Slugs and snails: These common pests can cause damage to growing tips, and can defoliate plants. They are most active at night and after rainfall.
Remedy: Protect vulnerable plants by hunting for pests by torchlight on mild, damp night, or by burying beer traps in asparagus beds. You can do this easily by half-filling a jar with beer and sinking into the ground. Chemical pellets should be used with care to prevent accidental poisoning of pets or wildlife. Ones containing ferric phosphate are especially likely to be benign.
Asparagus beetle: Adult beetles and their larvae strip the outer bark and leaves from the stem. Damaged areas become yellow-brown and dessicated. The black beetles are 6-8mm long with a red thorax and six yellow blotches on the wing cases. Larvae are grey-black in colour, 1cm (½in) long, with three pairs of legs.
Remedy: Destroy overwintering beetles by burning old stems at the end of the season. From late spring, search and destroy the pests by hand. On larger plots, use sprays containing pyrethrum.
Frost damage: Late frosts can damage the growing tips, leading to distorted or dead spears.
Remedy: Remove any damaged growth and protect the bed with a double layer of horticultural fleece if frost is forecast.