How to eliminate the mealybug from prickly pear cactus trees

How to eliminate the mealybug

If you want to know how to eliminate the carmine mealybugs from your prickly pears, you've come to the right place. In this article we are going to explain our experience with the treatment to eliminate the carmine mealybug in the prickly pear cactus fields we have in La Herradura, Spain

The prickly pear cactus belongs to the Cactaceae family, which consists of more than 300 species, all of which are native to the American continent, where they grow wild.

There are many species of this family that produce edible fruits (prickly pear, prickly pear), but the species that has been planted par excellence has been the Opuntia ficus-indica for the succulence and sweetness of its fruits and it is the one that the cochineal mealybug has been killing for 2-3 years in Spain

One option that we do not recommend is the use of insecticides that contain chemicals and are harmful to the health of humans, plants and the environment in general. In addition, the chemical product is not as effective in eliminating the carmine mealybug pest because of the cottony protection generated by the mealybug, a kind of cottony fuzz that prevents contact with the insecticides.

The rapid expansion of this pest is due to the number of prickly pear cacti that are no longer cared for as a result of the general abandonment of the Spanish countryside and the lack of action by the State as it is an "invasive plant"

What we do recommend is to use only organic products, the few that exist to combat this pest. Integrated control of this pest is not easy. What has worked for us so far has been mechanical elimination (brushing) and potassium soap. In any case, "prevention is better than cure" and attack the pest at an early stage, when the first white spots appear on your prickly pears.

The carmine mealybug is more difficult to eradicate when the pest has spread and can seriously affect our plants. In Spain the pest is very aggressive and treatment has to be repeated every 15 days or every month depending on the amount of mealybug in your area. On a small scale, a periodic brushing of the surface of the blades with a brush dipped in potassium soap (or dishwashing soap) is enough to keep them clean (clean in the afternoon, avoiding direct sunlight).

If the plant is badly affected, cutting off the affected blades and additional mechanical cleaning and cleaning with potassium soap is recommended. The affected shovels should be buried and not left on the ground or taken to the rubbish dump, otherwise the pest will spread and the problem will be transferred to another location.

Once the prickly pears have been cleaned, it is time to rely on biological control, so that the prickly pears' own natural enemies are responsible for naturally regulating their populations. Commercially available natural enemies can also be used for mealybug control, such as the ladybird cryptolaemus montruozieri and the parasitoid wasps Angyrus pseudococci and Leptomastix algirica.

Dactylopius coccus and Dactylopius opuntiae, an uncontrolled pest. The carmine mealybug, Dactylopius coccus, is a small insect native to Mexico, parasitic on cacti of the genus Opuntia Ficus Indica. Before the advent of synthetic dyes, the cochineal was widely bred to obtain the red dye carmine. It is also known as grana cochineal, natural red 4, crimson lake or natural dye E120. The substance that gives carmine its red colour is carminic acid.

Mealybug is used to give colour or to reinforce it in products such as: ice creams, yoghurts, jams, jellies, candies, Martini Rosso vermouth, Campari liqueur, jelly beans and other sweets, pharmaceutical and cosmetic products such as lipsticks, eye shadow, pink make-up powder, etc.

Some people develop an allergy to this dye. Lipsticks are especially dangerous. The carmine mealybug feeds exclusively on prickly pear cactus, mainly of the genus Opuntia (prickly pear cactus). The females are wingless and hide under cottony masses where they can live on the same cactus for up to 80 days. The nymphs are carried by the wind and thus colonise other palas, reproducing 2-3 times a year.

Males are very small and fly; they do not feed because they have no mouthparts and no defensive sting, so stinging is impossible. They fly from spade to spade during the night in search of receptive females. The mealybug weakens the cactus by sucking sage until the blades dry out. Attacks are massive and will eventually kill the prickly pear cactus if intervention is not made in time.

If an adult mealybug is crushed with the fingers, it turns out to be full of eggs immersed in carmine, a bright blood-red liquid. The spots left on the fingers take several days to disappear. Treatment: Mechanical and natural fight against the invading colonies.

There is no specific chemical product to combat the prickly pear pest in Spain.

The cottony masses serve as a refuge for the pest and make contact between the insect and the chemical product difficult, so chemical treatments are not very effective and should be repeated periodically, but are not recommended

As a treatment, it is suggested to cut the very affected blades and remove the cottony masses with a brush. Also apply pressurised water and potassium soap (1%)

Repeat the treatment monthly. In this way the pest can be controlled until a natural predator appears. It is essential not to leave the uprooted plants on the ground, and it is advisable to bury them

The predator Cryptolaemus montrouzieri is found in association with mealybug colonies, but its densities are too low to regulate the population of this new invasive pest.

ORGANIC POTASSIUM SOAP AGAINST THE CARMINE MEALYBUG

How to save our prickly pears with the recipe for making potassium soap:

Potassium soap, or potash, is a natural, ecological and effective method of attacking the carmine mealybug pest in our palms.

What we can use to make potassium soap:

• - Water
• - Vegetable oil
• - Potassium hydroxide (KOH)

Ingredients for one litre of oil:

• - 1L vegetable oil (olive, sunflower, corn or canola oil).
• - 166 grams of potassium hydroxide (KOH)
• - 166 grams of water

What we need to have to make organic potassium soap step by step:

• - Rubber gloves, kitchen gloves are perfect.
  - Safety glasses or large sunglasses
  - Weight or kitchen scales
  - Mixer, Blender or Thermomix
  - Plastic, glass or stainless steel containers for oil, potash and for storing soap
  - Wooden shovel for stirring

Protective measures are necessary because if we are splashed while the reaction between the potash and the water is taking place (it heats up very strongly), it can damage our skin and sensitive parts such as our eyes, so it is better to take precautions. If you have been splashed by the mixture, the best thing to do is to apply a little vinegar to soothe the burning. If the splash has reached your eyes, you should run to wash them with plenty of water and go to the emergency room as soon as possible.

How to make potassium soap step by step:

- Put on protection (goggles and gloves).
- Mix the potash with the water little by little and stir slowly until it dissolves completely, you will see that the temperature increases while the reaction takes place. Important, pour the potassium hydroxide into the water, NOT the other way. When it gets close to room temperature and clears we move on to the next step.

- In a metal pan pour and heat the vegetable oil of your choice (sunflower oil is cheaper, new or used). Let it heat for a few minutes and then remove it from the heat. It should be between 45-55 degrees.
- Transfer the hot oil to the blender.
- Gradually add the potash, blending with the wooden paddle. Important: do not turn the blender on yet.
- Once the mixture is uniform, turn on the blender at the lowest speed and leave it on for 5 minutes. Then increase the speed to medium for 3 minutes and another 3 minutes at maximum speed. The texture should be creamy.
- Pour it into a bowl, mix it with the wooden paddle until it becomes like butter. The texture should be thick and thick, and this is considered potassium soap. Cover and let it sit overnight.
- Our potassium soap is ready. Store it in a glass or plastic container. For later use on your plants, you will need to mix it with water to dilute it.

How to use potassium soap

The most recommended way to use organic potash soap is to spray under pressure, if possible, directly on insects (if visible), early in the day or in the evening at any time of the year. Avoid direct sunlight so that they do not burn.

Dosage of potassium soap

The most common dosage of organic potassium soap for plants is 1% or 2% potassium soap in water.