Abstract
S. elaeagnifolium is a deep-rooted summer-growing perennial plant, native to the Americas, but now widely naturalized beyond its native range in extra-tropical regions. It is considered a tenacious weed in many arid to semi-arid places including India, Australia, South Africa, the Pacific Islands, and the USA (Holm et al., 1979; Wagner et al., 1999; Randall, 2012; USDA-ARS, 2014). It is known to be invasive in Cuba (Oviedo-Prieto et al., 2012) and Hawaii (PIER, 2014), a principal weed in India (Holm et al., 1979), and an agricultural weed in Java (Randall, 2012). It has been declared a noxious weed in the U.S. states of Arkansas, California, Idaho, Nevada, and Washington, and an "A" designated weed for quarantine in Oregon and Washington (USDA-NRCS, 2014). The species competes with crops, interferes with livestock, acts as a host for insects and plant diseases, and spreads by forming dense colonies from its extensive root system as well as by propagation of seeds (Boyd et al., 1984; Wagner et al., 1999; EPPO, 2007; PIER, 2014). The species is difficult to control without chemicals (UC Davis Weed Research and Information Center, 2013) and it is essential to keep it out of uncontaminated areas (EPPO, 2007). The species is known to be toxic to cattle, causing damage to intestinal tract and nervous systems and, in severe cases, can cause hallucinations, paralysis, and death (Mas and Lugo-Torres, 2013).