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Beginner

Scientific Names
Crioceris asparagi

Identification

• Adults beetles are approximately 6mm long.
• They have blue-black wing covers with red margins and 3 cream-coloured markings on each wing-pad.
• Larvae are a dull olive-green colour with a black head and black legs.
• Eggs are small (1.5mm), oval and bullet-shaped. Initially they are yellow. They darken to brown as they approach hatching.
• Feeding during harvest will result in crooked, misshapen spears.
• The presence of eggs on the spears during harvest may render them unmarketable.
• Feeding after harvest causes defoliation and impacts the growth and vigor of the crown.
• The Spotted Asparagus Beetle, a different species, is less common and not as damaging. The larvae of this species feed only on berries. They are red with 12 black dots.

Period of Activity
The emergence of the adult beetles usually coincides with asparagus harvest. First generation larvae are often active after harvest, during fern establishment. A second generation of larvae emerges in late July. This generation is typically less damaging.

Scouting Notes
Carefully inspect 10 groups of 10 plants across the field. While scouting, look for eggs, larvae and adults. Newly established fields and emerging fern are more susceptible to damage than mature plantings.

Thresholds
Eggs: 2 eggs on 10 spears
Larvae: 50% of plants with larvae present or 10% defoliation
Adults: 5%–10% of plants infested

Advanced

Scientific Names
Crioceris asparagi

Identification
The adult beetles are blue-black with three cream-coloured patches on each wing pad. The wing pads also have bright red margins. They are approximately 6mm long.

Asparagus beetle larvae vary greatly in colour, ranging from a greasy translucent grey to olive green. They have black heads and a slug-like body shape.

The bullet-shaped eggs are laid in rows perpendicular to the stem or fern. They range in colour from light-yellow to dark-brown, depending on the age of the egg.

Both the adults and the larvae feed on asparagus spears and fern. Feeding during harvest will result in crooked, misshapen spears. The presence of eggs on the spears impacts marketability. If left uncontrolled, feeding during fern establishment causes severe defoliation.

The Spotted Asparagus Beetle, a different species, is less common and not as damaging. The larvae of this species feed only on berries. They are red with 12 black dots.

Biology
Asparagus Beetles overwinter as adults in the crop residue. They are also found in the needle mulch underneath adjacent evergreen hedgerows.

Beetles become active in early spring as the crop emerges. They immediately begin feeding and laying eggs. Eggs hatch in 1-2 weeks. The peak activity of the first generation larvae often coincides with fern establishment in immature plantings.

First generation larvae feed for 3-4 weeks before pupating. The adults emerge in late-July, spawning a second generation of larvae that feed on the crop during August. The overwintering generation of adults emerge in the early fall.

Period of Activity
The emergence of the adult beetles usually coincides with asparagus harvest. First generation larvae are often active after harvest, during fern establishment. A second generation of larvae emerges in late July. This generation is typically less damaging.

Scouting Notes
Carefully inspect 10 groups of 10 plants across the field. While scouting, look for eggs, larvae and adults. Newly established fields and emerging fern are more susceptible to damage than mature plantings.

Thresholds
Eggs: 2 eggs on 10 spears
Larvae: 50% of plants with larvae present or 10% defoliation
Adults: 5%–10% of plants infested

Management Notes

• Feeding during fern establishment may deplete the crown's carbohydrate resources and reduce its vigour, impacting yield for the following year and making it more susceptible to soil-borne diseases such as fusarium and phytophthora.
• Closely monitor new and 2-year-old plantings. Female adults are often attracted to the young green ferns during egg-laying. These plantings are also more susceptible to feeding induced stress.
• Avoid the repetitive use of pyrethroid insecticides as they may have a negative effect on the population of beneficial insects in the field, causing other insect pests, such as aphids, to build to damaging levels.