Understanding invasion history: genetic structure and diversity of two globally invasive plants and implications for their management

Aim Resolving the origin of invasive plant species is important for understanding the introduction histories of successful invaders and aiding strategies aimed at their management. This study aimed to infer the number and origin(s) of introduction for the globally invasive species, Macfadyena unguis‐cati and Jatropha gossypiifolia using molecular data. Location Native range: Neotropics; Invaded range: North America, Africa, Europe, Asia, Pacific Islands and Australia. Methods We used chloroplast microsatellites (cpSSRs) to elucidate the origin(s) of introduced populations and calculated the genetic diversity in native and introduced regions. Results Strong genetic structure was found within the native range of M. unguis‐cati, but no genetic structuring was evident in the native range of J. gossypiifolia. Overall, 27 haplotypes were found in the native range of M. unguis‐cati. Only four haplotypes were found in the introduced range, with more than 96% of introduced specimens matching a haplotype from Paraguay. In contrast, 15 haplotypes were found in the introduced range of J. gossypiifolia, with all invasive populations, except New Caledonia, comprising multiple haplotypes. Main conclusions These data show that two invasive plant species from the same native range have had vastly different introduction histories in their non‐native ranges. Invasive populations of M. unguis‐cati probably came from a single or few independent introductions, whereas most invasive J. gossypiifolia populations arose from multiple introductions or alternatively from a representative sample of genetic diversity from a panmictic native range. As introduced M. unguis‐cati populations are dominated by a single haplotype, locally adapted natural enemies should make the best control agents. However, invasive populations of J. gossypiifolia are genetically diverse and the selection of bio‐control agents will be considerably more complex.     

Biological control of a fungus Ustilaginoidea virens causing false smut of rice

BioControl - False smut caused by the flower-infecting fungus, Ustilaginoidea virens has become an important disease of rice seriously hampering production worldwide. An experiment on the...     

Achieving Brownfields Clean Up at a Radium-Contaminated Site

One of the U.S. Army Corps of Engineer's (USACE) primary goals in the management of removal actions is to safely implement work activities and cost effectively clean up sites contaminated with residual radioactive materials. The US ACE has successfully pursued a removal action under the Brownfields Initiative at the Cuneo Press Site in Chicago, Illinois. The residual radioactive contamination at the site exceeded background radiation levels for the Chicago area. Residual quantities of Radium-226 (Ra-226) were detected during preremoval characterization surveys performed at the site. The aggressive removal action performed at the site demanded immediate and accurate radiological screening and exposure data. Radiological screening consisted of field monitoring using portable instruments and gamma spectroscopy analysis for Ra-226. The screening data provided verification of compliance to the off-site disposal facility waste acceptance criteria and the site clean up criteria. The screening data, along with the application of guidance presented in NUREG-1575, “Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)”, demonstrated that the removal action meet clean up criteria established by the Illinois Nuclear Regulatory Commission and the USACE.