Common asparagus beetle

{{short description|Species of beetle}}

{{Speciesbox

| name = Common asparagus beetle

| image = Crioceris_asparagi.jpg

| taxon = Crioceris asparagi

| authority = (Linnaeus, 1758) {{ITIS |id=719888 |taxon=Crioceris asparagi}}

}}

{{Wikispecies|Crioceris asparagi|Common asparagus beetle}}

The common asparagus beetle (Crioceris asparagi) is a major pest of asparagus crops both in Europe and in North America. Asparagus is its only food plant. The beetle is 6.0 mm to 9.5 mm long and slightly elongated. It is metallic blue-black in color with cream or yellow spots on its red-bordered elytra. The larvae are fat gray grubs with dark heads.{{cite book |last1=Cranshaw |first1=Whitney |title=Garden Insects of North America: The Ultimate Guide to Backyard Bugs |publisher=Princeton University Press |isbn=978-0691167442 |edition=2nd|date=2017-12-05 }}{{cite web |last1=Sorensen |first1=Kenneth |last2=Baker |first2=James |last3=Cameron Carter |first3=Cathy |last4=Stephan |first4=David |title=Pests of Asparagus |url=https://content.ces.ncsu.edu/insect-and-related-pests-of-vegetables/pests-of-asparagus |website=NC State Extension Publications |publisher=North Carolina State University |accessdate=8 July 2019 |language=English |date=1 January 2003 |archive-date=11 April 2023 |archive-url=https://web.archive.org/web/20230411132320/https://content.ces.ncsu.edu/insect-and-related-pests-of-vegetables/pests-of-asparagus |url-status=dead }}

The adult beetles and the larvae strip the needle-like leaves off the asparagus fronds, depriving the plants of the ability to photosynthesize and store energy for future years. Additionally, they chew the spears and lay a lot of eggs on them, rendering the crop unusable. The larvae feed on the plants for a few weeks, then drop to the ground to pupate. One year may see two or three generations of the beetle. The adults overwinter in a dormant state underground or in nearby leaf litter.

The parasitic wasp, Tetrastichus coeruleus, occurring mainly in the United States and Europe, can cause up to 71% mortality in the field and has been successfully used for biological control.{{cite journal |last1=Capinera |first1=J. L. |last2=Lilly |first2=J. H. |title=Bionomics and biotic control of the asparagus beetle, Crioceris asparagi, in western Massachusetts |journal=Environmental Entomology |date=1 February 1975 |volume=4 |pages=93–96 |doi=10.1093/ee/4.1.93}}{{cite journal |last1=Morrison |first1=William R. |last2=Szendrei |first2=Zsofia |title=The Common Asparagus Beetle and Spotted Asparagus Beetle (Coleoptera: Chrysomelidae): Identification, Ecology, and Management |journal=Journal of Integrated Pest Management |volume=5 |pages=B1–B6}}

Various insecticides (such as carbamates, pyrethroids, spinetoram, and spinosad) can be considered for pest control.{{cite web |last1=Hahn |first1=Jeffrey |title=Asparagus beetles |url=https://extension.umn.edu/yard-and-garden-insects/asparagus-beetles |website=UMN Extension |accessdate=8 July 2019 |date=2018}}{{cite web |last1=Espiritu |first1=Kevin |title=Asparagus Beetles: All You Need To Know About The Crioceris Species |url=https://www.epicgardening.com/asparagus-beetle/ |website=Epic Gardening |accessdate=8 July 2019 |date=13 February 2019}}

The similar spotted asparagus beetle (Crioceris duodecimpunctata) is also a pest as an adult, feeding on tender shoots and leaves, but since the larvae feed only on the asparagus berries it is not considered to be as important.

File:Crioceris asparagi 4 beentree.jpg|Eggs of the asparagus beetle, laid on the stem of a flower of an asparagus plant

File: Chrysomelidae - Crioceris asparagi (larva).JPG|Larva of Crioceris asparagi