Skip to main content
ARS Home » Research » Publications at this Location » Publication #121853
Title: INCREASED SEVERITY OF ERWINA SOFT ROT ON CALLAS IN THE PRESENCE OF PHOSPHATE

Author
item GRACIA-GARZA, J - AG & AGRIFOOD CANADA
item BLOM, T - UNIV OF GUELPH
item BROWN, W - OMAFRA, CANADA
item ALLEN, W - AG & AGRIFOOD CANADA
item Roberts, Daniel

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A series of tests were conducted in a closed irrigation system with calla lily rhizomes naturally infected with Erwinia carotovora subsp. carotovora (E.c.c.). Rhizomes were planted in pots containing growing medium with or without phosphate (PO4) and later irrigated with a fertilizer solution with or without PO4. Presence of PO4 in the solution had no significant effect on the severity of soft rot, 44% with PO4 vs 41% without PO4. However, addition of superphosphate (0-20-0) to the growing medium significantly increased the number of diseased plants, 53 % with PO4 vs 32% without PO4. Drenches with a copper-based compound reduced disease severity from 51% to 34%. Addition of PO4 to growing medium gave similar results in a commercial greenhouse trial with a large sample size. Mortality was higher (51% vs 44%) on rhizomes planted on growing medium with PO4, although this difference was not statistically significant. Preliminary studies indicate that activity of E.c.c. pectolytic enzymes is higher in the presence of PO4.