Rhinocyllus conicus Froel. Rhinocyllus conicus is a species of true weevil. Rhinocyllus conicus Froel. A head weevil (Rhinocyllus conicus Froel., Coleoptera: Curculionidae) was selected for introduction into Canada and the United States for biological control of Carduus species (2, 3, 4, 10). lus conicus, was introduced from Eurasia to control musk thistle by reducing seed pro-duction. Description . 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. Larvae develop in the flower head and consume the seed as it develops. Area studied for presence of Rhinocyllus conicus Figure 3. and C. horridulum Michaux, and significant reductions in seed numbers of both species occurred during 2008. Between 1992 and 1996, the frequency of weevil damage to native thistles consistently increased, reaching 16 to 77 percent of flowerheads per plant. 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 INTRODUCTION Thistles in the genus Carduus have been the target of classical biological control programs in several coun-tries, including Argentina, Australia, Canada, New Zealand, and the United States (3). Thistles which reproduce only via seed, such as musk thistle, are controlled well by this weevil and its seed head destroying larvae. Identification difficulty. 1984; Kelly et al. We examined the presence of the exotic weevil Rhinocyllus conicus Fröelich on native thistles at high elevations in the Rocky Mountains of Colorado. Curculio conicus Froelich, 1792; Curculio thaumaturgus Rossi, 1794; References . The weevil Rhinocyllus conicus Froeh., introduced to control exotic thistles, has exhibited an increase in host range as well as continuing geographic expansion. Rhinocyllus conicus (Froehlich) tribe,(Coleoptera: Curcu-lionoidae), nodding (musk) thistle receptacle weevil, is (Paynter known to attack different athistle species but displays a clear preference for nodding thistle, Carduus nutans L. (Zwölfer asand Harris, 1984). Adults of Rhinocyllus conicus (Froel.) 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. … collected in south-eastern Italy were released in See Canyon, California, in 1973 for the biological control of Italian thistle (Carduus pycnocephalus). I found a few of these Short-snouted Weevils on Wilford Bridge on Monday, this I think is Rhinocyllus conicus. In 25–30 days, the larvae pupate and the pupae develop into adults in 8–14 days. Abstract. horridus on Rhinocyllus conicus (Coleoptera: Curculionidae) ... conicus adults developed from T. horridus-infested thistles. 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. (Col.: Curculionidae) larvae feeding within the capitula of Carduus thistles may reduce production of viable seeds. Proceedings of the 28th N.Z. 1993: Larvae of Curculionoidea (Insecta: Coleoptera): a systematic overview. Some larvae tunnel through the upper stem instead of chambering in a flower head; this can also be destructive to the plant. 6 nutans (Harris 2005), however, six weevil larvae in one C. vinaceum flower head was the largest number found at Silver Springs (Sivinski 2007). 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. Rhinocyllus conicus is a species of true weevil. They are supposed to be a Southern species, but it appears they are heading North. 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. Adults do some damage as well when they feed on the foliage. 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. CURCULIONIDAE Latreille, 1802. This weevil was introduced into Kansas by the Department of Agriculture to aid in the control of musk thistle. Image 5512294 is of musk thistle head weevil (Rhinocyllus conicus ) adult(s). 1975: Introduction of a weevil for biological control of nodding thistle. Field data on the incidence and increase of this weevil at this colonisation site are presented. They are associated with Thistles, the larvae develop in the flower heads. Thank you. The rostrum is very short. Pupation in the receptacle. Additional index words: Biological control. Weed and Pest Control Conference: 205–206. We tested whether the distribution of R. conicus was related to elevation by performing 2 separate studies. Habitat. Few data exist on the environmental risks of biological control. Jessep, C.T. 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. Herbicidal effect on Rhinocyllus conicus Froet., a thistle head weevil, was studied by examining the mortality, emergence rates and weights of weevils A black weevil with a tessellated pattern of pale pubescence on the elytra. RHINOCYLLINI Lacordaire, 1863. They are lovely little Weevils and are about 4-7mm in length. The adult weevil is black and covered in a thin black and yellowish mottled coat of hairs. Some larvae tunnel through the upper stem instead of chambering in a flower head; this can also be destructive to the plant. Rhinocyllus conicus Froel. Developing larvae feed on the receptacle and the young seeds, reduc-ing or preventing the production of viable seeds. RHINOCYLLUS Germar, 1817. May, B.M. Length: 4 to 7 mm. Rhinocyllus conicus Rhinocyllus conicus Species; Additional images; Click here to support NatureSpot by making a donation - small or large - your gift is very much appreciated. Adult Rhinocyllus conicus Fröelich on a thistle Photo by: Julia Hicks Figure 2. 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. CURCULIONOIDEA Latreille, 1802 . Abstract. Each female lays about 100 to 200 eggs on the bracts of thistle heads. Adults do some damage as well when they feed on the foliage. Adult R. conicus are dark brown in color and 10 to 15 mm long. Rhinocyllus conicus (Froelich, 1792) Synonyms . 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