Q.I planted an
asparagus bed this spring.
This is the first time I've grown asparagus, and I've been dismayed
to see these small, dark, worm-like creatures eating the foliage.
Can you tell me what they are and how I can protect my asparagus
A.Asparagus beetles are the most common pests of asparagus
in our area. There are two species, common asparagus
beetle (Crioceris asparagi) and spotted (Crioceris
duodecimpunctata). Common adults
have reddish bodies with black stripes and cream-yellow
patches on their wing covers. The worm-like creatures
you noticed are the larvae. They are typically dark gray
to olive green with black legs and head.
asparagus beetle adult is reddish-orange with six black
spots on each wing cover. The larvae are
yellowish-orange with black legs and head.
in garden debris, emerging as asparagus begins to grow
in spring. They feed on the tender new tips and soon lay
eggs on them. The larvae hatch in three to 12 days.
larvae of common asparagus beetles feed on the foliage
and stems while those of the spotted species prefer to
feed in the berries of female plants. When grubs are
mature, they move to the ground and build earthen cells
where they pupate.
ASPARAGUS BEETLE CONTROL OPTIONS
include cutting the shoots off cleanly at the ground
during the harvest season. This helps eliminate the eggs
of common asparagus beetles before they build up a large
population in the garden. Gathering and disposing of the
berries helps provide non-chemical control of spotted
asparagus beetles. Handpicking the adult beetles and
dropping them into a bucket of soapy water can be
effective in small asparagus patches.
Be sure to clean
up the asparagus patch thoroughly in the fall by cutting
the plants to the ground after they have been killed by
frost. Remove any summer mulch and re-mulch with fresh
straw or shredded leaves. This eliminates many of the
overwintering places for the adults. Pyrethrins and neem
are plant-based insecticides that are labeled to control
asparagus beetles and are approved for organic
production. Conventional gardeners can use Sevin (carbaryl)
to control these pests.