Asparagus beetle has a colorful and, frankly, visually appealing appearance.
They look like ladybugs and are often confused with the same.
However, these orange and black beetles are a bad omen for your garden as they are responsible for the destruction of your plants.
Primarily, they attack their namesake asparagus plants.
Common asparagus beetle which is known by its scientific name ‘Crioceris asparagi’ and the spotted asparagus beetle, also called crioceris duodecimpunctata, are two common types of the beetle, which wreak havoc in your garden and attack both wild plants and garden plant.
Even though it is originally from Europe, the species is now found throughout the United States.
What Is Asparagus Beetle
The common asparagus beetle is bluish-black with white or yellow spots throughout the body.
It has a black head and visible legs.
The spotted asparagus beetle is a little bigger and has a blue-black body with black spots.
The common asparagus beetle adults are egg laying dark brown eggs on the spears, flower buds, or ferns of the asparagus plant.
The eggs hatch within a week after which the larvae feed on the fronds.
After about two weeks, the larvae fall to the ground and turn into the pupae in the soil.
The spotted asparagus beetle has the same life cycle, but it appears late in the garden – sometime around mid-May and leaves by late-July.
The spotted asparagus beetle larvae, for a long time, have no negative impact on the overall health of the plant and only keep feeding on asparagus berries and.
What Damage Does Asparagus Beetle Cause?
Asparagus beetle is a common pest of asparagus in North America.
They feed on the leaves of the asparagus plant, which ends up weakening the plant.
This has a negative impact on the plant’s ability to produce sufficient nutrients.
The defoliation of the asparagus plant also makes the plant susceptible to a fungal disease called Fusarium.
How to Control Asparagus Beetle
These annual pests of asparagus are notorious for causing the significant defoliation of the asparagus plant, which, sometimes, lead to the death of the plant.
Controlling the asparagus beetle population may seem to be a daunting task at first but with the right management strategies, you may be able to protect your garden against beetle damage.
#1 – Handpicking the Beetles
- Asparagus beetle adults feed on and attack the plants during the plant growing season.
- Look out for the signs of the beetle on the plant.
- In early May or just after the plant emerges – in early Spring, you may be able to spot the beetle.
- The best time of the day to go look for these pests of asparagus is in the afternoon when they are full of energy.
- If you have a small garden, you may consider handpicking the beetles.
- After picking the insect, drop them in a container filled with soapy water.
- When handpicking the adult beetles, take off the dark brown asparagus beetle eggs from the asparagus spears.
#2 – Preventative Measures
Asparagus beetle infestation turns out to be too damaging for your plants.
And before you take effective steps for beetle control, the pest has had already destroyed the existing plants.
This is why it is crucial to adopt some preventive measures to keep the beetle population away from your garden.
Since asparagus beetles overwinter in plant residue, removing the plant residue in a timely manner will disturb the pest’s overwintering process.
Since they will not have any place to hide in your garden, they won’t be able to make their home there.
#3 – Biological Control with Beneficial Insects
You may have spotted a tiny metallic green wasp in your garden.
Called Tetrastichus asparagi, these wasps are one of the beneficial insects, which are vital in killing both common asparagus beetle larvae and spotted asparagus beetle larvae.
This is because these parasitic wasps live and feed inside the eggs.
Other predators such as lady beetle larvae also chomp through asparagus beetle eggs.
The parasitic wasp, for example, can easily kill up to 70% of the eggs.
#4 – Pesticides
Even if you are successful in killing half of the asparagus beetle eggs, you still have to take steps to get rid of asparagus beetle adults before they lay eggs.
These garden pests are a nuisance and if every method fails in controlling their population, you must protect your plants with the help of a pesticide.
The effective pesticides are those which have the following active ingredients:
- Pyrethroids
- Spinosad
- Carbaryl
- Pyrethrins
- Malathion
- Natural Neem pesticide oil
The pesticides are toxic by nature, so avoid using them when other plants are flowering as the fumes from the spray may end up killing honey bees.