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Cytology and Histology

Association of Squash Leaf Curl Virus with Nuclei of Squash Vascular Cells. Lynn L. Hoefert, Botanist, U.S. Department of Agriculture, ARS, Pacific Basin Area, 1636 East Alisal Street, Salinas, CA 93905; Phytopathology 77:1596-1600. Accepted for publication 21 May 1987. 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-77-1596.

Squash leaf curl is a whitefly-transmitted virus disease affecting members of the Cucurbitaceae and is caused by a geminivirus. It is associated with nuclei of vascular tissues in leaves of zucchini squash and with maturing phloem sieve elements. Whiteflies probe leaves mainly from the abaxial surface, and internal symptoms are expressed to a large extent in the vascular tissue of the abaxial phloem. Severe necrosis of sieve elements occurs after only 9 days of infection. The disease is discussed in comparison to other whitefly-transmitted geminivirus diseases of plants.