Effect of Irrigation on Susceptibility of Sunflower to Macrophomina phaseoli. M. A. Blanco-López, Adjunct Professor, Department de Patología Vegetal, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Córdoba, Córdoba, Spain. R. M. Jiménez, Professor, Department de Patología Vegetal, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Córdoba, Córdoba, Spain. Plant Dis. 67:1214-1217. Accepted for publication 15 April 1983. 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, 1983. DOI: 10.1094/PD-67-1214.

Inoculations with Macrophomina phaseoli were done in 1977 and 1978 in flood-irrigated field plots. Inoculating with infested toothpicks was more effective than infesting soil at planting. Highest incidence and severity occurred in unirrigated plots. Irrigating at flowering or at flowering and ripening stages decreased disease incidence. In both years, inoculated plants matured earlier than uninoculated controls, but infection by M. phaseoli hastened plant senescence to a lesser extent than drought.