Root aphids in soil

Root aphids — aphids that stay at or above the soil line — are from the family Phylloxera, a near-cousin of aphids. They are an escalating problem, especially among indoor growers, and spreading through parts of the country where they haven’t been seen before. They’re hard to spot and unlike small colonies of green and other aphids found on stems and leaves, root aphids are more likely to get out of control. They can multiply quickly, unseen, and sap enough vigor from your plants to kill them.


Because they’re small — about the size of a mite — and often colored to blend with roots and soil, Phylloxera is hard to spot. Often, growers will see the white, waxy material that the aphids secrete, a chalkier type of the honeydew secreted by other aphids. Their bodies are more pear-shaped than oval as are mealybugs. They’re about the same size or slightly smaller than stem-and-leaf aphids with shorter legs and antennae. They come in a variety of colors, including pink, but are mostly white and brown. They’re commonly confused with the larger mealy bugs, because of the white substance they spread. In their winged stage, they can be confused with fungus gnats. Like other aphids, they have small cornicals or “tail pipes” at the end of their abdomen which also distinguishes them from mealybugs.

Because of their size and below-soil habitat they can go unnoticed, even through one or more grow cycles. They can be spotted attached to the sides of grow cups when growers take the trouble to look. Root aphid damage is often mistaken for other problems, especially nutrient deficiencies. Plants that appear to be suffering from magnesium or iron deficiency should be checked carefully for root aphids.

In outdoor gardens, root aphids may be accompanied by ants. Once established in soil or hydroponic systems, root aphids are difficult to completely remove.


Root aphids are surprisingly adaptable and their lifecycle can vary tremendously. They reproduce asexually during the growing season. Eggs over-winter in soil or, in warm seasons, are attached to leaves and stems above the root line where they hatch and fall to the ground. The aphid bores into the root, creating scars that leave plants vulnerable to mildew and disease. As infestations increase, “crawlers” will move up the stem to feed. Once a plant is nearly destroyed, some root aphids will develop wings that enable them to seek new plants to attack. In the fall, winged aphids, now male and female, mate in brush and trees and produce more eggs. Ants are known to carry aphids from exhausted plants to un-colonized ones.


Damage from root aphids is usually visible in a lack of vigor from plants. Withered, curled, and yellow leaves, similar to signs of nutrient deficiencies, appear and plants fail to reach the size of uninfested plants. Fruits and blossoms on aphid infested plants will be small, stunted, and generally less desirable as nutrition is siphoned away from them.

Attacks from root aphids can leave plants vulnerable to root rot, mildew, and disease.

Visible symptoms, like yellowing leaves, often lead growers to consider adding certain minerals, usually magnesium, to their nutrient mixture, often with no result.

In addition to greenhouse and garden perennials, various types of root aphids attack rice crops, the roots of a variety of trees including fir, walnut, and hickory. Root aphids can also cause problems for perennial herbs, including those grown in pots.

Root Aphid Control

Detecting the first signs of root aphids, especially when growing indoors, is crucial to saving your plants vegetating and fruiting abilities. At a certain point, usually sooner rather than later, affected plants and containers should be removed from the grow space completely and destroyed.

Waiting for fruits or flowers to mature in an attempt to save something of a crop is not advised. This only gives root aphids a chance to inoculate themselves into your entire grow area. It’s best to start over, sanitizing all containers and growing equipment that’s been used. Indoor growers should clean their entire grow space.

Outdoor plants:

  • Avoid introducing commercial grade soils, including bagged composts, that may contain aphids and their eggs. This is probably the most usual way that aphids have been spread to gardens throughout the country. Buy soil and compost from a reliable, local source, make your own.
  • Attract birds who will pick aphid eggs from trees and the ground.
  • Several types of parasitic wasps attack aphid eggs. Ladybugs will also predate aphids they find on the surface but not those burrowed in the soil.
  • Introduce beneficial nematodes (link below) into soil at the first sign of root aphid infestation or, better, in anticipation of them. Nematodes will attack a number of soil-borne pests yet are harmless to earthworms, pets, and humans. Make sure the soil is moist when applying nematodes.
  • Use AzaMax as a preventive treatment to keep aphids from feeding on roots. Because it’s slow acting, AzaMax is not a good choice for treating infestations, but can be effective, over time, for minor infestations.
  • Neem oil can help stop aphid infestations from growing, especially as crawlers move up stems.
  • Do not use insecticidal soaps to control soil-borne aphids. While they will kill crawlers moving up plant stems, they will do little to stop aphids in the soil and may harm your plants’ roots.
  • Pyrethrum-based sprays can be effective if used early enough in the infestation. Water lightly after applying to disperse this chrysanthemum-based botanical into the soil. Reapply every two weeks (eggs in soil may continue hatching) until plants regain vigor and all aphid sign disappears.
  • When removing infected plants, be careful not to drop soil or spread aphids into other parts of your garden. Put plants, roots and all, in a bucket, and take away with minimum disturbance. Removal, in conjunction with preventive spraying, may be your most effective form of control.

Indoor plants:

  • Avoid importing soil or other growing medium of unknown origin into your growing space. Many nursery plants, especially those from large, commercial growers, have been found to carry root aphids and their eggs into green houses.
  • Use yellow sticky traps across indoor grow spaces to discover signs of root aphids on the move.
  • Pay careful attention to your plants. Roots that are visible in grow cups and other hydroponic methods should be periodically inspected. The small, usually white mite stage may be noticeable attached to the sides of grow cups, tanks and trays.
  • Beneficial nematodes introduced to hydroponic solutions at the first sign of infestation may slow the spread of root aphids.
  • With lights off, saturate the growing medium with a solution of Nuke Em (1 oz/ 31 oz water). Slowly pour near the plant stem into the soil and let stand for at least 1 hour — longer contact times are best. Rinse the media before turning lights back on.
  • BotaniGard ES is a highly effective biological insecticide containing Beauveria bassiana, an entomopathogenic fungus that attacks a long-list of troublesome crop pests – even resistant strains! Weekly applications can prevent insect population explosions and provide protection equal to or better than conventional chemical pesticides.
  • When treating aphids in various indoor growing mediums, complete and thorough coverage of infected areas is critical to control. Submerge infested grow cups and root balls completely in a pyrethrum concentrate for a half-minute or more, gently swirling roots and medium to insure complete saturation.
  • Remove badly infested plants. No orchid, no herb or flowering perennial is worth risking your other plants and the health of your entire grow space in an attempt to wait out harvest on an affected plant.

Dealing with root aphids, indoors or out, is an evolving and ever-changing set of practices. Don’t be tempted to use harsh, chemical treatments if you already have an infestation. A University of Maryland Cooperative Extension study conducted inside two greenhouses with root aphids on gallardia, aster and boltonia perennials found applications of Talstar (bifenthrin) and Marathon (imidacloprid) applied as a soil drench gave poor results. Keeping aphids out of your garden or grow space in the first place is the most effective practice. And with this problem spreading, it is becoming harder and harder to do.

Need help with what to do in your garden?

Q What are root aphids?

A They are greenfly-like creatures which live on the roots of plants. Just like their counterparts above ground, they feed by sucking sap, but from roots instead of stems or leaves. They are not easily seen, but they are a common pest.

Caption: Root aphids are a common pest

Q How do I know if root aphids are present?

A When plants wilt, are stunted, have unhealthily coloured foliage and lose leaves prematurely, suspect root aphids. Remember that other factors, especially drought, can have the same effect. Often there will be many ants around infested plants, feeding on the honeydew aphids produce, even below ground.

Q Which root aphids am I likely to come across?

A There are several fairly common root aphids.

Lettuce-root aphid (Pemphigus bursarius) is a very common pest of summer lettuce outdoors. It overwinters as eggs in cracks in the bark of black These common pests go largely unnoticed because they are hidden away underground. The damage they do mostly affects plants when conditions are dry poplars (including the common Lombardy poplar). In spring, the eggs hatch and cause pouch-like galls on the leaf stalks of the tree. Inside each gall 100-250 aphids develop. By midsummer the winged forms disperse on the breeze to lettuce crops and the closely related weed sowthistle. Wingless forms soon colonise the new host’s roots. The yellow/white aphids become covered in a greyish waxy covering. They reach maximum numbers in August. By late summer, winged forms set off to find the winter host trees to breed and lay eggs for next year. Some will survive winter in the soil.

Rose-root aphid (Maculolachnus submacula) seldom harms plants, but looks unsightly as it lays eggs on plant stems in autumn.

Currant-root aphid (Eriosoma ulmi) is only damaging to young or newly planted plants.

Gooseberry-root aphid (Eriosoma grossulariae) is only damaging to young plants.

Grape phylloxera (Daktulosphaira vitifoliae) is the pest that destroyed 19th-century continental vineyards. It has never become established in the UK. If you suspect that it’s attacking your grapes, tell your local agricultural government department.

Pear-parsnip aphid (Anuraphis subterranea) does no real damage.

Auricula-root aphid (Pemphigus auriculae) mainly attacks pot plants in greenhouses, but will also attack outdoor primulas. The pale-green or white aphids with a mealy covering surround the roots.

Elder aphid (Aphis sambuci) attacks the roots of pinks and saxifrages, such as London pride.

Artichoke-tuber aphid (Trama troglodytes) feeds on artichoke tubers.

Bean-root aphid (Trifidaphus phaseoli) occurs in large numbers on broad, French and runner bean roots.

Q What do root aphids look like?

A They usually look like a waxy mould or powder on the roots of the affected plants. They can build up to huge numbers. The affected roots often split.

Q What could I mistake root aphids for?

A Mealy bugs also infest roots of pot plants indoors and could be mistaken for root aphids.

Some harmless fungi cover roots with a powdery covering. Look out for the tiny aphids.

Apples can sometimes have woolly aphids on their roots, but this is not a true root aphid, being mostly a pest of shoots and trunk.

Ants are thought to take a few ordinary aphids into their nests, which may be around the roots of plants.

Q Can do you control root aphids?

A The damage they cause is worst in dry conditions, so keeping plants watered will often help them shake off an attack. In the case of lettuce, plants may survive long enough to heart up and be harvested.

If you catch infestations on pot plants early enough, plants can be saved by washing off the aphids from affected roots and repotting in fresh compost.

Covering lettuce with insect-proof mesh – from June until August prevents the aphids getting to their roots.

There is no chemical control for root aphids, so try to avoid the problem or grow a resistant variety.

Caption: Cover lettuce with fine mesh to protect it from root aphids

Q Can root aphids be avoided?

A Only lettuces sown or planted between mid-April and the end of June are at risk. At these times use resistant varieties. Other root aphids probably can’t be avoided.

Q Which varieties are resistant to root aphids?

Q What should I do with affected roots?

A Composting, burning or burying affected plant material will reduce the number of survivors. Always aim to get rid of as much of the aphid-infested root and surrounding soil and compost as possible. Avoid growing susceptible plants in the same soil or site for a year.

Root aphids are a big problem for succulent plants and root crops.

These pests invade the roots of plants and deplete their root systems by sucking the juice from the roots.

This stunts plants’ growth and causes their leaves to wilt and turn yellow.

Some of the favorite plant “roots” these aphids’ love include:

  • Hosta
  • Coreopsis
  • Asters
  • Veronica plants
  • Sedum many varieties

They can cause significant damage to hickory, walnut and fir trees and have been known to devastate rice crops.

They can also do a great deal of damage to herbs such as basil and oregano and are incredibly problematic to marijuana growers.

What Do Root Aphids Look Like?

There are three types of root and crown aphids. They are:

  • Hawthorne/Parsley aphids (Dysaphis foeniculus and D. apiifolia) is grayish white in color.
  • Tulip bulbs aphids (D. tulipae) looks something like a mealy bug because it is coated with white waxy powder.
  • Hawthorne carrot aphid (D. crataegi) may be yellowish or greenish gray and has a light waxy dusting.

Because the root aphid is white, many gardeners mistake them for mealybugs.

You can tell these two types of pests apart because mealybugs are quite a bit larger than aphids found on roots.

Additionally, root aphids’ bodies are teardrop shaped, and they have two pointy protrusions (cornicals) on their hind ends.

Aphids feeding on roots are closely related to leaf and stem sucking aphids. All belong to the Phylloxera family of insects.

Unlike their aboveground cousins (e.g., green peach aphids and melon aphids) root aphids are relatively stationary.

How Do You Know You Have Root Aphids?

Aphids attacking root area congregate in groups underground on the roots of plants causing root aphid damage.

You can recognize their presence by the masses of soft, white tissues on infested plants these colonies create in the roots.

They’re sometimes referred to white soil mites.

However, if you find big infestations on your plant roots, it will be too late to do anything about it.

Root aphids move from one to place to another on their own in a very slow manner. You may occasionally see them spread about on the lower parts of the plant.

They may crawl up plant stems and attack the body of the plant. But for the most part, they congregate in the roots.

You may see aphids at the base of plant stems and the tops of the roots. They congregate in colonies and occasionally form just below the surface of the gardens soil.

Even if you don’t see the aphids, you may be tipped off to their presence because ants tend to be attracted to the honeydew these pests excrete.

Additionally, ants may manage aphids on leaves and roots by carrying them from ‘old,’ spent plants to fresh ones.

Related Reading: Aphid Control on Succulents

What Kind of Damage Do Root Aphids Cause?

Root aphid eggs overwinter in the garden, and immature aphids emerge in the spring to go to work using their piercing-sucking mouthparts on the tender roots of young plants.

Affected plants wither, turn yellow and die.

Gardeners often misidentify this condition as nutrient deficiencies, lack of the mineral, magnesium, but it may be your first indication of an aphid infestation.

If their devastation goes unchecked, these pests will multiply rapidly and destroy the plants they infest.

Once they consume all food sources, the insects slim down, grow wings and fly off to mate, lay eggs and start the whole process over.

In the autumn, you may see quite a few winged root aphids flying around.

At this life stage, they tend to resemble fungus gnats.

However, you can identify them by the tell-tale cornicals which still protrude from their hind ends.

How To Get Rid Of Root Aphids

The best thing to help eliminate root aphids is to keep your garden equipment clean, rotate your crops and be vigilant to catch the presence of these pests quickly.

Yellow sticky traps will not work.

Practice good garden hygiene. Irrigation water running from one plant to another can carry root aphids from plant to plant.

They may also travel on gardening tools or inside reused containers.

Always sterilize garden tools, pots and any other item which may come in contact with aphids in soil root balls or on the roots of your plants.

Avoid root aphid infestation by checking the roots of your plants occasionally. This is easier with container plants than garden plants.

When you see aphids in plant roots, you are far better off just getting rid of the plant than attempting to treat it.

When you remove affected plants, dig up a large amount of surrounding soil.

Contain the soil in a bucket or plastic bag to avoid spreading the aphids as you carry the plant and soil to the garbage bin.

Introducing beneficial nematodes to the soil can help keep root nematodes under control. Some parasitic wasps and birds do eat root aphid eggs.

Generally, it is difficult to control these pests through natural means.

Throughout the root aphid life cycle, these aphids are underground and protected from most natural parasites and root aphid predators.

Furthermore, the ants who attend them will fight off these natural garden helpers.

Are Pesticides Effective For Aphid Pest Control?

It is challenging to manage and kill root aphids through the use of insecticides. Use a soil drench and thoroughly soak the growing medium.

The type of growing medium used makes a big difference in how effective the method of drenching to control root zone pest.

If the soil drains rapidly and contains a great deal of peat moss or bark, it will not work as well as a more dense soil.

Additionally, the wax coating on these insects provides them with a great deal of protection against contact insecticides.

Systemic insecticides may eventually be useful, but these bugs reproduce rapidly and are very likely to get out ahead of you even with a systemic insecticide.

If you do want to try a pesticide to control root aphids, the Michigan State University Extension recommends the use of dinotefuran or imidacloprid.

Other possible choices include cyfluthrin, malathion, and thiamethoxam.

Even though these are the most effective insecticides against root aphids, it’s important to understand that, used as a soil drench, the pesticide will move up into the plant and may not remain in the roots long enough to affect the pests very much.

Use Pesticides With Care

If you choose to use one of these pesticides be sure to follow up with a second application approximately two weeks after the first.

Understand that using these pesticides can do quite a bit of harm to beneficial pollinators.

Both dinotefuran and imidacloprid are neonicotinoids and are quite toxic to bees, butterflies and other valuable beneficial insects.

As a natural alternative, try using a neem oil drench solution. However, this solution has the same drawbacks as any other drench solution.

Furthermore, if you decide to use a neem oil drench, you’ll need to reapply it every couple of weeks throughout the plants’ growing season.

Source: 1

GREETINGS MY GREEN FRIENDS, and welcome to another addition in my pest series in, The Highway. Root aphids literally suck. They bore into roots tapping the plants for nutrients and leaving behind those “open wounds” on the roots that things like parasitic fungi like to take advantage of. For you serious all-natural growers in soil, you know that there are likely soil mites present in your soil, and these are really good-guys. Root aphids and soil mites can pretty easily be confused with each other. A few things make them easy to distinguish. I’ll share those things, along with a way I have used to combat them for friends that have been infested with root aphids. Get comfy, do a couple rips and away we go…

Rule #1 is: Avoid These Pests Proactively

These parasites come in a wide range of colors, some are camouflaged, some are white, and I read that even pink is a possibility—pretty sure it would be easy to notice pink ones, heh heh—anyway, since they lay eggs in soil/compost; also, they can leave eggs on plants, especially during their flying stage. So first of all, I would suggest you make sure your air intake for your indoor gardens is screened; better yet draw air from an alternate source that is not directly outside. I draw my air flow passively through/from my house, so I can easily avoid the flying version of these Root Aphids (and many other “bad guys”) from getting sucked in.

During Root Aphids final cycle of life, their 5thstage that is also their flying stage. One friend I cured of these pests thought he just had fungus gnats, but it was actually a huge infestation of Root Aphids, many in the flying stage—and every stage in between as well. But the flying stage is when they can really spread out in your gardens; so, double check those “fungus gnats” maybe too 😊

Commercially available soil, as I have read many accounts of, possibly can contain dormant Root Aphid eggs, so this is of big concern to many of you, and these appear to be prevalent especially along the west coast, USA. Now myself, I have never had the “pleasure” of getting these little parasites, but I have helped several people personally get rid of them, and I’ll share that info in a bit. I use G&B brand Potting Soil, for transplanting freshly rooted clones into, and I have never gotten these Root Aphids; I have been a loyal G&B fan for at least 5 years now, and if I am teaching someone how to make their own soil blend, that’s a perfect starting mix, in my opinion, and experience. I recycle all my soil and re-amend it, so it is a bit too strong for freshly rooted clones. So, I guess the bottom line here is thinking about your intake venting and finding a good bagged soil that hopefully won’t have any of these pests (or others) along for the ride waiting to happen in your garden.

As with so many other little parasites that can cause havoc in your gardens, avoid bringing plants (like clones in soil) into your gardens from a shop or friend’s garden. In my experience, this is how about 75% of pests get into gardens in the first place.

Identifying These Root-Sucking Minibeasts

They like hanging around on top (very shallow and often along sides of pots) of the soil. In hydro gardens, they can swarm roots utterly—but at first, glance when growing in soil, appear much like soil mites, which are totally beneficial to your plants. One thing they do differently is if they have been there awhile, Root Aphids will leave kind of a chalky residue where they are concentrated at; don’t confuse calcium “lime” build up with this if you use harder water, or a lot of liquid fertilizers, or salty teas. Also, upon closer examination with a magnifying glass or Jeweler’s Loupe, you can see telltale signs these are not mites at all, and the very familiar little “spouts or pipes” can be seen on these bad-guys like their cousins, regular aphids have on their rear abdomen. Soil mites do not have these. Another dead give-a-way is that the Root Aphids are insects and have 6 legs; soil mites are more like spiders and ticks and also have 8 legs.

They like the plant roots closest to the surface of the soil, and even can often be seen where the main stem meets the soil line. When you are transplanting plants have a look in the containers after you have pulled out the root ball, they are often along sided of containers, and so, will also be on roots down the sides as well. Soil mites wander around in the soil processing organic matter and never have their attention on the actual living plant at all. The Root Aphids will be gathered near plant roots, especially right off the main stem, and while some will be wandering most will be feeding on the plant until disturbed. Again, keep eyes peeled for that chalky white residue they leave behind, that is one of the Root Aphids’ signature marks.

Getting Rid of Root Aphids

I have used predatory nematodes, which themselves are alive and kill a wide range of pests in the soil, without causing any harm to earthworms, pets, or people. I have used these to help friends out with Root Aphid problems 4 or 5 times with 100% success ratio, and total eradication. Here’s the link to these predator nematodes at Amazon. Make sure to read all the instructions carefully/thoroughly so you don’t waste your money. These will cost you about $30.00 USD: LINK:

A cool bonus about these nematodes is that if you happen to have fungus gnat problems, these guys will also kill fungus gnat larva in the soil.

Make sure to wash out all your growing containers always, and thoroughly between plants. The nematodes work best in moist soil, so I always water the plants 24 hours before using the nematodes, and I also apply the nematodes just before lights out/darkness. I have never had to drench the roots with these nematodes, I simply use about 2 cups of the nematode-inoculated water, per 3 gallons of container size you are treating. Within 10 days they were gone using this method.

You can learn how to recycle your soil, plants, and roots, in the 2nd Edition of my book: True Living Organics. So, check that out if you are curious about doing this and much more. I hope this helps some of you out, Root Aphids make plants they are feeding on look like they are experiencing magnesium deficiencies very commonly, and could easily be misdiagnosed as this.

Rev Rambles at the End

Here’s what these nematodes attack and kill

Sorry for the lack of predator photos, my gardens are just literally pest free almost all the time. Every 4 or 5 years I get hit with something, usually garden-variety spider mites. In my next article here in The Highway, I will share with you all how to use what I call “The Nuclear Option” to rid yourselves of certain infestations of things like mutant-strong spider mites, and russet mites. I showed you how to get rid of Powdery Mildew already in this series, along with Fungus Gnats. Important to note these nematodes also kill Thrips. I hear from some of you guys who get hit with these—knocking on wood—I have never had these in my life, and I’m good with that, heh heh.

Personally, I would rather get pest advice from an all-natural style grower, that didn’t have pest problems, rather than a pest infested advisor—sometimes I just think funny things. So, go into your preferred online search engine and check out some photos of Root Aphids, and Soil Mites as well. The next article is gonna be a big one, revolving around a radical move to become pest free, and tips on how to stay that way. Cheers humans, until next time; keep the shiny side up and the dirty side down.

PS: the bud photo is a Riffraff Thai, under a full spectrum CX-6 LED 350w, in a Gorilla Tent; All TLO All the Time. Here’s the link to my latest book on Amazon:

Root Aphids, Fungus Gnats, and Spider Mites: Eliminate These Marijuana Pests Completely

Marijuana has been grown outdoors for thousands of years. During that time, cultivators have faced dozens of threats in the form of disease and pests. While humans don’t usually eat raw cannabis, it seems to fit the palate of many bugs, insects, and other animals. If you are unable to spot an infestation in time, there’s a chance that your entire crop will be ruined.

A simple and effective way to deter and kill pests is to use chemical insecticides. However, these products can damage the crop too, and ruin the taste. Think about it for a second. Would you like to smoke weed that has been heavily sprayed with commercial-grade chemicals?

In this guide, we provide you with natural methods of removing three of the most common cannabis pests. These are: Root aphids, fungus gnats, and spider mites.

Rhopalosiphum rufiabdominale, the Rice Root Aphid, is a soft-bodied insect that infests the foliage and root systems of its host plants. These bugs can range from reddish-brown to bright green in coloration.

If a plant is heavily infested, the leaves become yellow and begin to wilt. Aphids also produce a large amount of honeydew, a sugary liquid waste. The honeydew emitted from the aphid’s anus often attracts sooty mold, which accumulates on leaves and branches, turning them black.

Your cannabis garden can become infested when a winged aphid lands and lays eggs. It only takes a handful of aphids to cause an infestation. The eggs quickly hatch to produce ‘nymphs’ which begin feeding on your crop. These young aphids mature in 7-10 days, and when they shed their skin, they leave behind silver-colored exoskeletons.

Removing Root Aphids

A root aphid colony can get out of control within a couple of weeks, so you have to act fast. Examine your plants at least once a week and look beneath new leaves for clusters. If you spot some, it is a sign that several colonies are well-established in your garden. Here is a quick list of things to do once you spot an infestation of aphids:

  • Insecticidal soaps: These soaps suffocate or dissolve the exoskeleton of aphids. As soaps don’t stay on plants for long, we recommend several follow-up applications.
  • Neem oil: Azadirachtin, the active ingredient in Neem oil, is effective against most pests. The chemical can, however, be damaging to buds (and is potentially harmful to humans), so spray carefully.
  • Spinosad: They kill aphids on contact, but aren’t very strong. As a result, you need to use them numerous times.
  • Introduce predators (like ladybugs and lacewing larvae): You can introduce these insects to your garden for the most natural of solutions. One issue with ladybugs is that they tend to fly away after a couple of days.
  • Remove ants: Ants farm aphids to collect their honeydew. As a result, you have to get rid of ants in your garden because they keep the aphid population high!

These pests look similar to tiny mosquitoes and are just 2-4mm long. They produce larvae up to 6mm long, which live in your growing medium. The problem with these larvae is that they damage the roots of the marijuana plant. A severe infestation reduces a plant’s strength and makes it susceptible to diseases such as root rot.

Fungus gnats thrive in moist conditions, which means they love it when growers overwater their soil. After fungus grows or overwatered matter decays into the soil, gnats lay their eggs in the wet soil’s top layer.

How to Remove Fungus Gnats

To reduce the risk of a fungus gnat infestation, make sure the humidity in your grow room is low. Signs of gnats include:

  • Tiny black bugs crawling on the soil or flying around the plants.
  • White/translucent larvae with black heads on the soil.

If left untreated, fungus gnats can result in a nutrient deficiency, a halt in plant growth, and reduced yields. If you find gnats, here’s how to get rid of them:

  • Yellow sticky cards: These are special traps designed for gnats, which love the color yellow. The glue traps the gnats and severely reduces their numbers. You can monitor the cards to see if an infestation is being managed. If your cards become less covered in gnats, it is a sign that the population has been severely reduced.
  • Use a fan: Place a fan in a position where it blows air out the top of the growing medium. It helps dry out the top layer and stops gnats laying more eggs.
  • Dry out the soil: Avoid watering your plants for a few days to dry out the soil. This should kill a large percentage of larvae. Once the first few inches have become dry, the next step is to add a treatment.
  • Kill the larvae: Spray the top layer of soil with neem oil. Make sure you don’t use the oil less than a week before harvest, and that it doesn’t touch the buds. Alternatively, sprinkle food-grade diatomaceous earth overexposed parts of the growing medium.

If there are still larvae remaining after your treatment, it’s time to switch things up because they are resisting treatment. Products such as Bacillus thuringiensis (a species of bacteria), SM-90, and Essentria IC3 Insecticide should do the job. That is if you don’t mind going down the chemical route. After a fungus gnat infestation, water your crop less often and keep using your sticky cards.

These mites are the most common cannabis pest. As they are only 0.4mm in size, they are tough to spot with the naked eye. You will probably need a magnifying glass to spot these insects.

As small as they are, spider mites can ruin a crop. They have sharp mouths that pierce the individual plant cells, removing the contents.

You may spot orange, white, or yellow specks on your plant’s leaves and wonder what they are. We’re afraid to say; they are probably spider mites! Their diminutive nature means it can take days or even weeks to spot them. Here are a few reasons why growers dread spider mites:

  • Spider mites easily re-infest a crop if they are not entirely eradicated, including ones in nearby areas.
  • Spider mites produce silk webbing, which covers buds and leaves. Even if you get rid of the mites, their webs can still ruin the quality of your crop.

Spider mites become resistant to different methods of eradication.

Removing Spider Mites

Even when you destroy a spider mite infestation, it can quickly repopulate. Early detection is vitally important. You can only do so by thoroughly inspecting both sides of the leaves of your plants. Once you spot them, you must assume your garden is infested for the duration of the marijuana plant’s growth cycle. Here is how to get rid of spider mites once you have found them:

  • Because they are exotherms, consider increasing the temperature above 30 degrees Celsius. This is because spider mites cannot regulate their body temperature in excessive heat.
  • Spinosad products such as Mighty Wash and Azamax work well when sprayed directly on the roots.
  • Stethorus punctillum is the Spider Mite ladybeetle, and it feeds on spider mites voraciously. Phytoseiulus persimilis is another predatory mite that evolved specifically to feed on spider mites as well!
  • Be sure to rotate treatments as part of an integrated pest management approach.
  • After your initial treatment, follow up in 2-3 days with a different method. Let’s say you used neem oil. This time, try the DIY alcohol spray remedy. You will need to repeat the treatment at least once more. Remember, it must be different from the first two treatments.

Prevent spider mites by carefully checking new plants and clones by ensuring good airflow and maintaining a comfortable room temperature. It is also worth sprinkling diatomaceous earth on top of your soil and around the grow room.

Final Tips on Preventing and Removing Pests from Your Cannabis Garden

Growing cannabis can be challenging, and there is nothing worse than having your hard work ruined by unwelcome pests. Prevention is better than cure. If you find root aphids, spider mites, or fungus gnats damaging your crop, you have to act fast. Otherwise, you risk the ruination of your crop. Here are some quick tips to kill pests and keep them at bay:

  • Don’t use anything other than sterilized soil or fertilizer. To sterilize the soil, put it in the oven at a temperature of 160-180 degrees Fahrenheit for 30-45 minutes.
  • Consider growing ‘companion’ plants such as basil, garlic, mint, or marigolds. Leaf eating pests tend to hate the smell of these plants and steer clear.
  • For mammalian pests, purchase the urine of their enemies. Some stores specialize in these products.
  • Make sure all of your cannabis growing equipment is sterile. You must wash your hands before touching plants and remove any debris you find as soon as possible. A clean grow room is a safe one!
  • Build a fence around your cannabis garden if it is outside. Animals carry a bevy of pathogens and bugs, so keeping them away from your crop is half the battle.
  • If you are growing weed indoors, seal your grow room. Spray foam or caulk is useful to fill in gaps, and also seals windows and doors effectively.
  • Change your clothes before entering your grow room if you were outside. Otherwise, you run the risk of bringing in pests.

How to Get Rid of Root Aphids

Root aphids – a cousin of standard green or stem-and-leaf aphids – belong to the family Phylloxera, and typically exist at or below the soil line. They are a prominent issue for indoor gardeners, but may also affect outdoor crops. Unlike other aphids, root aphids are much more likely to overwhelm your plants and kill your crops. This is because they attack the central source of the plant’s nutrition – the root system.

Dealing with a Root Aphid Problem

Root aphids are minuscule and colored to blend in with the soil. The primary way to identify a root aphid infestation is via the waxy substance that they leave behind. If you begin to notice a chalky, white residue (also known as “honeydew”) on any part of your plants, you should begin to suspect that something undesirable is feeding upon them.

Similar to mealybugs, root aphids’ bodies are somewhat teardrop-shaped. As a matter of fact, root aphids are often confused with mealybugs due to their shape and the honeydew substance they leave behind. Some root aphids progress into a winged stage in order to travel to other plants, at which point they are also commonly mistaken for fungus gnats. One simple way to distinguish all breeds of aphids from these other insects is to look for the conical tail protruding from the end part of their torso.

Root aphids are most destructive because they are quite adaptable to both indoor as well as outdoor conditions. When found outdoors, they are often accompanied by ants, which only further compounds the problem and makes their eradication that much more difficult. The ants will often carry the root aphids’ eggs to other locations, spreading the problem. Root aphids’ eggs are capable of surviving through the winter beneath the soil, or they will attach to low-hanging stems and leaves in the warm season, allowing the root aphids to fall to the soil once hatched.

Many commercial-grade soils also contain root aphid eggs. Probably the best advice for avoiding root aphids is to always avoid purchasing bagged soils unless they are from a local, reputable source. Additionally, avoid purchasing soil from large nurseries, or otherwise importing soil or compost from unknown locations. Always make your own soil and compost whenever possible.

Plant Removal

The most effective method for treating a plant that is noticeably affected by root aphids is to remove and destroy the entire plant. Waiting to see if the plant will still flower, produce fruit or otherwise thrive is not recommended as the longer the aphids are allowed to remain, the more widely the problem is likely to spread. When removing the plant, take care to keep the root aphids and eggs as contained as possible – avoid shaking the plant and dropping any aphids or eggs onto the soil or any healthy plants below.

If you are not keen on removing your entire plant, it is possible to cook the soil in order to kill the aphids. If you have an indoor garden, remove the plant from the soil, then remove the soil from the container. Place soil on a baking sheet and bring up to temperature. If outdoors, the same effect can be achieved by placing a black tarp over the affected garden soil on a sunny day. The effectiveness of this solution varies, so be sure to check for remaining root aphids after treatment.

Sticky Traps

Yellow sticky traps are recommended to assist in trapping any moving root aphids. Beneficial nematodes can also be added to your soil in order to help with the eradication of these insects.

Insecticidal Soaps

Insecticidal soaps are not recommended as a treatment for root aphids. This is due to that fact that they will not kill any bugs located beneath the soil. Instead, we recommend you treat your plants with neem oil or a pyrethrum-based spray, which will need to be used early during the infestation. You may also water a Spinosad-based insecticide into the soil, or utilize Beauveria, a fungus that contains spores that will attack the root aphids.

Beneficial Predator Insects

Finally, we recommend attracting predator species such as birds which will pick the aphids off of your outdoor crops. You can also introduce parasitic wasps and ladybugs, which will both eat any root aphids found above the soil.

Root aphids can certainly do quite a bit of damage to indoor and outdoor grow spaces if not caught early. Make sure to stay vigilant, as these creepy crawlers are one of the big reasons we check our plants daily! If you notice signs that the root aphids have moved in, evict them quickly and save your plants following our instructions above. But remember, if you must destroy one plant, it is much better than losing half of your garden due to an infestation that has been left to spread.

You enter your grow room and notice your plants looking a little sad and undernourished — almost like they aren’t getting enough nutrients. You check for all the regular quick fixes. They’re adequately watered, but not overwatered. Your feeding schedule ensures all your nutrient levels are all ideal. The pH is also in the ideal range. No visible pests, nor signs of spider mites. So finally, you check the roots. And it’s your worst fear.

You have a root aphid infestation.

Root aphids destroy crops by leaching nutrients from the plants’ roots and leaving lesions there that are unable to heal due to an enzyme the little jerks leave behind. These nasty, pervasive pests are an issue for cannabis growers all over North America and beyond.

But in order to prevent, identify and treat root aphids, it helps to first know a bit about them.

What Is The Root Aphid And What Can It Do To Your Crop?

The root aphid has been an enemy of horticulturists for more than a century. Before terrorizing cannabis growers, they decimated the crops of vineyards in France, almost destroying the wine industry in an incident known as the Great French Wine Blight.

Root aphids, part of the phylloxera family of bugs, are native to the eastern and southeastern United States, and were first found in California in the 1850s, according to “Grape Phylloxera”, published by Oregon State University. In 1860, American grapevines were exported to France to help fight powdery mildew, and root aphids hitched a ride with them. This led to two-thirds of the destruction of Vitis vinifera vineyards in Europe by 1900. Cannabis growers have also become accustomed to this infamous pest in recent years.

Part of what makes root aphids so prevalent is their prolific life cycle.

The article “Grape Phylloxera – Pest Management Program for Grape Series” by Ontario’s Ministry of Agriculture, Food and Rural Affairs explains the complex life cycle of these hated pests:

In the spring, as soil temperature rises. nymphs begin feeding on root sap and mature to adults in 15 to 20 days. The spring and summer feeding adults, which are strictly females, reproduce without male fertilization. One female can produce 100 to 150 eggs over a period of approximately 45 days. New nymphs move to other root areas, begin feeding and cause gall formation. When mature, they will start producing the next generation of eggs. Five to nine overlapping generations can occur during a growing season. In September and October, newly hatched first instar nymphs begin hibernation for the winter.

With such a diverse and fertile reproductive cycle, it’s no wonder cannabis growers have such a difficult time eradicating these pests.

Ants can carry root aphids from drained plants to healthy, uncolonized ones.

How To Identify Root Aphids In Your Cannabis Crop

So, how do you know if you have root aphids? After you’ve ruled out all other possibilities that may be making your plants look unhealthy, you can look for some telltale signs that root aphids are in fact the cause of your problem.

Firstly, the plants themselves will look like they need feeding, with small flowers and stunted growth. They’ll also show signs similar to magnesium and iron deficiencies, such as yellow leaves, because root aphids are in fact sucking these nutrients from your plants.

Once you’ve ruled out other possible causes above ground, it’s time to inspect the roots. If root aphids are to blame, infected cannabis roots become yellow, swollen and hard. Once the plants have been damaged, they become vulnerable to other issues, such as fungus and root rot.

The pesky little devils themselves can change form, which can make them easily confused with other bugs, like fungus gnats, and somewhat difficult to identify. Root aphids measure about 1 mm, are pear-shaped, and have been observed in shades of white, yellow, green, brown and orange. They tend to camouflage with whichever roots they’re feeding off, so cannabis aphids tend to be in the white to tan to brown color range.

Root aphids do grow wings during their life cycle, which is when they start to resemble fungus gnats. To tell the two apart, remember that root aphids are shorter, stockier, with shorter legs. The wings of root aphids are longer and slenderer than that of fungus gnats, who also have longer legs and rounder wings than root aphids.

One way to help detect root aphids, at least in their flying form, is to use yellow sticky tape. While yellow sticky tape doesn’t take care of enough root aphids to put much of a dent in their population, it can help you identify them, and if you use gridded tape, it can also help indicate volume.

So, bottom line, if you inspect your sad plants and find unhealthy roots swarming with little bugs, then you probably have a root aphid infestation.

Plants that are suffering a root aphid infestation will display yellow leaves.

How To Prevent Root Aphids In Your Cannabis Grow Op

The best way to deal with root aphids is to never get them in the first place! The nasty little suckers are so difficult to get rid of, preventing them altogether is the ideal scenario.

If you’re an outdoor grower, there is no surefire way to completely prevent root aphids. Nature will do what nature pleases. You can, however, use some of these methods listed below, but the root aphids will likely reside on nearby plants and come back again. So, growing indoors is the only way to really prevent root aphids.

Following are top tips to help you keep your cannabis roots aphid free:

  • Keep your grow area clean.
  • Seal your grow room completely.
  • Make sure your grow equipment, and every crevice and wall, is sterile. Root aphids like to lay eggs in walls, which can then remain dormant over the winter. So, you can be free from root aphids for months — then those little suckers will hatch and infest your plants, seemingly out of nowhere.
  • Avoid using unknown, nonsterile soil or grow medium. Source your soil carefully! Ask whoever sells you your soil if they know of any brands that have been infected with root aphids.
  • Root drench fresh clones with organic pesticides.
  • Introduce parasitic wasps or ladybugs. They’ll eat any root aphids living on the surface.
  • Keep household pets out of your grow! They can have all kinds of critters on them, including root aphids.
  • Use beneficial nematodes in the soil. These naturally occurring, microscopic roundworms are a nontoxic, safe prevention method.
  • Don’t overwater your cannabis crop! Root aphids seem to like moist soil.
  • Pyrethrum concentrates, which are extracted from chrysanthemum, can be an effective organic pesticide to help control and kill root aphids when root balls are submerged in a pyrethrum solution.
  • Rosemary oil and lemongrass oil are organic, plant-based pesticides that can be effective at prevention and also as a light treatment for root aphids.
  • Azadirachtin, which is extracted from neem seed kernels, is another plant-based pesticide option that has been proven effective in preventing and even treating small infestations of phylloxera.
  • Make sure you stay vigilant about maintaining the cleanliness of your pots if using rockwool and coco coir, mediums that root aphids seem to prefer.
  • Use soil and amend it with sand and diatomaceous earth. While this method will not treat infestations, it can help prevent them.
  • Bti (bacillus thuringiensis israelensis) larvicide can be put in your water reservoir to help kill root aphids at the larva stage when watering.

Best Treatment For Root Aphids In Your Cannabis

Once you face the awfully reality of a full-fledged root aphid infestation in your cannabis crop, getting control of it can be a struggle. The best way to be rid of a root aphid infestation is to ditch all your plants and genetics after harvest. Starting from scratch isn’t ideal, but neither is having a repeated root aphid infestation every grow season. If you catch the bugs early enough, there are a few methods that will help keep root aphid populations down, or possibly even eradicate them, while not injuring your roots beyond repair.

All of these methods require a root drench, as foliar applications will only work for prevention, not treatment:

  • Citric acid-based pesticides: A nontoxic, organic, effective, safe solution to root aphids.
  • Beauveria bassiana: An entomopathogenic fungus, meaning that it acts as a parasite on various arthropods, including root aphids. It occurs naturally in soil, and can be found in commercial pesticides.
  • Hydrogen peroxide: Can be used in soil in small amounts to help treat root aphids. But be careful to not overdo it because hydrogen peroxide can be harmful to plants, and it can also kill other beneficial microbes in soil.

As far as pests go, root aphids are among the worst. Nothing kills a cannabis grower’s buzz quite like discovering a root aphid infestation. Luckily, we’ve given you plenty of preventative steps to take to stop or treat a root aphid infestation once discovered. Whatever you do, don’t ignore the problem, and take action quickly. Because one thing is for sure, left untreated, root aphids will not go away on their own.

Controlling aphids in a hydroponic crop. Part 1.

Without a doubt aphids are one of the most common pests affecting crops worldwide. There are both root and leaf aphids, the former which generally live only around plant roots – producing winged offspring only to infest new plants – while the later live generally in plant stems, leaves and – when infestations are bad enough – even within plant flowers and fruits. Today we are going to talk about several alternatives to deal with aphids, from traditional insecticides to more natural alternatives such as biocontrol options. We are not going to discuss mechanical options here – we’ll leave that to part two – as we’ll focus only on chemical and biological control within this first part.

There is one clear winner when controlling aphids. At the present time nothing will beat neonicotinoids in fighting aphids as these insecticides are very effective against a wide range of sucking insects (which are insects that suck material out of plant tissues). Originally made during the mid 1980’s and massively popularized during the 1990’s (see here) insecticides like imidacloprid have been huge winners in the fight against aphids. They are applied via soil applications – no need for foliar applications – where they are absorbed by the roots and effectively make plant tissue completely toxic for aphids, affecting their nervous system.

However everything is not rosy with insecticides like imidacloprid. Neonicotinoids affect beneficial insect populations – bees in particular (see here) – so they are not good for the environment in general. As a secondary problem they also remain within plants for a really long time so they should only be used when plants are a significant time away from harvest (at least 60 days is usually recommended). When using on edible crops make sure you get a formulation that has been specifically designed for this purpose (like this one). However some legislations require no imidacloprid to be present in plant tissue meant for human consumption so it is important to check with regulatory guidelines regarding its use. There are several studies showing how imidacloprid can accumulate in fruits and flowers (see here for an example in maize, here for an example in tomatoes).

Perhaps we can resort to less damaging alternatives but still control aphids effectively. Predatory insect applications don’t work very well (another post about this coming soon!). But one of the best alternatives I have found so far is to use Lecanicillium Lecanii – and other Lecanicillium species – as a parasitic fungus to attach the aphids. Not only are they effective in attacking aphids but they can also be used as a two-for-one control against powdery mildew and other pathogens as well (see here, here and here). I have had a few recent experiences with customers that have had good success using such fungi to control aphids in several crop types, including parsley and tomatoes. I have had great personal success in parsley, basil and mint plants. These two are the products that I have seen used containing this fungi (here and here). Image below taken from this paper and first image in this post taken from this paper.

There are also some naturally occurring insecticides that can be used, such as neem oil based products. The problem with these insecticides is that they do work – sort of- depending on the plant and aphid specie you are trying to tackle (see here). Generally 0.2-0.5% emulsions of the oil are effective against aphid populations with such application generally killing most aphids when they work (see here and here). Although neem oil applications shouldn’t be considered as a stand-alone solution they can provide a strong head-start when dealing with aphid infestations since they can kill a large portion of the population – if they are susceptible – without harming beneficial insects that might be predating on the aphids already. Last image in this post taken from this paper.

For root aphids the option to use beneficial nematodes also exists. These worms enter the insect bodies and feed on their internal fluids, killing them in the process. However in contrast with fungal spores nematodes do actively seek their pray, so they will hunt the aphids down within the media while a fungal spore needs to meet the aphids randomly. Single nematode species like Heterorhabditis bacteriophora can attack aphids although combinations using other nematode species are usually more effective since different nematodes usually attack different species with different efficiencies (see here). Mortality rates when using nematodes are usually at most around 80% so they need to be effectively used in combination with other methods to provide effective control.

As you can see there are several options for aphid control in your crops. Although using synthetic insecticides like imidiacloprid might be the most effective alternative there are in fact other options that can also be used successfully if the use of a neonicotinoid is not desired. Application of Lecanicillium species has shown to be most effective in peer reviewed studies while nematode and neem applications can help compliment this approach and provide a defense against other insects and pathogens. On the next post in this series we’ll talk a bit more about additional aphid control using mechanical means that are neither chemical nor biological.

Root Aphid Info: Learn About Killing Root Aphids

Aphids are an extremely common pest in gardens, greenhouses, and even in potted houseplants. Theses insects live and feed on various types of plants, gradually causing their health to decline. Though aphids are most commonly found the leaves and stems, another type of aphid can be found below the soil surface. These root aphids attack the root system of plants and can cause quite a bit of trouble for growers. Read on to learn about root aphid treatment.

Root Aphid Info – What are Root Aphids?

The physical appearance of root aphids is very similar to that of other aphids. Most often, they can be identified by their tiny and almost translucent bodies. These pests use their mouths to feed on the roots of the plants, causing the plants to begin turning yellow.

While plants begin to yellow for many reasons, growers are able to further investigate by examining the base of the plant. Often, colonies of root aphids will establish at or just below the level of the soil. Upon removal of the infected plant, gardeners are likely to notice small clumps of a white wax-like material throughout the root system.

Like many issues in the garden, one of the best methods by which to avoid root aphids is through prevention. General garden routines, such as weed control and even watering, can greatly reduce the likelihood that root aphids are able to invade. Turning and working the soil in the fall will also help to prevent the overwintering of this pest.

Comparatively speaking, root aphids tend not to spread in the garden. However, these aphids do spread to other plants through irrigation run off and may be “washed” from one planting to another. Root aphids may also be transported from one container to another via transplants or rooted cuttings.

Once established, the process of killing root aphids may become somewhat difficult. Though some chemical treatments are an option (in potted plantings), it is often not realistic as a choice to thoroughly drench the soil. If choosing a chemical control, always make certain to carefully read labels and instructions for safe usage.

Other root aphid treatments, such as predatory nematodes,may also be marginally effective. In most cases, however, the reproduction rate of the aphids will outpace the control. Once established, many growers choose to discard and dispose of the infected plants.

5 Hidden Menaces of Indoor Gardens

The most destructive pests in an indoor garden may be the least noticeable. Spider mites, mealybugs, scale, and other insects do their damage in the root zone or under the cover of the leafy canopy. Here’s a guide to help you identify and eliminate them without poisons or other harsh chemicals.

Signs of trouble: The tiny sap suckers are one of the most destructive pests of indoor crops. Their silky webs on the undersides of leaves are the most visible sign of infestation, but you may also notice stippling (small white spots) on leaves.

Where to look: Check beneath the leaves, especially where the branches meet the stems, for the white webbing. The pests are miniscule, but with a magnifying glass you can see them as small black specks.

What they look like: Like other members of the arachnid family, spider mites have eight legs and no antennae.

What to do: A shower with a steady stream of water can often wash spider mites off plants. For a heavy infestation, spray the pests with insecticidal soap blended with pyrethrin (a natural bug killer made from chrysanthemums).

For a heavy infestation, spray the pests with insecticidal soap blended with pyrethrin (a natural bug killer made from chrysanthemums).

Signs of trouble: Curled, yellowing, or distorted leaves and stunted shoots are the symptoms of a root aphid infestation. Aphids produce large quantities of a sticky excretion known as honeydew, which turns into black mold spots on stems and roots.

Where to look: Root aphids thrive in rock wool, clay pellets, and soil mixes, where they find shelter as they suck juices from roots. Aphids often feed in dense groups and do not move rapidly when disturbed.

What they look like: The small, pear-shaped insects with long legs and antennae may be green, yellow, brown, red, or black depending on the species. Most types have a pair of tube-like structures called cornicles on their back end. The adults are usually wingless.

What to do: Insecticidal soap sprays dissolve the protective coating on aphids’ outer shell. Neem oil concentrate, made from the seeds of a tree native to India, disrupts the pests’ hormonal balance and keeps them from molting. It also reduces insect feeding and acts as a repellent. After using either of these treatments, be sure to flush your feeding system thoroughly with water so the roots are rinsed clean.


Signs of trouble: When no insects are in sight and the plants are stunted with flimsy stems and yellow leaves that then drop, sap-sucking scale are often the culprit.

Where to look: Check the stems and undersides of leaves for brown or grayish-white waxy bumps. They’re most common on the main stem, close to leaf cover where they are not readily noticed.

What they look like: Females and nymphs are circular or oval-shaped and wingless, and they lack a separate head or other easily recognizable body parts—they really just look like a waxy growth. The adults stay in one place as they suck away the vital juices inside plant stems. Their nymphs have a brief crawling stage before they too eventually become stationary.

What to do: Insecticidal soap sprays block the pests’ breathing pores and dissolve their protective coating, leaving them to dehydrate and die. Scale are very resilient, and you may need to spray affected plants three times, about a week apart, to be sure you’ve eliminated all of the adults and nymphs.


Signs of trouble: A pest of soil only (they’re not found in water-only hydroponic systems), symphylids cause plants to die mysteriously because they live entirely underground, relentlessly chewing through roots.

Where to look: You can see these tiny wormlike pests when you rapidly water the soil because they will float up.

What they look like: Symphylids look a lot like whitish mini centipedes. They’re less than a 1/2 inch long, with 12 legs and 2 long antennae.

What to do: Discard any plant that has been infested so that you keep the problem from spreading in your indoor garden. Protect plants that have not yet been afflicted with a drench of neem oil concentrate.


Signs of trouble: Like other sap-sucking insects, mealybugs cause leaves to curl and turn yellow. Each mealybug is very small, but in large clusters, they can make your plants’ stems look like they are covered in cotton.

Where to look: Mealybugs cluster at the base of plants’ stems and in the crevices where the branches meet the stem.

What they look like: Soft-bodied insects that look like they are covered in cotton, mealybugs are just 2 to 4 millimeters long (less than 1/5 inch). The females have no wings. They suck the sap from plants through plant-piercing mouthparts.

What to do: Spray them with a soap that contains potassium salts of fatty acids, which penetrates the pests’ cottony layer and dehydrates them.

Did You Battle Any Of These Pests?

Hopefully your infestation is under control at this point or at least well underway. Safer® Brand offers a variety of products, including insecticides, that are compliant for use in organic gardening. Visit our Facebook page to share your pest control or gardening stories and pictures with other gardening enthusiasts or sign up for our e-Newsletter to get exclusive offers on the products you love and notifications about new or upcoming articles. Another great resource is the Safer® Brand Learning Center. There are lots of articles, tips, and interesting facts that will help answer questions and transform you into a better gardener.

Root Aphids: The Ninjas of the Plant Pest World

What used to be a more prevalent problem on the West Coast has now become a crisis nationwide.

Root aphids are increasingly being found feeding on the root systems of a vast variety of herbaceous perennials. They come in many colors, including pale green, yellow, gray, brown and pink.

They have ovoid bodies and are normally less than an eighth of an inch long. They are almost identical to common, above-ground aphids, except they often have shorter legs and antennae, making them well-adapted for life underground.

Root aphids can be winged or non-winged. The winged variety tend to spawn when a population of aphids has reached such a high density on an existing host plant that they need a new food source to support the burgeoning colony.

The winged root aphid then flies to a new host plant and starts a new colony. As if flying, plant-destroying ninjas were not scary enough for a gardener, root aphids can reproduce parthenogenetically, meaning a female does not need a male to reproduce, she can impregnate herself and multiply.

In the summer, every new aphid is a female and a potential mother. Each female aphid can give birth to 30 or 35 new aphids, and each of these is mature and ready to produce baby aphids of her own in just 10 to 20 days.

Root aphids feed on the root system of various plants, sucking so much sap from the roots that the plants do not receive proper sustenance.

As a result, leaves turn yellow and little new growth occurs. Root aphids tend to congregate en masse, especially on the outer edges of the root ball, forming a white, waxy, snow-like covering over the roots.

This white, waxy coating is an important characteristic gardeners can use to identify a root aphid population.

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Plants fed with high doses of nitrogen can be a superfood for aphids. When aphids siphon sap from the phloem of a well-fed plant, the high-nitrogen fertilizer supercharges the plant’s sap and simultaneously the aphids’ reproductive capabilities.

Ways to Control Root Aphids in the Garden

Root aphids can be controlled by several measures. It may be necessary to start heavy-handedly if the population of root aphids has already reached epidemic proportions.

The products listed here are not for use on edible crops and I recommend you read the label of any product before applying it to your garden.

The first step in integrated pest management starts with scouting and monitoring. Paying close attention to your plants is the best way to discover potential insect problems.

Root aphids, living underground, represent a particularly difficult pest to take notice of, but yellow sticky traps are a great way to discover the presence of winged aphids trying to establish new colonies.

One or two yellow sticky traps should be placed for every 1,000 sq. ft. of growing space and monitored weekly to monitor populations and alert a grower to a potential infestation.

The next level of control is the use of beneficial insects. For root aphids, the best beneficial predators are microscopic entomopathogenic nematodes.

Entomopathogenic nematodes are a group of nematodes, or thread worms, that kill insects. Although many other parasitic thread worms cause diseases in living organisms, entomopathogenic nematodes only infect insects and are safe for use around people and pets.

Nematodes make their way into the guts of the root aphid larvae where they multiply until they kill the pests and the nematodes explode out of the stomach of the aphid.

Nematodes are usually sold in a sponge that is placed in a bucket filled with 1-gal. of dechlorinated, pH-neutral water and then rung out repeatedly.

Then the water/nematode mixture is either applied to individual plants or added to a hydroponic reservoir. After that, the nematodes act as a microscopic army with the single goal of killing even more pests. (Read more: Hydroponics: Pros and Cons of Hydroponic Gardening)

Another organic, food-safe level of root aphid control can be achieved with an entomopathogenic fungus called Beauveria bassiana, which is sold as an active ingredient in some specialty gardening products.

The fungus works similarly to the nematodes, killing the aphids from the inside out. Insecticidal soap is also effective against root aphids, provided the root ball is submerged long enough in the soap.

A recent study found submerging the root ball in insecticidal soap for 30 seconds resulted in less than 30% mortality, submersion for 60 seconds yielded close to 70% mortality and submersion for 90 to 120 seconds yielded 95% mortality.

Escalating the arsenal leads one to neem oil, which uses the active ingredient azadirachtin. Azadirachtin is in the limonoid family and is distilled from the neem plant’s seeds.

Azadirachtin has three unique modes of action as a pesticide. It acts as an anti-feedant, a repellant and an insect growth regulator.

As an added bonus, most neem oil products are organic and OMRI certified. Neem oil has been shown to provide some level of systemic protection and is best applied as a soil drench for control of root aphids.

When organic controls are not doing the job, it is time to bring out the big guns. There are new products on the market containing an active ingredient called imidacloprid, which acts as an insect neurotoxin.

Imidacloprid belongs to a class of chemicals called neonicotinoids, which act on the central nervous system of insects but have a low toxicity to mammals. While registered for use on food crops, this is not an organic solution. (Read more: Are Organic Pesticides Always Safer?)

The method is systemic, meaning it is absorbed into the plant tissue and will poison the root aphids if they eat the roots, leaves or any part of the plant.

Bugs outnumber humans 200 million to one, so when fighting an insect army that multiplies faster than you can kill them, an insect growth regulator is a valuable tool.

There are several on the market that are effective on root aphids as well as a host of other garden pests.

One popular insect growth regulator uses the active ingredient fenoxycarb, which blocks the ability of an insect to change into an adult from its juvenile stage. It also interferes with the molting of larvae. Insects have a rigid external covering called an exoskeleton.

To grow and mature, insects must periodically shed or molt their old exoskeleton and produce a new, larger one. By interfering with this process, an IGR prevents an insect from ever becoming sexually mature, thereby eliminating their ability to reproduce.

When all else fails, the no-nonsense nuclear option to eradicating a root aphid infestation is acephate, an organophosphate insecticide that provides a powerful knock down and some level of systemic protection.

It is used as a primary control of aphids, including resistant species and root aphids. Products containing acephate may be sold as powders, liquids, granules, tablets or water-soluble packets.

If you suspect your garden has been invaded by root aphids, there are several options at your disposal to eradicate them before these little ninjas suck the life out of your garden.

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