Journalist @baltimoresun writer artist runner #amwriting Chaplain PIO #partylikeajournalist

Journalist @baltimoresun writer artist runner #amwriting Chaplain PIO #partylikeajournalist
Journalist @baltimoresun writer artist runner #amwriting Md Troopers Assoc #20 & Westminster Md Fire Dept Chaplain PIO #partylikeajournalist
Showing posts with label Ag Landscaping Plant Diseases. Show all posts
Showing posts with label Ag Landscaping Plant Diseases. Show all posts

Friday, May 04, 2007

20070503 MDA: Eastern Tent Caterpillars at Annoying Levels this Year

MDA: Eastern Tent Caterpillars at Annoying Levels this Year

Maryland Department of Agriculture News Releases

May 03, 2007

Unsightly Caterpillar No Threat to Trees

Eastern Tent Caterpillars at Annoying Levels this Year

ANNAPOLIS, MD – May 3, 2007 – One of the most visible signs of spring this year is the abundance of Eastern tent caterpillar (ETC) nests. This native insect gets its name from its familiar silken tents in roadside trees. Typically there are only one or two tents per tree; however, many trees this year are sporting multiple tents, causing residents to be concerned for the trees as the caterpillars eat all the leaves.

“Residents are noticing the nests and may experience an annoyingly large population of caterpillars in their yards in the next couple of weeks,” said Agriculture Secretary Roger Richardson. “While the Eastern tent caterpillar does eat the early leaves of trees and shrubs, the defoliation usually does little damage to trees, and rarely do trees die from an infestation.”

The lack of damage is due to the timing not the severity of the defoliation. Because the caterpillars hatch as soon as the young leaves unfurl in the spring, the tree has put little energy into the leaves and typically re-foliate in June, seemingly no worse for wear. The young caterpillars venture out to feed on leaves during the night and return to the tents for protection during the day. They will feed on most kinds of fruit trees, many hardwood trees such as ash, maple and oak, and other plants in the rose family, like ornamental crabapples and plums, and even pyracantha. Curiously, ornamental flowering cherry and pear (“callery pears”) both exotics, are left alone.

Homeowners concerned about particular plants may wish to keep an eye on them and consider EPA-approved insecticides before the caterpillars mature and are done feeding. The ETC finishes eating in mid- to late-May and leaves the tent to seek a place to spin a cocoon. By this time in the lifecycle, it is too late to use insecticides to control the fully grown tent caterpillars since most insecticides available to the public must be sprayed on leaves and ingested by the caterpillars to be effective. Mature caterpillars can easily be recognized by the solid white line down the middle of their back, and a pattern of blue markings on the sides. Later in the summer after laying eggs, the tent caterpillar emerges as a moth.

The Eastern tent caterpillar contrasts with the gypsy moths which finish consuming the leaves of oaks in early to mid June, after the leaves are fully developed. When heavy gypsy moth defoliation occurs, the trees are using depleted stores of energy to try to regenerate leaves and are vulnerable to other stress factors such as other insects and diseases, often leading to death of the trees. This is why the Maryland Department of Agriculture has had a gypsy moth suppression program for 25 years to control this exotic insect. Eastern tent caterpillars, on the other hand, are native to North America, do little damage to the trees, and their populations are eventually controlled by native predators, parasites and diseases and so there has been no statewide control program for eastern tent caterpillars.

For additional information, visit www.mda.state.md.us/go/tent.php.

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Wednesday, October 12, 2005

20051012 Evergreen Tree Canker Diseases

Evergreen Tree Canker Diseases

Downloaded 20051012


http://www.agnr.umd.edu/USERS/HGIC/diagn/needle/evergreen_cankerdiseases.html


A large number of cankers occur on evergreens that cause dieback. These are more common on stressed trees planted in marginal sites or infect poorly maintained trees. Young cankers are slightly darker in color than adjacent bark and appear slightly sunken.


As cankers enlarge they kill the living woody tissue within the trunk or branch. Canker growth may cause the bark along the edges to crack and fall away, exposing the dead wood underneath. After a canker enlarges enough to girdle a branch or trunk, the portion beyond the canker dies. Small twigs are killed more quickly than larger branches. Symptoms may include progressive upper branch dieback, disfigured branch growth, or target shaped areas on trunks with concentric rings of dead bark.

Seiridium Canker

Seiridium canker is a fungal disease that can attack cypress and junipers. The most common landscape plant in Maryland that is infected is Leyland cypress.


This disease is caused by the fungus Seiridium cardinale. The first symptoms usually appear in the spring or early summer, as a fading or yellowing of the foliage on branches, or the tops of trees. These symptoms gradually lead to browning of affected parts. The fungus causes girdling lesions around the bases of branches or main stems, and these lesions characteristically exude large amounts of resin. Trees may be killed if many small cankers occur or if large enough to girdle the main stem. The reproductive spore forming structures (acervuli) appear as small black dots embedded in the bark near the canker margins. During wet weather the infective spores are dispersed by rain, but they can also be spread by wind, insects and pruning tools.


Management: There are no chemical controls for this disease. The best strategies for disease prevention are avoiding stresses to the plants. Provide adequate water during dry periods, avoid over crowding of trees, and don't over mulch or plant too deeply.

Cytospora canker

A common canker disease of both blue and Norway spruce trees is Cytospora canker. Typical symptoms include poor growth, profuse sap flow and pitch accumulation (white resin patches) on lower branches, and eventual dieback of lower branches. Diagnostic symptoms are revealed after cutting into pitch coated bark and finding dark resin soaked wood along with small black dots just under the bark. These small black dots, are the spore producing structures. In wet weather, the infectious spores ooze out as small yellowish threads, that can be spread by rain to other branches in the tree.


Management strategies: There are no chemical controls for cankers and they cannot be stopped once they become extensive. Pruning off affected branches back to healthy wood is the only control measure available. Drought stressed trees should be watered during dry weather to promote better tree vigor.

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Agriculture Nursery Stock and Landscaping Plant Diseases