Abstract
does not appear. First page follows. Pansies (Viola tricolor var. hortensis) and violas, or tufted pansies (V. cornuta) in California are subject to two virus diseases, celery calico and western cucumber mosaic. These diseases are treated in a companion article (Severin, 1947).3 The vectors are aphids, or plant lice. Celery calico was first investigated (Severin and Freitag, 1938) as a disease of celery. There are no less than ten aphid species feeding on celery in California. Other species which ordinarily do not feed and propagate on this host may also transmit the celery-calico virus under experimental conditions. The only species apparently restricted to violaceous plants in this state and in other parts of North America is the common violet aphid, Micromyzus violae (Pergande). Nine additional species have been recorded as feeding on Viola spp. (Patch, 1938) in various parts of the world. The purpose of this paper is to furnish those interested in the virus diseases of plants, particularly of ornamental violas and pansies, pertinent information concerning the aphid vectors of these diseases. Certain of these aphids have previously been discussed in relation to celery calico as a disease of celery in California (Essig, 1938a); and therefore the treatment of these particular aphid species excludes detailed descriptions and emphasizes more particularly synonymy, host plants, distribution, and bibliography. It is expected that the illustrations may enable those interested in this problem to identify the aphids responsible for the dissemination of the celerycalico and western-cucumber-mosaic viruses. The Pea Aphid Macrosiphum pisi (Kaltenbach) Aphis pisi(Kaltenbach (1843), p. 23-24) Aphis ulmariae(Schrank (1801), p. 116-17) Aphis onobrychis(B. de Fonscolombe (1841), p. 61) Adactynus pisi (Kaltenbach) (Kafinesque 1819, p. 18) Siphonophora corydalis(Oestlund (1886), p. 25-26) Nectarophora destructor(Johnson (1900), p. 58-59) Macrosiphum trifolii(Pergande (1904), p. 21-23, fig. 4) Illinoia pisi(Wilson (1910b), p. 318) Acyrthosiphon onobrychis (B. de Fonscolombe) The pea aphid is one of the largest and most conspicuous economic aphids. Its all-green color and its propensities for leguminous plants make it easily recognized.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
