After investing time and garden space to asparagus, one of the last things you want to see is something attacking your spears. Originally from Europe, this tiny fly is now found everywhere asparagus grows. While asparagus miners do not cause serious damage, they can carry a disease that will
Asparagus miner description and lifecycle
You won’t see the early life stages of asparagus miners. Whitish eggs are only 1/1000” in diameter and laid under the epidermis, at the base of asparagus stalks. Slightly larger larvae (15/1000”) are also white and tapered at both ends, with black mouth hooks. After feeding, they will grow to 1/5” in length before pupating. Pupae are dark brown and flattened and can be up to 17/100” long. These pests overwinter in the pupal stage, either in the soil or in stalks.
Adult flies are small (1/10”), shiny black and somewhat humpbacked. They have clear, tapered wings. In California, they appear in May and again near the end of the summer.
Damage caused by asparagus miners
Damage is usually seen during the fern growth stage. As they feed, asparagus miners burrow a meandering pattern just below the surface. This feeding behavior can result in girdling, which causes chlorosis. More often, the damage is mostly cosmetic.
The real problem associated with asparagus miners is that they are vectors for Fusarium root and crown rot. If you see bright yellow discoloration or wilting in your asparagus plants, it may be that asparagus miners have brought Fusarium root and crown rot to your asparagus bed. In that case, both the affected plant and the surrounding soil should be removed and thrown in the trash.
Controlling asparagus miners
Generally, parasitic wasps keep asparagus miners in check. If a heavy infestation occurs, remove the fern growth at the end of its season and throw it in the trash. Insecticides are not effective.
Now you know.
Fusarium crown and root rot means death for asparagus.
Heavy soil, poor drainage, over-harvesting, and insect feeding all work to create the perfect habitat for this ubiquitous fungi.
Fusarium is a large fungal family that causes several different disease in many garden plants. You may have already heard of Fusarium wilt, but there are several different crown and root diseases caused by these pathogens. One version attacks pumpkins, melons, and other cucurbits. Another group of Fusarium fungi attack asparagus.
Rather than having a single cause, there are three different forms of the Fusarium fungi that cause this fungal disease of asparagus. This trio of Bad Guys go by the names Fusarium oxysporum f. sp. asparagi, F. verticilliodes, and F. proliferatum. [Don’t worry, there won’t be a quiz.] All three fungi colonize the roots and crown, and the first one listed can also infect xylem tissue.
Symptoms of Fusarium crown and root rot
Asparagus plants infected with the Fusarium fungi decline over time. At first, you may see one or more stunted, bright yellow ferns. This bright yellow coloration is a warning flag that should not be ignored. Wilting is also common. If you look at the crown area, you will see reddish brown discoloration. At this point, it is a good idea to pull the plant up, for closer inspection.
Cut open the crown or below ground area of the plant, to see if sunken brown lesions or reddish flecks are present. Then, look closely at the roots. Infected plants will have reddish brown, elliptical lesions on the storage roots. Feeder roots will probably rotted off completely, though any remaining tendrils will have the same reddish brown discoloration seen elsewhere.
Unfortunately, these fungi can survive in the soil indefinitely, and they are found pretty much everywhere. The disease is often spread as infected soil is moved from place to place on shoes, tools, and equipment. It can also be carried on seeds, which is why choosing reliable seed sources is so important. This disease can occur anywhere underground. Very often, insect feeding creates points of entry for these fungi. Asparagus miners are a common culprit.
Controlling Fusarium crown and root rot
Environmental conditions that keep plants healthy also improve their ability to prevent these fungi from entering in the first place, so avoid water stress and feed plants regularly with top dressings of aged compost. [Asparagus plants are very heavy feeders.]
Once a plant becomes infected, it should be removed completely, along with nearby soil, and disposed of in the trash. To reduce the chances of the disease taking hold in the first place, your asparagus plants should be rotated every five years and be sure to provide proper drainage.
Remember, perennial asparagus can provide you with many years of delicious spring and autumn spears, so don’t let these pathogens stop you from trying to grow your own!
Parsley - it’s not just for restaurants any more.
As a kid, I always turned a suspicious eye toward that sprig of greenery on my plate. My mother urged me to try it, so I did. Unfortunately, my young taste buds were not impressed. The mildly bitter bite of parsley was not my idea of delicious until many years later. Now that my taste buds are older and wiser, the refreshing tang of parsley adds a bright balance between flavors, cleanses the palette, and spices things up. If that weren’t reason enough to add parsley to a landscape, parsley packs one heck of a nutritional punch and, hey, it looks nice in the garden!
Parsley is a central Mediterranean plant, which means that it grows well in California, as long as it is protected from our scorching hot summers. Parsley makes an excellent shade garden or container plant. You can even grow it on your kitchen window sill for easy access and nice color if you have strong enough sunlight.
Parsley is related to celeriac and celery, which explains its Latin name (Petroselinum crispum), which means ‘rock celery’, but it’s a heck of a lot easier to grow than celery. Parsley prefers well-drained soil that is kept moist, but my plants seem to grow under just about any conditions. In spite of my heavy clay soil, I have several parsley plants that thrive under roses, trees, and shrubs. Research has shown that parsley also repels asparagus beetles, making it a good companion to asparagus and tomato plants.
Growing parsley does require some patience if you are starting from seed. Seeds should be planted 1/2 inch deep, 6 inches apart, and they can take 4 to 6 weeks to germinate. Germination rates are pretty high, so growing parsley from seed is the most cost effective method. While you’re at it, plant some extras and give young plants to family and friends as gifts!
In tropical areas, flat-leafed and curly parsley are grown as annual herbs. In more temperate regions like ours, parsley is biennial. Biennial plants take two years to go from seed to seed, but some of my parsley plants keep on growing for another year or so. In addition to leaf parsley, there is a variety called Hamburg root parsley (P. crispum radicosum). Root parsley is grown for the taproot, which looks, cooks, and eats like a white carrot. (I may have to try that!)
Parsley plants allowed to go to seed provide habitat, pollen, and nectar to honey bees and many other beneficial insets, some swallowtail butterflies, and even goldfinches.You will probably also end up with many free, randomly placed parsley plants next year!
If flavor and looks weren’t reason enough to grow your own parsley, the CDC says it’s a nutritional gold mine. They ranked parsley at #8 as a food that reduces chronic diseases, such as cancer, coronary disease, and osteoporosis. To learn more, check out the U.S. Dept. of Agriculture’s nutritional analysis website that allows you to look up the nutritional value of pretty much any food. Just 10 sprigs of parsley provides 22% of the RDA for Vitamin C and 200% of Vitamin K.
It’s pretty. It’s durable. It’s good for you. And it tastes good.
Where’s your parsley planted?
April is an excellent time of year to start planting asparagus.
Now, growing asparagus is not a task for the impatient. You will not get a crop the first year. You won’t get a crop the second year, either. However, those succulent stalks are certainly worth the wait. Plus, once they start producing, you will continue to get harvests for many years.
Asparagus was offered to the Egyptian gods over 5,000 years ago, and people have been enjoying it ever since.
Unlike many of our vegetable crops, asparagus grows from crowns, which are food storage rhizomes. The familiar spears, left to their own, will open up and grow into ferny branches that can reach 4-5’ in height. Asparagus leaves are actually modified stems, much like conifers. The root system is adventitious. Yellow to greenish-white flowers emerge and become red berries when fertilized.
DO NOT EAT ASPARAGUS BERRIES. They are poisonous to people.
How to grow asparagus
Before you starting planting asparagus, give the site some thought. Asparagus plants may take a few years to really start producing, they will continue to produce for 20-30 years or more! Asparagus loves raised beds in full or partial sun, and lots of compost-rich soil. Asparagus does not compete well against weeds, so be sure to keep the asparagus bed weed free. Mulching will help a lot.
One year old crowns are the best way to start. Dig a trench 12” deep in the bed and place asparagus crowns 18” apart. Spread the roots out, cover with soil and water, but do not fill in the trench. Watch for new growth. As shoots begin to appear, add more soil, repeating until the trench has been filled. If you want to grow asparagus from seed, the seeds must be germinated between damp paper towels and then gently transferred to soil.
Keep the asparagus bed consistently moist, but not soggy. While spears may appear the first year or two, force yourself to ignore them. Allow the plants to go through their annual cycle. This will help them develop a strong root system, necessary for long term production.
Asparagus pests & diseases
Asparagus is susceptible to Fusarium wilt and asparagus rust. Remove and discard diseased shoots. Aphids can also become a problem. To get rid of the aphids, simply spray the plants with the hose.
By the third year, you should be able to harvest some, but not all, of the spears. They taste the best when they are 5-7” tall. Cut or snap the spears off at or near ground level. By late spring or early summer, your asparagus harvesting season is done. Allow any spear that come up to complete their normal cycle.
If you want white asparagus, you will need to blanch them. That means covering them with soil, newspaper, or some other material that will halt photosynthesis as they grow.
If you end up with a bumper crop of asparagus, you may be tempted to eat it all. That might be a bad idea. Eating a lot of asparagus can make urine smell pretty awful. Instead, the shoots can be pickled and stored for several years. They taste particularly good in a Bloody Mary.
Asparagus is one of those crops that requires a lot of patience.
We eat the immature shoots of new plants that emerge from the roots of the previous year’s growth. To ensure the longevity and production of your asparagus plants, you need to restrain yourself from harvesting new shoots for the first 2 or 3 years to allow for adequate root development. If you can wait, you will be rewarded with 20-30 years of production. That is, of course, unless your plants become infested with the European Asparagus Aphid!
European asparagus aphid description
Native to Eastern Europe and the Mediterranean region, European Asparagus Aphids (Brachycorynella asparagi) were first seen in the U.S. in 1969. They are now found throughout North America. Similar to the over 4,000 other varieties of aphid, the Asparagus Aphid is a tiny (1 mm), soft-bodied, powdery greenish-blue or grayish-green, pear-shaped insect with a pair of cornicles at the tail end of the abdomen. You can think of cornicles as tailpipes that spew a waxy substance in retaliation to attack. Some aphid varieties feature chromed-out monster truck cornicles, but the asparagus aphid is far more subtle and inconspicuous. It has short antennae and a relatively long cauda. The cauda is a tail-like appendage used to fling honeydew away from the insect’s body as it is excreted.
Ants and aphids
Ants are big fans of the honeydew excreted by aphids. So much so that ants will fight off aphid predators, groom aphids, and, I suspect, they might even bring aphids a latte every now and then, to keep them producing. It was the number of ants on my asparagus plants that drew my attention.
I planted my asparagus bed last fall using 1-year old crowns. Most of the crowns made it through our nonexistent winter and our scorching summer, but the ants were a clear indication that something was wrong. Closer inspection showed small, shiny black globules, which turned out to be egg clusters. I also noticed flat grey, oval bodies of immature aphids, upright green bodies of wingless adult females, and black winged adult males. The European asparagus aphid life cycle was in full swing in my asparagus patch and I should have noticed it a lot sooner. (That’s what happens when you go to Burning Man for three weeks at the height of the growing and harvesting season!)
One of the most common methods of controlling aphids is to use short, powerful bursts of water to displace the bugs from their host. This can work pretty well in most cases and it beats the heck out of using pesticides, which tend to kill off beneficial insects (predators and pollinators) along with the Bad Guys. Unfortunately, asparagus aphids damage your plants in a rather unique way that makes hoses an inadequate treatment. In addition to sucking sap from plant veins, these little buggers inject a toxin that reprograms the way the plant grows!
This reprogramming causes the spaces between leaves and twigs ("internodes") to become shorter, creating a tufted appearance called bonsai growth. This increases the number of the aphids’ favorite feeding sites. It can also delay bud break the next spring (which is struggle enough in our winter-less region). New shoots then emerge all at once, thinner and smaller than normal, draining the root system of desperately needed nutrients.
So, what’s an asparagus-loving gardener to do?
So, go check on your asparagus plants and let me know what you see!
You can grow a surprising amount of food in your own yard. Ask me how!
To help The Daily Garden grow, you may see affiliate ads sprouting up in various places. These are not weeds. Pluck one of these offers and, at no extra cost to you, I get a small commission that allows me to buy MORE SEEDS!