Common pests and diseases of Aloe Vera or Aloe Vera

Once again I welcome you to this humble website where I try to collect useful information for lovers of succulents and especially those of Aloe Vera or Aloe Vera . Today I bring you an article full of useful information about diseases and problems that we can find in our Aloes and also in our succulents.

I receive comments daily saying;

My aloe has black dots, is it normal?
My Aloe plant is turning brown, is it sick?
Why did my Aloe appear blackheads?
My Aloe has brown spots, what is it?
I think my Aloe is dying, Help!
My aloes have bugs, what do I do?

I have had to resort to texts in English to collect the maximum possible number of diseases and pests. I know that I have left some out of this article but I will try to complete it when I learn more about them.

For now I hope you can identify your problem and understand how to fix it. Without further ado I begin to list:

Brown and Black Spots on Aloe Vera Leaves – Aloe Mold

Name: Asian Soybean Rust – Phakopsora Pachyrhizi

Category: Mushroom

About this fungus I did find information in Spanish but nothing in relation to how it attacks aloes so it is my duty to explain it here.

This is a fungal-type disease that could affect any succulent, including Aloe Vera. It is of special interest in the cultivation of Aloe Vera due to its commercial purpose, since the attack of this fungus could ruin an entire plantation.

This fungus is self-limited and does not spread throughout the affected leaf, but remains in the points where it appears.

Symptoms:

Small pale yellow spots on leaves that expand and turn brown; masses of orange spores may be present on the underside of the leaf; leaves can fall off the plant.

These spots appear when the phenols in the aloe vera sap oxidize and are permanent once they appear. The spots could appear anywhere on the sheet, however, they are more common at the edges, since that is where raindrops and environmental condensation usually end up.

The centers of the stain tend to dry out as time progresses, while the outer area spreads slightly. Holes are created that pass through the plant and the affected leaves end up succumbing and dying, leaving parts of the plant devoid of leaves.

This fungus has adapted very well to travel long distances; it is transmitted by spores, being able to be displaced to other plants by the wind or rain splashes.
The temperatures in which it develops best are between 15 and 27 degrees Celsius, while above 30 degrees its activity slows down.
The spores are produced 10 days after infection and are released into the environment for three weeks as long as the infection in the leaf has humidity and the ambient temperature is adequate. It is believed that spores cannot go through cold spells without a host.

Causes:

The appearance of other diseases and cool temperatures along with high humidity.

Management:

As soon as you see a black dot, remove them with a knife and burn them.
If the previous step doesn’t fix the problem, remove all the leaves from the plant and burn them. You must start from scratch with that plant.
Dissolve 1 tablespoon of sodium bicarbonate in 4 liters of water and apply it on the leaves; This will help fight the fungus.

You could also try antifungals like these that I put below; The first is specific for rusts and the second is more generic and has an insecticidal effect, although organic.

Prevention:

If you plant from seed, always use disease-free seed.
Maintaining good air circulation in our plants is essential. Remove excess old leaves to improve air circulation.
Use of preventive fungicides.
Water in the morning to allow the plant as much time as possible to dry the possible water that has fallen on its leaves.
Don’t let water collect on its leaves as this will make the plant susceptible to fungi.

Black Spots and Holes on Aloe Vera Leaves

Name : Alternaria brassicae

Cause: Fungi

Symptoms:

Symptoms appear on the leaves as small dark brown necrotic spots on both sides that gradually get larger and eventually cover an area 2 to 8 cm in diameter. The spots gradually coalesce and the infected areas turn from dark brown to black. The surface of the leaf becomes covered with numerous lesions of this type, which in turn rot and dry within 4-7 days, with each lesion eventually developing into a central cup-shaped depression with a depth of 5–8 mm, which indicates the presence of leaf spot.

Comments:

The disease is favored by the hot and humid climate; spreads easily during wet weather by splashing water

Management:

Application of suitable fungicides such as Dithane M-45.

Blackheads and Scabs on Aloe Leaves

Name: Sooty mold – Cladosporium

Category: Mold

This mold is identified by the appearance of black patches, as if it were soot, but nothing is further from the truth because it is a complex of fungi such as Cladosporium , Aureobasidium and Antennariella.

Size: Small spores

Color: black

Transfer: Wind, humans, pets, ants, aphids, …

Cause: This type of mold develops as a secondary infection caused by other insect pests that produce some type of honey; sweet and sticky that clings to the leaves of the Aloe Vera plant.

The Aloe plant is very susceptible to the Aloe Vera aphid or aphid. When this aphid sucks the sap of Aloe Vera, it excretes a kind of honey that results in sooty mold.

Management: This mold, apart from being unsightly, is not harmful to the plant in small quantities. In extreme cases it could prevent the absorption of light by Aloe.

To eliminate it, you can hit it with your finger or with a damp cloth, but it will reappear as long as you do not eliminate the cause; those happy aphids that excrete honeyed and sweet liquid.

Pests of the Aphid or Aloe Vera Aphid

Name: Aloephagus myersi

Category: Insects

Symptoms: Both adults and nymphs feed on the bases of leaves or on the rolled ends of damaged leaves. They also secrete molasses, which results in the development of sooty mold. Severe infestation leads to slow growth and stunted growth.

Cause: Insect

Comments: One of the important quarantine pests.

Management: Acceptable organic control methods include application of insecticidal soap and preservation of natural enemies .

Red Spider pest on Aloe Vera leaves

The spider mite is not actually a spider, but a mite . They both have 8 legs, which makes them part of the arachnid family (along with ticks and scorpions). These particular arachnids are super tiny. You may need a magnifying glass to see them, or you may only be able to see spots that move.

The reason they are called spider mites, then, is because they weave tiny webs to protect themselves from predators. These cobwebs do not look much like spider webs, which are usually designed with an intentional pattern and made from various types of strong webs. No, spider mite webs are messy and disorganized.

They tend to live on the underside of leaves or in the crevices where the stem and leaves meet. Red spider mites are also almost always found in colonies; large groups of dozens or hundreds of individuals.

This common pest is easily identifiable by the small pale marks left on the surface of the aloe leaf . The leaf can become covered by these spots.

The relationship between this pest and other problems that affected aloes display is not clearly understood. Suffice to say, aloe doesn’t like these mites at all. Even the flowers can be deformed when subjected to the bites of the mites when they begin to emerge.

Visible mites like these are easily contained by a spray of insecticidal dust in the center of the plant, and will succumb to most insecticidal chemicals in aerosols as well.

Treatment of spider mites

If you have these bad boys, you’re in it for the long haul. There are few other pests that rival spider mites in terms of tenacity and stubbornness.

They are also particularly difficult to treat because, not only are they on the protected underside of the leaves, but they are also protected by their net. Some chemical treatments won’t work unless applied directly, so you’ll probably have to deal with cobwebs first.

Neem oil

Like almost all other pests, neem oil is a great first step. However, unlike any other pest, you can’t just spray neem oil on your aloes and finish them off.

Spider mites hang on the underside of leaves, remember? And neem oil is a bit sticky, it won’t drip and cover the underside of the leaf enough.

If you want to use this oil, you will have to make a conscious effort to get under the plant. I would recommend securing some plastic over the soil and then turning the pot upside down; This will save most of the soil and can spray directly on the mites.

As with all use of neem oil , reapply every 2-3 days until the infestation is gone. You can also use it as a preventive measure.

High pressure water

Let me be clear, water alone will not solve your mite problem. It may slow it down at best. Water treatment is best used in conjunction with another solution.

If you are lucky enough to find these pests early in the infestation, an aggressive spray of water could dislodge them. More importantly, the water will remove your «web.» Without their web, spider mites are very vulnerable to both natural predators and chemical treatments.

Use a garden hose or pressure spray bottle under the leaves to target the cobweb in the fountain.

Insecticidal soap

Insecticidal soaps are a great option for treating spider mites. It is gentle enough to use repeatedly without damaging the plant and strong enough to kill mites and their eggs.

You can buy the soap at garden stores or online. You can easily do it yourself, just put a few drops of soap in a spray bottle and shake it.

Keep in mind that it has to be real soap. Dish soap, and many hand soaps, are actually a detergent and not a soap. Detergents can harm your plants.

Insecticidal soap is very similar to neem oil in both application and effect, only weaker. It will take much more persistence and a longer treatment to get rid of mites for good. However, neem oil doesn’t kill bees and insecticidal soap does, so keep that in mind as you collect your poison.

Predatory mites – Ladybugs

Fighting fire with fire!

Not all eight-legged beasts are evil (although arachnophobics may disagree). There are many species of mites that do nothing more than eat smaller mites. Ladybugs will be your best friends.

Most regions have a natural wild population of predatory mites (but they can also be purchased online). They are probably responsible for keeping your plants protected the rest of the time that they are not infested with mites. They can eat lots of adults and eggs every day, keeping pests in check.

Predatory mites are a great preventative measure, but they are of limited use in treating an entire infestation. They just can’t eat enough spider mites to make a dent in a really bad stage, and they can’t reproduce fast enough to keep up.

However, if you are on time, they can stop you before the mites establish themselves.

Don’t use predatory mites with poisonous treatments like neem oil or insecticidal soap. That thing kills predators as dead as prey.

Basal stem rot

Name: Fusarium spp

Category: Mushrooms

This fatal disease for aloes appears in damp and cold conditions in which the base of the trunk of the aloe plant will turn dark red or black and immediately begin to rot.

Normally this rotting of the stem base occurs when the plant is settled on a poorly drained substrate and which remains wet most of the time, which is why I highly recommend the soaking and drying technique.

Symptoms: The base of the plant turns reddish-brown to black and rots.

Cause: Fungi

Comments: Deadly Aloes Disease; the appearance of the disease favors cold and humid conditions. The upper part of the substrate must remain free of moisture, therefore it is advisable to use substrates with great draining power and fast drying.

Management:

Plant pieces can be saved by taking cuttings above the rotten portion.
Treat or discard substrates where there was an affected plant.
To prevent this disease from attacking your plants you can use Dithane M-45

Bacterial Soft Rot

Name: Pectobacterium chrysanthemi

Category: Bacterial

Conditions that favor the presence of these bacteria:

These bacterial attacks benefit from the remains of infected plants and leaves that have been left on the substrate previously.
They also benefit from the presence of nematodes in the roots which cause lesions in the roots and leave the plants weaker.
Wounds and cuts in the plants.
Warm climates with abundant rainfall trigger bacterial attacks since they need the presence of water to invade the plants.

Symptoms: Watery, rotten leaves, darker in color; young leaves that wilt and collapse; leaves that protrude due to the formation of gas inside.

The first leaves attacked are closest to the substrate, but quickly spread throughout the plant, including the youngest leaves.

Bacteria feed on the inside of the leaves, even leaving the outside intact. That is, the leaf is rotting from the inside.

Interestingly, when one realizes the attack of bacteria is when the central and younger leaves of the plant have succumbed, expelling a bad smell.

Cause: Bacteria

Comments: Bacteria survive on plant debris in the field; the appearance of diseases is favored by the hot and humid climate.

This disease spreads so fast that in two or three days the plant dies completely, turning into a gelatinous mass that sometimes comes off its leaves.

Management: Deadly disease; avoid overwatering the plants.

Prevention:

Control nematodes.
Prepare a fast-drying, well-draining substrate.
Avoid cuts and blows to the plants.
Burn the affected plants and the substrate they were in to prevent spread to new plants.

If you liked this article on Common Pests and Diseases of Aloe Vera or Aloe Vera , I think you will also like this other article: Why does the aloe vera plant turn brown?