Plant Fungal Diseases

 

The time to treat plant fungal diseases is approaching!  Most treatments will begin in the early spring just as the leaf buds are opening.  Timing is important for good results.

Here are some helpful questions in determining if your landscape plants have fungal problems.

  • Do the leaves or stems have black or brown spots or patches?
  • Do the evergreen needles have tiny black spots on them?
  • Is there a white powdery or sooty appearance on leaves and/or buds?
  • Are the tips of the twigs wilting and/or dying?
  • Are there gelatinous gobs oozing from the stems and leaves/needles?
  • Is the interior of the plant dying?

If you witness any of these symptoms or suspect fungal problems, let us know and we would be happy to assist you.  Many of these issues can stem from over watering (such as a sprinkler hitting trees and shrubs every day), overgrown and thick plant interiors (such as a shrub that has not been pruned lately), or if a plant is under stress or is in poor health to begin with.

There are some fungal problems that will persist and deteriorate a tree year after-year such as needlecast.  There are also fungal diseases that persist, such as apple scab, that will not kill the tree.  We can assist in determining if a fungal problem exists and if remedies need to occur in order to sustain the life of your landscape plants.

Please call (616) 301-1300 extension 118 to schedule a free estimate with one of our certified arborists.

Hemlock Woolly Adelgid

The Hemlock Woolly Adelgid (HWA) is an invasive, aphid-like insect which feeds on the hemlocks’ stored starches and is identifi ed by the white, cottony wax the adelgid produces. HWA was discovered in the eastern states in the early 1950s and has been spreading ever since. Recently, HWA has been identifi ed in Muskegon and Ottawa counties.

WA feeds along the twigs of hemlocks by inserting its mouthpart into the tree tissue and feeding on starch reserves. Over time, the tree will lose vigor and may eventually die. HWA is spread by migrating birds, mammals, humans, and infected nursery stock.

Once established on a hemlock, the HWA reproduces asexually and can quickly cause a mature hemlock to decline.

Once the HWA is identifi ed, Integrity Tree Services can help control it by several means. Trunk sprays and soil drenches of insecticide have been shown to lower HWA populations. We treated hemlocks on several properties last year and we are looking forward to seeing the results.

Be on the lookout for the invasive HWA. Located under the branches of the eastern hemlock, the insects will appear as white, cottony masses along the twigs at the base of the needles. Do not attempt to move the insect or try to take care of it yourself because this can spread the pest

Signs of Nutrient Deficiency

Now that new leaves and needles are out, you may be noticing something peculiar about them. It is common for trees and shrubs to experience nutrient deficiency, which is noticeable from the color or stunted size of the leaves or needles. Whether the tree or shrub is low on iron, manganese or any other type of micronutrient, more than likely you will be able to identify this by observing the leaves.

A micronutrient is required by plants in very small quantities, as opposed to macronutrients, such as nitrogen, phosphorous, calcium or sulfur which are required by plants in large quantities. Plant tissues are made up of mostly macronutrients such as nitrogen, phosphorous and the others, therefore they are required by the plants in larger quantities. Micronutrients are minerals in the soil that are also required for healthy, stable plants. Micronutrients such as iron, manganese, silicon, copper and zinc are commonly present in the soil where a landscape plant is experiencing signs of nutrient deficiency, it is simply that when a soil has a high pH (is more alkaline as opposed to acidic), these micronutrients are in a form that cannot be taken up by plant roots.

Testing the soil pH can help determine whether or not a specific soil type will be suitable to easily sustain a tree or shrub. If a landscape plant is already established and is showing signs of nutrient deficiency, there are several fertilization techniques (micronutrient and macro-nutrient) that Integrity Tree offers that can temporarily strengthen the health of your plants. Temporary, meaning that the treatment will most likely be needed again the following season, as the micronutrient is applied for the plant and does not change the overall soil pH.

A few common micronutrient deficiencies are iron chlorosis and manganese deficiency. The leaves will be yellowing and will be greener along the leaf veins. The leaves or needles could also be stunted, not being able to grow to their full potential because they do not have the proper nutrients. If you are thinking your landscape plants may be experiencing nutrient deficiencies, please call our office. We offer soil testing and can explain what fertilizer and fertilization technique would be best for your landscape.

Scale Insects

To the untrained eye, a tree or shrub may look unhealthy or unsightly for no apparent reason. Upon closer inspection however, the culprit may be present in plain sight.

Scales are tiny insects that feed on plant sap, and certain species of scale may injure plants. In large numbers, scales may cause significant damage to trees or shrubs if left untreated. Because of their miniscule size, these insects may go unnoticed until it may be too late to revive a landscape plant. Monitoring visits are important in this regard, as technicians will visit customer landscapes with the changing seasons in order to be on the lookout for cryptic threats such as these.

There are two main types of scales, armored scales and soft scales. Armored scales produce a waxy, hard coating overtop of their bodies acting like a shell, protecting the insect from the environment. Euonymus scale, pine needle scale and oystershell sales are a few examples of armored scale. Armored scales can have several generations a year and usually spend the winter as eggs, first instar nymphs (first growth stage), or as a mature female (depending on species and location). Eggs usually hatch late May or early June. Once scales hatch from their eggs they are called crawlers. Unlike the adult scales, the crawlers are mobile insects which travel to the leaves to feed during the summer and migrate to the twig before the leaves drop in the fall. Using a long mouthpart called a stylet, which is usually 6 to 8 times as long as the insect itself, the straw-like stylet is inserted into the plant tissue to feed on sap. Once the crawlers produce the waxy, armored coating, they lose their legs and become immobile. If a plant is heavily infested with scale, not enough sap is left for the plant to maintain proper vigor for growing and the plant will begin to decline.

Soft scales, appropriately named are soft compared to armored scale, they do not produce a shell-like coating, merely a waxy, penetrable coating. They are generally larger in size than armored scales. A few examples of soft scales are cottony maple scale, magnolia scale and lecanium scale. Soft scales usually have only one generation per year and generally spend the winter as second instar nymphs (second growth stage), and remain attached to twigs. They complete their development in the spring when the females lay eggs. Soft scale eggs hatch later in the year than armored scales, usually in late June or early July. When soft scales feed on plant sap, also with a stylet, they produce a sugary liquid called honeydew. The honeydew attracts ants and flies. If scales are in large in number, there can be so many wounds on the tree or shrub that sap can drip, creating sticky sidewalks and landscapes. A black fungus called sooty mold eventually
also sets in to feed on the honeydew.

Here at Integrity Tree Services, we have had many phone calls from Tree & Shrub Care customers regarding their trees or shrubs looking unhealthy. Occasionally, upon inspection the culprit for the plants’ decline is scale. The significance in the scale infestation depends on the species of scale, the size of the population, the species and value of the plant the scales are affecting as well as other environmental factors. Not all scales are harmful to landscape plants. Scales usually feed on plants that are already stressed, however, it is perfectly normal for a tree or shrub in the landscape to house some scale. Scales have many predators in the landscape such as parasitic wasps, ants, lacewings, ladybugs, beetles and mites; an abundance of predators may not warrant chemical action. Sometimes, if simply a branch is infested, just pruning the branch can be enough to prevent infestation.

If a landscape plant has significant value, is heavily infested with scale and if natural predators are not abundant in the landscape, chemical control can help fend off scales. If you’re suspicious that scales are a reason for the decline of you tree or shrub, please feel free to call us to set up a free estimate with one of our certified arborists. Call (616) 301-1300 extension 118 to schedule an appointment. We can help determine if scale is present, if it is harmful to your landscape and if chemical treatments could be beneficial to the health of your plant. As usual, the easiest method
to prevent infestation is prevention. Keeping your landscape plants healthy with proper irrigation and maintaining optimum, growing conditions can make your plants more resistant to insect infestation.

Signs of Nutrient Deficiency

Now that new leaves and needles are out, you may be noticing something peculiar about them. It is common for trees and shrubs to experience nutrient deficiency, which is noticeable from the color or stunted size of the leaves or needles. Whether the tree or shrub is low on iron, manganese or any other type of micronutrient, more than likely you will be able to identify this by observing the leaves.

A micronutrient is required by plants in very small quantities, as opposed to macronutrients, such as nitrogen, phosphorous, calcium or sulfur, which are required by plants in large quantities. Plant tissues are made up of mostly macronutrients such as nitrogen, phosphorous and the others, therefore they are required by the plants in larger quantities. Micronutrients are minerals in the soil that are also required for healthy, stable plants. Micronutrients such as iron, manganese, silicon, copper and zinc are commonly present in the soil where a landscape plant is experiencing signs of nutrient deficiency, it is simply that when a soil has a high pH (is more alkaline as opposed to acidic), these micronutrients are in a form that cannot be taken up by plant roots.

Testing the soil pH can help determine whether or not a specific soil type will be suitable to easily sustain a tree or shrub. If a landscape plant is already established and is showing signs of nutrient deficiency, there are several fertilization techniques (micronutrient and macronutrient) that Integrity Tree offers that can temporarily strengthen the health of your plants. Temporary, meaning that the treatment will most likely be needed again the following season, as the micronutrient is applied for the plant and does not change the overall soil pH.

A few common micronutrient deficiencies are iron chlorosis and manganese deficiency. The leaves will be yellowing and will be greener along the leaf veins. The leaves or needles could also be stunted, not being able to grow to their full potential because they do not have the proper nutrients.

If you are thinking your landscape plants may be experiencing nutrient deficiencies, please call our office. We offer soil testing and can explain what fertilizer and fertilization technique would be best for your landscape.

How to Identify Your Oak Trees

Daylight savings, melted snow, brown grass turning green, tree buds swelling—these are all wonderful signs that spring is (hopefully) here. As the temperature in Michigan slowly begins to increase, the time approaches to discourage pruning oak (Quercus) trees. The Michigan Department of Natural Resources recommends avoiding oak pruning between April 15th and July 15th. Although wounding in oaks may be accidental such as severe storms breaking branches or animals scratching or pecking into the bark, oak wilt is most preventable if pruning ceases in spring and summertime.

Michigan climate does indeed vary greatly. Therefore, why between the dates April 15th through July 15th should oak trees remain undisturbed? It is not solely the wounding that makes the tree susceptible to oak wilt, it is the beetles that feed on the oak sap and transmit oak wilt fungal spores from an infected tree to a healthy tree. Mid-April is generally when the beetles become active and they remain active until mid-to-late summer, around July 15th. Although these dates are arbitrary, it does remind us that during this time of year oak trees are most susceptible to become infected with the oak wilt fungus. We recommend if you are going to use these dates, prune or trim your oaks either much earlier than mid-April or much later than mid-July to ensure beetles are not still active. If you’re ever skeptical about whether it is a proper time of year to trim your oaks, give us a call. We are more than willing to you determine whether the time of year is right. After all, once an oak (depending on the type of oak) is infected with oak wilt, unless treated immediately, it is likely to die within a few months to a few weeks.

Not all oak trees are extremely susceptible to oak wilt. While red oaks are extremely susceptible to oak wilt, white oak trees are much more resistant. If you’re thinking of planting oak trees on your property, depending on your soil type and landscape environment, we strongly recommend planting white oak trees since you will have a
better chance of having oak trees with long lives. For some reason unknown to scientists, the oak wilt disease progresses much more slowly in white oaks than it does in red oaks. Simple clues in identifying what type of oak tree you have are red oaks have pointed lobes and white oaks have rounded lobes. If you need assistance in identifying your oak tree, please send pictures of the oak leaf, bud, twig, bark and whole tree to KimB@integritytree.com along with your name and phone number.

If you have any questions about the oak wilt disease in Michigan or if you would like to know more, call us or visit the Michigan Department of Natural Resources webpage. Oak trees have more of a chance by prevention of infection and a part of prevention is sharing knowledge about oak wilt.

There’s A Fungus Among Us

With the spring finally here, we’re constantly thinking fungus. A wet spring brings about new growth coming on the trees, so we have to think about treating these trees for fungus. The trees that have struggled the last few years are evergreens, mainly spruce trees. Many of the trees we are seeing decline are the older, more mature trees. New research is showing that there is another type of fungal issue to watch for other than needle cast.

Phomopsis is a canker causing fungal pathogen known to cause branch death. We now know that a group of Phomopsis strains of unknown species are at the center of the current landscape spruce problems that we are now calling “Phomopsis spruce decline”. Normally, Phomopsis, a fungal pathogen, is only found on young trees in nurseries and on tree farms, including Christmas tree farms. For some unknown reason, this pathogenic fungus has moved out of the nurseries and tree farms and is now causing mature tree defoliation, branch death, and, in some rare cases, tree death. Phomopsis appears to cause these symptoms by establishing cankers (bark infections) on older branches, usually on the lower half of the tree. The cankers can be found somewhere on the large branches near the dying small branches extending from the branch. We have also found trees with severe defoliation throughout the trees but without too much branch death (terminal buds are still alive). This would look very similar to a true needle cast disease. Keep in mind that on spruce there are other cankers caused by other pathogenic fungi, such as Cytospora and Diplodia, but the predominant canker-causing pathogen currently appears to be Phomopsis. It may appear as a needle cast problem, but it is a canker disease and finding the canker without skinning all of the thin bark from the branch 
is difficult.

There is not much outward appearance to the canker infection. That is, there is little in the way of a sunken canker that can be observed without removing the bark. What we believe is occurring is a fungal infection that expands around the branch, girdling the current year’s sap-conducting vessels or phloem. As the fungus grows deeper into the resinous branch, the branch begins losing connections with the main stem and the needles begin to drop from the older portions of the branch outward. It is similar to cutting a branch off a tree and putting it in a vase of water. It will stay fresh for a while but, sooner or later, the nutrients and water resources are lost and the branch begins to fail and finally dies. This is why we are seeing so many spruce trees dropping needles which is followed by branch death. The progression of the symptoms will depend on how much of the branch is girdled by the canker caused by the Phomopsis infection and how long the infection has been in present on the tree.