. . . "The cause of variation in the incidence of blackarm disease of cotton in the Sudan Gezira"@en . "The Cause of Variation in the Incidence of Blackarm Disease of Cotton in the Sudan Gezira"@en . "Blackarm disease of cotton in the Sudan Gezira"@en . . . "The Cause of variation in the incidence of blackarm disease of cotton in the Sudan Gezira" . . . . . . .