Asparagus is a favored perennial vegetable, recognized for its tender spears and distinctive flavor. These appealing qualities attract various animals, both small and large, seeking a meal from the succulent plants.
Insect Pests of Asparagus
Among the most common insect threats is the asparagus beetle (Crioceris asparagi), identified by its metallic blue-black body with three yellow spots. Both adults and their grayish larvae feed on spears and ferns, causing browning and defoliation that weakens the plant. A related species, the spotted asparagus beetle (Crioceris duodecimpunctata), is orange with 12 black spots and primarily targets asparagus berries, which can reduce seed production.
Cutworms, larvae of several moth species, are a concern in early spring when young spears emerge. These plump, grayish-brown caterpillars hide in the soil by day, emerging at night to chew through the base of young plants, severing them completely. Slugs and snails also pose a threat, particularly in moist conditions, rasping holes into tender spears and ferns and leaving behind tell-tale slime trails.
Mammalian and Other Wildlife Eaters
Larger animals also find asparagus appealing. Deer are a common culprit, quickly decimating patches by browsing on tender, emerging spears in spring. This prevents the plant from developing its ferny foliage necessary for photosynthesis. Rabbits also target young spears, nipping them off close to the soil surface.
Groundhogs, or woodchucks, consume both emerging spears and mature fern growth, leading to widespread defoliation. Voles, small, mouse-like rodents, primarily gnaw on asparagus crowns and roots underground, which can severely weaken or kill plants without visible above-ground signs. Birds, particularly robins and starlings, may occasionally peck at the tips of emerging spears, though their damage is generally less severe than that caused by mammals.
Protecting Asparagus from Animals
Protecting asparagus from animal threats involves a combination of methods. For insect pests, hand-picking adults and larvae is effective in smaller patches, while row covers provide a physical barrier against egg-laying adults. Maintaining garden hygiene by removing plant debris in the fall helps reduce overwintering sites.
Deterring larger mammals requires robust physical barriers. Fencing at least 8 feet high prevents deer access, while shorter, buried fences exclude rabbits and groundhogs. For voles, burying hardware cloth around the patch perimeter or within the planting bed protects crowns. Repellents, commercial or homemade, can also be applied to foliage, though effectiveness varies and requires reapplication after rain.