Emerald Ash Borer is a current concern in southeastern Pennsylvania. The insect has migrated from the midwest, where it devastated over 20 million Ash trees in Michigan, Indiana, Illinois and Ohio. It was found in western Pennsylvania in the summer of 2007 and again in June of 2008 in a county adjacent to the original PA infestation. It was just discovered this February in Mifflin County PA. Its spread eastward is almost inevitable. You should be concerned if you have one or more large, specimen Ash trees on your property. There is a preventative treatment which has shown great promise in protecting trees as long as it is done at the proper time and probably yearly. It is hard to estimate when Emerald Ash Borer will show up in our area but you should educate yourself about this pest and its symptoms. Detailed information can be found on www.emeraldashborers.com.
Bacterial Leaf Scorch (BLS) is probably the single most important shade tree disease currently facing many areas of the country today. Some have stated that it may become the major shade tree disease for the new millennium. The disease is caused by a bacterial pathogen named Xylella fastidiosa. The primary hosts include the Red Oak and Pin Oak. Other Oaks that are confirmed hosts include Scarlet, Shingle, Bur, Laurel and Water. The chronic effects on infected tree crowns are similar to that seen from severe soil compaction. The slow and gradual decline of an infected tree is caused by the limited uptake of water to the crown. During early stages of infection, brown leaf scorched symptoms typically affect a small area of the crown (e.g. a single branch). Usually the scorch symptoms initially show up late in the season (late July or August). As the years go by, other areas of the crown are often progressively affected. Often it takes only 3-5 years for the entire crown to show symptoms. It typically requires about 10 years for a diseased tree to lose most of its aesthetic value. Early defoliation in September on affected Oaks is another good indication for the possible presence of this disease, since Oaks typically hold their leaves well into November/December. During the early years of infection this symptom does not necessarily indicate the branches are dead, since they often leaf-out again the following year.
This insect has recently been found in Bucks County. It attacks many varieties of evergreens including Arborvitae, Japanese Cedar, Juniper and Hinoki Cypress. Japanese Cedar Longhorned Beetles are considered a secondary pest problem in that they prefer to feed on trees already weakened by other problems such as drought stress. The larvae kill the tree by feeding on the nutrient-conducting tissue of the tree, eventually cutting it off completely. The adult insect leaves oval-shaped exit holes in the bark. Treatment is available. Call us if you are concerned or suspect a problem.
As the season progresses, discoloration on your Azalea or Andromeda leaves could mean that you have an infestation of Lace Bug. The leaves will appear "mottled" and yellowish in color. This insect does damage by sucking the nutrients out of the leaves. It is easily controlled with a properly timed treatment. Call us if you need help!
Many Hollies and Azaleas have been affected recently by Scale insects. Cottony Camellia Scale is being seen on many Hollies on the underside of the leaves. Azalea Bark Scale is active on Azaleas, Andromeda and Rhododendrons on the stems of these plants. Both insects appear as white "fluff" which protects hundreds of eggs. Yellowing and dropping leaves are common symptoms of these pests. Black "soot" on the leaves and stems of the plants is also an indicator of a Scale infestation. The Scale insects secrete a substance called "honeydew" which is clear and sticky. After some time, the sticky honeydew becomes covered with the black "sooty mold". Bees and flying insects are also very attracted to the honeydew. Call us for an estimate for treatment of these problems.
Do the leaves on your hawthorn trees look blighted? Have you been watering the tree because you thought the scorched leaves were due to drought? You need to look more closely at those leaves. Hold a leaf up to the light and you may see that they have been 'mined' by a sawfly insect pest called Hawthorn Leaf Mining Sawfly. Call us if you need treatment.
If so, they could be suffering from an attack of the Spruce Spider Mite. These are cool season insects that cause discoloration of the needles of your evergreens. Take note of which needles are discolored...inner needles browning are a sure sign of Mite infestation.
We are seeing alot of Boxwood Leafminer on all varieties of Boxwoods in southeastern PA. The insect burrows between the layers of the Boxwood leaves causing blistering and discoloration. If you bend a leaf infested with the insect, you can break open layers and see the small, orange/yellow larvae crawling around inside. Treatment can be done with soil injection (recommended) or spray application. Check out our pest alert on this problem click here.
