Spotted Asparagus Beetle

HOSTS

• Asparagus

OVERVIEW

The spotted asparagus beetle, Crioceris duodecimpunctata, is a leaf beetle in the family Chrysomelidae. This beetle feeds exclusively on asparagus and is native to Europe. The spotted asparagus beetle is less economically injurious than the asparagus beetle. Both spotted asparagus and asparagus beetle are equally abundant in Utah.

DESCRIPTION

Spotted asparagus beetle eggs are brown or olive green and oval shaped. Eggs are individually cemented on asparagus plants. Spotted asparagus beetle eggs can be distinguished from asparagus beetle eggs because they are cemented on their side rather than their end. Larvae are plump with a orange to brown head capsule and chewing mouthparts. The pupa resembles the adult except for the poorly developed wings and yellow color. Adults are brightly colored leaf beetles, reaching approximately 6-8 mm in length. The spotted asparagus beetle is mostly orange, but has black spots on the forewings and black legs, eyes, antennae and "knee caps". Adults will quickly fly away when disturbed and stridulate (make clicking sounds) loudly if captured.

BIOLOGY

There are 2 generations of spotted asparagus beetle per year in Utah. Spotted asparagus beetles overwinter as adults in hollow asparagus stems and other sheltered areas. Depending on spring temperatures, adults begin feeding on spears when they break through the soil surface. Spotted asparagus beetle eggs can be distinguished from asparagus beetle eggs because they are cemented on their side rather than on their end. Larval populations build up in late June after the ferns are established, and prefer to feed on asparagus berries when available. Pupation occurs within the berry and adults will emerge from berries. Sometimes females will delay oviposition until flowers are fertilized or berries are present.

SYMPTOMS

• Adults can consume leaves, and scar spears and stems.
• The most serious damage is caused during the spring when adults are feeding on new spears.
• Occasional damage can occur during summer, but rarely stunting growth or reducing yield.
• Larvae feed on berries, but this is usually not economically important unless growing asparagus for seed.
• Females cement eggs onto spears or ferns causing aesthetic damage (eggs are not easily washed away or easily removed).

GENERAL MANAGEMENT

Predatory beetles and parasitoid wasps will help keep populations to tolerable levels in most situations. Removing volunteer asparagus will prevent population spread over time. Minimizing weeds or other debris near asparagus will make sheltered areas less favorable for overwintering adults. 

INSECTICIDES

For asparagus with persistent beetle damage, insecticides can be used to control adults and larvae. Consider reduced risk insecticides first because they have a short residual and are not broad spectrum.

• Residential: neem oil, kaolin clay (Surround), diatomacious earth, pyrethrins, spinosad
• Commercial: pyrethrins (Azera), spinosad (Entrust, Success), carbaryl (Sevin), permethrin (Ambush)