Carrasco L.R.,Imperial College London |
Carrasco L.R.,UK Environment Agency |
Harwood T.D.,Imperial College London |
Toepfer S.,CABI Europe |
And 7 more authors.
Annals of Applied Biology | Year: 2010
Europe is attempting to contain or, in some regions, to eradicate the invading and maize destroying western corn rootworm (WCR). Eradication and containment measures include crop rotation and insecticide treatments within different types of buffer zones surrounding new introduction points. However, quantitative estimates of the relationship between the probability of adult dispersal and distance from an introduction point have not been used to determine the width of buffer zones. We address this by fitting dispersal models of the negative exponential and negative power law families in logarithmic and non-logarithmic form to recapture data from nine mark-release-recapture experiments of marked WCR adults from habitats as typically found in the vicinity of airports in southern Hungary in 2003 and 2004. After each release of 4000-6300 marked WCR, recaptures were recorded three times using non-baited yellow sticky traps at 30-305 m from the release point and sex pheromone-baited transparent sticky traps placed at 500-3500 m. Both the negative exponential and negative power law models in non-log form presented the best overall fit to the numbers of recaptured adults (1% recapture rate). The negative exponential model in log form presented the best fit to the data in the tail. The models suggested that half of the dispersing WCR adults travelling along a given bearing will have travelled between 117 and 425 m and 1% of the adults between 775 and 8250 m after 1 day. An individual-based model of dispersal and mortality over a generation of WCR adults indicated that 9.7-45.3% of the adults would escape a focus zone (where maize is only grown once in 3 consecutive years) of 1 km radius and 0.6-21% a safety zone (where maize is only grown once in 2 consecutive years) of 5 km radius and consequently current European Commission (EC) measures are inadequate for the eradication of WCR in Europe. Although buffer zones large enough to allow eradication would be economically unpalatable, an increase of the minimum width of the focus zone from 1 to 5 km and the safety zone from 5 to 50 km would improve the management of local dispersal. © 2009 Association of Applied Biologists.
Rauth S.J.,Colorado State University |
Hinz H.L.,CABI Europe |
Gerber E.,CABI Europe |
Hufbauer R.A.,Colorado State University
Biological Control | Year: 2011
Incorporating population genetics into research on candidate biological control agents can help improve the safety and success rates of biological control of weeds. As a case in point, the population structure of Ceutorhynchus scrobicollis, a candidate agent for garlic mustard (Alliaria petiolata) in North America, was evaluated using mitochondrial sequence data and amplified fragment length polymorphisms (AFLPs). The region surrounding Berlin, Germany, from which individuals have been collected for host-specificity tests, was examined to determine whether individuals from this area constitute one or more populations, to estimate numbers of individuals required to capture 90-99% of the diversity in AFLPs within the region, and to evaluate dispersal capabilities. Significant differentiation of C. scrobicollis between sites was observed, however most (94%) of the genetic diversity was found within sites. The area around Berlin appears to be a network of connected subpopulations. Estimates for the number of individuals needed from the focal area to capture 90% and 99% of the diversity present in AFLP loci were 10 and 27. Assignment tests indicated that while few individuals disperse, some move up to 65. km. Inclusion of more distant samples from Romania and Georgia revealed substantial genetic differentiation between them and German samples. These areas might therefore be useful to explore further should populations with different ecological characteristics be sought. These findings increase confidence in host-specificity tests, which incorporated more than 4000 individual weevils from the Berlin area, provide guidance for eventual release strategies, and illustrate how basic population genetic data can be incorporated into biological control programs to increase safety and efficacy. © 2010 Elsevier Inc.
Gaskin J.F.,U.S. Department of Agriculture |
Schwarzlander M.,University of Idaho |
Williams III L.,U.S. Department of Agriculture |
Gerber E.,CABI Europe |
Hinz H.L.,CABI Europe
Biological Invasions | Year: 2012
Perennial pepperweed (Lepidium latifolium L.) is a Eurasian plant species that is invasive in North America. The invasion often forms large, dense monocultural stands. We investigated the genetic diversity along transects in dense populations in the western USA using Amplified Fragment Length Polymorphisms. We also analyzed transect collections from the native Eurasian range for comparison. In addition, we conducted crossing studies to determine possible modes of seed production (sexual outcrossing vs. self-fertilization vs. apomixis). In our study of seed production we determined that self-fertilization and outcrossing both produce germinable seed in perennial pepperweed. Genetic diversity in the USA was unexpectedly low, with only three genotypes in 388 plants, and those three had genetic similarity of ≥98%. Up to 97% of the plants from Turkey and Russia transects were unique genotypes, while <4% of USA plants in a transect were unique. This lack of diversity in the USA samples suggests that perennial pepperweed, despite its success as an invader, is not well-positioned to adapt to new selective pressures, or to recruit pre-adapted genotypes that may vary in resistance or tolerance to disease or herbivory. Because 99% of the USA plants were genetically identical, we were unable to determine if increases in stand size were due to spread by rhizomes or seed derived from outcrossing between genetically identical parents or self-fertilization, as each of these methods produces shoots genetically identical to parental plants. © 2012 Springer Science+Business Media B.V. (outside the USA).
Senkardesler A.,Ege University |
Buyck B.,French Natural History Museum |
Hofstetter V.,Station de Rechercheagroscope Changins Wadenswil |
Verberen A.,Ghent University |
And 24 more authors.
Mycotaxon | Year: 2010
Formal proposals to conserve or protect fungal names as well as proposals to amend the INTERNATIONAL CODE OF NOMENCLATURE of immediate interest to mycologists are now published concurrently in MYCOTAXON and TAXON. Conservation proposals include Prop. 1918 (to conserve the name Dermatocarpon bucekii against Placidium steineri), Prop. 1919 (to conserve the name Lactarius with a conserved type), Prop. 1926 (to conserve the name Cladia against Heterodea, and Prop. 1927 (to conserve the name Agaricus rachodes with that spelling). Props. 117-119 to amend the CODE ask for pre-publication deposit of nomenclatural information in a recognized repository for valid publication of fungal names.
Hernandez-Vera G.,University of East Anglia |
Mitrovic M.,Institute for Plant Protection and Environment |
Jovic J.,Institute for Plant Protection and Environment |
Tosevski I.,CABI Europe |
And 2 more authors.
Molecular Ecology | Year: 2010
Plant feeding insects and the plants they feed upon represent an ecological association that is thought to be a key factor for the diversification of many plant feeding insects, through differential adaptation to different plant selective pressures. While a number of studies have investigated diversification of plant feeding insects above the species level, relatively less attention has been given to patterns of diversification within species, particularly those that also require plants for oviposition and subsequent larval development. In the case of plant feeding insects that also require plant tissues for the completion of their reproductive cycle through larval development, the divergent selective pressure not only acts on adults, but on the full life history of the insect. Here we focus attention on Rhinusa antirrhini (Curculionidae), a species of weevil broadly distributed across Europe that both feeds on, and oviposits and develops within, species of the plant genus Linaria (Plantaginaceae). Using a combination of mtDNA (COII) and nuclear DNA (EF1-α) sequencing and copulation experiments we assess evidence for host associated genetic differentiation within R. antirrhini. We find substantial genetic variation within this species that is best explained by ecological specialisation on different host plant taxa. This genetic differentiation is most pronounced in the mtDNA marker, with patterns of genetic variation at the nuclear marker suggesting incomplete lineage sorting and/or gene flow between different host plant forms of R. antirrhini, whose origin is estimated to date to the mid-Pliocene (3.77 Mya; 2.91-4.80 Mya). © 2010 Blackwell Publishing Ltd.
Toepfer S.,CABI Europe |
Kurtz B.,CABI Europe Switzerland |
Kurtz B.,University of Gottingen |
Kuhlmann U.,CABI Europe Switzerland
Journal of Pest Science | Year: 2010
The use of entomopathogenic nematodes is one potential non-chemical approach to control the larvae of the invasive western corn rootworm (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe. This study investigated the efficacy of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Rh., Heterorhabditidae) and Steinernema feltiae Filipjev (Rh., Steinernematidae) in reducing D. v. virgifera as a function of soil characteristics. A field experiment was repeated four times in southern Hungary using artificially infested maize plants potted into three different soils. Sleeve gauze cages were used to assess the number of emerging adult D. v. virgifera from the treatments and untreated controls. Results indicate that nematodes have the potential to reduce D. v. virgifera larvae in most soils; however, their efficacy can be higher in maize fields with heavy clay or silty clay soils than in sandy soils, which is in contrast to the common assumption that nematodes perform better in sandy soils than in heavy soils. © 2010 The Author(s).
Li H.,CABI Europe Switzerland |
Toepfer S.,CABI Europe |
Kuhlmann U.,CABI Europe Switzerland
Journal of Applied Entomology | Year: 2010
Morphometric traits and body weight are often used to study changes in fitness. For the invasive alien maize pest, Diabrotica virgifera virgifera LeConte, little information is available regarding the possible relationship between morphometric traits and adult activity, which reflects the ability to disperse and invade. Flight and crawling activities of D. v. virgifera adults were investigated in relation to six different morphometric traits as well as body weight, sex and age. This laboratory study revealed that flight activity of D. v. virgifera differed between sexes and changed with age. Young adults of both sexes flew more frequently and took off faster than mature adults. Males flew more frequently and took off faster than females, regardless of age-class. No such differences were found for crawling frequency, but young males crawled faster than young females. Further analysis revealed that fresh body weight and morphometric traits of young adults were better predictors of flight and crawling activity than the same measurements made on mature adults. Particularly pronotum and elytra measurements on young adults are recommended for bioassay studies on activity parameters of D. v. virgifera. © 2009 Blackwell Verlag, GmbH.