9 LATE-SEASON LANDSCAPING TIPS

Tree & shrub spraying

1. Schedule pruning to promote good canopy structure and prepare trees for winter storms. This especially applies if you have oak or elm trees.

2. Aerate your lawn to reduce soil compaction, allow nutrients a better path into the soil and improve the root density of your turf.

3. Schedule dormant oil treatment to reduce overwintering insect populations.

4. Use hardware cloth or fencing to protect susceptible trees or shrubs from rabbit or mice damage over the winter.

5. Schedule a deep-root fertilization or soil amendment treatments to optimize fall root growth and development.

6. Give your evergreen plants one last deep watering before putting the garden hose away for the winter.

7. Schedule an anti-desiccant treatment to reduce moisture loss from evergreen trees and shrubs over the harsh winter months.

8. Burlap any plants that could suffer from salt spray, strong winds or deer feeding over the winter.

9. Remove any large accumulations of leaves that could cause turf dieback over the winter.

Oak tree pruning

CRABAPPLES LOSING LEAVES?

A common ornamental tree disease arborist’s encounter in Michigan is apple scab. This foliar disease infects crabapple leaves in the spring, but does not make itself apparent until later in the summer. After the apple scab fungus has infected enough of the crabapple leaf the leaf will fall from the tree.

Crabapple trees infected with apple scab usually start to show the effects of the disease between mid-June and early July. By August some crabapple trees may have even lost most of their leaves.

If your crabapple tree has lost a lot of its leaves from apple scab it is really not worth spraying the tree with a fungicide at this time. The disease is already in the leaf tissue and further apple scab infection is not going to be significant in the warmer and drier months of the year. Make sure the tree is receiving ample water and you may want to consider fertilizing in the fall to assure adequate nutrients are available to the tree.

The best way to prevent apple scab in the future is to apply a foliar fungicide spray in the early spring. Crabapple spraying for apple scab should start soon after the leaves begin to emerge. A couple follow up treatments will give you the best level of control.

To learn more about controlling apple scab click here:
http://www.owentree.com/Apple_Scab.php

Apple scab infection

 

WHY IS MY PINE TREE BROWN?

Shortly after summer temperatures become the norm pine trees affected by pine wilt start to turn brown. 

Scots pine killed by pine wilt. Photo: USDA Forest Service - 

North Central Research Station , USDA Forest Service, Bugwood.org 

Pine wilt is a disease of pine trees caused by Pinewood nematodes, a microscopic roundworm. Though all species of pines found east of the Rocky Mountains in the United States are hosts, Pinewood nematode is most commonly found on Scotch pine. Native pine tree species are resistant, with the nematodes being more of a problem on introduced species of pines.

Most often the first sign of pine wilt is the sudden decline and death of an entire pine tree, usually from the warmest part of the summer through the fall. The dead tree could retain its needles for as long as one year. Because the dead wood is dry it becomes very brittle.

Pinewood nematode is transmitted from tree to tree by pine sawyer beetles which overwinter as larvae in dead pines or pine logs which still have the bark attached. After pupating, the adult pine sawyer beetles, carrying nematodes in their tracheae, fly to healthy host pine trees where the nematodes enter through feeding wounds. Pinewood nematodes migrate to resin canals where they feed and rapidly reproduce. The resin canal system is damaged and water movement in the tree is disrupted. Once the pine tree dies the nematodes continue to feed and reproduce on blue stain fungus which infects the tree. In summer, female pine sawyer beetles carry nematodes as they fly back to dead pine wood where they lay their eggs. Eggs hatch and the larvae and nematodes overwinter together after which the cycle starts again. 

Pine sawyer beetles vector the nematodes that cause pine wilt. 

Photo: L.D. Dwinell, USDA Forest Service, Bugwood.org 

 Because decline and death of a pine tree infested with Pinewood nematode occurs very quickly, it is usually too late to save a single tree. If there is a group of pine trees on the site insecticide treatments can be done in an effort to save the remaining trees. Dead branches should be pruned from live trees to reduce the attraction of pine sawyer beetles. Any dead pine trees or firewood should be removed or destroyed. Do not use the mulch from an infested tree for mulch. When replacing dead trees choose species which are immune to pine wilt such as Norway or Colorado blue spruce, Douglas-fir, cedar, hemlock or white pine trees.

The International Society of Arboriculture certified arborists at Owen Tree Service are experts at recognizing pine wilt in both young and mature trees. If your think your browning pine tree might have pine wilt give our arborists a call. Our company was founded on tree and shrub care services. 

Blue stain fungus on pine logs. 

Photo: L.D. Dwinell, USDA Forest Service, Bugwood.org

 In addition to pest control services our experienced tree crews perform pruning trees or trimming shrubs and tree removal. Professional tree care services do not do topping of trees because of the harm it causes. Owen Tree Service can make trees smaller by proper crown reduction pruning.

Owen Tree Service provides lawn fertilization and weed control, in addition to insect and disease control for trees. We also have landscaping crews that can plant new trees or shrubs for you or apply organic mulch to freshen up your shrub beds.

GROUND COVER DISEASES

Three common ground covers used in Michigan are pachysandra, vinca/myrtle, and English ivy. Although mostly problem-free, on occasion they can be subject to disease problems. In most instances of diseases on ground covers a fungicide program in combination with good cultural practices can eliminate the problem.

 Pachysandra ground cover. 

Photo: Jil Swearingen, USDI National Park Service, Bugwood.org 

 Pachysandra. Volutella leaf and stem blight is the most common disease on pachysandra. The disease is usually promoted by excessive moisture for long periods of time. The fungus causes black blotches on the leaves and black cankers on the stem. To control Volutella leaf blight, avoid excess moisture from overhead irrigation. A fungicide spray program started in the spring can usually prevent the disease from spreading.

 Volutella blight on pachysandra ground cover plants. 

Photo: Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org 

 Vinca (periwinkle) ground cover. 

Photo: Jil Swearingen, USDI National Park Service, Bugwood.org 

 Vinca/Myrtle. Phoma stem blight is the most common disease of Vinca in Michigan. The fungus generally rots and girdles lower stems. Often the first symptom noticed by homeowners are wilted leaves as a result of girdled stems. Like Pachysandra, Vinca diseases will be minimized to some extent by avoiding excessive moisture, particularly in shaded areas of the landscape. Excess fertilization will also cause lush dense growth and greater susceptibility to the disease. Fungicide sprays will usually eliminate this ground cover disease over time.

 Phoma stem blight. 

Photo: Howard F. Schwartz, Colorado State University, Bugwood.org 

 English ivy. 

Photo: Jan Samanek, Phytosanitary Administration, Bugwood.org 

 English Ivy. Several fungal leaf spots and a severe Xanthomonas bacterial leaf spot are possible causes for brown or black spots on English ivy. Although bacterial leaf spot often has a yellow halo surrounding the dark lesion on leaves, the fungal and bacterial disease can appear similar. Moisture control is particularly important for the bacterial leaf spot. Fungicides may actually spread the bacterial disease but may inhibit the fungal leaf spots. A lab test may be warranted to confirm which disorder is affecting the plants. Where practical, infected leaves may be picked and destroyed.

 English ivy with bacterial leaf spot. 

Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

PINE ROOT COLLAR WEEVIL

Fallen pine tree damaged by pine root collar weevil. 

Photo: Manfred Mielke, USDA Forest Service, Bugwood.org

 Although this is more of a pest in Christmas tree plantations, every once in a while we come across pine root collar weevil damage on landscape trees.

Pine root collar weevil will attack both young and large pine trees. Host trees include Scotch pine, Austrian pine, red pine and occasionally white pine.

The larvae feed in the phloem tissue around the root collar, killing the cambium in the process. This girdling of the tree will eventually cause them to die. Pine trees weakened by root collar weevils may fall over and die one to four years after being attacked. Larvae complete development in June and July and adults emerge from July through September. After emerging, adults will feed on the trees for a short time before moving to sites to overwinter. Adult root collar weevils overwinter in the soil and in bark crevices.

It’s fairly easy to determine if your tree has been killed by pine root collar weevil. Dig around the base of the tree at the soil line. If it is root collar weevil, you will find black pitch-coated bark at the root collar and just beneath the soil. Digging around the tree you might even find yellow-white, C-shaped larvae up to a third of an inch long with an amber brown head.

 Pine root collar weevil damage at base of small pine tree. 

Photo: Steven Katovich, USDA Forest Service, Bugwood.org 

If pine root collar weevil is found then you should check around the base of any other pine trees on your property. Treatments can be made to reduce or prevent root collar weevil damage to your other pine trees.

There are two periods during the growing season when pine root collar control treatments can be applied. The first is with a soil drench around the base of the tree in mid-May. The next control window will be when the majority of emerging adults are active, mid-August to the first week in September. Apply insecticide to the foliage at this time.

Pine root collar weevil (pupal life stage) in its feeding tunnel. 

Photo: Joseph OBrien, USDA Forest Service, Bugwood.org  

GLOBS OF SAP ON PINE TREES

An often unnoticed insect pest that attacks pine trees is the Zimmerman pine moth. This tree borer often goes undetected because homeowners don’t think that the sap on the trunk of their pine tree is unusual. Another problem with finding Zimmerman pine moth damage is that the foliage of the pine tree conceals the damage from view.

Zimmerman pine moth isn’t as damaging as some tree borers in Michigan, but the feeding does disrupt the vascular system of the tree. Because this borer is often present where branches meet the trunk it is not unusual to have pine branches break because of Zimmerman pine moth feeding.

Spraying to control Zimmerman pine moth is done early in the spring. Most borer sprays for this tree insect are done in April, sometimes treatments can extend into early May if we have a cool spring.

You can learn more about Zimmerman pine moth at:
http://www.owentree.com/Zimmerman_Pine_Moth.php

Zimmerman pine moth damage on white pine tree

2016 FOREST HEALTH REPORT

The Michigan DNR has released an updated report on the health of Michigan’s forests. The report includes threats that could come from insect and disease pests.

While some of the pests discussed aren’t common in the landscape, there are several that could affect your landscape trees. Hemlock woolly adelgid, oak wilt and Asian longhorned beetle are three pests everyone in Michigan should be aware of and on the lookout for.

The report can be found at: http://www.michigan.gov/foresthealth

OAK WILT FOUND IN DETROIT

 The discovery of  oak wilt on Belle Isle in Detroit emphasizes the need to prune your oak trees during the dormant season.

Oak Wilt found in Detroit