Yellows disease of celery, lettuce, and other plants, transmitted byCicadula sexnotata(Fall.)

Abstract

even abandoned. Aster plots showing 90 to 95 per cent of yellowed plants are not uncommon throughout the eastern United States." Aster yellows first made its appearance in California during 1925 and in the next three years the disease has spread rapidly through the middle and southern sections of the state. Yellows of flowering plants is already causing some concern to seed and flower growers in certain localities. An investigation was undertaken to determine whether insects, especially leafhoppers, transmitted this disease to celery. Experiments were conducted to determine the relation of the celery disease to aster and lettuce yellows. The relation of yellows to curly top of sugar beets was also investigated. The characteristics, distribution, flights, food plants, and overwintering stage of the six-spotted leafhopper are discussed in this paper. NAl\IE OF THE DISEASE A large number of plant diseases are designated by the term "yellows" some of which belong' to the virus diseases, as does the one under consideration, while others are caused by fungus parasites. Kunkel (5) has experimentally transmitted aster yellows with the sixspotted leafhopper, Cicadula sexnotata (Fall.) to more than seventy species of plants in twenty-eight families. Celery yellows has been proven to be identical with aster yellows and should be classified with this disease. , , Yellows" of celery caused by a species of Fusarium occurs in Michigan, Indiana, Ohio, Pennsylvania, New York, Massachusetts, Connecticut, and New Jersey but has not been reported from California. OCCURRENCE OF YELLOWS IN CALI~-'ORNIA Methods of Introduction into California.-The six-spotted leafhopper, Cicadula sexnotata (Fall.) has been known to occur in California for a long time, but the yellows disease which it transmits is a recent introduction into the state. Yellows disease may have been introduced into California through shipments of diseased perennial flowering' plants from the Middlewest or East, or through cut flowers brought from the Middlewest or East by the traveling public. Successive migrations of infective six-spotted leafhoppers from the Middlewest to California appear to be entirely out of consideration

Additional ornamental flowering plants naturally infected with California aster yellows

“…The host range of the aster-yellows virus among ornamental flowering plants naturally infected includes 45 species and 1 interspecific hybrid in 38 genera belonging to 17 families, including those previously reported (Severin, 1929, 1942a, 1942b, 1943, Severin and Freitag, 1934. The season's duration of each plant is given in the following list:…”

“…Among economic plants of the family Umbelliferae, curving, twisting, and intertwining of the petioles occur, as described for celery (Severin, 1929), celeriac (Severin and Frazier, 1944), carrots, parsley, and parsnips (Severin, 1932). Thus far these symptoms have not been found on any naturally infected ornamental flowering plant.…”

Diseases of plants in the United States in 1929 /

“…ASTER YELLOWS (virus). Severin (53) has reported that yellows of celery and also of lettuce is identical with the aster yellows and is transmitted by Cicadula sexnotata. Folsom in Maine found what seemed to be this same disease and systematic sweepings resulted in capturing the leafhopper.…”

Effects of Chlorpyrifos andLambda-andGamma-Cyhalothrin on Suppression of Aster Leafhoppers,Macrosteles quadrilineatus(Hemiptera: Cicadellidae) in Spring Wheat1

“…Aster leafhoppers are known vectors of aster yellows (Black 1941, Nielson 1968, Frost et al 2011), a disease caused by mycoplasma-like organisms that can cause significant losses to vegetable production (Severin 1929, Beanland et al 2005, Frost et al 2013. While a recent report described a fairly high incidence of aster yellows disease in wheat, oat, and barley in the Upper Midwest of the U.S. (Hollingsworth et al 2008), aster yellows is not commonly reported on wheat and aster leafhoppers are rarely considered an economically important insect pest of wheat.…”