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Emerald Ash Borer – Invasive Species Highly Destructive to Ash Trees

The emerald ash borer (EAB, or Agrilus planipennis) is a green beetle native to Asia and Eastern Russia. Outside its native region, the emerald ash borer is an invasive species, and emerald ash borer infestation is highly destructive to ash trees, having infested millions of ash trees in its introduced range. The Emerald Ash Borer was first discovered in the United States in Michigan in 2002. Experts believe the insect was brought to North America unintentionally in ash wood used to stabilize crates during shipping. Stein Tree Service offers helpful information about this invasive pest.

Life Cycle of the Emerald Ash Borer

A key part of emerald ash borer awareness is knowing the emerald ash borer life cycle. Understanding the life cycle will help you understand what to do when you see any activity on or around your property. Below are the different life cycle stages of this highly destructive invasive species.

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Adults

The adult emerald ash borer is a dark metallic green, bullet-shaped beetle, and about 1/3 inch long (8.5 millimeters), and 1/16 inch wide (1.6 mm). The body is narrow and elongated, and the head is flat with black eyes. After emergence, adults fly into the ash canopy, where they feed on leaves throughout their lives. EAB adults start mating one week after emergence, and females begin laying eggs 2–3 weeks later. A typical female will lay approximately 100 eggs during her 2-month life; 56% of these eggs, on average, will be female. EAB adults are readily observed mating and egg-laying on the trunks of ash trees on warm, sunny afternoons and evenings in the field. The adults of both sexes are strong fliers.

Eggs

A female EAB may lay more than 100 eggs in her lifetime, depositing them individually or in groups on the bark of ash trees along the trunk and portions of the major branches. Eggs are laid in areas where the bark is rough and between bark layers or in bark crevices. 

Eggs are approximately 1.0 mm long x 0.6 mm wide and creamy white when laid; fertile eggs gradually turn amber after a few days and hatch after about two weeks.

Larvae 

Newly hatched larvae bore through the bark to the phloem and outer layer of new sapwood, where they feed until the weather gets too cold in the fall. There are four stages of larval development (instars). As they feed, the larvae create long serpentine galleries filled with frass, which enlarge in width as they grow.

Larvae are creamy-white and dorso-ventrally flattened. When fully mature, fourth-instar larvae are 26 to 32 mm long. Their head is mainly retracted into the prothorax with only the dark brown mouth parts visible. The prothorax is enlarged, with the mesothorax and metathorax narrower. Larvae have 10 bell-shaped abdominal segments and a pair of small brown structures called urogomphi, which are characteristic of all larvae in the genus Agrilus.

Overwintering Larvae, Pre-pupae, Pupae, and Adults

In the fall, mature fourth-instar emerald ash borer larvae excavate pupal chambers in the sapwood or outer bark where they fold into overwintering “J-shaped larvae.” In the spring, the J-shaped larvae shorten into prepupae then shed their cuticle to become naked pupae. Pupae are initially creamy white, but the eyes turn red, and the bodies begin to darken as they develop.

Another critical aspect of emerald ash borer awareness is identifying signs of infestation. Adults chew D-shaped exit holes through the bark to emerge 

Emerald Ash Borer Larvae

from infested trees and can immediately fly upon emergence. EAB larvae that are immature as cold weather arrives in the fall will overwinter in their larval gallery. Larger larvae complete development the following spring, whereas smaller larvae may require another summer of feeding to complete development.

Symptoms of EAB Infestation

Look for these telltale signs that your ash tree suffers from EAB infestation. To properly identify the presence of this Asian native, look for a combination of two or more symptoms.

  • Crown Dieback – as a result of multiple years of EAB infestation, the larvae will disrupt the delivery of nutrients and water flow to the upper canopy, resulting in the dieback of the upper and outer crown.
  • Epicormic Sprouting – as a defense mechanism, your trees will try to ensure survival when sick or stressed. Signs of new growth at the tree’s base or on the trunk—often just below where larvae feed- indicate infestation.
  • Splitting Bark – feeding EAB larval galleries will develop surrounding callous tissue, causing vertical splits to the bark. One can see these larval galleries when the split bark is pulled away.
  • Woodpecker Feeding – woodpeckers love to feed on EAB larvae underneath the bark. With excessive feeding on large numbers of larvae, the damages will look like strips of the tree’s bark have been removed.
  • Distinctive D-shaped Exit Holes in Bark – emergence holes are made as the larvae mature into adult beetles and emerge from underneath the bark.

Effect on Trees

The most significant damage to a tree by EAB infestation occurs when the insect is in its larval stage. The larvae feed on the conductive tissue of the tree. This tissue transfers nutrients and water from the roots to the leaves, and when this transfer  is disrupted, the infested ash tree begins to die. At the onset of winter, the larvae relocate to the tree’s bark, effectively cutting off the tissue more. This ultimately results in the death of a tree. This can take place over several years, and the first noticeable sign is usually some die back in the crown of the tree. The tree will usually be dead by the following year or soon after. In areas where the insect is invasive and has no natural predators, the emerald ash borer can and usually does have a devastating effect on the local ash tree population.

Treatment

Prevention of the emerald ash borer infestation is possible by injecting a systemic insecticide into the base of the tree. This treatment can prevent damage to the tree for up to two years. Note that arborists must reapply application every two years.

Soil injections are another option for the prevention of EAB. These insecticides are injected directly into the soil surrounding the tree’s base and are then transported through the rest of the tree via the roots. For these treatments to have the greatest effect, the soil must be moist when applied. Waterlogged or dry soils will result in less insecticide being absorbed into the tree.

USDA Map of Emerald ash borer spread in US- emerald ash borer invasive species - Stein Tree Service

image courtesy of USDA

Arborists can use two insecticide spray treatments:

  1. The first is a spray applied to the trunk and absorbed through the bark. This treatment is less invasive to the trees and soil. However, absorption is slow and limited if the tree has thick bark.
  2. The second spray treatment is a protective cover spray applied to the branches and trunk of the tree. This treatment kills adult beetles and newly hatched larvae but will not kill eggs.

Emerald Ash Borer in Winter

While the wintertime cold temperatures kill off many insects and pests, emerald ash borer can survive the freezing winter temperatures. These pests spend the winter preparing to feed on nearby ash trees. EAB survive the winter due to them living within trees and a natural “supercooling” ability.

How does EAB Survive the Winter? Trees

When female emerald ash borer lay their eggs between June and August, the beetles lay eggs between layers of outer bark and cracks and crevices of the trunk and major branches. Once the eggs hatch, the larvae burrow deeper into the tree, feeding on the tree until becoming adults in early spring. The outer bark provides insulation to EAB from the cold weather, so the in-tree temperature is more relevant to EAB’s survival than the temperature outside the tree. Trees that receive much sunlight in the winter can also be warmer despite the cold weather. The other primary reason these beetles can survive cold weather is supercooling.

Supercooling

Supercooling lowers the temperature of gases or liquids below the freezing points without becoming solids. Many animals use supercooling by producing antifreeze proteins that bind to ice crystals, preventing water molecules from binding to the ice crystals and the ice from spreading. Insects can also create these proteins and other sugars or alcohols to prevent themselves from freezing and improve their cold tolerance. Supercooling is common among insects, and that process is the other primary reason why EAB survives the winter.
Emerald ash borer’s supercooling has a limit on how low the temperature can get to be helpful. Most research has shown that a significant portion of larvae begins to die at around -10°F and the number increases with the lower temperature. The icy weather conditions needed to do so are much more common in northern, colder regions such as the Midwest or Canada. Pennsylvania, Delaware, and Maryland winters are unlikely cold enough or may only have short, extreme cold snaps instead.

What You Can Do During Winter

If you want to keep your trees safe from the effects of EAB, here are a few things you can do during the winter while EAB larvae are dormant and have yet to spread to other trees.

  • Look for signs of emerald ash borer on your property and among your trees.
  • Get your trees inspected by a professional, certified arborist.
  • Remove EAB-infested trees and care for surrounding trees to reduce the risk of future infestation.

Removing trees infested with EAB can be done carefully at any time, but the ideal times to remove trees are during the fall and winter. From October to May, EAB is mostly inactive, with the larvae burrowing under the bark of a tree. The dormancy results from the beetles protecting themselves from the cold weather. Because the pest is primarily dormant during the winter, the chances of the pest spreading are reduced. Therefore, the ideal time to remove infested trees is between October and May, with the lowest risk of other ash trees becoming infested.

Emerald ash borer’s supercooling has a limit on how low the temperature can get to be helpful. Most research has shown that a significant portion of larvae begins to die at around -10°F and the number increases with the lower temperature. The icy weather conditions needed to do so are much more common in northern, colder regions such as the Midwest or Canada. Pennsylvania, Delaware, and Maryland winters are unlikely cold enough or may only have short, extreme cold snaps instead.

Camping & Preventing Emerald Ash Borer Spread

If you love camping, be careful about transporting firewood, as that is one of the ways Emerald Ash Borer has spread throughout the United States. First, be aware that improper handling and movement of firewood could cause the spread of invasive pests, such as the emerald ash borer  Stein Tree Service warns that the emerald ash borer is dangerous to various ash and olive tree species, and failure to follow handling guidelines could spread the insect to the camping area you visit or to your home trees if you transport wood from the site.

If you plan to have a campfire, and campfires are allowed at your site, purchase wood at the campground. This practice is generally recommended to avoid introducing non-native insects to a site. However, the emerald ash borer is particularly harmful and destructive.

campfire - be aware of threats such as emerald ash borer and the lone star tick when camping - Stein Tree Service

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ITo ensure your property has healthy ash trees from emerald ash borer invasive species,  contact Stein Tree Service at (302) 478-3511 to request your free, no-obligation consultation with one of our tree specialists.

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Inspect for Emerald Ash Borer infestation - Stein Tree Service - 1000

Spotted Lanternfly Quarantine Areas

Stein has a permit to work in spotted lanternfly quarantine areas in Pennsylvania and Delaware. Tree Service Companies have to be trained in proper moving and disposal of materials to avoid spread of the spotted lanternfly and Stein has completed the training courses.

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Inspect for Emerald Ash Borer infestation - Stein Tree Service - 1000

Emerald Ash Borer Inspection

In the spring, destructive ash borer (EAB) adult beetles begin to emerge.  These invasive pests can destroy your ash trees.  Our specialists are certified to treat for EAB in Pennsylvania and Delaware.  For A free consultation, contact us today.

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Stein Discusses Treating for Spotted Lanternfly in Delaware and Pennsylvania

Treating for spotted lanternfly has become a more significant concern among homeowners as the invasive pest continues to spread and be a nuisance in Delaware and Pennsylvania. Controlling the spotted lanternfly population can be done by knowing how to identify the pest and preventing further spread. Homeowners can take preventive measures, such as purchasing firewood locally and scraping off egg masses on their property, as well as ensuring that none of the insects are hitching a ride on their vehicles when they travel. Here are a few tips on how to identify and treat for spotted lanternfly on your property.

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Identifying Spotted Lanternfly

Spotted lanternfly with wings open | invasive species in Delaware | Stein Tree Service

Treating for spotted lanternfly requires identifying their presence. Regarding the insects themselves, spotted lanternfly are small planthoppers with black heads, gray-brown forewings, and black spots on their forewings. The adults also have red hindwings underneath their forewings. Spotted lanternfly can also be detected and identified in their other life stages:

  • Early nymphs are tiny (⅛ to ½ inch) and can be challenging to find due to their size. The nymphs are all black with white spots.
  • Late nymphs are around ½ inch long, and have red bodies with black stripes and white dots.

Adult spotted lanternfly is the easiest to identify, thanks to their bigger size and distinct body coloration.

Spotted lanternfly will typically lay eggs on trees in the fall, although any hard surface (decks, rocks, houses) can be a potential spot for laying eggs. Egg masses are usually around 1 to 1½ inches long and make items appear to be covered in mud. These egg masses can also typically be found in the late fall.

Treating for Spotted Lanternfly

If you see spotted lanternfly on or around your property or trees, the best solution is to contact a professional, certified arborist. An arborist can closely examine the situation and determine the best treatment options for your trees. Also, homeowners can do a couple of things to help keep their trees safe from the spotted lanternfly’s dangers.

Prevent Transporting Spotted Lanternfly

spotted lanternfly young on plant

One of the significant reasons spotted lanternfly has become such a big problem is how easily the pest can move from one region to another, often through human activity. If you plan on going camping soon or transporting firewood, keep your firewood at home and purchase firewood locally instead. Hopping on firewood and moving from county to county is one of the primary reasons spotted lanternfly has been able to spread so quickly. Be sure to check your wheel wells and under your car for any egg masses or insects, too. Parking away from infected trees, keeping items away from those trees, and rolling your windows up when you are parked are effective ways to prevent spreading the pest.

Scrape Egg asses from Trees

If you see any spotted lanternfly around your property, check your trees, deck, car, and any outdoor surface on your property for any of their egg masses. After finding one, scrape off the egg mass with plastic cards or a putty knife. Make sure to scrape the egg mass into a bag or container filled with rubbing alcohol or hand sanitizer. Some eggs may be unreachable, resting at the tops of trees or well-hidden.

Tree Traps

Another effective means of treating for spotted lanternfly, particularly nymphs, is to use bands or tree traps to catch them. Sticky bands around trees where spotted lanternflies feed (such as the Tree of Heaven (Ailanthus altissima)) can catch nymphs. To prevent other animals or insects from being caught on the traps, only apply the tape if you know you have an infestation, reduce the band’s surface area by cutting, and use a wire or mesh around the band.

Call a Professional, Certified Arborist

Some of the other tactics for controlling spotted lanternfly involve insecticide or pesticides. You should use these options with caution due to the effect chemical controls may have on the rest of your plants and local ecosystem. If you want the best results for getting rid of spotted lanternfly, contacting a certified arborist who will inspect your property and advise you on the solution is ideal.

Contact Stein Tree for Spotted Lanternfly Treatment & Tree Care

If you see this invasive species on your property and want to keep your trees safe, contact Stein Tree Service. Stein performs commercial and residential plant and tree care services, including plant health care (PHC), tree removal, trimming, and pruning. Our team of tree care specialists is certified to treat in areas of spotted lanternfly infestation in Delaware and Pennsylvania. Contact us for a free consultation.

Stein Discusses Invasive Species in Delaware

One threat that the Delaware environment faces is damage by invasive species. An invasive species is a non-native plant, insect or animal that is introduced into a region and causes some harm. That harm can affect plants or humans, and the damage can be economic or environmental. Many people have likely heard of some invasive species in their regions, but may be unaware of the harm caused by these species. Stein discusses a few of the invasive species in Delaware.

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What Is Beneficial Insect Release And How Do Beneficial Insects Work?

Maintaining healthy landscaping, trees, shrubs, and other plants often requires work and labor from either the owner or a tree and plant health care specialist. But one method is to let insects do the job instead. Beneficial insect release has become an increasingly popular method for homeowners to maintain their gardens and landscapes in a natural, sustainable way.

What Are Beneficial Insects?

Beneficial insects are insects that perform valuable tasks to sustain an ecosystem, such as pollination and pest control. Many people perceive all insects as pests, but insects are vital to their ecosystems. In addition to pollination and pest control, many insects provide soil fertilization or food for other insects and animals.

For example, bees pollinate flowers, collecting the nectar, and using that nectar to produce honey. A farmer can take advantage of this by using bee boxes and creating a sustainable cycle that benefits both him and the bees.

Pest Control

Mature Birch Leafminer | beneficial insect release | Stein Tree Service

Using insects as a form of natural pest control has become more prevalent in recent years. Organic farmers and gardeners commonly use this form of biological pest control, as do tree and plant health care specialists as part of integrated pest management plans. An example of beneficial insects used for pest control is the ladybug.

Ladybugs are predators to aphids, which are small, sap-sucking insects that can damage plants and leaves. If a gardener is having trouble with aphids, a pest control specialist can distribute ladybugs to control the aphid population, without using chemicals that might cause more harm to the gardener’s plants. Other insects, such as green lacewings and praying mantises, are also used for pest control. A special kind of wasp, parasitoid wasps, which are natural predators of emerald ash borer (EAB) in their native Asia, has been released in some areas to fight the EAB invasion.

Benefits of Beneficial Insect Release

Leafminer Larva | beneficial insect release | Stein Tree Service

One of the primary benefits of using beneficial insect release is that the process avoids chemical pest control methods such as pesticides. While pesticides are effective at controlling and eliminating pests, some plants and beneficial insects like bees can be affected negatively. Beneficial insects are a natural, organic, and environmentally sustainable way to control pests. Many insects have also shown to have growing resistance to pesticides. Predator creatures avoid that issue entirely.

Beneficial insects also fit into the larger goal of integrated pest management: to control pests while preserving the natural environment and ecosystem as much as possible. Nature has many self-regulating elements, and predator insects are one element from which humans and landscapes can benefit.

How to Use Beneficial Insects

Taking proper advantage of beneficial insects involves much more than only releasing them into a landscape.

Choose the Right Species

The first step to utilizing beneficial insect release is to determine what pests are affecting a landscape, the location of the pests, the extent of the damage, and any other information a pest management specialist needs to create the best plan. The pest management specialist uses this information to determine what species of insects would lead to the best results. Different pests have different natural predators. Selecting the best species for the job is a crucial first step.

For example, the Tetrastichus planipennisi parasitoid wasp is too small to be effective against EAB in mature trees. A larger specimen, the Spathius agrili, can penetrate the thicker bark of mature trees.

Maintain the Environment

Beneficial insects need to be in an environment that allows them to thrive. For example, Delaware’s yearly climate tends to be moderate, with average monthly temperatures ranging from 76 to 32 degrees Fahrenheit. So, a proper beneficial insect release plan needs to select insects that thrive in these temperatures. Humidity is another factor that affects which insects will thrive.

Choose Optimal Timing

When the pest management specialist and the property owner are ready to distribute the insects, timing is key. If, for example, parasites are being released into a landscape, a host (the organism attacked by the parasite) must be available. Some releases are dependent on the life cycles of the pests. Beneficial insects should also be released when food sources are plentiful, allowing the insects to survive for longer periods.

Contact Stein Tree Service for Tree and Plant Health Care Services

If you have issues with pests in your landscape, call Stein Tree Service. We have provided quality service in areas such as Wilmington and Philadelphia for over 35 years and we are certified to treat for EAB and to work in spotted lanternfly quarantine areas. Our certified arborists have decades of knowledge and experience, and our equipment is state-of-the-art. For a free consultation, contact us today.

What is Integrated Pest Management (IPM)?

Every landscape and home face the problem of pests. Usually, the solution for most is to eliminate a pest problem when the issue is discovered. But this is a short-term solution that can lead to damaging an affected area and its surroundings without careful consideration. Stein certified arborists and plant health care management specialists emphasize and promote Integrated Pest Management, or IPM, for any pest-related issues. Integrated Pest Management (IPM) is a process that pest control specialists use to eliminate pests while minimizing any risk to people and the environment. This process can be used in any environment, too: urban, suburban, rural, agricultural, natural areas, and more.

The Goal of Integrated Pest Management (IPM)

The purpose of having an integrated pest management system is to focus on long-term prevention of any damage caused by pests. The specific plan is based on the ecosystem of the affected area and uses a combination of biological control, habitat manipulation, cultural control, and using resistant varieties of plants and/or crops. Rather than a single method of eliminating a pest infestation, integrated pest management (IPM) is a whole system of comprehensive pest management practices.

Reducing risks to both humans and the environment is a major goal of IPM practices. Preserving the sustainability of the local habitat and environment while managing pests is what separates IPM from other (often short term) pest control methods. Resolving the root cause of pests also provides economic benefits in the long-run.

What Are Pests?

Wine leaf with mite and smallpox infestation – Integrated Pest Management (IPM) – Stein Tree

When an arborist is developing an integrated pest management plan for you, what constitutes pests is vital. Generally speaking, a pest is any organism that interferes with or damages our desirable plants and homes, as well as human and animal health. Some pests may carry diseases that can affect you or your plants, while others may just be annoying to deal with. Usually, people think of pests as insects such as termites or ticks, but even organisms as big as birds and rodents, and as small as weeds and bacteria, can be pests.

Every environment deals with unique pests, and plant health care specialists need to be aware of how the environment allows these pests to thrive. Knowing pest populations, life cycles, and more, is crucial to creating effective, sustainable IPM programs.

How Does Integrated Pest Management Work?

As we mentioned, IPM is about finding long-term solutions to pests, and that involves creating and modifying the environment to be unfavorable for those pests. Growing healthy crops, using disease-resistant plants, or sealing cracks in a building are all ways that prevent pests from thriving and can help control the issue.

Farmer on tractor using pesticides - Integrated Pest Management (IPM) - Stein Tree

Monitoring the environment, including identification of the pests and the damage caused is the first step in determining what level of action is necessary. Knowing about the pests and the conditions that allow them to thrive gives pest control specialists the information to create the best plan for your needs.

After the initial monitoring of the environment and the pests, the issue needs to be evaluated as either tolerable or a problem needing to be solved. A few weeds scattered throughout a garden may be a small issue that can be solved by simply pulling them out from the ground, while a large infestation of disease-carrying insects is a major problem.

IPM and other pest control methods should be used in conjunction with one another, as opposed to being used separately. Some of the methods involved in integrated pest management (IPM) include the following:

  • Biological control – Using natural enemies, such as predators, parasites, pathogens, and competitors, to control pests.
  • Cultural controls – Reducing pest establishment, reproduction, dispersal, and survival. An example of a cultural control would be changing irrigation practices because too much water can increase root disease and weeds.
  • Mechanical and physical controls – Killing pests directly, blocking pests out, or making the environment unsuitable for pests. Examples of mechanical or physical controls include traps for rodents or some type of barrier or screen to keep birds and/or insects out.
  • Chemical control – Using pesticides and other chemical-based solutions.

We all know about farmers using pesticides on their fields, and while pesticides are effective, some cause health and environmental concerns. Usually, pesticides are used only in combination with other methods, chosen carefully, and used conservatively. Examples of pesticide applications in IPM would be using a selective pesticide to only target organisms that are causing the issue, or spraying pesticides in selected areas rather than a whole field.

Call Stein Tree Service for Pest, Plant, and Other Tree Services

If you are having issues with pests and need integrated pest management (IPM) in areas such as Wilmington or Philadelphia, call Stein Tree Service. Our certified arborists have decades of experience, our equipment is state-of-the-art, and we have been dedicated to quality service for over 30 years. For a free consultation, contact us at 610-723-8056 today!

Cottony Camellia Scale

Cottony Camellia Scale insects tap into plants and feed on plant sap, weakening and even killing plants over time. Cottony scale insects produce a cottony egg mass from which the mobile crawler stage hatches. The young crawler stage is also the easiest stage to control.

Scale insects are closely related to aphids but most don’t look like insects at all, appearing legless and attached to the plant’s leaves or stems (see photo right). Scale insects feed by tapping into the plant stem or leaf and withdrawing plant sap. Like aphids, they are often associated with sticky honeydew which supports the growth of black, sooty mold.

Some scale insects produce a cottony sac (see photo right) that contains hundreds or thousands of eggs. Scale insects that make these cottony egg sacs are called cottony scales. Eggs generally hatch in early summer and release the crawler stage, the only highly mobile stage in the insect’s life cycle. The active crawler stage is also the one that must be targeted for effective control.

There are many scale insect pests of ornamental plants and they have very complex life cycles and host plant interactions. One of the best comprehensive sources of information about these pests on ornamental plants is Insects That Feed on Trees and Shrubs by Johnson and Lyon (see Amazon below right).

Plant damage caused by scale insects

Plant damage is related to the sap that scale insects take from the plant. Over time as more sap is extracted the plant weakens, leaves may drop and eventually whole branches may die.

Plants that are stressed by drought, root damage or disease are better hosts for many pests including scale insects. These same stressed plants may be killed by high scale insect populations. In addition, sooty mold growing on the leaf surface can interfere with normal processes and can further weaken the plant.
Scale insect control

The most important part of scale insect control is timing. Control measures must be timed to coincide with hatching of the crawler stage which usually occurs in early summer for cottony scales. If properly timed, and good spray coverage is achieved, soft insecticides like insecticidal soaps and oils are just as effective as conventional insecticides (see Using Insecticidal Soap For Garden Pest Control). Over the long run soaps and oils may be more effective since they preserve the natural enemy complex which may account for most of the long term control of these plant pests.

Scout plants starting in late spring. Use a hand lens to look for scale crawlers on the underside of leaves or near cottony egg sacs. Scale crawlers will be about the size of spider mites but amber in color. Once crawlers are found control treatments can begin. It may take several seasons to completely control a severe scale infestation. Scale infestations often take years to develop and it is unlikely that you’ll eliminate them overnight.

Birch Leafminer – Among the Most Common Insect Pests Affecting Birch Trees

Birch leafminers Fenusa pusilla (Lepeletier) are sawflies, which are closely related to bees and wasps. They are among the most common insect pests affecting Birch trees (Betula spp.) in North America. Areas inside the leaves are consumed by the larvae affecting the leaves’ ability to produce food. Yearly browning of birch leaves are noticed in mid-July and August, but the leafminers have been feeding inside the leaf tissue since early spring.

Life cycle

Leafminer Larva

Leafminers overwinter in the soil as prepupae. Adults emerge in May to late June to early July, depending on temperature and humidity. Oviposition (egg-laying) peaks during the last week of June. Adult birch leafminers are small (about 1/8 to 1/4 inch long), black and fly like. Females deposit their eggs singly in slits cut in the central areas of young leaves, usually near the tips of branches. More than one female may lay eggs in a leaf.

The eggs hatch into legless, worm-like larvae. These immature larvae feed individually between the leaf surfaces, creating blotchy kidney shaped mines. The immature leafminers feed for several weeks, then drop to the ground where they enter the soil layer to develop into pupae. They pupate and remain there until the following spring. After overwintering as prepupae in the soil below the tree, the adults emerge just as the birch trees are leafed out. Adults are almost all females.

Damage

The areas of leaves that are consumed by the amber marked birch leafminer larva turn brown. Because people often do not see the early signs of birch leafminer feeding, it often appears the tree has suddenly dried up or become diseased. This browning is caused by the outer layers of the leaf drying out after the leaf miner larva has consumed the green tissue between the outer layers of the leaf. Early mines appear as light green or whitish discolorations on the leaves.

Larvae sometimes can be seen easily when leaves are held up to sunlight, especially as the mines and larvae grow larger. Feeding over several weeks causes the blemish to take on a blister-like appearance. A single leaf can contain as many as 40 larvae whose mines may merge to destroy the total photosynthetic area of the leaf. Heavy infestations of leafminer larvae can seriously affect a tree’s photosynthetic capacity. Repeated attacks will generally cause stress which may induce susceptibility of the tree to other injurious agents.

Species Responsible

There are two species mainly responsible for defoliation and browning of birch trees in the United States and Canada. In Northern forests, it is the Amber Marked Leafminer, Profenusa thomsoni, which were accidentally introduced from Europe to North America early in the 1900s. The other is the Birch Leafminer, Fenusa pusilla, which is more common in Eastern forests.

Biological Control of Birch leafminers

Mature Birch Leafminer

Presently there is no commercially available biological control agent to control Amber marked birch leafminers, however Canadian trees in the Edmonton area have been successfully controlled with releases of a parasitic wasp, Lathrolestes luteolator. Populations of the tiny parasitoid wasp selectively attack the most damaging birch leafmining pest (Profenusa thomsoni) have developed and drastically reduced the problem in the Edmonton area of Canada.

Following trials in 1995 that supported a dramatic reduction in birch leafminer damage by the first parasitoid, the City of Edmonton, Canada discontinued pesticide treatments to almost 3,500 city birch trees in 1996 and 1997. These trees continue to show very little leafminer damage without any treatment.

Chemical Control

Spinosad can be used to control birch leafminers prior to extensive damage. Spinosad is a new chemical class of insecticides derived from a soil dwelling bacterium discovered in 1982. It is considered practically non-toxic to humans, pets, and beneficial insects. Unlike other insecticides, Spinosad will not harm beneficial insects including the Amber Marked Leafminer parasite.

Horticultural oil applications applied at the right time may help kill eggs or tiny larvae within the leaf tissue. Oil applications should be made as soon as adults have emerged in the spring and egg laying has occurred and should continue weekly until mid June. Pesticides made with botanical plant oils may be especially useful to prevent egg laying. Neem oil acts as a repellent and may interfere with the egg laying activity of female leaf miners.

Systemic insecticides are chemical pesticides that are absorbed into the tissues of plants. These pesticides make the entire plant, or parts of the plant, poisonous to insects that feed on the plant tissue. Most systemics are very toxic to people and pets. Trunk injections are confined to the tree’s cambium layer, where it is carried to the leaf tissue by the movement of the tree’s sap.

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Content sourced from Wikipedia

Bagworms – Destructive Tree Pests Coming This Summer

It looks like the very destructive Bagworm is going to be around this summer.  Spring is the perfect time to make a plan for this pest and protect your at-risk trees.

Below is an excerpt from a Penn St. article on the Bagworms and their destructive activities in Southern Pennsylvania. (Full Article)

The Bagworm (Thyridopteryx ephemeraeformis) is a perennial insect pest of arborvitae, juniper, pine, spruce, and many other evergreen species. It also attacks certain deciduous trees such as black locust, honeylocust, and sycamore. The bagworm is most common in southern regions of Pennsylvania. Infestations have recently been noticed north of Interstate 80 in the state. The spread of the bagworm is slow since adult females are unable to fly. Their dispersal over wide areas occurs mainly through movement of infested nursery stock and ornamental plants, or by ballooning (wind dispersal) of small bagworm larvae during early June.

Description

This insect is most easily recognized by the case or bag that the caterpillar forms and suspends from ornamental plants on which it feeds. The bag is made of silk and bits of host foliage. These materials are interwoven to disguise and add strength to the case. When the larva is mature, the bag may be 30 to 50 mm long. Young larvae hatching from the eggs are approximately two mm long, glossy black on the back and dull amber on the undersurface of their bodies. Mature larvae are dull, dirty gray and splotched with darker markings toward the head. Fully developed larvae are about 18 to 25 mm long. The adult female is worm-like. The adult female lacks eyes, wings, functional legs and mouthparts. She never leaves the bag that she constructed as a larva. The adult male is sooty black and moth-like with transparent wings that are nearly devoid of scales.

Stein Tree Service has significant experience at treating Bagworm and helping keep your trees healthy.  Don’t wait!  The time to make a plan is now.  We offer a free, no obligation consultation with an ISA Certified Arborist who can offer guidance, discuss risks and a plan to manage all your landscape health care needs.


Why Choose Stein Tree Service?

Our staff is the best in the business and has hundreds of years of combined experience. We have ISA Certified Arborists, Registered Consulting Arborists, Certified Tree Risk Assessor, Licensed Forester, Certified Professional Horticulturalist, Registered Tree Expert and Certified Applicator.

Our equipment is state-of-the-art and radio dispatched for immediate response. The company fleet consists of several aerial lift trucks, chippers, chipper trucks and stump grinding machines as well as various pieces of machinery for right of way work.

Our reputation speaks for itself. We have served thousands of customers throughout the Delaware Valley and maintain the highest level of customer satisfaction. The vast majority of our business comes to us via referrals from past customers.