Got Nature? Blog

Dr. Rado Gazo, professor of wood processing and industrial engineering who has been a part of the Purdue Forestry and Natural Resources faculty since 1997, has been named as the 2025 recipient of the Wood Engineering Achievement Award – Lifetime Achievement by the Forest Products Society.

“I joined the Forest Products Society as a graduate student in 1990 and have actively participated in various roles ever since,” Gazo said. “While I did not seek this award, now that I have received it, I am very humbled by the recognition of my colleagues and peers.”

The Forest Products Society is a premier international not-for-profit technical association founded in 1947. The award recognizes accomplishments and innovations in the discipline of wood engineering including structures, structural elements, building codes, consensus standards, design procedures and education.

According to the FPS announcement,

“Gazo has educated students, industry professionals and the public about the applications of industrial engineering and operation research techniques to problems in primary and secondary wood products manufacturing industries. His research and development activities have focused on evaluating tree, log, and lumber quality using CT, laser, and image scanning techniques. His efforts led to the first commercially available industrial-grade CT scanner and related optimization software, as well as the first successful automated hardwood lumber grading system. Dr. Gazo also created Hardwood University for the continued education of hardwood industry professionals and landowners in the Central Hardwood Region.”

In 2020, Gazo created Hardwood University, a self-sustaining collaborative program with the Indiana Hardwood Lumbermen’s Association, which aims to provide hardwood industry professionals and landowners in the Central Hardwood region with cutting-edge information and training. Gazo is one of the primary instructors for the program, which trains around 200 professionals annually.

Hardwood University, which consists of 10 sessions annually, is intended for new employees in the hardwood industry as well as those preparing for advancement or cross-training. The program, which takes place monthly at various Indiana hardwood plants and Purdue agricultural centers, offers informational and technical sessions on topics ranging from forest taxation to tree and log scaling and grading; log bucking; marketing hardwood veneer, stave and sawlogs; grade-sawing lumber; air drying and kiln drying lumber; hardwood lumber grading; lean manufacturing and logistics; and sawmill efficiency and quality control.

In addition, Gazo has worked with more than 130 companies, providing technical assistance, troubleshooting and consulting services as well as implementation of manufacturing best practices.

Most recently, Gazo was named among Purdue researchers working on the Indiana Wood Utilization Team, which will aim to create and implement a strategic plan to increase awareness of the benefits of using forest resources in the state, after gathering input from an industry advisory board and a series of roundtable discussions across the state.

Gazo has authored or co-authored more than 320 publications and has given more than 450 presentations in his field.

In 2017, he received the Southern Regional Extension Forestry Award for Excellence for the online book chapter “Critical Factors Affecting Supply Chain Management: A Case Study in the US Pallet Industry,” coauthored with Dr. Henry Quesada and Scarlett Sanchez.

To view this article along with other news and stories posted on the Purdue Forestry and Natural Resources website view: Rado Gazo Receives Lifetime Achievement Award from Forest Products Society.

Resources:
Wood Products Manufacturing Technology Minor, FNR Minor
Hardwoods of the Central Midwest, The Purdue Arboretum
Wood Products, Purdue Extension – Forestry & Natural Resources (FNR)
Wood is Best Video, Forestry and Natural Resources YouTube Channel, Woodisbest.org
An Introduction to Trees of Indiana, The Education Store, Purdue Extension resource center
Native Trees of the Midwest, Purdue University Press
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
ID That Tree, Playlist, Subscribe to Purdue Extension – Forestry and Natural Resources YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Investing in Indiana Woodlands, The Education Store
Forest Improvement Handbook, The Education Store
Finding help from a professional forester, Indiana Forestry & Woodland Owners Association
District Foresters for 10 plus acres, Indiana Department of Natural Resources
Hardwood Tree Improvement & Regeneration Center (HTIRC)

Wendy Mayer, FNR Communications Coordinator
Purdue University Department of Forestry and Natural Resources

Welcome to ID That Tree! In this episode, Purdue Extension Forester Lenny Farlee introduces us to a striking native shrub known as Wild Hydrangea. Found in forest understories and along wooded slopes in southern Indiana, this plant is especially noticeable in summer thanks to its large, white flowers. Learn how to identify this species by it’s unique characteristics. Whether you’re a student, hiker, gardener or just curious about native plants, this video offers a quick and informative look at how to spot Wild Hydrangea and appreciate its role in Indiana’s woodland ecosystems.

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

Resources:
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Fifty Common Trees of Indiana, Purdue Extension – FNR
Habitat University, Episode 12 – Exploring the challenges of Invasive Species, Habitat University-Natural Resource University
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Find an Arborist, International Society of Arboriculture
Forest Improvement Handbook, The Education Store

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

The Wisconsin Forestry Center at the University of Wisconsin–Stevens Point has just released a new episode of SilviCast, the go-to podcast for silviculture professionals. In this episode, titled “Black Gold,” forestry expert Lenny Farlee is interviewed about the science and management of black walnut, one of North America’s most valuable hardwoods.

Eastern black walnut is often regarded as one of the most valuable timber species in central and eastern North America. A single high-quality tree can be worth thousands of dollars, sometimes even shaping the outcome of an entire timber sale. Given that level of interest, it may seem like we already know everything about this remarkable species. While researchers and foresters have gained a deep understanding of its silviculture and genetics, there is still more to discover.

Lenny Farlee is a Purdue University Extension Forester and a member of the Hardwood Tree Improvement & Regeneration Center (HTIRC). With decades of experience in hardwood silviculture, he brings practical insight and research-based knowledge to the conversation around managing black walnut for long-term forest health and productivity.

To listen, search SilviCast on your favorite podcast app or listen directly on the SilviCast: Black Gold episode page. You can also explore the full series at linktr.ee/SilviCast.

Other Resources:
ID That Tree: Black Walnut
Hardwoods of the Central Midwest: Black Walnut
Hardwood Lumber and Veneer Series: Black Walnut
Morton Arboretum: Black walnut
Facts About Black Walnut, The Education Store
Purdue Arboretum Explorer
Black Walnut, Native Trees of Indiana River Walk, Purdue Fort Wayne
The Woody Plant Seed Manual, U.S. Forest Service
Fifty Common Trees of Indiana
An Introduction to Trees of Indiana
Native Trees of the Midwest, Purdue University Press
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Investing in Indiana Woodlands, The Education Store
Forest Improvement Handbook, The Education Store
ID That Tree, Purdue Extension-Forestry & Natural Resources (FNR) YouTube playlist
Woodland Management Moment , Purdue Extension-FNR YouTube playlist

University of Wisconsin-Stevens Point

Diana Evans, Extension & Web Communications Specialist
Purdue University Department of Forestry and Natural Resources

With rainfall well below average, watering your trees is more important than ever. Indiana typically receives around 3.14 inches of rain in September, but as of 2025, only 1.31 inches have fallen—making this month even drier than last year. These conditions can lead to dry, wilted leaves and stress for trees across the state, especially during prolonged heat. To see how drought is affecting your area, visit the U.S. Drought Monitor for Indiana-specific maps.

In this video, Lindsey Purcell, Executive Director of the Indiana Arborist Association, explains why consistent watering is critical and shares practical tips to help your trees stay healthy through dry spells.

Extreme heat 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. Check out this publication titled Drought? Don’t Forget the Trees! to learn what to look for for any weakening issues including pests that like the dry conditions.

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

More Extreme Heat Resources:
Climate and Drought Maps, Purdue Indiana State Climate Office
Summer Tree Care, Purdue Landscape Report
Drought? Don’t Forget the Trees!, The Education Store, Purdue Extension resource center
Extreme Heat Including Fact Sheets, Purdue Extension – IN-PREPared
Extreme Heat – Resources, Extension Disaster Education Network (EDEN)
Drought Information​, Indiana Department of Natural Resources
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Tree Selection for the “Un-natural” Environment, The Education Store
Tree Pruning Essentials Video, Purdue Extension YouTube Channel
Tree Defect Identification, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Surface Root Syndrome, The Education Store
Submit Sample, Purdue Plant & Pest Diagnostic Lab
Find an Arborist, Indiana Arborist Association

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

Step into the woods and into the legacy of sustainable forestry with a full-day field tour of the Goetsch property in Beloit, Wisconsin—one of the highlights of this year’s Walnut Council National Meeting. This unique site, donated to the Council in 2019, showcases nearly a century of hardwood forest management, including majestic walnut trees planted in the 1930s and thousands of younger trees carefully cultivated over the past four decades.

Participants will explore hands-on demonstrations in crop tree release, regeneration planting, drone-assisted monitoring, and sawmilling. The tour includes bus transportation, lunch, and expert-led discussions on real-world forestry practices in action.

Connect, Learn, and Share at the National Meeting in Rockford, Illinois
The full program runs Sunday, July 27 through Tuesday, July 29 at the Hilton Garden Inn Rockford Conference Center, offering a rich mix of networking, education, and inspiration:

• Sunday evening kicks off with a welcoming dinner and informal “Landowner Show & Tell,” where members share personal stories, tips, and lessons learned.
• Monday features the Goetsch property field tour, followed by an evening banquet with a keynote by Illinois State Forester Kenneth Jolly.
• Tuesday brings a full day of indoor programming, including expert presentations on hardwood management, roundtable discussions, and a landowner panel.

Companion tours are also available, including visits to Anderson Japanese Garden and Midway Village Museum.

Whether you’re a seasoned forester, a new landowner, or simply passionate about sustainable hardwood management, this event offers something for everyone. Register for the full event or individual days, and don’t forget to book your hotel by June 28 to receive the special group rate.

View the Meeting Agenda

Meeting Registration Page

This program will be submitted for CFE credits from Society of American Foresters.

Questions? Call 765-496-5013 or email walnutcouncil@gmail.com.

About the Walnut Council:
Founded in 1970, the Walnut Council is an international association representing nearly 700 woodland owners, foresters, forest scientists, and wood-producing industry representatives in 45 states and three foreign countries. The purpose is to assist in the technical transfer of forest research to field applications, help build and maintain better markets for wood products and nut crops, and to promote sustainable forest management, conservation, reforestation, and utilization of American black walnut (Juglans nigra) and other high quality fine hardwoods.

Resources:
Indiana Forestry & Woodland Owners Association (IFWOA) YouTube Channel
Deer Impact Toolbox, Purdue Extension Pond and Wildlife Management
Grassland Management, Purdue Extension Pond and Wildlife Management
District Forester, Indiana DNR Division of Forestry, for over 10 acres of woodlands
Directory of Professional Foresters, Indiana Forestry & Woodland Owners Association (IFWOA)
Indiana Woodland Steward E-newsletters, Eleven Member Organization
A Woodland Management Moment, Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
Forest Improvement Handbook, The Education Store
Invasive Species, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Invasive Plant Species Identification, Video, Purdue Extension – FNR YouTube Channel
Report Invasive Species, Purdue Invasive Species
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Subscribe – Purdue Extension-FNR YouTube Channel

Liz Jackson, IFWOA Engagement Specialist & Walnut Council Manager
Indiana Forestry & Woodlands Owners Association (IFWOA)

Welcome to ID That Tree! In this episode, Purdue Extension Forester Lenny Farlee introduces us to a relatively common Indiana shrub called Witch-Hazel. Discover the characteristics of the environment this shrub is found in, the features of the shrub itself and the interesting history behind it! As a nature lover, student or someone who’s simply just curious about local plants, this video is a great way to get a quick run-down on important information and identification.

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

Resources:
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Fifty Common Trees of Indiana, Purdue Extension – FNR
Habitat University, Episode 12 – Exploring the challenges of Invasive Species, Habitat University-Natural Resource University
Shrubs and Woody Vines of Indiana and the Midwest, Purdue University Press
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Find an Arborist, International Society of Arboriculture
Forest Improvement Handbook, The Education Store

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

Figure 1: Examples of volcano mulching (PLR)

Purdue Landscape Report: Tree care, in many cases, can be expensive if you require the assistance of an arborist for pruning or removals.  Extreme weather events, characterized by extensive rain and wind, can cause damage to the canopy or, in worst-case scenarios, lead to tree failure.  In cases of failures, weather is often the final push to already existing issues.  One cause that can lead to decay, decline, and failure if applied incorrectly can also extend the life of your tree with proper application.

Mulch is the double-edged sword that can promote healthy growth by maintaining soil moisture and temperature through extreme heat, cold, and drought, enrich the soil in the critical root zone, maintain a safety area from mechanical damage from lawn care tools, and add a nice aesthetic.

Figure 2: Digging out and exposing the root flare (PLR)

But it can also cause decay through excess moisture to the root flare, damage from pests like mice and insects that can live in mulch, expose the tree to pathogens, and promote unnecessary root growth and/or stem girdling roots that cut off nutrient supply between the root system and the rest of the tree.

The application is the same if it’s the first time mulching a tree or a re-application.  Add enough mulch so there is a 2–3-inch layer sloping away from the tree with at least a 3–5-foot radius around the stem (older, larger trees can benefit from larger mulch rings).  No volcano mulching, make sure you also have around a 1-2-inch gap between the stem and the start of the mulch ring.

Figure 3: Creating a 1–2-inch space between the root flare and the mulch.

If you are reapplying mulch, first rake the old mulch to even the layer and mix some into the soil if possible.  If your tree has already been mulched and has been volcano mulched, simply dig out the excess, exposing the root flare and creating that 1-2-inch gap between the stem and the mulch.

This simple act is relatively inexpensive, does not require a lot of time, and will help keep your tree healthy, extending its life.  If you notice any other issues with your trees, hiring an ISA Certified arborist is the next step in managing your trees’ health.  To find an arborist near you and verify credentials, use the link at Find an Arborist, Trees are Good, International Society of Arboriculture (ISA).

View the original article on the Purdue Landscape Report website: Simple Steps to Care for Your Tree: Mulching.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

Resources:
Re-mulch Your Trees, Purdue Landscape Report
Find an Arborist video, Trees are Good-International Society of Arboriculture (ISA)
Trees and Storms – The Education Store, Purdue Education’s resource center
Moist soil and rotten roots makes it easy for trees to come crashing down – Fox 59 News
Expert: Some storm damage can be easily prevented – Fox 59
Why Is My Tree Dying? – The Education Store
Tree Risk Management – The Education Store
Tree Pruning Essentials, Publication & Video, The Education Store
Mechanical Damage to Trees: Mowing and Maintenance Equipment – The Education Store
Trees and Electric Lines – The Education Store
Tree Defect Identification, The Education Store
Planting Your Tree, video, Purdue Extension
Tree Installation, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources

Welcome to ID That Tree! In this episode, Purdue Extension Forester Lenny Farlee introduces Coralberry, a small native Indiana shrub also known as Buckbrush. Learn how it got its name, what makes its leaves unique and where it typically grows. Whether you’re a nature lover, student or just curious about local plant life, this quick and informative video is a great way to expand your knowledge of Indiana’s native shrubs.

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

Resources:
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Fifty Common Trees of Indiana, Purdue Extension – FNR
Habitat University, Episode 12 – Exploring the challenges of Invasive Species, Habitat University-Natural Resource University
Shrubs and Woody Vines of Indiana and the Midwest, The Education Store
Native Trees of the Midwest, The Education Store
Professional Forester, Indiana Forestry Woodland Owners Association
District Forester, Indiana Department of Natural Resources, 10+ acres
Find an Arborist, International Society of Arboriculture
Forest Improvement Handbook, The Education Store

Lenny Farlee, Extension Forester
Hardwood Tree Improvement and Regeneration Center
Purdue Department of Forestry & Natural Resources

Purdue Landscape Report: Recently, there has been an uptick in questions related to one of Indiana’s most notorious invasive pests: the emerald ash borer.  Homeowners, businesses, even professionals have asked if ash trees are still present in Indiana, and if the insect is still a threat to our ecosystem.  Emerald ash borer wreaked significant havoc among Indiana’s hardwoods, and a person could be forgiven for believing that there are no ash trees at all in our state, but this is simply not true.  Ash still survives in Indiana and can be found both as ornamental plantings and in untended woodlots; unfortunately, emerald ash borer is also still present and just as deadly to them as ever.  The question of protecting ash versus removal them is complex, but entomologists and tree specialists have learned from this insect’s invasion.

Figure 1. Side view of EAB, John Obermeyer

The emerald ash borer (Agrilus planipennis), a wood-boring insect native to Asia, is responsible for decimating ash (Fraxinus spp.) throughout the United States and elsewhere.  In Indiana, this insect’s presence was confirmed in 2004, though it had probably been in the state for some time before then.  Since its arrival, Hoosiers have been forced to watch as ash trees have rapidly declined and died due to the insect’s feeding and life cycle.  The insect lays its eggs in crevices in the bark of an ash that is 8 to 10 years old, and after hatching, the new larvae begin to bore through the tree’s cambium tissue. The tree relies on its cambium tissue to transport water and nutrients and supply cells for new growth.  Often, the only signs of the insect’s presence are a reduction in canopy coverage and D-shaped exit holes in the bark, indicating adult emergence.  As time goes on, however, the tree will continue to lose canopy, experience limb death, and often have large chunks of bark detach. Unprotected trees will typically die within 2 to 5 years of infestation.  Dead and dying ash trees represent a serious hazard to health and property as infestation will leave them extremely brittle. Brittle ash will often fall during weather events or even collapse over time as limbs fall off.

While emerald ash borer did significant damage to ash tree populations in Indiana, they did not destroy the population entirely.  While virtually all untreated trees will eventually become infested, saplings with a trunk diameter of ½ to 1 inch will remain untouched, allowing annual replacement of trees to continue.  Since the initial invasion killed so many trees, the borer’s populations have been proportionally reduced as well due to a lack of a food source.  This combination of factors has created a cycle of growth and infestation that allows both populations to survive, but at significantly lower levels as compared to the period of the initial infestation.  Unfortunately, this also means that emerald ash borer is now a permanent fixture in the hardwood ecosystem in Indiana.

Figure 2. This photo illustration shows three ash trees in Bloomington, Indiana, with different levels of canopy lost to the emerald ash borer. (Purdue Tree Doctor app illustration/Cliff Sadof)

While many may believe ash trees are a total loss, there are still options to protect ash tree and even rescue ash that have already been infested.  The first step in this process is to determine the extent of damage in a given tree.  As the cambium tissue is consume by ash borer larvae, the tree will experience a steady loss of canopy and limb death.  The proportion of lost canopy makes a great indicator for treatment viability.  For example, a tree that has only lost 10% of its canopy will normally respond well to treatment.  As more canopy is lost, recovery is more challenging, until the tree has lost %30 of canopy coverage.  After that point, there is very little chance that a rescue treatment will be successful, and removal will most likely be necessary.  It is also important to remember that limb death may occur; these limbs will not recover and will need to be removed to avoid any potential hazards.

There are several insecticides with varying ranges of efficacy that can be used to manage emerald ash borer.  These include imidacloprid, dinotefuran, azadirachtin, and emamectin benzoate. Several studies have been conducted to find the best combination of chemical and application type, such as the difference between using a soil drench compared to a trunk injection. While all of the above chemicals can be effective against the insect, the combination of emamectin benzoate applied through a trunk injection offers the best, longest lasting protection from infestation.  This combination has a durable effect lasting for two years under dense infestations.  However, the reduction in emerald ash borer populations have spread the distribution of the insect thinner, and longer intervals between treatments are possible.  A ten-year study conducted by Purdue University demonstrated that treating trees once every three years provided sufficient protection from the beetles, while also showing that 4 to 5 years after last treatment coincided with an increase in damage to the trees.  This same study also found that by six years post-treatment, the trees would decline to the point of making removal a necessity.  This research concluded that increasing time between intervals after three years increased the risk of catastrophic damage due to emerald ash borer activity, thus the recommendation for three-year intervals.

Ultimately, many will see this as a financial issue: the cost of treatment over time against the cost of removal to avoid potential damages.  The above study estimated the cost of treating a single tree with an emamectin benzoate injection at $300 per treatment. Since treatment only needs to happen once every three years, the cost per year per tree would be $100, approximately.  Tree removal was estimated between $1800 and $3600, depending on tree location and other factors.  Also consider replacement costs if you wanted to continue to grow ash in that area, and how long the tree would need to grow to match the size of the tree you just replaced.  Additionally, add in any treatment costs to make sure it survives infestation.  When looked at from this angle, maintaining regular treatment on rescuable trees would appear to be the most cost-effective route for managing ash.  Any treatment plan should be discussed with a professional, such as a certified arborist.

Read the original article posted in the Purdue Landscape Report April 2025 Newsletter: Revisiting Ash Tree Protection.

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter.

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 Tools & Resources – Purdue Extension Entomology
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Tree Planting Part 2: Planting a Tree, Purdue Extension – Forestry and Natural Resources YouTube Channel
Indiana Invasive Plant List, Indiana Invasive Species Council, Purdue Entomology
Landscape Report Shares Importance of Soil Testing, Purdue FNR Extension
Find an Arborist website, Trees are Good, International Society of Arboriculture (ISA)
Tree Risk Management – The Education Store, Purdue Extension’s resource center
ID That Tree – Video Playlist, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Purdue Arboretum Explorer
Conservation Tree Planting: Steps to Success, Purdue Extension – FNR YouTube Channel
A Woodland Management Moment, Playlist, Purdue Extension – FNR YouTube Channel
Woodland Stewardship for Landowners, Playlist, Purdue Extension – FNR YouTube Channel
Indiana Department of Natural Resources: Invasive Species
Indiana Invasive Species Council
Cooperative Invasive Species Management Area (CISMA)
Report Invasive, Purdue Extension
Native Trees of the Midwest, Purdue University Press
Professional Forester, Indiana Forestry Woodland Owners Association
Forest Improvement Handbook, The Education Store

Bob Bruner, Exotic Forest Pest Educator
Purdue Entomology

Purdue Landscape Report: Sawflies are frequent pests in the landscape that attack a wide variety of plants, from ornamental flowers to large trees. You might start to see them damaging plants around this time of year as the first generations hatch and begin to feed on foliage. They are often mistaken for caterpillars, which are the larval stages of butterflies and moths (Order Lepidoptera). However, sawflies are actually wasp-like insects (Order Hymenoptera).

Let’s review how to tell them apart. Products that are labeled for caterpillars do not always work on sawflies, so proper identification is important.

• The most reliable characteristic are the prolegs. Sawflies have 6+ pairs of prolegs, or false legs, while caterpillars have < 6 pairs of prolegs. (Fig. 1)
• When disturbed, sawflies will lift their posterior into an “S” shape. Caterpillars don’t display this behavior. (Fig. 2)

Integrated management recommendations

Early in the year, before hatching starts, look for sawfly oviposition on your plants. This will vary depending on the species of sawfly. For example, the European Pine sawfly eggs look like yellow-orange spots evenly spaced on the needles (Fig. 3). The Bristly Roseslug sawfly uses her ovipositor to cut a slit into the leaf petiole where she inserts eggs. The gooseberry sawfly lays eggs on a leaf vein (Fig. 4).

If the eggs are readily visible, manual removal will help reduce the populations. This is best accomplished in early spring before the eggs hatch. Use a tool to smash the eggs, or prune of the affected plant material.

You may not notice any problem on the plant until you start to see holes appearing in the foliage. Monitor regularly in the spring for holes and “window pane” damage (Fig. 5). This is the time of year when sawflies are hatching, so don’t wait any longer to check your plants. Sawfly management is best accomplished when the larvae are still small. Prune or shake off the larvae from the plant, or spray with a biorational material so as not to disturb natural enemies and cause a secondary pest outbreak later in the summer.

For more information on sawfly biology, check out this five-minute video: Slaying Sawflies with Purdue Plant Doctor.

Specific management recommendations can be found on the Purdue Plant Doctor website. Type “sawfly” into the search and click on the species you would like to read more about!

Read the original article on Purdue Landscape Report: Sawflies: the caterpillar pests that are not caterpillars.