Callistephus Research Articles

Transmission of California aster and celery-yellows virus by three species of leafhoppers

does not appear. First page follows. Introduction It has been suggested that possibly an obligate relation exists between a specific insect vector and the aster-yellows virus, and that developmental changes and multiplication of the virus take place during the incubation period in the insect.(8) It has been assumed in the past that the aster-yellows virus could be disseminated only by the leafhopper, Cicadula divisa Uhl., which is widely distributed in America. Ogilvie(10) reported yellows of China aster (Callistephus chinensis) in Bermuda, where Cicadula sexnotata (Fall.), responsible for the transmission of the virus there, has been known to occur since 1924. The disease also occurs on cos lettuce, cabbage lettuce, eight species of ornamental flowering plants, and several wild plants in Bermuda. Fukuski(5) reported that aster yellows occurs in Japan. Kunkel(8) reported that Cicadula sexnotata occurs in Japan and probably throughout the Orient. Dobroscky3 reported that aster yellows was found in the gardens of the Budapest Experiment Station, and in the vicinity of Lake Balaton Biological Laboratory, Hungary. Cicadula sexnotata is widespread and common in Europe.(8) In California three species of leafhoppers transmit the aster-yellows virus. Cicadula divisa transmits the virus with greater efficiency than the mountain leafhopper, Thamnotettix montanus Van D. or the geminate leafhopper, T. geminatus Van D. Experiments with the leafhoppers Agallia californicum (Baker), A. cinera (O. &; B.), and Empoasca abrupta De L. bred on celery failed to transmit the yellows virus.(13)

The Origin of the Cultivated Cineraria

I HAVE read with some interest the communications on this subject which have appeared in NATURE, and I may add that I have examined living plants of the species in question with Mr. Thiselton-Dyer. My memory also serves me sufficiently far back to remember a great variety of different “strains” of Cineraria, in which they had not got so far away from the parent C. cruenta as they now are. I say the parent C. cruenta, because I believe that we have to deal with races or strains, obtained by selection according to the taste of the several selectors, and not with the descendants of hybrids between different species. I think Mr. Bateson has relied too implicity on the literature of the subject. Many of the records of hybrid productions in the vegetable kingdom are based upon groundless assumptions; mere seminal variations having been mistaken for crosses. It requires some skill and care to raise hybrids in the Compositae; and when you have raised your hybrid, even assuming a fertile one, you can only propagate it vegetatively. All stability is gone. But it is not so with selected seminal variations of a given species. They will intercross most freely, and give birth to new varieties without end; yet each one of those varieties may be reproduced from seed, by careful isolation, without a single “bastard” appearing. There are several instances among our cultivated plants of this great plasticity combined with stability, but I will give only one—the China Aster. I select this because there can be no question of hybridity; and there is as great, or even a greater, variety than in the herbaceous Cinerarias. But with regard to the latter, I think our experience and the trustworthy literature go to prove that it is an analogous case. Careful selection, year after year, has resulted in the various fixed races or strains offered by florists. I am aware that the letters on this subject by no means exhaust it; but I think it may be safely asserted that selection has yielded much more than sports.

Black Rust of Cotton: A Preliminary Note

Next article FreeBlack Rust of Cotton: A Preliminary NoteGeo. F. AtkinsonGeo. F. Atkinson Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 16, Number 3Mar., 1891 Article DOIhttps://doi.org/10.1086/326625 Views: 23 Citations: 3Citations are reported from Crossref Journal History This article was published in the Botanical Gazette (1876-1991), which is continued by International Journal of Plant Sciences (1992-present). PDF download Crossref reports the following articles citing this article:Sobia Chohan, Rashida Perveen, Muhammad Abid, Muhammad Nouman Tahir, Muhammad Sajid Cotton Diseases and Their Management, (Mar 2020): 239–270.https://doi.org/10.1007/978-981-15-1472-2_13R. J. Hillocks Alternaria leaf spot of cotton with special reference to Zimbabwe, Tropical Pest Management 37, no.22 (Jan 1991): 124–128.https://doi.org/10.1080/09670879109371557Kenneth F. Baker, Lily H. Davis Stemphylium Leaf Spot of China Aster, Mycologia 42, no.44 (Sep 2018): 477–486.https://doi.org/10.1080/00275514.1950.12017852