On Crops: Asparagus
All areas where asparagus is grown
Slender, elongated beetle with four white or yellow spots on its wings and reddish coloring around the wings and a distinctive dark red thorax. These small beetles are usually ¼ to 1/3 inches long. Their larvae are greyish green and soft-bodied, resembling miniature slugs.
These beetles emerge and chew notches in asparagus spears, causing them to become crooked. As the season progresses, larvae feed on asparagus foliage.
Remove old fronds and weeds from the asparagus patch in early winter and compost in an active compost pile. Asparagus beetles can overwinter in dead asparagus foliage.
Both adults and larvae can also be removed by hand and dropped into a bucket of water. Other creatures such as beneficial wasps and poultry can also help keep these insects under control. Neem is the best organic solution to more severe outbreaks, but do not use neem if you see evidence that numerous beneficial insects are present in your asparagus patch.
Keeping debris down from fall through winter forces the beetles to hibernate in the soil, where they are often eaten by other predators and thus will not threaten your crop in the spring. The most effective natural predator is the small black Eulophid wasp, which sabotages asparagus beetle eggs. Attentive harvesting and cleaning of early spears will keep many asparagus beetle eggs from hatching.