are two species of asparagus beetles which attack and can cause
economic damage to asparagus. They are the common asparagus beetle,
Crioceris asparagi (Linnaeus), and the spotted asparagus
beetle, Crioceris duodecimpunctata (Linnaeus).
common asparagus beetle is 6mm (1/4 inch) in length, has a bluish-black
head, legs and antennae tinged with green, a reddish thorax, and
wing covers marked by yellowish patches and reddish borders. The
larva of the common asparagus beetle is dark gray to olive-green
with black legs and head. The spotted asparagus beetle is slightly
larger and more robust than the common asparagus beetle. The adults
are reddish-orange in color with black antennae, eyes and underside
of the thorax. Each wing cover has six distinct black spots.
asparagus beetle (Clemson University Extension)
asparagus beetle (R.A. Casagrande)
beetle larva (Clemson University Extension)
the larvae and the adults of the common asparagus beetle damage
the asparagus plants. The overwintered adults emerge and begin to
feed on the tender growing tips of newly sprouted asparagus. They
chew holes in the plant and cause a brownish discoloration of the
tissue. The grubs will feed on the tender young tips and on foliage.
The plant growth is seriously reduced and proper root development
prevented, causing a decrease in the size and quality of the crop.
The spotted asparagus beetle causes the most injury in the early
season when the adults attack the growing tips and sometimes eat
the buds of newly sprouted asparagus. The beetles also feed on foliage,
eating out irregular areas. The larvae cause little damage because
they feed inside the berries.
adults of the common asparagus beetles overwinter in sheltered places
such as piles of rubbish and heaps of old asparagus tops. The beetles
emerge from their shelter and begin feeding on the tender tips of
new shoots. They soon lay eggs on the young shoots. The eggs are
elongate, oval, and deposited either singly or in rows of two to
eight. Later in the season the eggs are laid on leaves and flower
stems. The eggs hatch in three to eight days and the grubs begin
feeding on the tender tips. When the grubs mature, they drop to
the ground and construct a small earthen cell where they transform
into pale yellowish pupae. The adult beetles emerge from the pupae.
There may be two or more generations a year depending on the climate.
The adult spotted asparagus beetles overwinter in piles of debris.
They leave their winter quarters about one week later than the common
asparagus beetles and begin to feed on the tender young shoots as
well. They do not deposit eggs until the plant begins to blossom,
about three weeks after emergence. The egg is deposited singly on
plants, usually those bearing fruit. The egg is 0.5 mm (1/25 inch
in length, olive brown, and attached to the leaf by one side. The
larvae of the spotted asparagus beetle hatch in seven to twelve
days and are yellowish-orange in color with a black head and legs.
The larva finds a berry and enters it at the blossom end. Inside
the berry it feeds on the seeds and it may attack three or four
berries before it is mature. When fully grown, it drops to the ground
by a silken thread and spins a cocoon just under the soil surface
the shoots very clean and just below ground level every day or two
during the cutting season will tend to remove the eggs of the common
asparagus beetle before the larvae can establish themselves in a
home garden patch. In small gardens, gathering and destroying the
asparagus berries will help to give control of the spotted asparagus
beetle. Apply insecticides labeled for use on the asparagus beetles
when the beetles first appear. Apply as frequently as needed but
do not repeat applications within three days. Be sure to check the
number of days to harvest before applying any pesticide to edible
from the Cornell Cooperative Extension, 1999