Dealing with Aphids in the Growroom

By Rich Hamilton
Published: November 22, 2022 | Last updated: November 22, 2022 09:46:49
Key Takeaways

Aphids are a common pest affecting outdoor and indoor growers everywhere. Read on for a detailed look at what they are, how to spot them, control them, and how to avoid an infestation in the first place.

What are Aphids?

A typical garden pest everywhere, aphids are soft-bodied insects that can be many colors, including black, white, yellow, green, red, brown, and black. The bigger, rounder bugs are adult aphids whilst young aphids or ‘nymphs’ are much smaller, thinner, and paler. If you notice tiny flies on your plants, these could still be aphids, but with wings. The body shape is similar whether the aphids have wings or not.


What do Aphids do?

a plant stem covered with aphidsAphids usually congregate on the undersides of stems and leaves.

If a plant becomes heavily infested with aphids, its leaves can turn yellow and wilt due to excessive stress and leaf damage. Aphids usually congregate on the undersides of stems and leaves. They pierce the surface of the leaves with their mouths to feed on the juices inside. If an infestation is left long enough, your plants can wilt, turn yellow, and die due to excessive stress.

Aphids also produce large amounts of a substance known as “honeydew,” a sugary liquid waste. In turn, the honeydew attracts a variety of fungus called sooty mold. Sooty mold grows on the honeydew deposits, amassing on your plant’s leaves and branches, eventually turning them black. Along with discoloring the plants, the mold can disrupt normal plant processes. If this is not enough of a problem, the honeydew can also attract other insects such as ants.


What Causes an Aphid Infestation?

an aphid infestationExamine your plants weekly for signs of an aphid infestation.

The conditions in a growroom are very desirable to aphids. Warm, humid, and full of plants. Just a handful of aphids is all it takes to start an infestation. In indoor conditions, you will find that most aphids do not lay eggs. The females can give birth to live young without mating. A female can reproduce three to six new nymphs per day for several weeks.

You can understand how populations can increase so rapidly. The young aphids (or nymphs) begin feeding right after birth; feeding on plant sap while they slowly increase in size. They take seven to 10 days to mature, after which they shed their skin, leaving silvery exoskeletons behind.

After reaching adult status, they continue the cycle. Each one can potentially produce dozens of offspring. Because of how quick aphids reproduce, a few “colonizers” can soon lead to thousands of aphids feasting on your plants in just a few weeks.

Aphids are one of the most common indoor plant pests. Left untreated, they will often keep reproducing until the plant becomes so stressed and overcrowded it can no longer support their insatiable appetites. At this point, some of the winged aphids will fly off in search of a new host.



Prevention is Key: Check Your Plants for Aphids Regularly

Do not underestimate your plants’ chances of becoming infested with aphids just because you grow indoors. They can easily be transferred into your growroom via infested plants, attached to clothing, or by the wind through an open window.

It is vital to examine your plants weekly to guarantee they don’t become infected while you are not paying attention. When checking, inspect the undersides of new leaves first for clusters of aphids.

Dependent on the lifestyle stage and color, aphids will look different. They may look like regular tiny bugs or just like tiny, colored specks at first. You may see little white dots that aren’t moving as well. This is the skin they shed when the nymphs change into adult aphids.


How to Get Rid of Aphids

Grower spraying a plant with insecticidePlant-derived insecticides are practical and more gentle than chemical pesticides.

1. Wipe or Spray Off as Many as Possible
If you have a severe infestation, you need to eliminate as many bugs as possible. If your plant is quite robust, one way to do this might be to spray as many bugs off as possible with a powerful hose or sprayer. It’s also advisable to remove leaves and buds that are heavily infected. Take the infected plants out of the growing environment or risk re-infestation. You could try wiping most of the bugs off the leaves on more delicate plants. It may be quite time consuming, but it will make a good dent in the scale of your infestation.

2. Insecticidal Soaps
Insecticidal soaps are specially formulated to kill insects and not damage plants. These soaps will weaken the outer shell of aphids, eventually killing them. You can also use them frequently until you get the problem under control. Getting full coverage of your plant is essential with soap as it does not stay on the plant long; however, this can be tricky.

3. Horticultural Oil
Highly refined oils and horticultural oils are also very useful in controlling aphids. The oil suffocates the insects. They are highly refined and, under the proper conditions, can be applied to plant foliage without risk of any damage. Always check the label, however, in case of specific species sensitivity. Refined oils are also considered nontoxic, so they are less likely to harm beneficial insects. If spraying indoors, protect any surfaces that oil may damage.

4. Plant-Derived Insecticides

Many insecticides are registered for use indoors. Plant-derived insecticides are practical and more gentle than chemical pesticides. One very safe product, Neem, is made from tropical tree seeds. Other sprays contain a substance called Pyrethrin.

5. Spinosad
Spinosad is an organic insecticide made from specific soil bacteria. It kills aphids via contact by disrupting the insect’s nervous system. Spinosad is very toxic to aphids but is less harmful to many beneficial insects and spiders. Although less potent than some of the harsher insecticides, it works, and is very safe for plants, animals, and humans. Spray liberally anywhere you see aphids, especially under the leaves.

6. Limit Future Infestations
You should quarantine newly acquired plants for two to three weeks to prevent introducing pests to your indoor plants. Same with plants you may bring inside in the autumn/winter as this is another way of introducing insects indoors. Buy bug barriers to cover your growroom extraction vents. Have a set of growroom clothes to change in and out of when tending to your plants. This will stop any pests from getting transferred via your clothes.

You will inevitably suffer from insect pests in your growroom. Suppose you are prepared and know how to tackle them. In that case, you can hopefully avoid a severe infestation that could ultimately destroy your plants.


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Written by Rich Hamilton | Writer, Consultant, Author of The Growers Guide

Profile Picture of Rich Hamilton

Rich Hamilton has been in the hydroponics industry for more than 20 years, working originally as a general manager in a hydroponics retail outlet before becoming an account manager at Century Growsystems. He enjoys working on a daily basis with shop owners, manufacturers, distributors, and end users to develop premium products.

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