The invasion of an exotic dodder in Houston, TX

Abstract

In the summer of 2001, Cuscuta japonica Choisy, a dodder species native to east Asia, was observed in Houston, TX. This plant parasite was found at five locations in the city. The infected hosts were live oak (Quercus virginiana Mill.), waxleaf ligustrum (Ligustrum japonicum), crape myrtle (Lagerstroemia indica), Chinese tallow (Sapium sebiferum) and Chinese photinia (Photinia serrulata). Sites consisted of planted hosts on residential and commercial plantings. Vines were found flowering but no seeds were produced. The parasite was originally thought to be giant tree dodder (C. exaltata), a less aggressive native species. Asian dodder is listed on the Federal Noxious Weed list. There have only been a few previous introductions of C. japonica in the U.S. The source of the Houston outbreak is unknown. A program based on the use herbicides, host removals, eradicative pruning, burning of infected plant materials, and long-term monitoring is underway.