Disease Management

Asparagus Fusarium

Fusarium Crown and Root Rot of Asparagus

Crown and root rot of asparagus, caused by two species of Fusarium (Fusarium oxysporum f.sp. asparagi and Fusarium proliferatum), is the most economically important disease of asparagus worldwide. The pathogens are ubiquitous and appear to be present in most field soils where it can survive indefinitely. The disease is spread by movement of infested soil and by contamination of seed. Infection occurs at any point below the ground and once inside the plant, the fungi invade the water conducting tissue.

Symptoms of Fusarium include a gradual decline in plant productivity and growth, stunting, yellowing, wilting, dry rot of the crowns, and plant death. Reddish-brown elliptical lesions often form on stems and the cortex; when stems are cut longitudinally, vascular discoloration can be seen.  Most of the feeder roots are completely rotted and may have a reddish-brown discoloration. Replanted fields exhibit both pre- and post-emergent blights. Fusarium populations in infested fields have been shown to decline to a base level after five years; however, the low levels persist for long periods.

Management

Management of Fusarium crown and root rot is difficult; fungicide use is of little value. Adverse environmental factors such as poor drainage and poor cultural practices that increase plant stress predispose plants to disease.

• Treat seed with hot water or disinfectants to produce disease-free seedlings.
• Do not establish new plantings where asparagus has been grown within the past five years.
• Avoid excessive cutting periods which weaken the plant and reduce its ability to regenerate.
• Maintain plant vigor by proper fertilization and proper weed, Rust, and insect control.
• Plant tolerant varieties such as Jersey Giant, Apollo, Limburgia, and UC 157.

References

Elmer, W.H. 2001. The Economically Important Diseases of Asparagus in the United States.  http://www.apsnet.org/online/feature

Howard, R.J. et.al., eds.1994. Diseases and Pests of Vegetable Crops in Canada. Canadian Phytopathological Society.554 pp.

Asparagus Fusarium Wilt. http://www.ipm.ucdavis.edu .