Asparagus beetle control

 Asparagus beetle

Learn how to identify and remove asparagus beetles without resorting to toxic sprays or chemical powders!

There are two types of asparagus beetle. Both target their naming plant, causing damage to newly emerged darts and late leaves.

The common asparagus beetle (Cryoceris asparagus) attacks both garden and wild plants. First, a European race, which spread throughout the United States. Adult beetles (1/4 inch long) have metallic blue to blackish creamy yellow spots and red margins on their wing coverts.

The adult spotted asparagus beetle, which looks like a female beetle, is reddish-orange with 12 black spots. Their damage can be complex, but they are not as destructive as the common asparagus beetle.

The plump larvae (1/3 inch long) of two asparagus beetles are slug-like in appearance. The common beetle has a black head and visible legs and is gray or green. Beetle larvae with spots are orange.

For detailed descriptions of both species and concrete photos of beetles, larvae, and eggs - and a spectacular picture of the parasitic wasp violating the asparagus beetle egg - see the University of Minnesota expansion page.

Life cycle

Two types of adults spend more winter in plant litter and garden litter. The asparagus beetle emerges early, while the asparagus spear. Within a week of emergence, common beetles lay brown eggs in three to eight rows on new spears.

The larvae emerge within a week and begin to move upwards as the plant grows. After two weeks of intense feeding, they fall to the ground, where they hatch for a week. Then the adult beetles crawl out of the soil and the cycle begins again. Two life cycles are common in most regions but can produce up to five in areas with longer growing seasons.

The spotted asparagus beetle appears after a while, allowing the growth of leaves that lay a green egg. Larvae prefer to eat the berries of mature asparagus plants. Within two weeks, they fall to the ground and enter the soil where the beautification takes place. Ten days later new adults appear. Their breeding season ends in most places at the end of July.

Damage

Both adult and larval stages of common asparagus beetles feed on spears in the spring and early summer months. Their presence is often reported when darts take on "Shepherd's Croke Syndrome", twisting Asparagus' head will give the spear an unnatural hook.

Feeding beetles can cause visible scars and stains by chewing the waste they leave behind. Often, the spear tips turn brown. In summer, asparagus beetles move to feed on ferns. Significant decay at this stage weakens the plants and makes them susceptible to Fusarium wilt and other pathogens. Beetle damage can limit the amount of nutrients plants can take in the next growing season, resulting in fewer and fewer malignant darts.

Asparagus beetle control

Some asparagus growers report the presence of small but persistent asparagus beetles in their reefs that do not cause much damage or major infection. Detecting asparagus beetles with odd spots - their bright color makes them easy to see - does not indicate disaster. But finding some common beetles in larvae or adult stages means there are plenty more along the way. Distinguishing between two types of beetles can help protect your crop. Even the sight of a common asparagus beetle should warn you to take action.

Little focus on beetle management goes a long way. Removing them as adults emerge from the soil and still climb on the stems of smaller plants can then prevent large outbreaks. As soon as asparagus spears appear, start looking for plants in early April and early May.

Take the adults and larvae by hand from the plants and leave them in soapy water. Clear the spears of eggs when you harvest.

Early harvest of spears shortens the life cycle of beetles. When cutting asparagus to the table, make it a habit to look for adults, larvae, and eggs in the items you collect and leave. Adult beetles are most attracted to asparagus with leaves. Encourage them to harvest early and thoroughly.

Some gardeners use a thorny broom or soft counter to brush the larvae out of the spear. Recommend the use of wipes. The larvae that are brushed on the ground usually do not return to the stem and expire in the dirt.

The diversified, integrated pest management program will be discontinued before the problems of connecting the various natural controls begin.

Beneficial insects, especially ladybugs and lacewings, feed on eggs and small larvae. Anything you can do to promote these pests in your garden will help control various pests.

Excellent control is provided by a small wasp (Tetrasticus asparagus) not available in the business. The wasp lays its eggs in the larval stage

The asparagus beetle destroys it from the inside. The asparagus wasp is naturally attracted to asparagus patches. Do not destroy non-discriminatory, chemical pesticides by spraying, and other beneficial insects.

Birds take both plants and adults and larvae from the ground. Make sure your yard is pesticide free and provides an environment that encourages the arrival of birds.

For nasty infections, introduce beneficial nematodes in your attachment. These microscopic soil organisms will destroy the asparagus beetle pupae in the ground.

As a last resort, treat the grown beetles with botanical pesticides.

Take out the garden debris after harvest and turn the soil around the plants to prevent beetles in the winter.

Focus on the edges around your asparagus patch. Beetles often winter near or near areas where asparagus grows.

Burning asparagus patches and destroying adults or larvae who want to spend the winter in plant debris is an old-fashioned practice that in many places is not wise or legal. Do not attempt to burn your asparagus patch without first consulting local burning orders and laws. If it is legal and safe - not burning near buildings, trees, grasses or flammable fuels - remove asparagus pieces as much as possible and dispose of them, then use a propane torch kit to operate the flame and kill adults or chicks living in the soil and still in plant debris.

Spreading salt is another old-fashioned practice in the fight against asparagus beetles. While salt will shrink any pupae it comes in contact with, it is an inefficient practice that can adversely affect the condition of your soil. We do not recommend it.