Retrospective use of integrative taxonomy in classical biological control: The unintentional introduction of the weevil Rhinusa dieckmanni to North America

A seed-feeding weevil introduced to North America (NA) as a biological control agent of the invasive toadflax Linaria dalmatica (L.) Mill., identified then as Gymnetron antirrhini “Dalmatian host race” and subsequently confirmed as established, was revealed through our study to be a separate species, i.e., Rhinusa dieckmanni (Behne) (Coleoptera: Curculionidae). This weevil species was presumed to be endemic in its native range, with a distribution restricted to Mount Rila in southwestern Bulgaria. We conducted a comprehensive study of seed-feeding weevils associated with L. dalmatica, L. dalmatica ssp. macedonica (Griseb.) D.A. Sutton, L. genistifolia (L.) Mill., and L. grandiflora Desf. across a broad geographic area of their native range. Those results revealed that all four host plants were used by R. dieckmanni and thus the native geographic range of the species is wider than expected, encompassing the Balkans and the Anatolian Plateau. Our observations suggest that phenotypes of this weevil are highly variable and dependent on the seed capsule size of the Linaria host population. The haplotype network based on mitochondrial COII, 16S genes, and nuclear EF 1-α gene genealogy confirmed the conspecific nature of geographically distant weevil populations, that is, R. dieckmanni phenotypes utilizing L. genistifolia, L. dalmatica, and L. grandiflora for larval development. Specimens collected from L. dalmatica in the northwestern USA shared the same haplotypes as samples from L. dalmatica ssp. macedonica in southwestern North Macedonia, supporting the known introduction history of the North American population. Females from these populations have relatively short rostrums, which may limit their reproductive success on North American invasive L. dalmatica with larger seed capsules

Managing Invasive Plants on Great Plains Grasslands: A Discussion of Current Challenges

The Great Plains of North America encompass approximately 1,300,000 km2 of land from Texas to Saskatchewan. The integrity of these lands is under continual assault by long-established and newly-arrived invasive plant species, which can threaten native species and diminish land values and ecological goods and services by degrading desired grassland resources. The Great Plains are a mixture of privately and publicly owned lands, which leads to a patchwork of varying management goals and strategies for controlling invasive plants. Continually updated knowledge is required for efficient and effective management of threats posed by changing environments and invasive plants. Here we discuss current challenges, contemporary management strategies, and management tools and their integration, in hopes of presenting a knowledge resource for new and experienced land managers and others involved in making decisions regarding invasive plant management in the Great Plains

Managing Invasive Plants on Great Plains Grasslands: A Discussion of Current Challenges

The Great Plains of North America encompass approximately 1,300,000 km2 of land from Texas to Saskatchewan. The integrity of these lands is under continual assault by long-established and newly-arrived invasive plant species, which can threaten native species and diminish land values and ecological goods and services by degrading desired grassland resources. The Great Plains are a mixture of privately and publicly owned lands, which leads to a patchwork of varying management goals and strategies for controlling invasive plants. Continually updated knowledge is required for efficient and effective management of threats posed by changing environments and invasive plants. Here we discuss current challenges, contemporary management strategies, and management tools and their integration, in hopes of presenting a knowledge resource for new and experienced land managers and others involved in making decisions regarding invasive plant management in the Great Plains

Invasive Species Management: Ensuring the \u27Cure\u27 Is Not Worse Than the Condition

The challenge in effectively managing invasive species arises out of our subjective response to the problem: 1) these species do not belong in our ecosystems; and 2) their impact on our ecosystems will be negative. These visceral responses typically dove-tail into the fundamental management objective: get rid of it! Society promotes the idea that good management is timely, and the best approach is to catch an invasive species before it reaches exponential population growth and becomes widespread. Although this is a sound approach, multiple examples illustrate that it is not universally applicable. Exotic species that are intentionally introduced either for resource improvement or classical biological control purposes are now themselves targets of management programs. Negative publicity associated with adverse outcomes of invasive species management has resulted in widespread ‘management paralysis’. Risk assessment is presented here as a viable strategy to offset this trend, and can be significantly enhanced through the adoption of best management practices

Assessing Environmental Risks for Established Invasive Weeds: Dalmatian (Linaria dalmatica) and Yellow (L. vulgaris) Toadflax in North America

Environmental risk assessments characterizing potential environmental impacts of exotic weeds are more abundant and comprehensive for potential or new invaders than for widespread and well-established species such as Dalmatian (Linaria dalmatica [L.] Mill.) and yellow (L. vulgaris Mill.) toadflax. Specific effects evaluated in our assessment of environmental risks posed by yellow and Dalmatian toadflax included competitive displacement of other plant species, reservoirs of plant disease, animal and insect use, animal toxicity, human toxicity and allergenicity, erosion, and wildfire. Effect and exposure uncertainties for potential impacts of toadflax on human and ecological receptors were rated. Using publicly available information we were able to characterize ecological and human health impacts associated with toadflax, and to identify specific data gaps contributing to a high uncertainty of risk. Evidence supporting perceived negative environmental impacts of invasive toadflax was scarce

A retrospective analysis of known and potential risks associated with exotic toadflax-feeding insects

To date, eight exotic toadflax-feeding insect species have been accidentally or intentionally introduced to North America. Reports on their establishment and impact have been recorded for more than 60 years. Environmental risks linked to biological control of toadflax were identified in terms of host resources and undesirable impacts on the target species through the critical review of this record. Data gaps revealed during this retrospective analysis are addressed through suggestions for future research and associated experimental methodologies. Known and potential impacts of toadflax-feeding insects on both invasive toadflax and non-target species are examined. Recent programmatic demands for demonstrated agent efficacy and stringent host selectivity during the pre-release screening process clearly illustrate that classical biological control of invasive toadflax in North America is progressing beyond the so-called lottery approach

Ecology and Management of Tansy Ragwort (Senecio jacobaea L.) By

Agriculture, available from Bugwood.org Tansy ragwort, a member of the Asteraceae taxonomic family, is a large biennial or short-lived perennial herb native to and widespread throughout Europe and Asia. Stems can grow to a height of 5.5 feet (1.75 meters), with the lower half simple and the upper half many-branched at the inflorescence. Reproductive stems produce up to 2,500 bright golden-yellow flowers. Capitula (flowerheads) arranged in 20-60 flat-topped, dense corymbs per plant are composed of ray and disc florets; both produce achenes containing a single seed. Rosettes formed of distinctive pinnately-lobed leaves attain a diameter of up to 1.5 feet (0.5 meter). First reported in Montana in 1979 in Mineral County, tansy ragwort has since spread into Flathead, Lincoln, and Sanders Counties. Soils with medium to light textures in areas receiving sufficient rainfall (34 inches or 860 millimeters/year) readily support populations of tansy ragwort. This species is a troublesome weed in decadent pastures, waste areas, clear-cuts and along roadsides. Tansy ragwort produces pyrrolizidine alkaloids- these can be lethal if ingested by cattle, horses and deer, but are less toxic to sheep and goats. Unchecked infestations can result in significan

Biology and biological control of Dalmatian and yellow toadflax /

no.2016-0