond quickly and give you the guidance you need for your next steps.

Diana Evans, Extension Information Coordinator
Purdue Forestry and Natural Resources


This latest cold snap could kill some emerald ash borer populations in northern states like Minnesota. But in warmer states like Indiana, the invasive borer is one resilient bug.

“These guys are pretty good at burrowing in underneath the bark of the tree and that tree helps to insulate them from the bulk of the bad weather,” says Megan Abraham, director of the Indiana Department of Natural Resources Division of Entomology and Plant Pathology.

As a result, Abraham says it takes a long cold spell with really cold temperatures to kill off an emerald ash borer beetle. According to Purdue University, it would have to get down to about minus 28 degrees.

Kerry Bridges is an arborist with Tree Guy Incorporated in Bloomington. He says the emerald ash borer is not only used to Indiana winters, but it’s survived in much colder areas like Canada.

emeral Ash Borer

An adult emerald ash borer feeds off a leaf. (Purdue University Department of Entomology photo/John Obermeyer)

“I don’t foresee significant change or restriction of that bug’s reproduction and spread,” Bridges says.

READ MORE: ‘Tree Doctor’ App To Help Homeowners With Emerald Ash Borer

What’s more, emerald ash borer and some other insects have a unique way of keeping warm.

Purdue entomologist Cliff Sadof says the reason your nose starts to run when it’s cold out is because your body is trying to keep it from freezing. Mixing mucus with water lowers the freezing point. Sadof says insects like the emerald ash borer do something similar.

“But they are changing the composition of the fluids inside their body, so they act like antifreezes,” he says.

According to the Indiana Department of Natural Resources, the emerald ash borer has devastated ash trees in every county in the state. Bridges encourages homeowners that are having problems with emerald ash borer to keep treating their trees…

For full article view:
How The Emerald Ash Borer Will Survive Indiana’s Cold Snap, Indiana Public Media News from WFIU Public Radio and WTIU Public Television, Indiana University, written by Rebecca.

 

Resources
New Hope for Fighting Ash Borer, Got Nature? Purdue Extension-FNR
Invasive Pest Species: Tools for Staging and Managing EAB in the Urban Forest, Got Nature?
Emerald Ash Borer, Purdue Extension-Entomology
Emerald Ash Borer Cost Calculator – Purdue Extension Entomology

WFIU Public Radio and WTIU Public Television
Indiana University


Got Nature?

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