You would think that a plant like the cactus with all of its many spikes should be free from pests and diseases. Its armor-like should be able to protect it from flimsy disease-causing pests right?
And when your cactus plant got its first pest attack, you were disappointed. Turns out the cactus is big for nothing right?
Maybe, these pests and diseases that affect cactus plants have learned to skillfully evade the spiky parts of the cactus and feed on the softer parts of the plant.
This article clears the air about the cactus plant and its pests and diseases.
The cactus plant has a lot of varieties, each variety having different shapes and growth requirements. Some cactus plants love to grow in temperate regions while others grow in cold regions under relatively humid conditions.
Regardless of the shape, variety, and growth requirements of the various species of cactus, one thing is common with them. It is the pests and diseases that attack them.
Cactus plants are attacked mainly by an insect known as scale.
The scale is a tiny pest that is referred to as a serious commercial pest because of how difficult it is to control.
Scales are also a funny set of species that come in different shapes. Some of them have shapes like oysters while some others look like mealybugs.
Scales are generally winged insects, but the adult female cannot fly. All species of scales have adaptive tentacles that help them stick to a plant so well that they cannot be shaken off.
Scales reproduce in great numbers and can perform both the sexual and asexual forms of reproduction.
They destroy plants by attaching themselves to various parts of the plant, where they can suck the nutrient-filled sap off the plant. After a short while, the plant begins to show signs of death.
If scales are not controlled quickly, they can become a gardener’s greatest nightmare of pests and diseases.
In this article, everything about scales on cactus plants, causes of scales, signs of scales on cactus, and how to control scales that attack cactus plants, are explained.
This article focuses on the pests and diseases of cactus plants and suggests solutions to these pests and diseases.
What is Cactus Scale?
Cactus scales are pests of cactus plants. They are a continuously occurring pest with multiple species.
They are parasites that attack cactus plants, gaining nourishment as well as shelter from the cactus plant. Scales often attack cactus plants in colonies leading to an infestation.
Scales have a scaly covering that protects them from certain insecticides, which contributes to their nature of being difficult to control. They are very destructive and can destroy a population of cacti if they are not properly controlled.
in the United States some time ago, scale infestation was the cause of an agricultural loss of over five billion dollars. This is only a glimpse of all the havoc that the scale pest can wreck on a garden.
The scale pest is not entirely useless and capable of destruction. It has some form of economic benefit. It is useful in the production of high-quality dyes.
The scale insect is a highly evolving pest family, with newly evolved species being harder to control than the ones before them.
What Does Scale on a Cactus Look Like?
Scales that attack cactus plants are usually armored, having dark colors and round shapes.
Scales begin infestation of the cactus plants very slowly, and with time, these pests and diseases cover the entire cactus plant. Scale infestation on a cactus plant often looks like tiny shreds of cotton on the stems, white and widely spread across the plant.
The following signs appear on your cactus plant as pointers to the presence of scale on your cactus plant:
- Bumps that are round or oval on the stem of the cactus plant
- The cactus plants begin to develop white spots all around the leaves.
- The leaves and stem become wet and sticky
- There is the growth of molds on the plant which is caused by honeydew dew droppings of the scale insect
- The plant starts to brown up and looks wilted.
When these signs appear on your cactus plant, you should inspect the cactus plant to be completely sure that the infestation is a result of the scale pest.
What is the Cause of Scale on Plants?
In categorizing scale, it falls into both the categories of pests and diseases. This is because, aside from the parasitic feeding carried out on cactus plants, scale pests also release a fungal dropping called honeydew.
The honeydew hardens on the leaves of the cactus plant and grows into molds that inhibit the plant from carrying out the function of photosynthesis.
Scales are living organisms and are therefore not caused by anything. They are native to northern America and are dispersed as eggs to other parts of the world by clinging to succulent cactus during export and import.
Once in a new habitat, the scale pests hatch their eggs and grow on the leaves of the imported cactus plants. Fully grown, make holes in the cactus plant tissues and feed on the nutrient sap of the cactus plants.
Scales plants produce fungal liquids known as honeydews by excretion.
How Do You Remove Scale from Plants?
Yes, they are difficult to control because of their nature of returning to the plant often after being gotten rid of.
Yet, the following are ways to get rid of scale from plants, especially your cactus plants.
- Manually picking
- insecticidal soaps for wiping scales off the leaves.
- Introduction of natural predators
- Application of isopropanol
- Pruning of affected parts
- Use of commercially safe Pesticides
These procedures need to be done carefully and in the recommended patterns to prevent the destruction of the cactus leaves that have already been weakened by the scale of pests and diseases.
1. Manual Removal by Handpicking
This method is slow and effective in the early stages of infestation. It involves the use of hand or pickers like flat cards or smooth pickles to carefully remove and detach scales from the leaves of the cactus.
You should ensure you are careful in doing this, given that the cactus plant is usually filled with sharp spikes that could prick your skin.
2. Insecticidal Soaps for Wiping Scales Off Leaves
This method is faster than the manual method of wiping scales off with hands. Insecticidal soaps are not toxic to growing plants and cannot harm the soil.
They are made when fatty acids in oils used at home are mixed with alkaline chemicals which results in a potassium salt that can kill scales on the leaves of plants. Insecticidal soaps are applied to the plant by spraying the affected parts with a hand sprinkler.
Sprinkling the cactus plant should focus on the body parts filled with mites. You can easily identify affected parts by whitish cotton-like growth.
After application of the insecticidal soaps, allow the plant some time, within which the scales die off. Some of the dead scales fall off while a greater number of them stay dead and stuck on the plant’s stem.
Use a scraper to scratch off dead spider mites from the plant leaves.
3. Introduction of Natural Predators
This method involves the identification and introduction of scale predators into the cactus plant. Ensure that the new predator being introduced does not constitute further pests and diseases to the cactus plant.
Introduce only natural predators of the scale pests that do not feed on cactus sap-like scales. Insects like lacewings, ladybugs, and mealybug destroyers are effective scale predators.
They can be introduced to the cactus plant but need to be attended to regularly to ensure they are not flying off the cactus plant into other nearby plants.
4. Application of Isopropanol
Isopropanol is an alcoholic base that works just like insecticidal soaps. This method is often expensive due to the cost of purchasing enough isopropanol.
Use this method only if the cactus is reacting adversely to other removal techniques. If not, it is recommended to use the other cheaper methods.
Isopropanol can be applied using a sprinkler to spray all of the parts of the cactus affected by the scale and honeydew pests and diseases.
5. Pruning of Affected Parts
This method becomes an option when the cactus branch can no longer be saved.
Pruning should be done by deadheading. This ensures that every part of the affected stalk is cut away to prevent the transfer of scales to healthy parts of the plant.
6. Use of Commercially safe Pesticides
Pesticides are fast in action and can rid your cactus plant of pests and diseases within ten minutes of spray.
A disadvantage however is that some pesticides can end up destroying both your cactus plant along the scale insects. This is why we strongly advise the use of pesticides that are approved to be commercially safe for usage on plants.
In your application of pesticides to a scale-infested cactus, spray focus should be only on the part with the white cotton-like signs of the cactus. After the application of pesticides, give the cactus plant about a month, before another spray.
Remember the following:
- Scale falls under the categories of pests and diseases because of its ability to suck sap from the cactus as well as excrete fungal droppings on the plant that inhibit photosynthesis.
- Scale insects are tiny and can only be noticed due to the signs and symptoms they give off on the plant cactus stem.
- A symptom of scales on cactus is the appearance of tiny white spots that are wool-like, on the stems of the cactus.
- Scale on cactus is a result of the importation of affected traditional cactus plants to a garden with good growing ones.
- Pruning as a method of control of scale on cactus should be employed as a last resort to excessively invaded stalks.
Scale on cactus is a threat to the healthy growth of cactus plants. It can kill an entire population of cactus if not properly controlled and done so in time.
They suck the sap off the cactus plants, leaving them discolored and looking drooping.
Your cactus can be free of pests and diseases if adequate care and attention are given to it.