Tuesday, August 14, 2012

Elytroderma deformans will make a witch's broom in time for Halloween

I just wrote a blog post about the tree disease, dwarf mistletoe.  Dwarf mistletoe is a quick killing disease that affects pines and spruce and is often confused with elytroderma defromans or elytroderma needle cast.  Elytroderma deformans is a needle disease that often causes witches brooms in ponderosa pine. It is sometimes mistakened for dwarf mistletoe. The disease is restricted to "hard" or "two- and three-needle" pine species. Elytroderma needle cast has also been reported in North America on lodgepole, big-cone, jack, Jeffrey, knobcone, Mexican stone, pinyon, and short-leaf pine.

Elytroderma needle cast can be diagnosed through these easily identifiable signs and symptoms.  Needles begin to fade in the fall of the year of infection, and by late winter are lighter in color than uninfected needles. By spring, the infected needles turn straw color as the new needles break bud. The fruiting bodies are elongated (average 10 mm in length) and black when visible on dead needles. Distinctive “witches’ brooms” are formed by the sprouting of epicormic buds. Resin cysts can be found in infected twigs.

Biology:  Spores initially infect new needles through the epidermis following bud break, but infection can continue into the fall until temperatures are too low for spore germination and growth. There are two types of spores: one spore is spread by water and the other is spread by wind. Discharge of spores occurs during and after a rainstorm, when new needles are probably most susceptible to infection. The fungus spreads throughout the needles and into twigs before the needles are killed. When twigs become infected, the fungus can perennially infect needles on the same twigs. Conditions conducive to needle infection by spores only have to occur once, after which the disease can progress within the infected tree.

Figure 187. Cambium of infected branch has pockets of dark resin.Effects:  Although elytroderma needle cast is known as an occasional disease of ponderosa pine in the Southwest, it is common in some areas. In mature trees, if less than one-fourth of the branches are infected there is little or no effect on the tree, but if more branches are infected, needle cast alone can kill a tree or predispose it to attack by bark beetles.

Similar Insects and Diseases:  The witches’ brooms produced by elytroderma needle cast are similar to those caused by dwarf mistletoe, however, the existence of dead second year needles are indicative of needle cast and not dwarf mistletoe infection. Elytroderma is the only needle cast that is perennial.


If you are concerned about your trees for any reason, please contact Trees "R" Us, Inc.  Trees "R" Us, Inc. has 4 certified arborists in their plant health care division that are well trained on how to give your trees and plants the proper care they need.  Contact us for an analysis of your trees and plants.


Trees "R " Us, Inc. is proud to educate our communities on proper tree care and maintenance.

It is through education that we really save trees and help the environment.  We hope you found this post informative and educational. 
Trees "R" Us, Inc. is a professional tree service for the Chicago's North Shore, North and Northwest suburbs.  Tree trimming, tree removal, stump grinding, fertilizations, tree disease treatments and prevention as well as plant health care are just a few of our high quality, professional services.  Contact us today for a free analysis or quote at www.treesrusinc.com or at 847-913-9069.
Thanks for reading,
Nick

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