Asparagus is a perennial vegetable prized for its tender spring shoots, and its appeal extends far beyond the human table. A variety of animals, from microscopic insects to foraging mammals, are drawn to the plant at different stages of its life cycle. Understanding which creatures consume the spears or the mature fern is important for gardeners looking to protect their crops. The plant’s structure and timing of harvest make it vulnerable to different types of consumers throughout the growing season.
Insect Pests and Their Specific Damage
The main consumers of asparagus are two host-specific beetle species: the common asparagus beetle (Crioceris asparagi) and the spotted asparagus beetle (Crioceris duodecimpunctata). The common asparagus beetle is the more serious pest, emerging earlier in the spring from overwintering sites. Both the adults and their larvae feed on the plant, causing scarring on the spears that makes them unmarketable and later defoliating the mature fern.
Adult common asparagus beetles lay dark, rod-shaped eggs directly on the spears. Once the larvae hatch, they begin feeding on the plant tissue, which weakens the plant and reduces its ability to store nutrients for the following year. They also leave behind a dark fluid waste product as they feed, compromising the spear’s quality.
The spotted asparagus beetle becomes active later in the season. While the adults feed on the ferns, its larvae primarily consume the red berries that form on female asparagus plants, targeting seed production rather than the plant’s overall health. Other smaller pests, like cutworms, may sever young spears at the soil line, and slugs can leave feeding holes in the tender tips.
Wild Mammals That Forage on Asparagus
Larger mammals primarily target the plant opportunistically. Rabbits, such as the cottontail, are known to occasionally feed on the emerging young spears during the harvest season. Because the spears are new, succulent growth, they are attractive to rabbits seeking fresh vegetation in the early spring. The damage is often characterized by clean, angled cuts on the young shoots, typically close to the ground.
Deer are also known to browse asparagus, though the plant is often classified as deer-resistant. They will readily consume the tender spring spears when other forage is scarce, leading to significant crop loss. Once the spears mature into the tall, feathery ferns, the deer’s interest generally declines, though they may still trample the mature plants.
Groundhogs, also called woodchucks, are voracious herbivores that will eat asparagus, particularly the tender shoots, if the plant is in their foraging area. These animals have a diverse diet that includes many garden vegetables. If a groundhog discovers an asparagus patch, it is likely to return repeatedly, feeding on both the spears and the leaves and stalks of the mature plant.
Asparagus Safety for Domestic Pets and Livestock
Asparagus presents a safety profile for common domestic animals, with toxicity depending on the specific part of the plant and the species consuming it. For dogs and cats, the asparagus fern is considered mildly toxic due to the presence of steroidal saponins. Ingestion of the plant’s red berries, in particular, can lead to signs of gastrointestinal upset, such as vomiting, diarrhea, and abdominal pain.
The raw asparagus spears consumed by humans are not considered toxic to dogs and cats, but they can still cause digestive issues. The tough, fibrous nature of the raw spears can be difficult for a pet’s digestive system to process. Repeated dermal contact with the fern can also cause allergic dermatitis in sensitive pets, resulting in skin inflammation.
Conversely, asparagus is generally safe for livestock and poultry in moderate amounts. Chickens can safely eat the spears, leaves, and ferns, gaining nutritional benefits like vitamins and antioxidants. Similarly, goats can consume asparagus as a healthy dietary supplement. However, asparagus contains small amounts of compounds that can be harmful in excessive quantities, so it should not be a primary component of their diet, but rather a supplemental treat.