Rhinocyllus conicus (Froelich, 1792) Synonyms . They are lovely little Weevils and are about 4-7mm in length. 1993: Larvae of Curculionoidea (Insecta: Coleoptera): a systematic overview. Selected survey tracks in the study area showing where weevils we were present and absent from thistle habitats Figure 5. Adult Rhinocyllus conicus Fröelich on a thistle Photo by: Julia Hicks Figure 2. Identification difficulty. However, it was suspected that the phenology of the two seed predators issuchthattheyco-occuratacriticaltimefor U.solstitialis,whichcouldlimitthefly’sability tobuilduphighpopulations. one or more weevil larvae live in the receptacle, feeding on callus tissue that is induced by their activities; according to Redfern & Shirley the receptacle also sclerifies. RHINOCYLLUS Germar, 1817. Rhinocyllus conicus has the greatest temporal overlap with the dominant tephritid fl y Paracantha culta (Louda 1998). Area studied for presence of Rhinocyllus conicus Figure 3. A black weevil with a tessellated pattern of pale pubescence on the elytra. Eggs hatch in 6 to 9 days and newly hatched larvae feed through the bracts into the receptacle. (Col.: Curculionidae) larvae feeding within the capitula of Carduus thistles may reduce production of viable seeds. The effect of the red imported fire ant, Solenopsis invicta Buren, on Rhinocyllus conicus Froelich in a musk thistle, Carduus nutans L., biological control program was evaluated in laboratory and field trials in pastures in middle Georgia in 1999 and 2000. Pupation in the receptacle. 1978), Nebraska (McCarty and Lamp 1982), Kentucky (Townsend et al. Rhinocyllus conicus larvae often co-occur with maggots of P. gentilis and compete with the native fly for the food resource in flower heads of C. vinaceum. Establishment in NewZealand of all three biocontrol agents is well documented (Jessep 1975,1989b;Harmanetal.1996;Hayes2007). Rhinocyllus conicus was initially released and established in Virginia in 1969 where it successfully controlled musk thistle after six years (Kok and Surles 1974). I found a few of these Short-snouted Weevils on Wilford Bridge on Monday, this I think is Rhinocyllus conicus. Between 1992 and 1996, the frequency of weevil damage to native thistles consistently increased, reaching 16 to 77 percent of flowerheads per plant. The adult weevil is black and covered in a thin black and yellowish mottled coat of hairs. Developing larvae feed on the receptacle and the young seeds, reduc-ing or preventing the production of viable seeds. Adults do some damage as well when they feed on the foliage. Cirsium vinaceum flower head with three Rhinocyllus conicus egg sites. Larvae develop in the flower head and consume the seed as it develops. The weevil also has become established in Missouri (Puttier et al. Thistles which reproduce only via seed, such as musk thistle, are controlled well by this weevil and its seed head destroying larvae. 6 nutans (Harris 2005), however, six weevil larvae in one C. vinaceum flower head was the largest number found at Silver Springs (Sivinski 2007). Few data exist on the environmental risks of biological control. INTRODUCTION Thistles in the genus Carduus hav e been the target of classical biological control programs in several coun­ tries, including Argentina, Australia, Canada, New Zealand, and the United States (3). The larvae of R. conicus feed in the receptacles and thereby prevent the production of viable seeds, with each larva destroying approximately 28 seeds (Popay et al. Habitat. It is by Kansas Department of Agriculture . We tested whether the distribution of R. conicus was related to elevation by performing 2 separate studies. RHINOCYLLINI Lacordaire, 1863. Description . Thank you. Musk thistles that were infested with lower densities of T. horridus larvae (<20 per plant) also produced multiple stems that were usually shorter than uninfested thistles. thistles in North America suggests at least 8 lessons for future biological control efforts. The effect of the red imported fire ant, Solenopsis invicta Buren, on Rhinocyllus conicus Froelich in a musk thistle, Carduus nutans L., biological c Additional index words: Biological control. This weevil was introduced into Kansas by the Department of Agriculture to aid in the control of musk thistle. collected in south-eastern Italy were released in See Canyon, California, in 1973 for the biological control of Italian thistle (Carduus pycnocephalus). Thistles which reproduce only via seed, such as musk thistle, are controlled well by this weevil and its seed head destroying larvae. CURCULIONOIDEA Latreille, 1802 . Rhinocyllus conicus (Frölich, 1792) Suborder: Superfamily: Family: Subfamily: Tribe: Genus: POLYPHAGA Emery, 1886. The weevil Rhinocyllus conicus Froeh., introduced to control exotic thistles, has exhibited an increase in host range as well as continuing geographic expansion. Adults of Rhinocyllus conicus (Froel.) Herbicidal effect on Rhinocyllus conicus Froet., a thistle head weevil, was studied by examining the mortality, emergence rates and weights of weevils Image 5512294 is of musk thistle head weevil (Rhinocyllus conicus ) adult(s). The weevils can reduce seed production by near-ly 80%, but they are attracted more to earlier blooming rather than later blooming flowers. By feeding on re-ceptacle tissue, its larvae prevent development of some or … Rhinocyllus conicus- Insights to Improve Predictability and Minimize Risk of Biological Control of Weeds S. M. LOUDA School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA Abstract A review of information on the release of Rhinocyllus conicusto control of Carduus spp. Each female lays about 100 to 200 eggs on the bracts of thistle heads. lus conicus, was introduced from Eurasia to control musk thistle by reducing seed pro-duction. Establishment and Efficacy of Rhinocyllus conicus Froelich (Coleoptera: Curculionidae) in Controlling Carduus nutans L. In North Carolina R. C. McDonald and A. O. Robbing Musk thistle, Cardmis nutans L., has become a serious weed pest in North Carolina since its accidental introduction in contaminated hay from the Midwest during drought periods in the late 1980's. us, overall, the strategies of the herbivores in this fl oral guild are Abstract. musk thistle seed production. Includes mostly rare and very local species, only Larinus carlinae and Rhinocyllus conicus being widespread in the south. CURCULIONIDAE Latreille, 1802. May, B.M. Rhinocyllus conicus Froel. Of our five species of Lixus, four are probably extinct while the recently discovered L. scabricollis has spread rapidly around the coasts of England and Wales. The rostrum is very short. The late season flowers produce seeds with 1975: Introduction of a weevil for biological control of nodding thistle. We examined the presence of the exotic weevil Rhinocyllus conicus Fröelich on native thistles at high elevations in the Rocky Mountains of Colorado. Proceedings of the 28th N.Z. Rhinocyllus conicus has been widely used as a biocontrol agent of musk thistle in the USA (Surles et al., 1974, Kok and Surles, ... After 6–8 days, the eggs hatch and the larvae emerge and feed on the receptacle tissue, preventing seed formation. Rhinocyllus conicus Froel. Weed and Pest Control Conference: 205–206. structural damage by rhinocyllus conicus (coleoptera: curculionidae) within the flowerheads of nodding thistle - volume 116 issue 10 - j. d. shorthouse, r. g. lalonde Field data on the incidence and increase of this weevil at this colonisation site are presented. Distribution of Rhinocyllus conicus in Rocky Mountain National Park Figure 4. Abstract Rhinocyllus conicus is a flowerhead weevil deliberately introduced into the USA for the biological control of invasive exotic thistles in the genus Carduus.This study documents the course and magnitude of the weevil population expansion onto nontarget host plants. Some larvae tunnel through the upper stem instead of chambering in a flower head; this can also be destructive to the plant. Jessep, C.T. Rhinocyllus conicus is a species of true weevil. Rhinocyllus conicus Froel. Curculio conicus Froelich, 1792; Curculio thaumaturgus Rossi, 1794; References . 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