Macrophomina phaseolina Infection and Vine Decline in Cantaloupe in Relation to Planting Date, Soil Environment, and Plant Maturation. B. D. Bruton, Subtropical Research Laboratory, USDA-ARS, P.O. Box 267, Weslaco, TX 78596. M. J. Jeger, and R. Reuveni. Department of Plant Pathology and Microbiology, Texas Agricultural Experiment Station, Texas A&M University System, College Station 77843; and Agricultural Research Organization, Division of Plant Protection, Newe Yaar Experiment Station, Haifa Post 31-999, Israel. Plant Dis. 71:259-263. Accepted for publication 19 July 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/PD-71-0259.

The percentage of root systems of cantaloupe infected by Macrophomina phaseolina increased sigmoidly from the time of planting in eight experiments over three calendar years. There were no significant relationships between derived soil temperature and infection variates, although high temperatures consistently inhibited infection. At about flowering, the percentage of root systems infected was directly related to soil moisture content, whereas this effect was reversed after fruit set. Vine decline was directly related to soil matric potential before flowering. More than 80% of root systems were infected with M. phaseolina 49 days after planting, but symptoms in the crown area did not develop until after 85–90 days, indicating the importance of latent, especially early, root infection in vine decline.

Keyword(s): Cucumis melo, epidemiology.