Pest Activity -- June 12, 2009
Pest Activity
> June12
Welcome to the Woody Ornamental Pest Scouting Report for Western Pennsylvania
brought to you by Penn State Cooperative Extension. This report is updated weekly with growing degree day counts and insect activity
through the end of June. If you would like an email copy of this report,
send your request to
rab147@psu.edu.
As of June 12,
the following growing degree days with a base temperature of 50 degrees
have accumulated.
| Uniontown |
|
Armstrong |
|
| Verona |
930 |
Franklin |
|
| Wexford |
664 |
Mercer |
|
| Butler |
614 |
Waterford |
|
| |
|
Erie |
536 |
Pest Activity
Anthracnose
 |
Ash anthracnose is active in the Pittsburgh area due to the wet weather. |
|
Azalea Lace Bug
 |
Azalea lace bug adults continue feeding in the Pittsburgh area this week. |
Fact
Sheet
|
Black Wine Weevil
 |
Black vine weevil adults should be active at this time. Sprays to manage adults will reduce the number of damaging larvae feeding on the roots and stems of susceptible rhododendrons and yews. |
Fact
Sheet
|
Boxwood Psyllid
 |
Although the cupped leaves characteristic of boxwood psyllid feeding remain evident on affected plants, the actual insects are gone and it too late to apply control measures for this season. Applications of neonicotinoid insecticides in October or November of 2009 will prevent cupping of new growth next spring. |
Fact
Sheet
|
Calico Scale
 |
Calico scale crawlers were observed on a sample submitted to the Extension office from downtown Pittsburgh. |
Fact
Sheet
|
Euonymus Scale
 |
Euonymus scale crawlers appear to have settled and begun feeding. A second generation of crawlers should be active in late August. |
Fact
Sheet
|
Fourlined Plant Bug
 |
Fourlined Plant Bug adults remain active this week. They should be laying eggs and dying off soon, and we will be finished with their damage for the year. |
Fact
Sheet
|
Juniper Scale
 |
Juniper scale crawlers appear to have settled into place and have begun feeding on infested junipers in the Pittsburgh area. |
Fact
Sheet
|
Pieris Lacebug
 |
Pieris Lace Bug adults continue actively feeding on Japanese pieris and mountain laurel in Pittsburgh at this time.
|
Fact
Sheet
|
Pine Spittlebug
 |
Pine spittlebugs were observed in Oakmont this week. They are more of nuisance than truly damaging. They can be removed from trees near patios and decks with a sharp spray of water from a garden hose. |
Fact
Sheet
|
Spruce Spider Mites
 |
Spruce Spider Mites remain active in Pittsburgh this week. They seemed to disappear during the colder weather we had over the last few weeks, but they are back with a vengeance. The site where I scout in Pittsburgh has hemlocks growing near a fence – the mites had spread webbing from an infested branch to encircle the top panel of the fence. Maybe we should change the name to wrought iron spider mite! |
Fact
Sheet
|
Others:
Emerald ash borer adults are active now. EAB has now been positively identified in Allegheny Township, Westmoreland County. As of June 10, 2009, Westmoreland County was added to the quarantine imposed by the Pennsylvania Department of Agriculture.
This introduced pest has been found previously in Allegheny, Beaver, Butler, Lawrence, Mercer and Mifflin counties. The movement of ash nursery stock, green lumber, logs, wood chips and all firewood out of those quarantined counties is prohibited.
Recent research indicates imidacloprid is not as effective on trees over 15-inches DBH at the current label rate; Bayer is applying to the EPA for a doubling of the current label rate to overcome this limitation. Trunk injected emamectin-benzoate (TREE-age) has demonstrated excellent control in both large and small trees, and appears to provide two years of protection.
Apple scab continues to develop on susceptible crabapples in the Pittsburgh area. This fungal disease is characterized by yellowing leaves that drop prematurely. Resistant cultivars of crabapples include Adams, Callaway, David, Dolgo, Harvest Gold, Indian Summer, Jewelberry, Liset, Profusion, Red Baron, Selkirk and Sentinel.
Fire blight was observed on ornamental pear trees in Oakmont and Gibsonia this week. Blackened, wilted shoots with dead leaves that remain attached are characteristic of fire blight infection.
Hawthorn lace bugs continue to feed on cotoneaster and serviceberry this week.
Mountain ash sawflies were observed feeding on European mountain ash this week.
Oak Leaf Blister continues to develop in the Pittsburgh area. Cool, wet weather in spring favors development of this disease. It is most common on members of the red oak group, including red oak, pin oak, and black oak. Fungicides applications are rarely warranted, and it is too late now to spray for this disease. Fungicides must be applied at bud break.
The causal fungus (Taphrina caerulescens) is closely related to the fungus that causes peach leaf curl (Taphrina deformans).
A mating pair of redheaded ash borers was observed on a dead sugar maple in South Park this week. This native insect attacks newly planted or stressed trees, and does not limit itself to ash trees. Elm, lilac, mulberry, maple, hackberry, oak, sweetgum, linden, honeylocust, crabapples and others are also susceptible. Redheaded ash borers are common pest of cut firewood. Irrigation during dry periods and fertilization to maintain tree vigor can help protect landscape trees from this insect.
Rose black spot continues to develop on susceptible roses due to the frequent rain.
Viburnum leaf beetle damage has been observed on arrowwood viburnums in Oakmont. Yours truly missed seeing the actual larvae, but the damage is typical of the species. They are pupating now, and adults should be active by mid-July. Viburnum leaf beetles overwinter as eggs in the twigs of susceptible viburnums. Prune out egg-containing twigs from October through March before egg hatch to reduce damage from this introduced pest next year.
Viburnums that appear resistant to damage include Viburnum x burkwoodii, V. carlesii, V. plicatum var. tomentosum, V. x juddii, V. lantana and V. rhytidophyllum. Those most susceptible include Viburnum acerifolium, V. dentatum, V, opulus, and V. trilobum.
The next scouting report will be on June 19.
