Got Nature? Blog

Purdue Landscape Report: Tubakia leaf spot, caused by the fungus Tubakia, is the disease we find more commonly on oak than any other. Throughout the world, there are 11 species of Tubakia known to infect oak, with Tubakia dryina (previously known as Actinopelte dryina) being the most commonly encountered species in our landscapes. Apple, ash, black gum, chestnut, elm, maple, and redbud are all reported as hosts of Tubakia species, but oaks are the most frequently and severely affected. Among the oaks, the red oak group, specifically red, pin, and black oaks, are reported to be more susceptible to infection compared to those in the white oak group.

figure2

Figure 2: Oak leaf with circular shaped Tubakia leaf spots along with extensive veinal necrosis.

figure1

Figure 1: Oak leaf with irregularly shaped Tubakia leaf spots and veinal necrosis.

Leaf spots appear in mid to late summer (July –August) as small circular to irregular tan, red-brown, to dark brown spots (Figure 1, 2) that expand to approximately the size of a dime overtime, but can coalesce, forming large areas of necrotic tissue (Figure 3) . When a spot reaches a leaf vein it expands very quickly, causing a necrotic streak along the vein, and can cause blighting of most of the leaf (Figure 4, 5). Trees under stress from other causes will frequently exhibit more severe leaf spotting compared to healthier trees. Premature defoliation can occur in these situations.
figure3

Figure 3: Marginal blighting due to coalescing spots and veinal necrosis.

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Figure 5: Blighting of large leaf area caused by veinal infection by Tubakia.

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Figure 4: Typical Tubakia leaf spot symptoms illustrating how the fungus spreads along leaf veins.

The pathogen produces conidia within shield shaped structures called pycniothyria (Figure 6) which can be found on both the top or bottom surface of the leaf and along veins (Figure 7). These structures are very small and can only be seen with a 40x or stronger hand lens. The fungus overwinters on fallen leaves and on dead stems which act as the source of inoculum for the next year. During early spring, spores are spread by wind and water splash dispersal (rain) to healthy new foliage. However, it takes time for symptoms to develop throughout the season, depending on tree stress and environmental conditions (warm wet weather favors spread).
For full article view: Purdue Landscape Report, Purdue Landscape Report.

Recources
Diseases of Landscape Plants: Leaf Diseases, The Education Store, Purdue Extension resource center
Consumer Horticulture: Fertilizing Woody Plants, The Education Store
Tree Disease; Oak Wilt in Indiana, The Education Store
Diseases of Soybean: Frogeye Leaf Spot, The Education Store
Bur Oak, Purdue Arboretum Explorer
Bur Oak, Native Trees of Indiana River Walk, Purdue Fort Wayne
Find an Arborist, TreesAreGood.org

John Bonkowski, Plant Disease Diagnostician
Purdue Department of Botany and Plant Pathology

Tom C Creswell, Clinical Engagement Professor – PPDL
Purdue Department of Botany and Plant Pathology


NOTAwardBannerThe Nature of Teaching, a Purdue Extension signature program, was honored as the third place finisher in the central region for the Environmental Education Award presented by the National Extension Association of Family and Consumer Science (NEAFCS).
The Environmental Education Award recognizes NEAFCS members for outstanding educational programs conducted for families and/or communities on various environmental issues/concerns.
The Nature of Teaching includes formal standards-base curricula and informal activity-based curricula centered around getting youth outside. The program curricula is focused on three areas: Wildlife, Health and Wellness, and Food Waste. Classroom ready lesson plans for grades kindergarten through 12 are available as are professional development workshops for teachers, focused on science, the environment and getting students connected with nature.
“I’m very happy to have the Nature of Teaching team recognized by our professional association as many team members are also members of the National Extension Association of Family and Consumer Sciences,” health and human sciences extension educator Kelsie Jo Muller said. “The Nature of Teaching team has developed over multiple years and added different discipline areas all working together. It’s great to see all of the hard work recognized.”

NOTTeamThe Nature of Teaching team includes:

  • Deb Arseneau, HHS Educator, Newton County
  • Jarred Brooke, extension wildlife specialist
  • Jay Christiansen, health and human sciences extension educator for Vigo County
  • Robert Cordes, Maine Department of Inland Fisheries and Wildlife (MDIFW) wildlife special projects coordinator
  • Molly Hoag, health and human sciences extension educator for Wells County
  • Molly Hunt, health and human sciences extension educator for Delaware County
  • Rebecca Koetz, urban ag/home horticulture extension educator for Lake County
  • Tami Mosier, 4-H youth development extension educator
  • Kelsie Muller, health and human sciences extension educator for Benton County
  • Dr. Rod Williams, professor and extension wildlife specialist
  • Brad Zitscke, Maine Department of Inland Fisheries and Wildlife (MDIFW) assistant regional wildlife biologist
All of the NEAFCS awards will be presented in September as part of the NEAFCS Virtual Annual Session.
   
Resources
Nature of Teaching
Nature of Teaching YouTube Channel
Transporting Food Waste, The Education Store, Purdue Extension resource center
Resourceful Animal Relationships, The Education Store
Benefits of Connecting with Nature, The Education Store

Join Purdue Extension urban forester Lindsey Purcell, exotic forest pest educator Elizabeth Barnes and entomology extension specialist Cliff Sadof as they share about how to inspect trees, what to look for, who to contact, etc., as well what invasive pests and diseases you should keep your eye out for.

If you have any questions regarding trees, forests, wildlife, wood products or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources
Ask an Expert, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
Tree Risk Management, The Education Store, Purdue Extension resource center
Tree Appraisal and the Value of Trees, The Educational Store
Surface Root Syndrome, The Education Store
Iron Chlorosis of Trees and Shrubs, The Education Store
Facebook Live – Ask The Expert: Pests in Your Woods, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Fall webworms: Should you manage them, Got Nature? Blog
How to Identify Tree Defects and What to Do about It?, Got Nature? Blog

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

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

Cliff Sadof, Professor / Ornamental / Pest Management / Coordinator of Extension
Purdue University, Department of Entomology


Posted on September 29th, 2020 in Disease, Forestry, How To, Plants, Urban Forestry, Woodlands | No Comments »

Purdue Landscape Report: Trees are incredible survivors in spite of the challenges from pests of all kinds, including us! They are vulnerable to injuries such as mechanical wounds from lawn equipment, vehicles and ice. Pruning results in an intentional wound which is of importance to consider. Tree owners and managers need to prune trees to maintain aesthetic characteristics, remove infected limbs, reduce risk, or improve structural stability. Proper pruning practice and understanding tree wounds can minimize the impact of creating wounds on trees.

Wounds attract pests due to the phytochemicals dispersed from exposed tissue. When tree tissue is damaged or wounded, the newly uncovered tissue is exposed and that is when to expect an attack. Insect pests are drawn to trees in distress, feeding on the tissue and weakening the tree. Diseases affecting trees will introduce enzymes into the cells, digesting living tissue responsible for food and water translocation (phloem and xylem) or structural support resulting in unhealthy, unsightly, or unsafe trees.

Wound wood Formation
Trees attempt to close wounds by sealing or compartmentalizing the affected area, naturally.

damagedTreeTrunk

Tree trunk damaged by construction equipment developing wound wood around the edges to eventually seal the wound.

callus tissue

Pruning cuts will develop callus tissue on the exposed tissue giving rise to wound wood.

Wounding of trees during the growing season results in the formation of callus tissue which develops over the wound surface or parts of it. This callus tissue is an unorganized group of important parenchyma cells. As the callus develops and grows, wound wood develops which hopefully will cover the exposed tissue quickly and efficiently.

Wound recovery rates vary widely for different tree species. The speed of recuperation is greatly affected by developmental environmental conditions, vigor and health of the tree. Some trees may never completely close their wounds due to their genetic capacity or perhaps inadequate resources to keep the tree vigorous. However, numerous studies reveal that faster wound closure results in fewer health issues for the tree. Quick healing is always better!

A healthy tree will seal wounds faster and the same for younger trees as well. Trees that are planted in well-drained, quality soils, with good texture, structure, and containing adequate nutrition levels, grow in a way that favors the healing process. Thus, when planting trees, homeowners should be aware of the effects of site selection, soil quality, and other site factors that may impact tree growth.

Wound dressings

Wound dressings slow closure and can prevent healing.

woundClosure

Complete wound closure improves tree health and slows decay.

 

 

 

Faster closure
There are few ways wound closure can be hastened, or at least not inhibited. First, it is essential to avoid limiting oxygen availability to the wounded tissues. Oxygen is necessary for proper recovery. For example, painting a wound with any kind of material that interferes or impedes oxygen will slow or even prevent wound closure by poor callus formation. Wound treatment with petroleum-based products is not recommended. In fact, research indicates any type of wound dressing can slow the healing process. There is one exception for treating wounds. This is in areas where oak wilt disease occurs, wound paints may be useful in preventing insect spread of the oak wilt fungal pathogen.

Basically, the best way to help insure proper wound closure and quick and effective sealing of the tissue is a proper pruning cut and preventing damage whenever possible.

Find a professional
Be sure to always hire an insured, tree care professional, preferably and ISA Certified Arborist with the experience, expertise, and equipment to provide proper tree care. Require proof of liability insurance to protect yourself as well.

Another easy way to find a tree care service provider in your area is to use the “Locate Your Local Tree Care Industry Association Member Companies” program.For more information refer to the publication Trees and Utilities at the Purdue Education Store.

Find an ISA Certified Arborist in your area by visiting the Trees are good website.

Resources
Tree Pruning Essentials, Publication & Video, The Education Store, Purdue Extension resource center
Tree Pruning: What Do Trees Think?, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store
Tree Installation Process and Practices, The Education Store
Tree Pruning for the Landscape, Webinar, Purdue Extension – Forestry and Natural Resources Youtube channel

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


Posted on September 23rd, 2020 in Disease, How To, Safety, Wildlife | No Comments »

deerSeptember IDNR Wildlife Bulletin Newsletter: Indiana DNR is conducting targeted surveillance for chronic wasting disease (CWD) surveillance in northwest and northeast Indiana during the 2020-21 deer hunting season. Hunters may voluntarily submit samples for testing at select fish & wildlife areas (FWAs) and state fish hatcheries (SFHs) throughout the hunting season. Deer heads can be dropped into designated coolers at select FWAs and SFHs or hunters may make an appointment for their harvested deer to be sampled by a biologist during office hours. The 2020-21 sampling locations and their hours of operation are listed on the website. Indiana DNR biologists will intensively sample hunter-harvested deer at local businesses in the surveillance areas during three weekends: Nov. 7-8, 14-15, and 21-22.

Hunters interested in testing a deer for CWD that was harvested outside the CWD surveillance areas may take their deer to select FWAs and SFHs as well. Alternatively, hunters may independently submit their deer to the Purdue Animal Disease Diagnostic Lab (ADDL) for testing for a fee. Hunters should complete the submission form and follow the shipping instructions on Purdue ADDL’s website.

Hunters who submit a deer for CWD testing will receive a Deer Management Partner magnet and metal tag reminiscent of Indiana’s historical deer harvest confirmation process.

For more information, please visit the Indiana Department of Natural Resources website.

Resources
Chronic Wasting Disease (CWD), Indiana Department of Natural Resouces (IDNR)
New Indiana Hunting & Trapping Guide, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Wildlife Habitat Hint: Trail Camera Tips and Tricks, Got Nature? Blog
Bovine Tuberculosis in Wild White-tailed Deer, The Education Store, Purdue Extension resource center
Indiana Deer Hunting, Biology and Management Food Safety & Handling Take-Home Tips (80kb pdf), Indiana Department of Natural Resources (IDNR)
Handling Harvested Game: Episode 1, Field Dressing, Video, Purdue Extension Youtube channel
Handling Harvested Game: Episode 2, Hanging & Skinning, Video
Handling Harvested Game: Episode 3, Deboning, Video
Handling Harvested Game: Episode 4, Cutting, Grinding & Packaging, Video

Indiana Department of Natural Resources (IDNR)


Tree with drought stress.Many homeowners are finding their trees with dry and wilted leaves and no rain in sight. Urban Forestry Specialist Lindsey Purcell describes how homeowners can deal with these drought-stressed trees in his publication Drought? Don’t Forget the Trees!

Drought can have a major impact on tree health and survival. Water is the most limiting ecological resource for a tree, and without adequate moisture, decline and death are imminent. It reduces carbohydrate production, significantly lowering energy reserves and production of defense chemicals in the tree.

Trees in a weakened state from drought are more susceptible to pests, which can further weaken the tree, and even kill part or all of it. Although there is nothing we can do to prevent drought, it is important to know what can be done to reduce long-term effects of prolonged dry conditions.

Resources:
Trees in Times of Drought​, Video, Purdue Agriculture
Drought Information, Purdue Extension
Drought Information​, Indiana Department of Natural Resources
Tree Planting Part 1: Choosing a Tree video, Purdue Extension-Forestry and Natural Resources YouTube Channel

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


WalnutAnthracnose

Brown or black spots with yellowing are signs of anthracnose.

This time of year, many black walnut trees’ leaves may have black spots, turn yellow and begin to drop. This is commonly known as anthracnose, a fungal disease that causes trees to drop their leaves prematurely.

Anthracnose is worsened by wet weather, and some trees are more genetically susceptible to anthracnose than others. It is not fatal but can look like a serious problem. The absence of leaves can slow a tree’s growth and can reduce the nut crop, although by this time of year growth may have slowed or stopped for the season. It can also weaken

Anthracnose generally begins as small circular brown to black areas on the leaflets. Over the season those spots expand and cause leaf drop. There are a few other leaf spot diseases of black walnut, see the references below for descriptions of those diseases.

Although unsightly, there is no need for further action if you are growing timber and have anthracnose in a plantation or woods. It can be an issue if you are growing walnuts for a nut crop, and there are resources and spray products to help manage the fungus in those situations.

If you have individual landscaping trees and want to limit anthracnose spread there are few things you can do:

  • Gather fallen leaves and compost or remove them from the site.
  • Control weeds which could carry the fungus.
  • Plant walnut trees where there is good air circulation.
  • Keep the trees healthy and vigorous by managing soil fertility and thinning competition as needed.

Resources
Walnut Anthracnose, Walnut Notes, U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station
Planting and Care of Fine Hardwood Seedlings. Paula M. Pijut (ed.):
Diseases in Hardwood Tree Plantings, The Education Store, Purdue Extension resource center
Planting Hardwood Seedlings in the Central Hardwood Region, The Education Store
Regenerating Hardwoods in the Central Hardwood Region:  Soils, The Education Store
Fertilizing, Pruning, and Thinning Hardwood Plantations, The Education Store
Weed Competition Control in Hardwood Plantations, The Education Store
Resources and Assistance Available for Planting Hardwood Seedlings, The Education Store

Liz Jackson, Manager Walnut Council / IN Forestry Woodland Owners Association (IFWOA) & Engage Specialist
Purdue University Department of Forestry and Natural Resources


Purdue Extension forester Lenny Farlee tells you where to find and how to identify a species that clings to many of our trees, poison ivy. Protect yourself from the itch by recognizing this species before it is a problem.

If you have any questions regarding trees, forests, wildlife, wood products or other natural resource topics, feel free to contact us by using our Ask an Expert web page.

Resources
Poison Ivy, Purdue Landscape Report
Poison Ivy, Purdue Extension
Poison Ivy, The Education Store, Purdue Extension resource center
Investing in Indiana Woodlands, The Education Store, Purdue Extension resource center
Tree Appraisal and the Value of Trees, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources Youtube Channel

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


Purdue Landscape Report: Hot, dry summers are not that unusual in the Midwest, but 2020’s hot dry spell started considerably earlier than usual, before summer even officially began! To make it a triple whammy, the hard freeze in early May caused some landscape plants to burn up more stored carbohydrate reserves to produce a second round of foliage.

(Figure 2) July Heat Map

(Figure 2) July Heat Map

I’m sure I don’t have to point out that most of Indiana is currently experiencing abnormally hot, dry conditions. Although recent rains have brought relief to some areas, any respite is sure to be temporary. Seasonal thunderstorms may deluge some landscapes with water while other areas, even those close by, may stay fairly dry. Much of the area has experienced highs in the upper 80’s to over 90º F over the past month.

Leaf scorch on trees and shrubs, appearing as a browning along the edges of the leaves, is very common in dry summers. While minor cases of leaf scorch are not very harmful, prolonged lack of moisture can spell disaster for landscape plants.

Leaf Scorch on Lilac

Leaf Scorch on Lilac

Hydrangea wilting

Hydrangea wilting

Young and newly established plants are most susceptible to the dry conditions, but even established plants may reach a critical point during prolonged drought. If the heat and drought continue this summer, branch dieback, combined with eventual root death, will make plants more susceptible to winter injury. Plants that were already under stress from other factors may succumb to severely dry soils.

The intense heat makes it difficult for plants to keep up with water and cooling requirements, even in areas where moisture is adequate. One of the ways that plants cool themselves is through transpiration, which allows water to evaporate from the foliage. Plant leaves have pores called stomata that can open and close to allow water vapor and gas exchange with the environment. During extreme heat and/or drought, stomata will nearly close, thus reducing transpiration and exchange of carbon dioxide and oxygen. The end result is seen as wilting foliage and leaf scorch. But not so obvious is that reduced water uptake and gas exchange also leads to reduced production of carbohydrates through photosynthesis and reduced uptake of soil nutrients, having longer term impact on plant health.

There is still plenty of summer yet to get through to see the further challenges ahead. Meanwhile, we can mitigate some of the stress by watering landscape plants as needed where feasible.

Resources
US Drought Monitor
Indiana – Purdue Rural Emergency Preparedness, Purdue Extension website
In Times of Drought, Indiana Yard and Garden, Purdue Consumer Horticulture
Drought? Don’t Forget the Trees, The Education Store, Purdue Extension resource center
Turfgrass Disease Profiles: Summer Patch, The Education Store
Iron Chlorosis of Trees and Shrubs, The Education Store

, Extension Consumer Horticulturist
Purdue University Department of Horticulture and Landscape Architecture


Welcome to the Nature of Teaching Professional Development Webinar Series: Ecotoxicology Part 1. This webinar shared by Rod Williams, a professor and extension wildlife specialist with Purdue University Extension, and Jason Hoverman, an associate professor at Purdue University and a co-author on the unit on ecotoxicology, discusses the principles of ecotoxicology, contaminants, and threats to the freshwater ecosystems.

This webinar shares the resources teachers, and K-12 leaders, need to teach students about ecotoxicology. This state standard curriculum includes free downloads of posters, photos, charts, data sheets, and fun activities along with the opportunity to receive a Certificate of Completion

Resources
The Nature of Teaching: Ecotoxicology and Environmental Health, The Education Store, Purdue Extension resource center
Benefits of Connecting with Nature, The Education Store
The Nature of Teaching: Disease Ecology, The Education Store
Resourceful Animal Relationships, The Education Store
The Nature of Teaching, Youtube Channel
Nature of Teaching, Website

Rod Williams, Professor of Wildlife Science
Purdue University Department of Forestry and Natural Resources

Jason Hoverman, Associate Professor Vertebrate Ecology
Purdue University Department of Forestry and Natural Resources


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