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

Abstract

does not appear. First page follows. Introduction Celery affected with yellows was first observed in the San Joaquin delta in 1925 during an investigation of economic plants naturally infected with curly top. During 1926 and 1927 an average of 5 per cent of the crop was affected in the delta, the most important celery producing region in California; in 1928 about 10 per cent of the celery showed symptoms of the disease. Some celery growers hoe out the diseased celery so that an exact percentage of yellows could not be obtained in some fields. During 1927, 7,000 acres of celery, valued at $3,096,310, were grown in the San Joaquin delta so that the loss due to yellows amounted to $154,815. During 1928, 7,400 acres of celery are being grown in the delta, but the value of the crop has not been estimated; the loss due to this disease will probably exceed $300,000. Lettuce yellows, known as white-heart or rabbit-ear in New York, and Rio Grande disease in Texas, is a rather serious malady of lettuce. Lettuce yellows is of no economic importance at present in California, but its nature is such as to demand field observations year after year to determine its potential importance.