Garden Word of the Day
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European Asparagus Aphid
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 gray, 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!
Diatomaceous earth, or DE, isn't really earth at all. DE is actually the sedimentary rock formed by countless fossilized diatoms, a crusty little algae.
You can find food grade diatomaceous earth at many garden and feed stores. It can be used to kill pests, dust chickens, or clean your teeth!
Diatomaceous earth is very tiny and it has sharp edges. The edges are too small to hurt humans or chickens, but hard-bodied insects breath through their exoskeleton and DE blocks the insects’ breathing holes. Diatomaceous earth can be used as an insecticide against flea beetles, slugs and snails, mites, aphids, earwigs, and thrips, just to name a few.
You can dust around your house and garden to reduce the number of crawling insects that may be infesting your house or attacking your garden plants. Many grains that you buy in the grocery store contain small amounts of diatomaceous earth, to prevent insects from eating all the grain before you do.
It’s naturally abrasive character makes it an excellent choice as a toothpaste additive and pot scrubber. Chickens love to take dust baths in the stuff, as it helps remove dander, insects, and skin oils.
If you decide to use diatomaceous earth in your garden (or your henhouse), be sure to follow the directions on the package. You really should wear a dust mask and gloves. Use it very sparingly.
Do you ever notice tiny black or orange flying bugs emerging from the soil of your houseplants?
This could mean you have fungus gnats. Fungus gnats are actually flies that feed on organic matter found in soil, and they can be a real problem when soil is kept moist, because the larvae of these little buggers love to chew on your plants' roots. This can cause stunting and make your houseplants susceptible to other pests and diseases.
Overwatering is a common problem for houseplants and the appearance of fungus gnats means it is time to take action.
First, do not overwater. The use of an inexpensive moisture meter (~$10) is a great way to keep your plants healthy, avoid water waste, and make life difficult for your resident fungus gnats.
Second, since fungus gnats love to eat composting plant material, keep your houseplants free of dead and dying leaves, stems and flowers. Pesticides are generally considered a bad idea in this case.
Finally, you can make your own fungus gnat trap by half-filling a bowl or wide mouthed glass with apple cider vinegar and a few drops of dish soap. Place the container near your houseplants. Adult fungus gnats will be attracted to the smell and drown. This won't eliminate the destructive larvae, but, eventually, you will halt their life cycle. This can also help get rid of fruit flies in the kitchen!
To monitor for fungus gnat larvae in your houseplants, simply put a cut piece of potato into the soil for a few days. A simple magnifying glass should help you see if there are fungus gnat larvae present. Replacing the raw potato every few days can go a long way to interrupting the fungus gnat lifecycle.
You can also crumble up a mosquito dunk and sprinkle it over the soil.
Nothing exists in isolation. Our skin is covered with a thousand different types of bacteria, with a population close to a trillion. These critters help protect us against pests and diseases. Plants exist in the same way. There are microbes whose very existence relies upon the presence of a single plant variety's stamen. There are other bacteria that allow plant roots to absorb nitrogen.
As with all other living things, these microbes and bacteria are prey to larger, more complex beings. If these predators arrive too soon, or too late, they will starve, as will their predators, and so on.
Plant DNA contains a series of instructions on how to create the various parts of the plant and how to accomplish specific processes within the plant. As each plant part is developed, it is subject to external conditions: soil composition, temperature, humidity, sun exposure, rainfall, the presence of pollinators, and countless other variables that we have yet to identify.
In the world of gardening and agriculture, phenology models are used to predict the appearance of specific pests and diseases, allowing us to get a head start on protecting our plants. These models are generally temperature-based, since temperatures play such a large role in insect development.
One simple way to learn more about your local phenology is to collect the first fall leaf from your yard, or the first appearance of specific pests, and record the date. As years pass, you will see trends and changes as other factors are altered.
While most people think of the praying mantis as a relatively docile green insect, these insects can be found in many shades of green and brown, and they are one of the most deadly predators in your garden.
Many gardeners (this one included) have purchased beneficial praying mantis egg cases (ootheca) online with the dream of a friendly hunter to combat aphids, caterpillars, moths, and earwigs. Unfortunately, the praying mantis isn't very discriminating. They will eat whatever they can capture, good or bad. Also, many of the online varieties are actually from other countries. The Chinese Mantid can grow large enough to capture, kill, and eat a hummingbird!
The best way to attract native praying mantis to your garden is to provide a welcoming habitat free of pesticides and herbicides. If mantis hatchlings will find that your yard does not have enough food to warrant staying, they soon leave.
In addition to being a good addition to your garden, Praying mantis are also said to make interesting pets...
UPDATE: On 4/21/16, the egg case came to life! Tiny praying mantes emerged and began devouring pests almost immediately!
You can grow a surprising amount of food in your own yard. Ask me how!
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