Got Nature? Blog

Cockroaches are serious threats to human health. They carry dozens of types of bacteria, such as E. coli and salmonella, that can sicken people. And the saliva, feces and body parts they leave behind may not only trigger allergies and asthma but could cause the condition in some children.

cockroach in lab

A German cockroach feeds on an insecticide in the laboratory portion of a Purdue University study that determined the insects are gaining cross-resistance to multiple insecticides at one time. (Photo by John Obermeyer/Purdue Entomology)

A Purdue University study led by Michael Scharf, professor and O.W. Rollins/Orkin Chair in the Department of Entomology, now finds evidence that German cockroaches (Blattella germanica L.) are becoming more difficult to eliminate as they develop cross-resistance to exterminators’ best insecticides. The problem is especially prevalent in urban areas and in low-income or federally subsidized housing where resources to effectively combat the pests aren’t as available.

“This is a previously unrealized challenge in cockroaches,” said Scharf, whose findings were published in the journal Scientific Reports. “Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.”

Each class of insecticide works in a different way to kill cockroaches. Exterminators will often use insecticides that are a mixture of multiple classes or change classes from treatment to treatment. The hope is that even if a small percentage of cockroaches is resistant to one class, insecticides from other classes will eliminate them.

Scharf and his study co-authors set out to test those methods at multi-unit buildings in Indiana and Illinois over six months. In one treatment, three insecticides from different classes were rotated into use each month for three months and then repeated. In the second, they used a mixture of two insecticides from different classes for six months. In the third, they chose an insecticide to which cockroaches had low-level starting resistance and used it the entire time.

In each location, cockroaches were captured before the study and lab-tested to determine the most effective insecticides for each treatment, setting up the scientists for the best possible outcomes.

“If you have the ability to test the roaches first and pick an insecticide that has low resistance, that ups the odds,” Scharf said. “But even then, we had trouble controlling populations.”

For full article: Rapid cross-resistance bringing cockroaches closer to invincibility.

Resources
Report Invasive Species, Purdue Agriculture & Indiana Invasive Species Council
Purdue experts encourage ‘citizen scientists’ to report invasive species, Purdue Agriculture News
New Hope for Fighting Ash Borer, Got Nature? Blog, Purdue Forestry and Natural Resources
Mile-a-Minute Invasive Vine Found Indiana, Got Nature? Blog
Sericea Lespedeza: Plague on the Prairie, Got Nature? Blog

Michael E. Scharf, Professor and O.W. Rollins/Orkin Chair
Purdue Department of Entomology

Brian J. Wallheimer, Science Writer
Purdue College of Agriculture


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


Woodland Steward PublicationThe Indiana Woodland Steward Homepage has just been updated with a new newsletter and is available to view on the website. The Indiana Woodland Steward Newsletter is a resource that’s full of a variety of valuable information to foresters, woodland owners, timber marketing specialists and any woodland enthusiasts. This issue includes topics such as hardwood strategy, terrestrial invasive species rule, tick-borne diseases, spring time woodland evaluations, as well as much more.

Check out this IWS Newsletter  to stay current in the world of forestry, and feel free to browse archived articles dating back to 1992 for more information.

Resources:
Indiana Woodland Steward, IWS Newsletter Homepage
Hardwood Ecosystem Experiment, Purdue University FNR
Indiana Department of Natural Resources, Indiana DNR Homepage

The Indiana Woodland Steward Institute is an entity made from 11 organizations within the state including Purdue University, Indiana DNR, and Indiana Hardwood Lumbermen’s Association that works to promote best usage practices of Indiana’s woodland resources through their Woodland Steward publication.

Brian MacGowan, Extension Wildlife Specialist
Department of Forestry & Natural Resources, Purdue University


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


BoxTrap

Empty cage trap with door open. Image taken by Doug Beckers and courtesy of flickr.com.

Having raccoon, groundhog, or other bothersome wildlife problems? Thinking about setting traps to catch these animals? There is much to consider when using traps. Take a look at the latest publication for best results.

Wildlife specialists Brian MacGowan and Rick Shadel have collaborated to bring you this new publication: Considerations for Trapping Nuisance Wildlife with Box Traps.

Homeowners commonly set traps to capture and remove wildlife from their home or yard. Setting a box trap improperly can decrease their effectiveness and even lead to safety risks to both people and wildlife. The purpose of this publication is to 1) outline the legal and ethical factors homeowners should consider before setting a trap, 2) review the basic procedure for effectively trapping wildlife, and 3) help you to determine the fate of the captured animal.

If you have a serious, dangerous, or a nuisance wildlife issue, you may want to consider hiring a professional. Consider reading this publication before deciding whether or not you need to hire a professional: Selecting a Nuisance Wildlife Control Professional.

Resources
Preventing Wildlife Damage – Do You Need a Permit? – The Education Store, Purdue Extension resource center
Selecting a Nuisance Wildlife Control Professional, The Education Store
How to Construct a Scent Station, The Education Store
Question: How do I properly relocate raccoons from my attic?, Got Nature? Blog, Purdue Extension FNR
Nuisance Wildlife – Indiana Department of Natural Resources

Brian MacGowan, Wildlife Extensions Specialist
Purdue Forestry and Natural Resources


Article published: Morning Ag Clips: Citizen Scientists — Report Invasive Species
Written by: Emma Ea Ambrose, Agricultural Communication Service, Purdue University

National Invasive Species Awareness Week kicked off on Feb. 25 (Monday) and runs through March 3 (Sunday).Mile-a-minute vine

The campaign is designed to enhance awareness about invasive species and encourage reporting of invasive species from what Purdue University entomology professor Cliff Sadof calls “citizen scientists.” This includes people who spend time professionally or recreationally in the outdoors and is interested in learning about invasive species. A major tool in the fight against these species is the Report Invasive website, hosted by Purdue College of Agriculture and the Indiana Invasive Species Council. The website includes several ways that people can report invasive species, including a smartphone app from the Great Lakes Early Detection Network.

“There are not that many specialists and experts covering the state,” Sadof said. “When there are concerned citizens reporting, however, we have many more eyes and a better chance of detecting and eradicating a harmful species early.”

Please report any invasive species you come across including insects, plants, and animals to Report Invasive Species.

For full article see Citizen scientists-report invasive species, Morning AgClips.

Resources
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, Purdue Extension The Education Store
Invasive Plant Species in Hardwood Tree Plantations, The Education Store
Invasive Plant Species: Callery Pear, Purdue Extension The Education Store
Invasive Plant Species: Wintercreeper, Purdue Extension The Education Store
Invasive Plant Species Oriental Bittersweet, Purdue Extension The Education Store

Cliff Sadof, Pest Management & Extension Coordinator
Purdue Entomology

 


Posted on October 18th, 2018 in Disease, Forestry, Plants | No Comments »

The DNR Division of Entomology & Plant Pathology has discovered that a shipment of boxwood plants infected with boxwood blight was shipped to Indiana in May.

Boxwood Blight

The black streaks on these stems are typical of boxwood blight. Photo by M. Daughtrey, New York.

This is important because boxwood blight (Calonectria pseudonaviculata) is a fungal disease that infests members of the popular Buxaceae family, and is often transported through the nursery trade. Hosts include Buxus (boxwood), Pachysandra (Japanese spurge) and Sarcococca (sweetbox).

In total, 23 stores in Indiana received infected material in early spring (particularly “Graham Blandy” cultivar), and it’s possible that members of the public inadvertently purchased some plants.

The fungus, which can lay dormant in drier conditions, can be found on all above-ground portions of the plant and presents itself as dark leaf spots. It causes rapid defoliation, which typically starts on the bottom of the plant and moves toward the top. This fungal pathogen can move through sporulation  in water and from dropped leaves. As a result, infection can spread to surrounding plants from a single infected plant.

If you suspect one of your plants shows signs and symptoms of boxwood blight, please call (866) NO EXOTIC (866-663-9684) use the information at dnr.IN.gov/entomolo.

For more information on this pathogen see the following link extension.purdue.edu/extmedia/BP/BP-203-W.pdf

A DNR inspector found the plants at a national chain home and garden store in early October. The shipment originated at a nursery in Oregon. It was also sent to stores in 11 other states.

Upon confirmation of boxwood blight on these plants by the Purdue Plant and Pest Diagnostic Lab, the DNR required that the chain remove all boxwood from their shelves for disposal and that the stores mitigate the area through disinfection to ensure that the pathogen is no longer present and able to infect further shipments of plants.

The DNR is currently surveying for boxwood blight in Indiana. To date, the DNR has not found the pathogen, except for a few interceptions like this one.

To view all DNR news releases, please see dnr.IN.gov.

Resources:
Boxwood Blight Found in Indiana, full Landscape Report
Boxwood Blight, The Education Store, Purdue Resources

Tom Creswell, Clinical Engagement Associate Professor
Purdue Botany and Plant Pathology

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry and Natural Resources


Got Nature?

Archives