Asparagus

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Lesions, Spots, or Blisters

Asparagus Rust, a fungal pathogen


Cause

Asparagus rust, a fungal pathogen. Asparagus rust is characterized by light green oval lesions inearly summer followed by tan or black protruding blisters later in the season--sometimes accompanied by orange spores.

Treatment: 

Remove volunteer asparagus near commercial fields. Plant resistant varieties such as Jersey Giant, Martha Washington, and Viking KB3. Orient rows in the direction of prevailing winds, and thin rows if neccessary to facilitate air movement. Many approved fungicides are being removed from the market. Contact your local Extension Agent, or the U of M Plant Disease Clinic at: 612-625-1275 for current recommendations.

Insect Defoliation accompanied by Bent Spears

Crioceris asparagi, the common asparagus beetle


Crioceris asparagi, the common asparagus beetle.

Another view of the common asparagus beetle.

The common asparagus beetle feeding.

Crioceris asparagi, larval stage.

Larval crioceris asparagi feeding on asparagus.

Cause

The common asparagus beetle (crioceris apraragi) is a blue-black beetle with white spots. In the larval stage, it is gray with a black head.

Treatment

This insect can cause serious defoliation, sometimes weakening plants and pre-disposing them to seconday fungal pathogens. In addition eggs laid on spears can make them unappealing. Labeled pesticides such as permethrin formulations are available. The most effective treatment practice may be the removal or burning of plant residue each season to reduce overwintering sites for this pest. In addition, volunteer asparagus near managed fields should be removed.

Crioceris duodecimpunctata, the spotted asparagus beetle


Crioceris duodecimpunctata, the spotted asparagus beetle.

The spotted asparagus beetle, feeding.

Cause

The spotted asparagus beetle (crioceris duodecimpunctata) is an orange beetle with black spots; it is also orange in its larval stage.

Treatment

The spotted asparagus beetle appears later in the season than the common asparagus beetle and causes little significant damage. No treatment is usually neccessary. However if significant defoliation does occur, labeled pesticides such as permethrin formulations are available. The most effective treatment practice may be the removal or burning of plant residue each season to reduce overwintering sites for this pest. In addition, volunteer asparagus near managed fields should be removed.