Phoradendron - Disease Cycle

Disease Cycle

Phoradendron is a hemiparasite, meaning that it produces its own chlorophyll, but relies on the host plant to provide water and essential elements for growth and survival. Birds are the primary means of dispersal of the plant parasite. Birds consume the seeds inside of the fruits of leafy mistletoe, also called drupes, and excrete or regurgitate the seeds onto the branches of which the birds perch. Germinating seeds produce a radicle, a holdfast, and eventually the germinated seeds produce haustoria. The haustorium is a root-like structure that penetrates the host plant's bark and cambium, reaching the xylem and phloem where the haustorium extracts water and minerals, primarily carbon and nitrogen compounds, from the host tree or plant. The most important birds for effective dispersal include cedar waxwings, euphonias, silky flycatcher, bluebirds, thrushes, robins, and solitaires.