Specific Surveillance and Delimiting Survey of Ambrosia psilostachya in Tumkur District of Karnataka, India

An obnoxious ragweed was reported to occur in Tumkur district of Karnataka and was later identified as Ambrosia psilostachya DC, an invasive weed of Mexican and Northern American origin. The weed is of quarantine significance to India and regulated as quarantine weed under Schedule VIII of Plant Quarantine Order, 2003 and is known to be highly invasive in its native and introduced range. A delimiting survey was conducted for A. psilostachya with an objective to gauge the extent of its spread, arrest further spread and plan for its eradication. The mapping of infested area was carried out through delimiting survey employing Global positioning system (GPS) and other tools. The spread of the weed was found confined between N 13° 08´656½ to N 13° 11´189½ and E 76° 40´ 759½ to E 76° 42´ 426½. A three kilometre buffer zone surrounding the delimited zone was also created. Necessary awareness was created among stakeholders and a score of surveillance activities were conducted. Recommendations are given based on the survey and research findings to eradicate the weed when it is still amenable for eradication.