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Transmission Characteristics of the Beet Leafhopper Transmitted Virescence Agent. D. A. Golino, Plant pathologist, Agricultural Research Service, USDA-ARS, Boyden Fruit and Vegetable Insects Laboratory; G. N. Oldfield(2), and D. J. Gumpf(3). (2)Research entomologist, Agricultural Research Service, USDA-ARS, Boyden Fruit and Vegetable Insects Laboratory; (3)Professor, Department of Plant Pathology, University of California, Riverside 92521. Phytopathology 77:954-957. Accepted for publication 17 December 1986. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1987. DOI: 10.1094/Phyto-77-954.

Beet leafhopper transmitted virescence agent (BLTVA), which causes a disease with a presumed etiology by a mycoplasma-like organism, is vectored by Circulifer tenellus in a pattern consistent with other leafhopper-borne plant pathogenic mollicutes. The minimum acquisition access period (AAP) was 5 min; more than 50% of test plants developed symptoms after exposure to insects that had undergone a 4-hr AAP. Transmission increased with increasing AAP until 100% of test plants became infected after an AAP of 1 or 2 days. The minimum demonstrable latent period in C. tenellus was 12 days. Maximum inoculation efficiency was reached at 2627 days after which a gradual decline in efficiency occurred. An inoculation access period (IAP) of 5 min rarely resulted in transmission. IAPs of 2 days provided high rates of infection in test plants. Single C. tenellus transmitted to about 50% of young plants of Apium graveolens, Brassica geniculata, Catharanthus roseus, and Raphanus sativus. Groups of 5 or 10 inoculative insects gave nearly 100% transmission to the same hosts. Transmission efficiency was not related to sex; groups of 10 male and female leafhoppers transmitted to 82 and 81% of test plants, respectively.

Additional keywords: MLO, Spiroplasma citri, wall-less prokaryotes.