Common Asparagus Beetle
Common Asparagus Beetle
Crioceris asparagi is more commonly recognised by the name Common Asparagus Beetle. It is an important pest species that target asparagus crops throughout Europe and North America. Both the adults and grubs feed on the foliage and bark of asparagus plants. They can cause yellow-brown colouration and stem death if bark consumption is high.
Both adults and larvae can help support a variety of birds and predatory insects.
Adult beetles and larvae both feed on the foliage and bark of asparagus plants. They can cause yellow-brown colouration and damage stems if bark consumption is high.
Adult: These beetles have a black head and red thorax. The pattern on the wingcase can vary between individuals but generally should comprise a red border surrounding a black centre, with three cream splodges per wing.
The common asparagus beetle emerges from hibernation around the same time as asparagus plants. Adults begin to lay brown eggs on the asparagus spears. This pest causes yellow-brown colouration and possibly stem death if bark consumption is high. The tops of the spears can turn brown, and the damage caused by the beetles can cause asparagus heads to 'hook'.
Europe, Northern Asia (except China) and America
Adult beetles are attracted to lots of foliage, so to deter them it's advised to harvest crops earlier in the year and thoroughly, if possible. Beetles can be picked off plants with fingers and moved elsewhere. Planting tomatoes and parsley near asparagus has been known to minimise infestations from pests. For bad infestations, introducing beneficial nematodes to the soil has been suggested. It's not recommended to use chemicals because both adults and larvae are valuable food resources to birds and other garden creatures.
If you can count more beetles than the number of fingers on your hands, then it might be time for chemical action. If you intend to eat your crop, be sure your plant is listed in the instructions and to follow the quantity guidelines. More persistent products include synthetic insecticides with a contact mode of action (e.g. cypermethrin, phenothrin, lambda-cyhalothrin and deltamethrin). These can still be toxic to some wildlife and a pollutant to water bodies, so please take care to research products and read instructions carefully before using them. It's advised to check your pesticides and their ingredient authorisation annually. Feeling unsure? Just ask our community of plant lovers for help!