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Due to its red shell with black spots, some people may mistake the asparagus beetle as a relative of the ladybug. Unlike ladybugs, asparagus beetles spell danger for your asparagus.
Asparagus beetles can attack your precious plants, leaving them unattractive with a gray or stained appearance. Asparagus beetle larvae also feed on foliage and develop berries, affecting the next batch of plants.
Knowing which species you are dealing with can help determine how much damage you can expect on your produce. For instance, the larvae and adult common asparagus beetles can feed on your asparagus ferns. In the case of the spotted asparagus, only the adult asparagus beetles attack the fern area.
This short guide features the life cycle of the asparagus beetle. Visit our website for information on other types of insects and pests.
How to Identify Asparagus Beetles
There are two types of asparagus beetles: the spotted asparagus beetle (Crioceris duodecimpunctata) and the common asparagus beetle (Crioceris asparagi). They’re indistinguishable during their pupa stage as both have similar sizes and colorations. However, in other stages of this beetle’s life cycle, it is possible to distinguish between the species.
Common Asparagus Beetle
- Brown oval-shaped eggs measuring 1.5mm long are laid in sets of between three and eight in a row.
- The egg stands perpendicular to the plant, with only one end of the egg affixed to the host.
- Asparagus beetle eggs are typically found on the asparagus spear.
- Common asparagus beetle larvae exhibit a dark gray body with a black head.
- It becomes a silken cocoon once it reaches the pupa stage.
- New adult beetles will feature a black body and a metallic bluish-black head.
- Each wing has metallic yellow spots or white spots with red markings outlining the wing.
Spotted Asparagus Beetle
- Spotted asparagus beetle eggs are green in color.
- The eggs lie on the longer side.
- They are typically found around the fern.
- During the larval stage, the cream-colored spotted asparagus beetle larvae feed on the berries of the female asparagus plant.
- Like the common variety, the slugs will have a light cream silken cocoon.
- Once it becomes an adult, the spotted asparagus beetle will turn orange and have six black spots on the wing covers.
How to Control and Get Rid of Asparagus Beetles
Eliminating garden pests such as the asparagus beetle from your home garden requires time and effort. Here are a few options for conducting asparagus beetle control:
Option 1: Frequent Handpicking
A direct approach that does not involve pesticides or chemicals is best for smaller populations. Remove any asparagus beetles from the plant, regardless of the stage: egg, pupa, larva, or adult.
Visit any overwintering areas around your asparagus patch during the early spring, as this is the time the adults feed on new spears.
Have a bucket filled with soapy water nearby when you inspect your plants. Putting the beetles in soapy water will kill them immediately.
Check your plants and schedule harvests every day or two. The goal is to remove the beetles before the eggs hatch.
Option 2: Apply Neem Oil
If you cannot harvest your bounty or for more severe infestations, consider applying neem oil. Neem oil contains several substances that can act as a natural insect repellent, fungicide, and insecticide. This property can manage at least 200 species of insects, fungi, mildew, and rust.
Coat the spears thoroughly with the neem oil. Make it a habit to apply the oil to any new asparagus sprouts you see every week. If you have an issue with the spotted variety, remember to collect the berries before the season ends. Spotted asparagus beetles feed on berries. Removing the asparagus berries can keep them at bay.
Option 3: Use Chemicals
When all else fails, consider using short-acting chemicals such as pyrethrin, malathion, or carbaryl insecticidal dust. Using these chemicals, however, may also affect any beneficial insects that come into contact with the parts sprayed with insecticide. Some beneficial insects that might get affected include the caddis fly, caterpillars, nematodes, and green lacewings, among others.
Option 4: Introduce Natural Predators
Another organic method of eliminating pests like the asparagus beetle is to use its natural enemies against it. For instance, the Tetrastichus asparagi is a type of parasitic wasp. This tiny insect feeds on the egg of the asparagus beetle.
The parasitic wasp can also lay eggs and inject its own young into the asparagus beetle eggs. As the wasps grow inside the egg, they feed on the beetle grubs.
Studies reveal that using insects such as the parasitic wasp yield positive results. Approximately half of the beetle eggs die when the wasp feeds, while the other half become hosts to the next generation of parasitic wasps.
Know More About How to Prevent Pests in Your Garden
Asparagus beetles are a problem for any home garden with an asparagus patch. The tips listed in this guide can help you handle minor to moderate infestations. For more severe cases of infestation, call the experts.
You can trust Pest Guide to handle your asparagus beetle infestation. Call us today to discuss the right pest treatment plan for you!
Frequently Asked Questions
When insects ingest or come in contact with the dust, the carbaryl sends the bug’s nervous system into overdrive. As the nervous system is constantly stimulated, it prevents the breathing muscles from contracting, causing the insect to die.
Adult asparagus beetles overwinter in plant debris such as asparagus stems, weeds, and tree bark.
It is safe to consume asparagus with beetle eggs up to a certain amount. According to the FDA’s Defect Level Handbook, asparagus spears with a maximum contamination level of 10 percent or pieces with no more than six beetle eggs are considered safe to eat.