Control of Fusarium root rot of asparagus with different forms of chloride salt. T. C. REID and M. K. Hausbeck. Michigan State University, East Lansing, MI. Phytopathology 89:S65. Publication no. P- 1999-0467-AMA.

The objective of this study was to test whether NaCl and other forms of chloride salt could suppress crown and root rot of asparagus caused by Fusarium oxysporum f. sp. asparagi and F. proliferatum. Asparagus seeds were placed in test tubes containing Hoagland's solution and agar (1.2%) mixed with a low (17.1 mM), or high rate (34.2 mM) of NaCl, CaCl(2) (17.1 mM), NH(4)Cl (34.2 mM), or no chloride. Tubes were infested with F. oxysporum or F. proliferatum by adding 0.5 ml of a solution containing 1 × 10(^6) spores/cc. After 5 weeks, percent of root system diseased was assessed visually using a 0-4 scale (0 = no disease, 1 = 1-25%, 2 = 25-50%, 3 = 50-75%, and 4 = 75-100%). The study was conducted twice for each pathogen with 18 replicates per treatment. The high rate of NaCl (mean disease 1.5-1.9) consistently reduced disease incited by F. oxysporum significantly better than the control (mean disease 2.8-3.5), while CaCl(2) was better than the control in only one test. Against F. proliferatum NaCl and CaCl(2) decreased disease, but not significantly in all tests. NH(4)Cl gave disease ratings statistically similar to the control with both pathogens.