Archive for the ‘Tree Health’ Category

Gypsy Moth Attacking Michigan Trees…Again

Ugh, they’re back! Or maybe it’s more accurate to say they never left.

Gypsy moth has been a pest to Michigan trees for decades, ever since it was introduced to the state in 1954. While the invasive pest has never been eliminated, some years seem to be worse than others? This year seems to be particularly bad. Why? One word: drought.

Read the below article by Michigan State University Extension to find out how drought can cause booms in gypsy moth populations.

 

Gypsy moth caterpillars once again attacking trees in Michigan

Large numbers of gypsy moth caterpillars strip trees in Mid-Michigan as drought hampers fungal controls.

Barrier band for gypsy moth larva control. Photo by Pennsylvania Department of Conservation and Natural Resources - Forestry, Bugwood.org.

Barrier band for gypsy moth larva control. Photo by Pennsylvania Department of Conservation and Natural Resources – Forestry, Bugwood.org.

 

They are back! A Clinton County resident contacted the Michigan State University Extension Lawn and Garden Hotline to report heavy caterpillar feeding in maples, pines and apple trees. A few trees had lost much of their foliage. A photo of the caterpillars confirmed it is gypsy moth, Lymantria dispar. For Michigan residents that have dealt with gypsy moths in the past, it is an unwelcome sight but one that is not unexpected.

Twenty to 30 years ago, gypsy moth was a plague across Michigan, defoliating thousands of acres of trees each year. Without many natural controls, it wreaked havoc on oaks, pines, maples, birches, apples and many other species. In 1989, a fungal pathogen was found killing off large populations of gypsy moth caterpillars in Northeastern states. This fungus was identified as Entomophaga maimaiga, a natural biological control of gypsy moth in Japan.

Brought to Michigan in 1991, E. maimaiga quickly became a key factor in suppressing gypsy moth across the state. Naturally occurring in soils, it spreads to young caterpillars as they move from tree to tree. Caterpillars begin to die as the fungus grows inside them. The spores from these dying and dead caterpillars spreads by wind infecting other caterpillars. As the season progresses, large infected gypsy moth caterpillars are found dying on tree trunks. Dead caterpillars remain attached to trunks and branches, hanging straight down. E. maimaiga is so effective that areas of the state often go for years without any noticeable damage from this ferocious defoliator.

So why are gypsy moths back in large numbers and feeding on trees? Drought! The fungus cannot effectively reproduce during times of drought. A year ago much of Michigan was in a serious drought from spring to early summer.  This is the time the fungus is dependent on moisture for its development and of course it is also the time gypsy moth caterpillars begin to feed on trees. Callers to the MSU Extension state hotline in 2016 confirmed that more caterpillars were feeding on trees across southern Michigan. Without consistent moisture in the spring, more gypsy moth caterpillars survived into the moth stage to produce larger numbers of egg masses. It was not unexpected to see growing populations of gypsy moth caterpillars this year.

gypsy moth larva

Gypsy moth caterpillar. Photo by Bill McNee, Wisconsin Dept of Natural Resources, Bugwood.org.

 

Drought is the weak link for the Entomophaga maimaiga fungus and in years when this occurs gypsy moth populations begin to grow and impact landscapes and forests. Spring droughts in 2007 and 2012 led to higher population of gypsy moth the following years. The good news is that in most years we do have adequate rainfall in the spring. Many areas in southern and mid-Michigan had consistent rain this past May, allowing for good development of the fungal pathogen.

Inspect plants now for gypsy moth caterpillars and damage. Trees that lose a large percentage of leaves to gypsy moth feeding can become stressed as energy reserves are used to produce a second set of leaves. Conifers may be permanently damaged if totally defoliated, especially pines. Valuable pines and hardwoods in the landscape can be sprayed with insecticides labeled for caterpillars, or trunks of trees can be banded with a sticky material to trap caterpillars as they crawl up and down trees. This may help on individual trees that are out in the open but may have little effect on trees in the woods where insects can move between adjacent trees.

If valuable trees are infested, you can contact an arborist to spray for the caterpillars. You could also choose to let nature take its course.  In my conversation with the gentleman from Clinton County, we discussed how wet conditions in most of mid to southern Michigan this spring should lead to development of the fungus E. maimaiga. He observed that he was already seeing dead caterpillars hanging straight down, which is a symptom of the effect of the fungus on gypsy moth caterpillars. These dead caterpillars infested with E. maimaiga now become the future source of the fungus in this area protecting trees for years to come.

Michigan is a large state with different weather patterns. While one area is in a drought, another site can be experiencing heavy rains. Awareness of where spring drought occurs can provide an early indicator for possible gypsy moth outbreaks. Nature provides many clues if we pay attention.

Oak Wilt Striking Michigan Trees

There is a fungal disease that has made its way into Michigan and is taking out our oak trees. As if we needed another forest pest to worry about, oak wilt has made an appearance in several Michigan counties. This is causing mass clear-cuttings in portions of the state, including in state parks.

The reason? The only way to stop the spread is to cut down all infected trees, and in many cases any oak surrounding an infected tree.

Since it’s relatively new in Michigan, we have an opportunity to help stop the spread. Here are some tips we all can do to help:

  • Watch your trees closely. If something doesn’t look right, report it to the Michigan Department of Natural Resources. It may turn out to be nothing, but it’s better to be safe than sorry.
  • Don’t trim oak trees from April 15 until July 15, or even through the entire summer if you want to err on the safe side. Any injury can create a way for the fungus to get into the tree. This means intentional injuries like trimming, or accidental ones from lawnmowers, weed whips, and storm damage. If you accidentally nick the trunk of your oak trees doing yard work, seal it up with pruning sealer or tree paint.
  • And the last tip we’re going to give is please don’t move firewood. It is tempting to save money and inconvenience by bringing wood with you when you go camping, but this can cause problems by carrying forests pests long distances and bringing them to new areas. Oak wilt is no exception. The fungus spores can live in the bark of firewood and infect healthy trees at your destination. Please buy where you intend to burn!

A Warning for Great Lakes States: A disease called “Oak wilt” is striking Michigan Forests

Oak tree effected by Oak wilt.

By , Great Lakes Now

If you head to Northern Michigan this summer, you might see some disturbing landscapes across the shoreline and in other spots across the state: clear-cutting. In most cases, it’s not because a shopping development or a subdivision is about to be constructed. It’s because of a fast-moving and deadly fungus that takes aim at Oak trees and can kill them in less than four weeks. And the only solution to stop the spread of the disease is to kill the trees it infects.

It’s called “Oak wilt” disease. Great Lakes Now talked with Jenna Johnson who’s a forest technician with AmeriCorps at the Michigan Department of Natural Resources in Cadillac. She says Oak wilt was first discovered in Great Lakes states in the 1940’s. It has caused major damage in Midwestern States like Minnesota but has only recently made its way into Michigan. She says Roscommon, the Gaylord area, Missaukee County, and Kalkaska County are being particularly hard-hit right now.

Beetles spreading Oak wilt

 

Johnson says, “Oak wilt is a vascular disease. It makes the tree unable to absorb water. It starves the tree to death.” She says the tree starts to die the minute it’s infected, and starts dropping all its leaves. She says it strikes Red oaks, Pin oaks and some White oaks. It’s spread by sap-feeding beetles that take aim at freshly wounded trees. And once one Oak tree is infected, all other Oak trees in the area are in danger of being infected.

She says if the tree isn’t cut down and removed from the area – right into the roots- followed by what’s called “vibratory plowing” down at least 5 feet into the ground to destroy the fungus –   Oak wilt could sweep across the state. The DNR says if Oak wilt isn’t stopped by cutting down infected trees, it could continue to spread, possibly killing almost all the Red oaks in Michigan.

At least 21 states are dealing with the disease, but the majority of Oak wilt cases are being discovered in the Midwest.

The DNR says Oak wilt isn’t just spread through live trees. It’s also spread by firewood that still has its bark. That’s why the DNR wants to get the word out this summer that no one should cut any kind of Oak trees – including power companies – from April 15th to July 15th, and there’s a ban on cutting Oak trees for firewood during this time, too. Bill O’Neill, State Forester of Michigan and Chief of the Forestry Division of the DNR   tells Great Lakes Now if you are gathering or buying firewood, “use and buy your firewood locally – get it from the vicinity where you’re going to be using it.” 

For more information go to http://www.michigan.gov/dnr.

New Hemlock Quarantine Possible

It’s a tiny forest pest that is wreaking havoc across the Appalachian Mountain region and one that could cause the same kind of devastation in Michigan if we’re not careful.

It’s called the hemlock woolly adelgid (HWA), a small aphid-like, sap-sucking insect that is responsible for killing thousands of hemlock trees. It’s difficult to find due to its small size, but can begin killing trees as early as 4 years after infestation. The first reported sighting was near Richmond, VA in 1951. By 2005 it had spread to 16 states from Maine to Georgia.

It has been recently identified in west Michigan; first noticed in Muskegon county, but has also been found in nearby Allegan and Ottawa counties. An import quarantine is already in effect for Michigan, meaning that hemlock cannot be brought into Michigan from an infested state. However, since it has been determined that HWA is in several Michigan counties, an in-state quarantine is being considered. This would mean that movement within Michigan would be regulated, especially within the quarantined counties.

With the estimated 170 million hemlock trees in Michigan, including the virgin hemlock forest at Porcupine Mountains State Park, extra caution is a good thing.

 

Michigan is preparing to enact interior quarantine due to invasive hemlock tree pest

A recent outbreak of the pest within the state has prompted new legislation which will restrict the movement of hemlock products within Michigan in an effort to control this invasive pest.

Adelgid infested hemlock branches. Photo credit: USDA Forest Service - Region 8 - Southern, USDA Forest Service, Bugwood.org

Adelgid infested hemlock branches. Photo credit: USDA Forest Service – Region 8 – Southern, USDA Forest Service, Bugwood.org

 

Over the last several years, in reaction to the outbreak of hemlock wooly adelgid in forest stands across the eastern U.S., Michigan banned the shipment of hemlock trees and wood with bark into the state. However, a recent outbreak of the pest within the state has prompted new legislation which will restrict the movement of hemlock products within Michigan in an effort to control this invasive pest.

The exotic hemlock wooly adelgid insect was first identified in the eastern U.S. in early 1950s. It has systematically spread throughout the Appalachian region and is devastating the hemlock tree forest resource by the thousands. In an effort to help protect the estimated 170 million hemlock trees in Michigan, a ban or quarantine on bringing hemlock nursery stock and wood products with attached bark into the state has been in place for some time and was last revised in 2014.

In spite of the efforts to keep this destructive forest pest out of the state, an infestation has been identified in central West Michigan. First noticed in Muskegon County, closer inspection has identified colonies of the tiny sap feeding pest in neighboring Ottawa and in Allegan Counties as well.

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Pale crown appearance with no new growth indicates this tree is under severe attack from Hemlock Woolly Adelgids. Photo credit: James Johnson, Georgia Forestry Commission, Bugwood.org

In an effort to control or slow this tree-killing pest, the Michigan Department of Agriculture & Rural Development (MDARD) solicited public comment on a proposed hemlock woolly adelgid interior quarantine. The original draft stated that “the proposed quarantine, movement of hemlock nursery stock, branches, boughs, uncomposted chips, logs and firewood would be regulated. Specifically, movement out of, or within, the three county area would be prohibited except under compliance agreement issued by MDARD. The proposed regulated area includes Allegan, Muskegon and Ottawa counties.” Other counties may be added as the need arises to further limit the spread of hemlock woolly adelgid.

If the quarantine is enacted, the movement of hemlock trees, boughs, firewood, logs or limbs will be prohibited without a compliance agreement. This restricted movement would include movement within these counties from site to site. (Note: A compliance agreement are actions jointly taken by both producers and the State of Michigan to ensure hemlock nursery stock and wood products are free of the adelgid insect.)

For more information on the hemlock wooly adelgid, Michigan State University Extension has a bulletin available. Extension Bulletin E-3300  details the life cycle and highlights the negative impacts from this invasive killer with some available treatment options should landowners identify adelgid colonies in their trees.

In addition, people interested in becoming actively involved in identifying new infestations of this and other potential forest pests are encouraged to become involved in the MSU Extension Eyes on the Forest program by becoming a sentinel tree volunteer.

Firewood Awareness Month. Why do we need one?

Fall is here! That means that many will be travelling, looking for that perfect fall foliage that makes the covers of calendars everywhere. And there’s nothing wrong with that.  Michigan welcomes all who want to take a gander at her magnificent fall colors. We just ask that you do one thing.

Leave the wood at home.

This goes for everyone, both in-state and out-of-state travelers. It might seem harsh, or that it’s just another excuse to sell firewood, but there’s a good reason for it. Insects can hitch a ride in firewood, either as eggs, larvae, or even as adults depending on the time of year. Right now, a lot of insects are laying eggs that will overwinter and hatch next spring. By bringing your own firewood you may be unknowingly moving forest pests hundreds of miles to cause new devastation next year.

If we have learned anything from the destruction of the Emerald Ash Borer it is that prevention is key. We do not want a repeat of this kind of damage. So it becomes all of our responsibility to be part of the solution, instead of the problem.

By purchasing firewood where you intend to burn it, or even gathering it on site if it’s permitted, is one of the easiest things you can do to help stop the spread of unwanted insects and disease.

That is why this year, for the first time, the nature Conservancy’s Don’t Move Firewood program is teaming up with the U.S. Department of Agriculture – Animal and Plant Health Inspection Service’s (APHIS) Hungry Pests initiative for Firewood Awareness Month. Learn more in the article below.

We all need to do our part to protect our trees.

 

As the Weather Cools, Your Firewood Choices Matter

Don't Move Firewood pests graphic

Wood boring insect pests can continue their development deep within cut wood. They can emerge from wood left to sit outside to infest new areas.

 

This October, the Nature Conservancy’s Don’t Move Firewood campaign and Hungry Pests, an initiative from APHIS, are partnering to present the first-ever Firewood Awareness Month. The cooler nights and quickly approaching fall season brings an increase in RV camping, hunting, and home heating. Firewood Awareness Month looks to raise public awareness about the potential danger of firewood movement as a pest and disease pathway at this high-risk time of year.

Tree-killing invasive insects and diseases can lurk both inside, and on the surface, of firewood. While these insects and diseases don’t travel far on their own, transporting firewood allows them to move hundreds of miles and start infestations in new places, explains APHIS Deputy Administrator Osama El-Lissy.

Pest infestations can impact our forests by killing trees there as well as in our parks and communities. Infestations are also costly to control or eradicate.

Everyone’s firewood choices matter, says Leigh Greenwood, The Nature Conservancy’s Don’t Move Firewood campaign manager. When it comes to protecting our campsites, wildlife habitats, neighborhood trees, and other favorite places, we all have a personal responsibility to slow the spread of forest pests. Firewood Awareness Month serves as the perfect opportunity to inform the public on the different ways they can help protect the places they love.

Firewood in bags

Firewood that has been heat treated is often sold bagged, boxed, or wrapped. Look for a state or federal seal to certify it was properly treated. Photo credit: L. Greenwood, Don’t Move Firewood campaign, The Nature Conservancy

 

This Firewood Awareness Month, everyone can help protect the places they love from the spread of damaging forest pests by making one of these three safe firewood choices:

  1. Buy firewood near where you’ll burn it
  2. Buy certified heat treated firewood (look for a state or federal seal)
  3. Gather firewood on site when permitted

Anyone who will travel from one location to another, including campers, anglers, hunters, and RV owners, should not carry firewood—unless it is heat-treated and certified—to their destination. This can spread forest pests and may also violate state and federal laws, depending on the region. Plan to gather firewood on site if permitted or purchase firewood near your camping destination.

People who use wood to heat their homes or cabins can help by harvesting firewood locally or by purchasing firewood from a reputable dealer who is in compliance with state or regional firewood regulations. Some operations may be unaware of quarantine and movement restrictions, resulting in the unintentional and illegal movement of tree-killing pests.

Tourists, too, can help protect the places they love against the spread of pests. As thousands of “leaf peeping” fall foliage enthusiasts travel to view the changing leaves around the country, they should purchase firewood locally, buy certified heat treated firewood, or gather on site if allowed.

Get state specific firewood regulations and recommendations at Dontmovefirewood.org/map. Visit www.DontMoveFirewood.org or www.HungryPests.com to learn how to help stop the spread of invasive pests and report signs of them to the proper authorities, and use #firewoodmonth to join the conversation on Facebook and Twitter.

Firewood

When buying firewood for home heating, use a reputable dealer in compliance with local regulations. Photo credit: L. Greenwood, Don’t Move Firewood campaign, The Nature Conservancy

Tiny Bug, Big Problem

There’s something threatening our black walnut trees. Something so small that it almost can’t be seen.

It’s name? The walnut twig beetle.

These beetles are only 1/8″ long and are dark-colored which makes them hard to spot on trees. Yet look out for them we must because they carry the fungus that causes thousand canker disease (TCD) along with them as they move from tree to tree. I once heard a forester call this disease the “death of a thousand paper cuts.” When you look at photos of the damage thousand cankers causes it’s easy to see why.

 

Tiny insects pose huge risk for black walnut trees

Thousand cankers disease (TCD) is not yet in Michigan but has already been discovered in Ohio and Indiana. This fungal pathogen is responsible for spreading TCD, threatening the widespread health of black walnut trees across Michigan.

The walnut twig beetle’s tiny size make them very hard to detect on trees. Photo by: Whitney Cranshaw, Colorado State University

Everybody roots for the little guy, right? Rooting for the underdog always seems to capture both sports fans’ and the media’s attention. In the case of a new invasive forest health problem threatening black walnut (Juglans nigra) trees, it’s a “little guy” that poses a huge threat to our black walnut resource in much of the United States.

The invasive pest problem that is threatening black walnut trees is called thousand cankers disease (TCD). It is described as a disease or pest “complex” because it requires both a tiny beetle as well as a fungal pathogen to invade and kill black walnuts. The Walnut twig beetle (Pityophthorus juglandis) is the insect most responsible for spreading TCD to uninfected trees. The adult beetle is only about 1/8 of an inch in length. Its extremely small size makes it very difficult to spot, since the twig beetles usually attack the branches in the top of trees first.

The walnut twig beetle can carry spores of the pathogen Geosmithia morbida, (obtained from boring into other infected walnuts) and spreads them to healthy walnuts as it tunnels underneath the bark of twigs and small branches. The result is the formation of tiny dead (necrotic) areas or cankers around the area that was bored by the beetle. Because many beetles can attack a walnut tree at the same time, the result is a multitude of cankers being formed – hence the name thousand cankers disease. Given enough time and infestation, a black walnut will eventually die from repeated infections of TCD.

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Multiple small cankers end up girdling branches, eventually killing the tree. Photo by: Whitney Cranshaw, Colorado State University

Fortunately, TCD has not yet been found in Michigan. But the fungal pathogen that causes the canker or the twig beetle that spreads it have been found in both Ohio and Indiana – just south of the Michigan state line. So, the threat posed to Michigan from TCD is indeed very real!

According to the Michigan Deparment of Agriculture and Rural Development, Michigan’s forests contain over 8.5 million black walnut trees with an economic value of more the $86 million. Black walnuts also possess a high ecological value as a food source for birds, mammals and other wildlife. In addition, there are more than 80 walnut growers in Michigan with approximately 4,000 trees in nut production.

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TCD presence in black walnut has been confirmed in both Indiana and Ohio. | Map by: http://www.thousandcankers.com

Michigan residents who are interested can help keep TCD out of Michigan by becoming Sentinel Tree volunteers with the Michigan Eyes on the Forest and Sentinel Tree Network. Funded by the Michigan Invasive Species Grant Program, the MSU “Eyes on the Forest: Invasive Forest Pest Risk Assessment, Communication and Outreach Project,” links research with outreach and communication projects through the MSU Department of Entomology and Michigan State University Extension.

For more information, please visit the Michigan Eyes on the Forest webpage or the Midwest Invasive Species Information Network webpage. Preventing the introduction of new invasive species is the goal of the Michigan Sentinel Tree Network and Eyes on the Forest Project.

What is Spruce Decline & What to do about it?

Many Michigan residents have reported that their spruce trees are looking a little…ragged, to say the least. Most are seeing branches dying, starting at the bottom and moving up the tree.

There are several reasons for this, but the most common ones in Michigan are due to fungal infections or insect infestations. The following article by Michigan State University Extension lists several of the ones we typically see.

Do you have a spruce that’s not looking so hot? It might be because of one of these.

 

What is spruce decline and what should you do about it?

Frequently asked questions about spruce decline.

Photo 1. Declining spruce trees. Photo credit: Bert Cregg, MSU

Photo 1. Declining spruce trees. Photo credit: Bert Cregg, MSU

What’s wrong with the blue spruce trees in my neighborhood?

Colorado blue spruce trees have long been among the most popular conifers for landscaping in Michigan and the upper Midwest. Blue spruce trees are widely planted due to their good growth rate, stately form and, of course, their blue foliage. Unfortunately, blue spruce trees are subject to a wide range of insect and disease problems that can impact their growth and aesthetic appeal.

The prevalence of diseases on blue spruce trees has intensified in recent years and trees are declining rapidly in many areas (Photo 1). The key symptom of spruce decline is branch dieback, which progresses over two to four years and renders the plant’s appearance unacceptable for most homeowners (Photo 2). The rapid decline of many spruce trees in Michigan and surrounding states appears to be related to an increase of canker diseases coupled with other disease and insect problems that plague the species.

Decline starts on lower branches
Photo 2. Decline usually starts on lower branches. Photo credit: Dennis Fulbright, MSU

What kind of diseases affect blue spruce trees?

There are three principle types of diseases that affect blue spruce trees: needlecasts, tip blights and canker diseases. All of these diseases are caused by fungal pathogens and each produce specific symptoms that can be useful in diagnosing the problem.

1. Needlecasts. As the name implies, trees with needlecast diseases shed needles. Needlecast fungi often infect needles on the current year’s shoots. As the disease progresses, the needles die, usually the year following the infection. As a result, trees affected by needlecasts often have an outer “shell” of live needles on current shoots and dead needles on older shoots (Photo 3). The two most common needlecasts we find in spruce are caused by the fungal pathogens Rhizosphaera and Stigmina/Mycosphaerella.

2. Tip blights. Tip blights are fungal diseases that typically cause dieback to new, emerging shoots (Photo 4). Tip blights are most common on pines, especially Austrian pines, but can also occur on spruces.

3. Canker diseases. Canker diseases are caused by fungi that infect branches or the main stem of trees. Typical symptoms of cankers are sunken areas along a stem that may ooze resin (Photo 5). Trees may produce ridges of wound tissue around older canker infections as the tree attempts to restrict the fungus’ growth. As cankers develop, they can interfere with the branch’s ability to transport water and nutrients, resulting in the death of individual branches often referred to as “flagging.”

Needlecast disease on spruce New shoot tips Canker disease on branch
Photos 3-5. Left, Needlecasts kill older (inner) needles, but leave newer needles unaffected. Middle, New shoot tips killed by Phomopsis tip blight. Right, Resin oozing from a branch canker caused by Cytospora. Photo credits: Left and middle photo, Dennis Fulbright, MSU; right photo, Michael Kangas, NDSU, Bugwood.org.

What kinds of insects affect blue spruce trees?

Numerous insect pests can impact spruces in Michigan’s landscape, but the two most common are gall adelgids and spruce spider mites. In both cases, the insect pests are tiny and you may need a hand lens to see them. Often times, people are more likely to see the damage as opposed to the insect pests themselves.

1. Gall adelgids. Adelgids are small insects that feed on shoots by sucking plant sap. As they do so, they cause the shoots to deform and produce galls that resemble cones (Photo 6). Damage from gall adelgids is mainly aesthetic.

2. Spruce spider mites. Spruce spider mites cause needle discoloration and eventually kill needles, which can be mistaken for a needlecast disease (Photo 7). Technically, mites are not insects, but are related to spiders. This distinction is important since not all insecticides will control mites.

Cooley spruce adelgid gall Mite needle damage
Photos 6-7. Left, Gall caused by Cooley spruce adelgid. Right, Needle damage caused by mites. Photo credits: Jill O’Donnell, MSU

Why are we seeing increased decline in blue spruce trees?

There are a number of factors contributing to the decline we see in blue spruce trees, including environmental changes, poor site conditions and new pathogens. Colorado blue spruce is native to arid regions in the Rocky Mountains. Michigan’s climate is generally more humid, especially in the summer, which is ideal for fungal pathogens to thrive. In landscapes, Colorado blue spruces have been planted on some sites that are marginal for their success. As a result, they are stressed and more susceptible to fungal pathogens.

Finally, for decades the default diagnosis for most problems with blue spruce has been Rhizosphaera needlecast or Cytospora branch canker. However, a recent survey by Michigan State University researchers suggests two other fungal pathogens, Diplodia and Phomopsis, were much more commonly associated with branch death and tree decline than Cytospora (Photos 8-9). Diplodia and Phomopsis are both considered weak or secondary pathogens, so it is unclear at this point why they appear to cause major disease problems for spruce. Also, in many cases there may be more than one issue that is affecting your tree’s health.

Spruce decline symptoms  Phomopsis canker on branch
Photos 8-9. Left, Decline symptoms moving upward. Right, Wood staining on branch with Phomopsis canker. Photo credits: Left photo, Christine McTavish, MSU; right photo, Dennis Fulbright, MSU.

Can I do anything about these spruce problems?

As with any tree health problem, the first step in dealing with declining spruce trees is to diagnose the problem and identify the cause. For large or important landscape trees, homeowners should contact a professional arborist or tree care company.

For some disease issues, such as needlecasts, fungicides may be effective in preventing or controlling the disease. It is important to note that fungicide treatments for needlecasts only protect new growth. For control to be fully successful, it may take two to three years of yearly fungicide applications. For canker diseases, the effectiveness of fungicides is usually limited. Removing affected branches is usually the best action to improve the tree’s appearance and slow the spread of disease within the tree.

For insect or mite issues, insecticides or miticides can be effective, however selection of the proper product and timing are critical.

Should we continue to plant blue spruce trees?

This is a difficult question. Although spruce decline is widespread and appears to be increasing, it is not a certainty that all trees will be affected. In fact, it is not uncommon to see healthy, thriving spruce trees near or adjacent to trees that are in severe decline. Another complicating factor is that trees may be healthy for a number of years and then begin to decline as they mature and are more difficult and costly to remove.

The likelihood of having success can be improved by planting blue spruce trees on sites with conditions they favor. Key site factors for blue spruce trees are full sunlight, good air movement and excellent soil drainage. Michigan State University Extension recommends homeowners diversify their landscapes to help make their landscapes more resilient to pest and environmental changes, and seek to plant a variety of species wherever possible.

Healthy blue spruce tree
Blue spruce does best on exposed sites with good soil drainage. Photo credit: Bert Cregg, MSU

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Stink Bug Stress – How Can Homeowners Get Rid of Them?

Fall means change. For many animals this means migrating, gearing up for hibernation, or putting on fat to tough out the cold. Insects are not exempt from these changes. It’s true that many die off, the last of the season’s adults producing eggs that will overwinter, not to be seen until the weather warms again in the spring. Yet many find places to hide out. Often these places end up being in your house, garage, shed, etc. Places that many of us don’t want them.

The two most common examples around here are the Asian Lady Beetle (which resembles our ladybugs) and the Brown Marmorated Stink Bug (BMSB).

brown_mo_moThere have been several reports of the BMSB in particular this year. Several people have said they have seen unusually high numbers of them. While this agricultural pest has been in the U.S. since the late 1990’s and in Michigan since 2010, experts are predicting that their numbers will only increase in the coming years. These insects have very few predators here to keep their population in check. They also spread and multiply quickly, a nasty combination when it comes to a pest.

So if you get these insects in your house this fall what can you do about it?

Michigan State University Extension has put together a new homeowner tip sheet that can help you identify BMSB and how you can control them if you have them.

New tip sheet on brown marmorated stink bugs for homeowners

A new resource about brown marmorated stink bug identification and management in homes is now available.

Considering the diversity of agriculture in Michigan, the brown marmorated stink bug (BMSB) has potential to be a very damaging pest. In the eastern United States, crop yield losses in apples alone were 18-32 percent in 2010, with damage exceeding $37 million. Michigan’s economy depends largely upon agriculture, particularly specialty crops. We are first in the nation in specialty crops such as dry beans, red tart cherries, blueberries, squash and cucumbers for pickles, and are in the top 10 for 63 other commodities. Most of these are at risk of attack from the BMSB.

BMSB also feed on a wide range of native and introduced ornamental plants in the landscape and can be an unwelcome guest in homes during fall and winter. A new tip sheet, “The Brown Marmorated Stink Bug (BMSB): Information for Michigan Residents on a New Home Invader,” has just been released by Michigan State University Extension. Written by MSU Department of Entomology’s Paul Botch and myself, the tip sheet provides a handy reference for homeowners who may have not yet encountered BMSB, or for those who are beginning to find it in their homes. It contains a guide for identifying BMSB and illustrates other common home-invading bugs. Tips on preventing its entry into homes and for eradicating it once it enters are also covered.

Download the tip sheet at: The Brown Marmorated Stink Bug (BMSB): Information for Michigan Residents on a New Home Invader.

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