Tree Infection Process In American Mistletoe (Phoradendron serotinum)

<br /><br /> The life cycle of the American mistletoe (Phoradendron serotinum) occurs in the plain sight of everyone in the Southeastern United States. This mistletoe is a common parasite found in trees growing in open areas, around buildings, along forest edges, and in disturbed areas. This publication was prepared to help people understand how mistletoe infects trees. Only by understanding the infection process can we understand tree symptoms and potential treatment regimes. As in many plant lives, mistletoe begins life as a seed. The seed is delivered / deposited on a tree twig.&nbsp; <br /><br /> A mature mistletoe seed lives for only a short time, being prone to drying out and to fungal attack. In addition, mice and ants remove seeds from tree surfaces. A germinating mistletoe seed is extremely vulnerable on the open surface of the twig. Most seeds die within the first day outside their fruit covering. Light is needed to stimulate seed germination. The top portion of the embryo (the cotyledons) begin to develop chlorophyll but stay stuck down to the twig attached with dried viscin. As the top is held firm, the radicle (embryonic root) expands and curves away from light (negative phototropism) which pushes it into the twig. The radicle is well developed except it has no root cap. Gravity or gravitropism does not appear to have any impact on growth of the radicle.<br /><br /> [FOR03-008]<br /><br />

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