Apple Scab

What is apple scab? Apple scab is a disease to Malus trees (apple and crabapple trees). This disease is caused by the ascomycete fungus Venturia inaequalis. I know you are thinking...WHAT? When we think of apple scab in Michigan we think of an apple that has the brownish black dents in them or the crabapples that look bare and sickly by mid-July. But, apple scab is much more than this. Apple scab can affect tree leaves, buds or fruits. This disease is not a serious threat to these plants. However, if the tree is infected numerous times it may become very weak and become more susceptible to other insect or disease pests.

Apple Scab is dependent on cool, wet weather and infects tree leaves in the spring. In the late summer to early fall, apple scab infections can produce secondary spores and create new infections which will continue to infect the tree during wet periods. Wind and rain carry apple scab spores from infected leaves to new growth on nearby trees where new infections begin.

Owen Tree Service offers fungicide treatments to ensure your trees will be protected from apple scab. If you think you may have an apple scab problem give Owen Tree Service a call. Fungicide treatments are applied as new leaves are developing in the early spring. These treatments are started in April and continue through early June to ensure your chance of having apple scab is minimal. Apple scab not only ruins perfectly good apples it also takes away the beauty of your ornamental crabapple trees. When crabapple leaves start turning a dingy brown, black color it’s hard to admire the beauty of these ornamental trees. We spend tons of money making sure our yards, trees, and plants look stunning, so why take the chance of having your crabapple trees bare for half of the summer.

BLACK VINE WEEVIL

Black vine weevil was brought to the US on European nursery stock back in the mid-1800’s. This leaf-feeding insect is well established now throughout the Flint, MI area wherever yews are used as a landscape plant. These small insects are rarely seen because they are nocturnal feeders, but the crescent-shaped gouges left in the shrub leaves they feed on can easily be found. Black vine weevil feeding damage on yew shrubs is sometimes hard to find as the dense foliage obscures the notches, but on rhododendrons, holly shrubs, Japanese pieris, and euonymus it is usually pretty easy to spot. 

Although it is the notches that black vine weevils create that attract our attention, it’s the larval damage to the roots of plants that should be of most concern. Adult black vine weevils emerge in the Flint area in May and June and feed until fall.  The grubs, which are the larval form of black vine weevil, feed on shrub roots and stems until the ground temperatures force them deeper into the soil to hibernate. 

Homeowners can take some simple steps to reduce black vine weevil grub survival. Keep landscape mulch from becoming too deep and don’t overwater your shrubs - especially in July and August when the newly hatched grubs are most active. High soil moisture and over mulching can lead to grub feeding on the stems of susceptible plants, and girdled stems lead to extremely stressed or dead shrubs. 

Spraying susceptible shrub species, starting in the early summer, is effective at controlling adult black vine weevil insects and limiting the amount of foliar damage to your shrubs. In the Flint area we start spraying for black vine weevil adults in June and recommend follow up treatments in July and August.

The most common plants attacked by black vine weevil are yew shrubs, rhododendron, holly shrubs, Japanese pieris, or euonymus. If you have these shrub species in your landscape you may want to have your plants checked for black vine weevil feeding damage.

Tree Removal in Flint, MI

Owen Tree Service received a call on January 29th to look at a tree for a homeowner in Flint. The home was in the area of Belsay Rd. and Carpenter Rd. The customer said that her 70 foot sugar maple was making noises and she was concerned because the tree was only 10 feet from her home.

When the Owen Tree arborist arrived at the location he inspected the tree and diagnosed the problem to be three 15 foot cracks in the 35 inch maple trunk on three different sides of the tree! The homeowner wisely decided to have Owen Tree Service remove the tree the following day before it fell on her home. This was a potential disaster waiting to happen.

Our tree removal crew quickly assessed that this would not be a normal tree removal due to the fact of not being able to have any shock load on the structure of the tree because of the weakened condition of the tree trunk. A shock load is when the weight of a tree limb or piece of wood is put on a rope that has been ran through a tree crotch or pulley that is attached to an opposite section of the tree to move the object from one side of the tree to the other. This technique is used in most cases when removing trees or tree limbs over a structure. 

                      Photo 1. One of the cracks in the tree trunk is visible on the left side of the photo.

The crew realized that the first order of business would be to stabilize the tree trunk to keep it together during the tree removal. This was done by using a 5 inch ratchet strap, a chain and binder, and large diameter rope to secure the trunk from splitting apart during the removal process. With this completed, the tree was stable and ready to be removed. The first task was to alleviate the weight in the top of the tree to lighten the stress on the three cracks that were in the lower trunk. Once this was done the crew was able to rig and rope the sections that were over the house.  

 

   

  

Photo 2 & 3. As soon as the ratchet strap was removed the tree trunk fell apart.

 

 Photo 4. The bottom of the tree trunk - looking towards the top of the tree.

This tree removal went very well thanks to the Owen Tree Service team whose experiences came together to make this job safe for everyone involved. A situation that could have been a fallen tree on a house ended up being a complicated, but uneventful, tree removal.

This particular job shows the importance of having periodic tree inspections performed by a qualified arborist. If you are concerned about the condition of any mature trees on your property contact us for a Hazardous Tree Assessment or learn more about hazardous trees at: http://www.owentree.com/Hazardous_Trees.html