Last Updated December 22nd, 2022: Whiteflies, a common infestation, can wreak havoc on marijuana plants. To ensure your cannabis plants are free of whiteflies, you need to fight them early. The first step towards eradication is identifying them.
You can do this easily by shaking the leaves. If present, the flies will simply fly away. The presence of small dots on the leaves is another indicator.
What Does A Whitefly Look Like?
Originating from the Aleyrodidae family and with over 1500 species, whiteflies measure 1 – 1.5mm long. Depending on the species, each has two to four pairs of wings, with three pairs of legs. The male is usually smaller in size.
The species known to attack cannabis plants are called the greenhouse whitefly also known as the Trialeurodes vaporariorum. It is a yellow insect with four wings. These insects thrive in temperatures between 70 to 90 degrees. For this reason, they prefer indoors, greenhouse environments or warm climates.
The absence of predators indoors encourages their growth. Dust, which is common indoors, encourages whitefly outbreaks. Thus, it is important to keep these parameters in check.
How To Get Rid Of Whiteflies On Your Cannabis Grow
Consider these strategies to combat whitefly outbreaks during flowering;
Diatomaceous Earth
Diatomaceous Earth is my first recommendation when someone is dealing with whiteflies on their cannabis plants! Diatomaceous Earth is a powder that you just sprinkle on and around your cannabis plants. It’s completely safe for humans and pets, but it is effective against insects because it dehydrates their outer shells which causes them to die. It’s very effective against whiteflies specifically and it is cheap and easy to apply!
We Recommend This Diatomaceous Earth From Amazon!
Insecticidal Soaps
Insecticidal soaps or fatty acid salts are an effective remedy for whiteflies. They act by weakening the outer layer of aphid shells. The fact that they do not leave a high amount of residue means they’re safe to use.
Since soap does not stick on the plant, you must follow up on the application.
Neem Oil
Neem oil is a natural remedy for different types of bugs. Since water and neem oil separates faster and easily, for effective and even spraying, using a mister is necessary. A great alternative is a one-hand pressure sprayer.
Although neem oil is effective, you need to exercise caution when using it. This is because it causes an unpleasant taste and smells on the buds especially when used on flowering plants.
Spinosad
Spinosads are organic and completely safe. The effective insecticide is made from fermented soil bacteria. The bacteria used is known as actinomycete Saccharopolyspora spinose. It functions by acting on the nervous system of insects.
Spinosad is not toxic to beneficial insects. However, it is completely toxic to whiteflies. It is imperative to note that Spinosad is only efficient for 24 hours. Consequently, just mix enough product for use with water. What is left after use goes to waste.
For proper application, using a mister is recommended. A one-hand pressure sprayer is a great alternative.
Spinosad kills whiteflies in direct contact. You can apply it directly to the plant and particularly under the leaves.
It is safe for plants, animals, and humans.
Essentria IC3
The Essentria IC3 is an organic insecticide. It is made from several oils that are safe for animals and humans. This insecticide is mostly marketed for the control of bed bugs. However, it is equally effective on whiteflies.
The product is only effective for 8 hours meaning the regular application is necessary for complete control of whiteflies. It should be applied daily or combined with other options.
For proper application use a mister. A one-hand pressure sprayer would also come in handy.
Causes of Whitefly Infestation
Some of the common causes of whitefly infestations around cannabis plants include;
Drought
Water stress in plants is a common cause of whiteflies’ infestation. Areas with dry and hot summers tend to be more susceptible to these insects. If you fail to regularly water your plants, they can also be prone to infestation by whiteflies.
An increase in temperature characterizes drought-stricken regions. This encourages reproduction in whiteflies. With favorable temperatures, these insects reproduce and increase in number at high rates.
Insects that feed by sucking and piercing such as whiteflies, thrive in dry areas. Drought causes the death of natural predators that feed on these whiteflies such as the ladybug.
Since the ladybug cannot survive drought, whiteflies are left to thrive.
Overuse of Insecticides
A common solution to the infestation of whiteflies is the use of insecticides. This solution, however easy, comes with many negative effects. Most insecticides in the market are non-specific. This means that they lack a specific target for elimination.
Non-specific insecticides kill even beneficial insects and spiders. These include predatory insects that may control the whitefly population. Insects such as parasitic wasps, spiders, and ladybugs are predators.
Killing the natural predators causes high growth rates of the whiteflies.
Use of Nitrogen Fertilizer
Nitrogen fertilizer is effective for nourishing plants. On application, plants appear healthy and vibrant making nitrogen fertilizer an effective choice for revitalizing plants. What you might not be aware of is that it may be a reason for an infestation.
High amounts of nitrogen fertilizer have a negative effect because it causes an increase in nitrogen concentration in plant tissues. Whiteflies are more attracted to plant tissues with high nitrogen content.
The use of nitrogen fertilizer might just be the reason for whitefly infestation.
How to Prevent Whiteflies During Your Cannabis Grow
To keep your plants free of whiteflies, several methods can be used. It is best to investigate these methods to know the best, and where to apply them. Some of the popular methods include greenhouses, house plants, and the garden.
Prevent whitefly infestation by employing these strategies;
Frequent Inspection
One of the ways to keep your cannabis plants healthy is by regular inspection. Whiteflies tend to breed and reproduce fast. From a small whitefly population, a large infestation could develop in no time. Keep in mind that a large infestation is harder to control.
To avoid infestation, check on the plants regularly. You should especially be sure to check the underside of leaves. Shaking the plants is another way of routine checking. On shaking the plant, the insects flutter away.
In case you notice a large number of flies, you need to take action. Blast the leaves with a high-pressure hose to reduce the number of whiteflies to a manageable level.
Correct Moisture Levels:
Not only can having too much moisture in your cannabis grow to lead to mold, but it can also attract pests such as spider mites or whiteflies. If you are overwatering or even underwatering your cannabis plants, it creates a suitable breeding ground for pests that will damage your cannabis grow.
Reflective Mulch
The use of reflective mulch utilizes plastic mulch at the base of plants. This strategy is handy in the case of affected plants. The plastic mulch confuses the whiteflies, preventing them from attacking the plant.
Since the flies do not land on the plant, feeding becomes impossible. Reflective mulch not only prevents infestation but also keeps your plants healthy.
Sticky Traps
Sticky traps are popularly used in the garden and greenhouses by placing them around plants. They work by trapping whiteflies before they land on the plant. This is an effective chemical-free method of controlling whiteflies in your garden.
Apart from this, sticky traps help monitor population growth. By checking on the number trapped you can tell the population level making it a simple way of a routine inspection.
Natural Predators
Increasing the number of natural predators is a great solution. Ladybugs and parasitic wasps are naturally occurring predators to whiteflies. Buying these predators and releasing them reduces the whitefly population. This method is best for a persistent whitefly infestation.
These insects are safe for both animals and cannabis plants. This is one of the better natural solutions for cannabis growers and doesn’t rely on pesticides.
Neem Oil
Insecticides are usually not the best solution to an infestation mainly due to their toxic effect. However, neem oil is an organic insecticides perfect alternative to chemical insecticides. Neem oil is less toxic to other beneficial insects such as ladybugs, pollinators, and parasitic wasps and can make it a good solution for your cannabis garden.
It is applied liberally to plants to control whitefly. Neem oil kills both the larvae and adult whitefly ensuring it keeps the whitefly population in check. Use it regularly to keep your plant whitefly-free and healthy.
Final Thoughts On Whiteflies On Your Cannabis Plants:
Finding whiteflies on your cannabis plants can be frightening, and although they can destroy your grow, if you act quickly you can save your plants! I recommend using Diatomaceous Earth to safely and easily protect your cannabis plants and kill the whiteflies!
Resources: