Eradication of Primary Inoculum of Botrytis cinerea by Soil Solarization. C. J. LOPEZ-HERRERA, Research Plant Pathologist, Departamento de Protection Vegetal, C.I.D.A., 29.140 Churriana, Malaga Spain. B. VERDU-VALIENTE, Graduate Research Assistant, Departamento de Protection Vegetal, C.I.D.A., 29.140 Churriana, Malaga Spain; and J. M. MELERO-VARA, Research Plant Pathologist, Instituto de Agricultura Sostenible Apdo. 4084, 14080 Cordoba, Spain. Plant Dis. 78:594-597. Accepted for publication 16 February 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0594.

The primary inoculum source of Botrytis cinerea can be eradicated by soil solarization, thus retarding the development of gray mold in many horticultural crops. The effect of soil solarization on the loss of viability of inoculum of B. cinerea buried in sand-mulched soil at different depths was studied in two different years. In 1989, solarization during the last week of July eradicated the pathogen. The maximum average temperatures for the period were 36.4, 40.3, and 46.8°C at 25-, 15-, and 5-ctn depths, respectively. Soil solarization during the first week of July 1990 resulted in maximum temperature increments of +7.4, +4.3, and +9.4°C, depending on depth. Complete loss of viability of mycelium at depths of 5-25 cm, as well as of sclerotia buried at 5 cm, was observed after 2 days in solarized plots. Viability of sclerotia at 15- and 25-cm depth decreased linearly with temperature-time (degree-hour). Estimations of solarization periods required for eradication of sclerotia of B. cinerea, under the thermal regime of the first week of July 1990, were ft and 10 days at 15- and 25-cm dcpths, respectively, for the conditions stated above.

Keyword(s): vegetable crops