7 Steps to Eliminate Root Aphids from Your Plants

By Mark Boutwell
Published: June 19, 2017 | Last updated: May 4, 2021 07:22:39
Key Takeaways

Fighting black bugs was one of the most humbling experiences Mark W. Boutwell II had in his growing career. Now, after taking the time to step back and reflect on the experience, he’s here to share his new-found battle strategies.

Source: Mhlam/

Those black, sometimes yellowish bugs found on your roots are likely root aphids. There are many species of root aphids, including the sugar beet root aphid, conifer root aphid and turnip root aphid. I had my first root aphid encounter about two years ago and it was the most crippling and expensive problem I have ever encountered.


At this time in my life, I thought I had seen just about everything. I would have never had expected to go through as humbling an experience as I did when I fought these root aphids tooth and nail.

Unfortunately, there is no easy solution to root aphids. If you encounter root aphids, take a deep breath and go through the process with a more intent focus on learning from this experience instead of just saving your crop.


Getting root aphids is not the end of the world, it’s just probably the end of that particular grow. It is a great way to gain experience dealing with root rot, testing pesticides, wilting, plant deficiency, and identifying bugs at a fast pace. My first suggestion would be to go through this process all the way through until the plants die, or you feel you have learned everything you can learn.

When most growers first get root aphids, they don’t realize that bugs are the core of their problem. Inexperienced growers normally treat for root rot (also known as pythium) by using a disinfectant; this, however, only furthers the problem by exposing even more roots for the root aphids.

So, be sure to take your time to look thoroughly at the problem and find the main reason for your problem. By doing this, your small infestation of root aphids will stay that a small infestation. Don’t be a grower that treats for every other problem except for the root aphid until your plants die.


The solution below can only be used for growers that get root aphids after the fourth week into flowering.

Any grower that gets root aphids indoors before the fourth week into flowering should immediately kill their plants and sterilize their systems using the following checklist:


Indoor Garden System Sterilization Checklist

  1. Kill your plants
  2. Remove all growing media (further the better)
  3. Fog your room before you start sterilizing
  4. Clean everything:
    1. Inside and outside hoods
    2. Lenses and bulbs
    3. Walls
    4. Reservoirs and other H2O system
    5. Get new irrigation if auto watering
    6. Fans
  5. Apply fogger
  6. Shut down room for two to four weeks to insure complete death
  7. Start from scratch (that means new mother plants) and do not go back to the person that gave you the aphids—go to a new nursery!

Step 1

The first step to getting rid of root aphids is to reduce the temperature of your environment. By lowering the temperature, you will slow the spread of aphids hatching and will slow the winged aphids down.

Step 2

The second step is using a plant-friendly fogger. Foggers flush out and quickly eradicate insects on contact; however, the sprays will not kill eggs or nymphs, so repeated applications are required.

Just be sure to read the label and follow directions carefully, as foggers are harmful to humans too. Foggers should not be used in small, enclosed places, such as closets, cabinets, or under counters or tables, and I recommend placing an active fogger six feet or farther from all ignition sources.

Accidents involving total release foggers have occasionally occurred when homeowners released too much fogging material, which led to a high buildup of flammable vapors. Also, vacate the sprayed area during treatment and thoroughly ventilate upon returning because breathing the spray could be harmful.

Step 3

The third step is to reduce your light intensity if you have a digital ballast. As aphids bite into your roots, the roots loose the ability to take up water.

When you reduce the intensity of the light, you reduce the demand the plant puts on its root system for water uptake, as well as reduce excess stress on the plant; thus you have more time to treat the aphid infestation.

Step 4

The fourth step is to cut your fertilizer in half. This is also important because the aphids bite into the fibrous portion of the roots that is responsible for taking up water and nutrients. When the aphids eat this portion of the roots, it reduces your plants ability to take up plant food.

Cutting the fertilizer in half reduces the concentration of plant food, which in turn normally slows the onset of wilting because of osmosis. It also helps with plant deficiency like signs of over fertilization.

Step 5

The fifth step is to reduce the temperature of your water reservoir to 65ºF. This will help control the spread of other plant diseases because it will reduce the temperature of the water and the rate at which root rot can spread.

Step 6

The sixth step is put some Vaseline around the base stem of your plant. This is preparation for the next step when aphids try and climb up and get away.

Step 7

The seventh step is to completely drown your entire root system with an oil-based soil drench. To put is simply, root aphids are extremely hard to kill and an oil-based soil drench solution is the only things that will do a great job.

See all of our growroom Sanitation & Sterilization Tips


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Written by Mark Boutwell

Profile Picture of Mark Boutwell
Mark Boutwell II stepped into his first garden when he was about four years old. His father would tell him about how the Native Americans taught the pilgrims how to survive using different farming techniques. When Mark was in a garden, his father would always force him to use their space as effectively as possible. This is the reason why Mark gravitated to indoor gardening as he got older.

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