Are your crops infested with whitefly and are you looking for valid remedies to eradicate it? Then you're in the right place.

Knowing how to prevent whiteflies is undoubtedly the first step to take to prevent your cultivation from being attacked by these annoying, very small whiteflies .

The whitefly is a tiny white insect, very resistant and, therefore, problematic for growers and horticulturists, as it affects numerous plant species, including hemp.

This parasite, originally from tropical areas, has now spread throughout the world thanks to ongoing climate changes. Over the years, it has become increasingly resistant even at low temperatures.

In greenhouses, but also outdoors, it is able to survive throughout the winter, and then start reproducing again in spring. 

Its reproduction capacity is truly formidable, around 200 eggs every month. And the adaptation of the whitefly and its incredible resistance to most pesticides and chemical remedies on the market is equally surprising.

In this guide, however, we want to talk to you about biological defense strategies against whitefly and in particular about the best and most effective natural remedies to prevent and eradicate this annoying insect from your crops.

What will you find in this guide?

Keep reading.

What are whiteflies

Before talking to you about how to fight whitefly on cannabis and what the most effective remedies are to eradicate it once and forever from your crops, let's try to understand together what it is.

Whiteflies - better known as aleurodids - are homopterous insects that belong to the Aleyrodoidea family which has more than 1500 living species. They are relatives of aphids, plant lice , and just as feared as them.

Also called "white butterflies" in common language, they can infest even the toughest plants, weakening them and making them more exposed to diseases.

Originally from the tropical and subtropical areas of Asia, it has adapted very well to our climate. Obviously, given its origin, it is much easier to find it in all those hot , humid and poorly ventilated cultivation places .

The species most present in our territory are 3:

  1. Trialeurodes vaporariorum (greenhouse whitefly);
  2. Bemisia tabaci (vegetable garden whitefly);
  3. Dialeurodes citri (citrus whitefly).

All three species of whitefly are not easy to manage and to eradicate them it is necessary to implement different methods and natural remedies.

Now that you know more about this small and annoying insect, let's see how to visually understand if the whitefly has infested your plants.

How to recognize white flies?

The whitefly is an easily recognizable parasite, especially in the adult state. Generally, it looks like a cross between a small fly and a large midge.

The winged adults are about 2 mm long and are characterized by a whitish color, thanks to the white fluff, similar to flour, that covers the wings. The body, however, is pale yellow in color.

The embryonic state is called nymph , an insect that has a transparent oval body and many small legs. At this stage, fly larvae are difficult to detect.

Generally, adult insects and embryos are found on the leaves of the plant, in particular, in the lower part. Both the adults and the larvae, through a very pointed mouth, make a tiny T-shaped hole on the leaf, stealing sap and nutrients from the plant.

In this way, the plant weakens and becomes more susceptible to attack by viruses and bacteria.

What is the reproduction cycle of a whitefly?

The whitefly, as we said previously, is a particularly prolific parasite. The female is able to lay from 150 to 200 eggs per month in the lower part of the leaf.

The eggs, which have a conical shape, are firmly attached to the leaf with small peduncles and are laid very close to each other, so that they are quite visible.

The reproduction of this insect is very rapid. This allows for several reproductive cycles during an entire year. A whitefly, in fact, is able to reproduce even twice a month, guaranteeing up to 200 eggs.

Approximately 10-12 days pass between the laying of the eggs and their hatching. Then, larvae or nymphs need more or less 4 weeks to become adults. The life cycle consists of the passage through 4 larval stages (three nymphal and one nymphal):

  • First stage : the larvae are about 0.25 mm large, they begin to feed by sucking the sap of the plant. In this phase the larva is able to move, subsequently it will close itself in a shell to protect itself during the mutation;
  • Second stage : the size of the larvae reaches approximately 0.4 mm. In this phase the 6 legs begin to form;
  • Third stage : having reached a length of about 0.5 mm, the larvae begin to take on a translucent colour;
  • Fourth stage : in this stage the larva, which is called pupa, develops some organs such as eyes. Once they reach maturity, they emerge from the shell and begin to attack the plants.

Generally speaking, this parasite can have 2 to 4 reproductive cycles per year . But if the climatic conditions are extremely favourable, as can happen in greenhouses or grow rooms, the reproductive cycles can reach up to 10 in a single year. This is why whitefly is a rather serious pest for a crop. 

Which plant do the white fly attack?

We have already told you that this parasite attacks a large variety of plants, both those found indoors and outdoors.

If you have specimens of begonia, dahlia, cyclamen you should pay more attention. But whiteflies also prefer many other species of plants, both vegetable (tomato, aubergines, cabbage) and fruit (watermelons, citrus fruits). 

Cannabis plants are also often subject to infestation by this parasite which tends to hide on the leaves, behind the lower part, feeding on their lifeblood. In this way it weakens the plant, slowly leading it to death.

In the event of an assault, the most obvious damages could be:

  • Progressive defoliation;
  • Leaf necrosis and drying;
  • Honeydew, with consequent mold formation and difficulty in normal chlorophyll photosynthesis ;
  • Virosis.

Do you want to know how to eradicate whitefly on cannabis permanently? Continue reading the next paragraphs and you will discover how to combat whiteflies with 100% natural remedies.

Control and remedy to get rid of the white flies

To prevent whitefly, you need a lot of perseverance. If you are growing in a greenhouse, prevention work must begin as early as winter, trying to eliminate - even by hand - all the eggs and all the adult insects.

By eradicating the adults, during the period in which they are weakest and do not reproduce, it is possible to ensure healthy cultivation during the summer period.

However, as regards open field cultivation, it is necessary to notice promptly when the insect colony is still small in number and, therefore, unable to ruin your plants.

Generally speaking, some of the strategies to prevent whitefly are:

  • Protect the cultivation place and the plants with special fine mesh nets, which prevent the passage of even the smallest insects;
  • Periodically monitor the plants you want to protect;
  • Install yellow chromotropic traps about 10 cm away from the plants - a color that attracts whiteflies - sprinkled with glue to trap them;
  • Use natural predators , such as the hymenopteran Encarsia formosa, an insect capable of containing the proliferation of the whitefly;
  • Create an inhospitable environment for the insect by frequently ventilating the growing environment and letting in cold air.

This type of parasite, like many others, proliferates with high temperatures and humid environments , making greenhouses, growrooms and grow tents their ideal environments. 

To avoid this aspect, therefore, healthy and well-ventilated cultivation environments are necessary . Air circulation and exchange are essential in both greenhouse and indoor cultivation.

These biological strategies are also accompanied by a whole series of natural remedies against whitefly , as we will see in the next paragraph.

White flies natural remedy

Natural remedies to prevent whitefly exist and are very effective. However, as often happens, growers treat plants with an already established infection. This is a big mistake.

The whitefly is fought when it has not yet managed to proliferate. This means that, for example, already in the early stages, young hemp seedlings must be treated on a weekly basis, before contamination even occurs. 

It is no coincidence that treatments against the whitefly that affects plants are called preventatives . However, the parasite's incredible resistance to many of the chemical insecticides on the market makes it very difficult to eliminate.

Among the products allowed in organic farming, the most effective in combating and eradicating the whitefly are:

  • Neem oil;
  • Pyrethrum;
  • Powdered sulphur.

We'll talk about Neem oil in a separate paragraph. As for pyrethrum , it is a substance that is extracted from flowers very similar to daisies, easily available in gardening shops.

This product has demonstrated good efficacy. However, it is not a type of selective insecticide . This means that it could also kill those insects that are harmless and useful to the life cycle of a plant. Therefore its use is to be limited exclusively to those plants that are already highly contaminated.

Powdered sulfur is also an effective biological remedy against whitefly. If sprayed on the plants beforehand, the pungent smell of sulfur will repel the fly, thus avoiding infestation. However, you need to be very careful when using it, because if applied too frequently it can burn the leaves.

Against whiteflies, other natural remedies well known due to its repellent effect are an infusion of garlic and chilli pepper , particularly effective for whiteflies.

By macerating them together in an aqueous solution for about 48 hours, possibly in the sun, they will release all their natural repellent and antibiotic power. However, this remedy requires a certain consistency in applications, which must be carried out on each individual leaf.

Potassium soap should also be included among the organic treatments against whitefly . Applied in the early hours of the day, it kills parasites by asphyxiation when the soap in contact with sunlight begins to dry on their body. It is also useful for cleaning plants from honeydew.

Vinegar is also effective against whitefly. Antiseptic and disinfectant, acetic acid is a fermented food that is highly attractive to whiteflies. Place it in a container near your plants, you will see that the flies will enter and remain trapped.

What is the best natural insecticide for whitefly?

For whitefly, a particularly effective natural treatment is azedirektin A , the active ingredient of neem oil , a powerful natural pesticide and insecticide , non-toxic for the environment. 

It is a vegetable oil that is extracted from the seeds of Azadirachta indica , a plant native to South-East Asia and in particular India.

It is a substance that is as harmless as it is effective in fighting insects and plant parasites, perfect for organic and biodynamic agriculture, because:

  • It has antiseptic and antibacterial properties;
  • It interferes with the hormonal system of insects and parasites, blocking their development in the embryonic stages and moulting;
  • It acts as a phage deterrent against egg deposition (oviposition);
  • Inhibits the feeding need of adult insects;
  • It has an intense odor, which acts as a repellent for bedbugs, mosquitoes and other parasites.

Furthermore, neem oil is able to activate the natural defenses of plants. But how can you use it to combat whitefly? Add approximately 5 ml of neem oil to 1 liter of hot water. Also add 2 ml of soft soap, even better if with sulfur which makes the mixture more effective. Once the ingredients have dissolved and the water has cooled, use it by spraying it on the plants, especially the undersides of the leaves. Like all natural products, this product also has a very rapid decay. In fact, it should be used within 8 hours of preparation. Therefore, at least one application per week will be necessary, especially in the hottest periods.

When purchasing, always make sure that the neem oil you have chosen has been cold-pressed. In those hot extracted, in fact, part of the effectiveness of the active ingredient could be lost.

The whitefly is not dangerous for humans, but it can irreparably compromise your cultivation, frustrating efforts and economic investments.

As we have already mentioned, the best ally to fight whitefly is prevention and ad hoc natural remedies . In fact, by anticipating treatments that strengthen the plant's natural defenses, you will be able to contain proliferation to a level that is not harmful.

Visit the pesticide and protective category of Grow Shop Italia and purchase the most effective product to prevent and combat whitefly and eliminate it once and for all from your indoor hemp crop.