Found an EXTREMELY helpful write-up on these two garden pests. Source:
http://www.kushmagazine.com/knowledge-base/grow/growers-grove-jade-kine/2079-rootaphidsarch-enemyofcannabis
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Diagnosis and Biological Control
Quiet but vicious, root aphids are the worst kind of pest that a Cannabis gardener can face. Commonly confused with fungus gnats, even by experienced growers, root aphids are a separate and significantly more aggressive pest facing Cannabis gardeners today. Proper diagnosis between these pests is crucial in order to control them. Aphids are notorious for their ability to adapt to new environments, especially when it comes to
developing resistance to chemical controls. To effectively control these pests using biological methods, insect-eating worms called parasitic nematodes can be recruited to hunt down root aphids. There are also certain types of fungi that infect and grow on insects, killing them in the process. The key to using these biological products effectively is to understand the type of environment that favors the growth of the product, whether it is an insect or a fungus. When properly applied, these biological controls offer more complete control over aphid populations than chemical controls.
Know Your Enemy
Root aphids can quickly build to large infestations if misdiagnosed. The first sign of this terrible pest in plant growth is just a simple
yellowing of the leaves from the bottom up. This common effect can also be caused by over-watering, under-watering, under-feeding or pH imbalances. Typically, growers begin to address the yellowing by adjusting one of these variables while the pest populations build quietly in the root zone where they often go unnoticed. Fungus gnats produce flying adults very quickly in their life cycle. But
root aphids typically do not form winged adults until the populations in the root zone have reached infestation levels. By the time you see them flying, the roots are covered in many generations of aphids. Inspect the root zone of your garden regularly.
Root aphids (possibly related to the genus Phylloxera although I don't believe that's definitive yet) can enter the garden either as wingless nymphs on infected plants, can fly in as winged adults or can even hitch a ride on the gardener's shoes or clothing. Avoid walking through landscaped, muddy or grassy areas before entering your grow room. Sealing your garden space and
filtering your intake air is an excellent preventative measure. Root aphids can vary widely in color, but are typically
brown or black when they get larger and are green, reddish, translucent or brown in the younger stages. They are rounded to teardrop-shaped with six legs. Aphids use an appendage that looks like a long, snout-like dagger (called a stylet) to pierce into the roots and suck the sugars from the plant as they are transported down from the leaves into the roots via the vascular tissue. Under a magnifying scope (a 30x or more jewelers loupe works great for easy identification of pests and is cheap and portable), the stylet can be seen by putting the aphid on it's back the stylet is kept tucked back against the abdomen. From the top view,
aphids can be clearly identified by the presence of two short structures protruding from their back end that look like dual exhaust pipes. They're called siphunculi and some aphids use them to excrete compounds that signal danger to the other aphids. This mechanism has been called a pheromone alarm. Other species of aphids use these structures to excrete defensive compounds. More research is needed to determine the specific function of the siphunculi in Cannabis root aphids.
When it comes to reproduction, aphids are truly incredible. Capable of both sexual and asexual reproduction according to environmental cues, these insects
can reproduce at lightning speed when conditions are good, and then later go into sexual reproduction mode to create winged individuals capable of flying to another host plant. Aphids seem to sense how abundant the resources are as they're colonizing. When resources become scarce and/or the population becomes too large, they produce adults with wings in order to move on to the next area of juicy plants. When reproducing asexually (through a process called parthenogenesis),
aphid colonies expand quickly due to the mother's ability to give birth to live offspring, many of which are already pregnant with the next generation in them when they are born. As long as there are plenty of roots to infect, they'll keep silently colonizing at top speed and won't produce the easily observable flying individuals until they've already infested the entire root zone of the garden. Another cue they use to know when to make winged adults is the short days and colder temperatures of fall and early winter. During these months, aphids sprout wings and search for a warmer place to destroy crops, like a nice grow room with unfiltered air coming in.
Gnat's So Confusing!
Root aphids are commonly mistaken for
fungus gnats, another Cannabis pest that hatches in the root zone and then starts flying around. Compared to root aphids however, fungus gnats are relatively benign. They eat the roots a little and they vector fungal root diseases, but often the plants yield moderately despite the pest even if there's no major grower intervention to control them. Of course, their decent yield of nugs is covered in gnats that got stuck to the resin, which is gross. But bad as that is, root aphids are much, much worse still. They will suck every bit of life out of the plants, pulling them just about back into the medium that they grew out of and then they'll all start flying around trying to find another garden to infest. Plus, they also get stuck to whatever buds remain.
Fungus gnats in the larvae stage don't really look like classic bugs at all.
They look like tiny white worms with a black dot on one end - that's its head. Once they mature, they fly around and lay more eggs in the soil surface. You can use a number of different controls, but the bacterium Bti (bacillus thuringiensis israelensis) is organic, effective, safe and available in many different formulations for easy application in any garden.
The most important thing to remember is that these products only work for fungus gnats and will not affect root aphids at all. I hear this repeated too often: that growers can treat root aphids with Gnatrol or Mosquito Dunks. This is simply not true and will only cost you valuable time in gaining control.
Fungus gnats and root aphids can both collect on sticky traps and it's not uncommon to have gnats in the same gardens with the root aphids, which can further lead to a misdiagnosis. Differentiating between the pests is easy when looking at the roots, so if you can gently slide a plant out of its pot for inspection, this is the easiest way to see them.
The gnats are white worms with black heads and the aphids look like tiny, brownish grapes with legs. The white worms of gnat larvae like to hang out in the top few inches of soil. Aphids tend to colonize on the exposed roots at the edge of the pot and near the drain holes.
The aphids vary in size but are roughly the size (and color) of coco fiber grains, making identification in coco more difficult still. Sticky traps can be used to monitor adults of both pests. The wings are roughly the same size between the 2, but
the body of the gnat is thin and elongated whereas the aphid body is plump and teardrop-shaped.
Send in the Troops: Parasitic Nematodes
Predatory nematodes are microscopic worms that parasitize and feed on insects. Applying them is like having your own army to battle it out with the aphids and these are some aggressive soldiers. Nematodes infect by burrowing inside soil pests, then release specific bacteria to kill it. They continue feeding on the inside of the bug while they reproduce as many generations as they can before they've finally consumed everything but the exoskeleton. Then, they break open the cadaver's exterior and a pile of hungry little worms are released to go find more prey. I've used several types of nematodes over the years, but in my experience,
heterohabilis bacteriophera is the most effective species. Sold under the brand name
NemaSeek by Arbico Organics, these microscopic worms are the most mobile nematode species. Within 48 hours of application, Nematodes will already have infected and slowed the feeding and reproduction of the aphids. Within a week, aphid populations should be devastated and it should be difficult to find moving individuals on the roots. A follow up application should be done if pest populations were extremely high before the first application of nematodes just for good measure.
Nematodes must be shipped quickly and should ideally be applied the day they arrive for maximum viability. Arbico claims they can be stored for a few weeks in the refrigerator, but the sooner the application the better. Most biocontrol suppliers including Arbico will offer the ability to schedule shipments in advance if you know you want to do 2 applications separated by a few weeks for instance. Have your root zone wet before applying the nematodes and mix them in a small amount of water like a bucket. Then apply a small amount of nematode concentrate to each plant site.
Fight Back with Fungi
Beauveria bassiana, (sold under the brand names Mycotrol and Botaniguard), is a fungus that parasitizes insects. Growers will want to obtain the WP version, which stands for Wettable Powder in order to apply it to the root zone. Spores infect the insect by contact, and then the bug gets sick and dies. The mycelium (fungus roots) of the beauveria bassiana digests the bugs insides and, in spots where the humidity is high, can actually mummify the insect in a cottony-looking growth that is made of more infective spores.
It's like the Bubonic Plague for soft-bodied insects. Beauveria bassiana prefers humid conditions but still works on contact at moderate humidity levels. It needs to be significantly humid (85%+) in order to grow new spores and mummify the bug, but the microclimate of the root zone is typically very humid even when the rest of the grow room is not.
The major limiting factor in a grow room situation is the fact that high levels of nitrates in the fertilizer solution can kill fungus spores. In soil or soilless mix systems, growers should apply the fungus product by itself without other additives, then reduce their fertilizer concentration for the following few days to week. The lower nutrient levels of cloning and early veg are typically not too much, and later in flowering, the lower nitrogen levels increase the effectiveness of the fungus. It also works well as a preventative measure around the perimeter of the grow space during rainy months, especially if there are landscaped or wooded areas adjacent to the growing environment. Beauveria bassiana is a naturally occurring soil fungus and is compatible with parasitic nematodes. Both organisms are referred to as entomopathogenic, meaning they infect bugs. For more information, look up entomopathogenic fungi or entomopathogenic nematodes on Wikipedia, as there are several types of each.
Chemicals, Resistance and The Importance of Hungry Soldiers
Controlling aphids with chemical controls is difficult because of their adaptability and large populations. Most organic (and even inorganic) pesticides fail to completely remove the aphid population. Because aphids give birth to live pregnant young without the need for a mate,
it only takes a single individual surviving to re-establish an aphid colony.
The new colony started by the resistant individual will tolerate the same chemical application much better next time and many resistant individuals will survive, making it easier to re-establish faster. When using biological organisms to control pests, growers take advantage of the fact that the new parasitic organism wants to live and aggressively take over wherever conditions are favorable.
Because
nematodes will die in the absence of prey,
they will continue hunting and feeding and reproducing until every last aphid has been found. In fact, the more aphids that get eaten, the more nematodes are being produced. So the last few aphids remaining will face the largest population of nematodes. Because the nematodes will hunt for food until they die from a lack of it, you can be sure they'll look high and low for stubborn, hidden aphids. Also, both nematodes and beauveria bassiana fungus are applied in massive numbers as well, effectively matching the large populations of the aphids. Nematodes are available in packs of 5 million, 10 million and up. Beaveria bassiana spores are released in increments even larger than that.
The only time a grower may want to use an (OMRI approved) organic pesticide as a drench is to create an initial knock down of pest populations before application of a biocontrol. For instance, if you discover you have root aphids and you order nematodes right away, it will still take a few days to get them. In some areas, hydroponic stores have started to carry refrigerated nematodes, but if there isn't one locally to you, you'll want to order online with express shipping. In the meanwhile, you can try drenching a refined azadirachtin product such as Azamax or Azatrol. This will reduce their populations significantly and temporarily inhibit their feeding and reproduction as well. I've seen conflicting research on the compatibility of Azamax with predatory nematodes. To be safe, I'd suggest rinsing the Azamax out before applying nematodes.
There are many biocontrol suppliers online. For nematodes, I like Arbico's NemaSeek, but many places have H. bacteriophora available. Some companies also have different shipping days, so it may pay off to shop around. Another good biocontrol supplier is Rincon Vitova they're based in Southern California and have very good deals on predatory mites (that eat bad mites) and soil inoculants. They also carry nematodes as well.
Root aphids are no fun, but there's no need to panic and drench chemicals in the root zone. Nature has provided us with plenty of useful tools to fight this parasite with other aggressive parasites, both nematode and fungal. Inspect your roots regularly, avoid other gardens and if you see them show up - send in the troops to kick their siphunculi into next month.
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Hope this article helps y'all as much as it helped me. Although it was more of a peace of mind kind of thing for me as I am still not 100% certain what these fliers I have are. 
