Cochineal: how to combat one of the most voracious cannabis pests

Cannabis growing is a really comforting activity which can unfortunately become quite a challenge if your plants are attacked by cochineal. This is one of the most common pests in cannabis, especially in outdoor grows. In this article, we show you a step-by-step guide on how to prevent and eliminate this annoying intruder in your cannabis plants.

Cochineal is a small insect with a voracious appetite that feeds on the sap of marijuana plants. Even the most seasoned growers have had to deal with this pest at one point or another. Therefore, it’s important to know the right preventive measures to avoid it, as well as some treatment methods for its eradication.

What do cochineals look like?

These small Hemiptera, of which there are approximately 1500 different species in the superfamily Coccoidea, have a soft and flattened oval-shaped body that can measure from 1 to 5 millimetres (although appearance may vary depending on the species). The types of cochineal that usually attack cannabis plants are Planococcus Citri, commonly known as ‘cotton mealybug’, and Coccus hesperidum, which has a tough brown shield-shaped shell.

The cotton mealybug is very easy to recognise because it’s covered in a whitish, waxy, and cotton-like secretion which it uses to protect its eggs. This insect attaches itself to the branches and to the space between the leaves and the stems of the plants ― from there, it sucks the sap, weakening the marijuana plants and causing all kinds of problems in their development. In addition, it can also attract and be the vector for other insects and diseases.

Its quick development means that there may be several generations of cochineal within the same season. This ability to proliferate has paradoxically made it a very profitable insect throughout history, thanks to its carmine red or ‘cochineal red’ pigment. This is one of the most widely used natural pigments in the world, which is obtained from the dried and crushed body of the female grana cochineal (Dactylopius coccus, a parasitic insect of the nopal, the national cactus of Mexico). The high value of this pigment was already known by the Aztecs before the arrival of the Spanish in America. From the 16^th century, there was a great obsession in Europe to obtain this perfect red pigment, which became one of the most valuable products from overseas.

Life cycle of the cochineal

The cochineal goes through different phases throughout its life, which may vary according to the sex of the individual. Cochineals exhibit sexual dimorphism, meaning that adult males and females are physically different:

• Female cochineals go through an egg phase, three nymph phases, and finally the adult stage.
• Male cochineals experience an egg phase, two nymph phases, and a pseudo-pupal stage before finally becoming adults. Commonly, males have wings and do not feed because they lack mouthparts, so their only function when emerging from the cocoon after their last moult is to fertilise the females.

What damage can cochineals cause to cannabis plants?

Cochineals affect the vitality and vigour of cannabis plants because they feed on their sap, which in turn can interfere with their development. If this insect settles on your grow during the vegetative phase, it can hinder the growth of new branches and leaves, slowing down the plant processes and preventing them from developing the structure that they need for the production of a good yield.

During the flowering phase, cochineals may decrease the quantity and quality of the flowers, meaning that your precious harvest could also be compromised.

The threat of the cochineal lies not only in its appetite, but also in its ability to reproduce: these intruders can lay up to 2000 eggs in optimal environmental conditions, although this number is usually between 300 and 500. This means that this pest could quickly become a serious infestation. What’s more, males can also fly to search for females to mate with and thereby expand their domain.

Another issue is that, when cochineals suck the sap from the plants, they can also infect them with toxins that can transmit viruses. And, to top it all off, these insects can secrete a type of molasses that attracts ants and can contribute to the proliferation of fungi, such as smut or sooty mould. Quite a lethal combo that can complicate things considerably for even the most experienced growers!

How to prevent the appearance of cochineals in your marijuana plants

Cochineals thrive in warm and dry environments. Therefore, whether you’re growing indoors or outdoors, you must always try your best to make their life as difficult as possible:

• For indoor grows, maintain good ventilation, and control the temperature so it doesn’t get too high (keep it within the parameters that cannabis plants need to develop correctly).
• Check your marijuana plants regularly, looking for early signs. Pay special attention to the stems, the underside of the leaves, and the joints between the main stem and the branches.
• Look for sticky traces of molasses or for the white cover that protects this insect.
• Favour the appearance of the natural enemies of cochineal, such as ladybugs or parasitic wasps.
• Place yellow adhesive traps ― the males will stick to them given that they can fly, so you’ll find it much easier to identify this pest.

How to eliminate cochineal from your marijuana plants

If cochineals have managed to sneak into your cannabis grow, even after taking all the preventative measures, it will be crucial for you to act as soon as possible to make sure that they don’t spread. The first step is to detect and separate the infested plants from the rest, before proceeding with a specific treatment to eliminate them:

• Manual removal: Moisten a cotton ball in a soapy solution with methylated spirits and carefully remove any cochineals you find on the branches. Remember that cochineals ‘cling’ to the plant and hide under their protective cover, so this can be a very laborious task; but it is the most effective way to ensure that you get rid of this annoying pest.
• After manual removal, check your plants daily and remove any possible cochineals that got away during the first removal session.
• Clean the sticky residue left by the cotton mealybugs with potassium soap to prevent the appearance of ants and fungi.
• You should also eliminate any ants that have been attracted by the molasses produced by the cochineals.
• During the vegetative phase, you can use organic pyrethrin to remove cochineals from your marijuana plants.
• After harvest, thoroughly examine the buds to make sure there are no cochineals hidden in them.

When it comes to cochineal or to any other pest, disease, or pathogen which may threaten your cannabis plants, prevention is always key. Remember that maintaining proper hygiene and good habits in your grow will help you avoid many headaches. Besides, quick intervention is also crucial to keep your crop healthy and pest-free. Therefore, if you spot the first signs that cochineal has made an appearance, act carefully and with determination… Your cannabis plants will certainly thank you for it!