The crown also becomes susceptible to attack by soil-borne fungi. Small, round to oblong, reddish-brown, powdery masses later develop on stalks and leaves of plants in producing beds. Later in the season, black masses gradually replace the reddish-brown pustules. Asparagus wilt and root rot are also common diseases. Spears of the infected plants may wilt and collapse.
Cankers develop at or near the soil line, restricting water and food movement.
Plant only healthy crowns in soil free of wilt and root-rot. The organisms live indefinitely in infected soil, so choose planting sites where asparagus has not previously been grown. Also provide good soil drainage, and avoid wounding the plants during cultivation. The two most important insect pests are the common asparagus beetle and the 12-spotted asparagus beetle. These beetles overwinter in the field under plant debris and other protected areas.