Asparagus Rust

Asparagus rust, caused by the fungus Puccinia asparagi, occurs worldwide wherever asparagus is grown. All above ground of the plant may become infected. Severely diseased plant may be killed during summer. Asparagus plants weakened by rust are also susceptible to the Fusarium wilt and root rot. This diseases occur in Illinois every year.

Symptoms. Asparagus rust appears in four stages. The first symptom, occurring in early seasons, is the appearance of inconspicuous, light green, oval spots (brownish pycnia and then aecia) on the first shoots or spears. If these spears are harvested, the rust cycle will be broken and the disease does not develop further. Where the spears are not harvested, these spots develop into yellow, cup-shaped spore bearing aecia in concentric ring patterns. The common, cinnamon-brown, blister-like pustules (uredinia) develop about two weeks later. Large number of brick-red, almost spherical urediniospores are produce in the small, dusty, cinnamon-brown pustules. During late summer or autumn, blackish brown lesions, called telia, are produced which give a blackened appearance to the plants.

Disease management. Remove all infested crop residues to minimize the amount of primary inoculum. Destroy wild or volunteer asparagus within 1,000 feet of commercial planting. Locate new planting or nurseries away from established planting. Field should be clean cut after harvest and spear should be cut below soil level to avoid infection of the stubs by rust spores. Practices that promote the rapid drying of plant surfaces, such as planting rows in the direction of the prevailing wind, may help to limit infection.

Use resistant or tolerant asparagus cultivars, when are available. If the rust is recurring problem, spray application with chlorothalonil, mancozeb, and Nova is recommended. Mohammad Babadoost (phone: 217-333-1523; website ). For more information on asparagus rust, refer to the following website here and here.