What's That Bug? does not endorse extermination

Subject: Cocoon
Location: Westminster Maryland
April 3, 2016 10:43 am
In pine tree
Signature: Barry

Cedar Apple Rust Gall

Cedar Apple Rust Gall

Hi Barry,
This is not a cocoon.  It is a Gall.  According to Wayne’s Word:  “Galls are caused by many organisms living on plants, including insects, mites, mistletoe, fungi and bacteria.”  This marvelous website continues with “The mysterious origin of strange growths on the stems, leaves, flowers and roots of plants have intrigued naturalists for centuries. Called galls or hypertrophies, these tumorous (neoplasmic) outgrowths develop from rapid mitosis and morphogenesis of plant tissues and come in an astounding array of colors, shapes and sizes. Galls may be smooth, spiny or fuzzy, and resemble everything from marbles and ping-pong balls to dunce caps, saucers and sea urchins. Many galls provide the food and brooding structure for various species of harmless insects.”  The Propaedeuticist makes up in images what it lacks in information regarding your particular Gall, the Cedar Apple Rust Gall,
Gymnosporangium juniperivirginianae.  The Missouri Botanical Garden also refers to two additional, closely related species of fungus in stating:  “All three rusts can infect most varieties of eastern red cedar (Juniperus virginiana) as well as many other junipers and an alternate host. Of these alternate hosts, cedar-apple rust is primarily a disease of apples and crabapples. Cedar-hawthorn rust, in addition to affecting apples and crabapples, sometimes infects pears, quince, and serviceberry. Cedar-quince rust has the broadest host range and can infect many genera in the rose family. In addition to those plants already mentioned, mountain-ash, flowering quince, cotoneaster, chokecherry, and photinia are also hosts for this disease.”  Your tree is a cedar, not a pine.  The Missouri Botanical Garden site also states:  “Symptoms on juniper: Brown, perennial galls form on twigs. When mature (usually in two years), the galls swell and repeatedly produce orange, gelatinous telial horns during rainy spring weather. The galls of cedar-apple rust are often over 2 inches in diameter, while cedar-hawthorn rust galls are rarely over 2 inches in diameter. Occasionally the twig beyond the gall dies, but usually no significant damage occurs on the juniper host.”  If you or a neighbor has an apple orchard, there may be additional cause for alarm as the site states as the leaves of apple trees are affected, according to the Missouri Botanical Garden, when:  “Circular, yellow spots (lesions) appear on the upper surfaces of the leaves shortly after bloom. In late summer, brownish clusters of threads or cylindrical tubes (aecia) appear beneath the yellow leaf spots or on fruits and twigs. The spores associated with the threads or tubes infect the leaves (needles) and twigs of junipers during wet, warm weather.”

What's That Bug? does not endorse extermination
Location: Maryland
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