Succulents are relatively susceptible to damage from small insects. Below, we will introduce in detail the methods for preventing and controlling pests in succulents.

Pest Control Methods for Succulents

1. Red spider

It primarily infests succulents in the Asclepiadaceae, Euphorbiaceae, Asteraceae, and Liliaceae families. It sucks the sap from young stems and leaves with its mouthparts, causing yellowish-brown spots or yellowing and leaf drop. These scars are permanent. Generally, you can check the underside of the leaves for spider webs and small red/white/dark-colored insects; if present, it's usually a spider mite.

Control measures include increasing environmental humidity to reduce and prevent the spread of the virus, using 40% trichlorfon at a dilution of 1000-1500 times for absorption, or abamectin.

2. Scale insects

It has a wide range of damage, often affecting succulents such as agave and haworthia with tightly packed leaves. It sucks sap from the stems and leaves, leading to poor growth and, in severe cases, wilting and death. Its peak infestation period is earlier than that of spider mites, often multiplying in large numbers as early as early spring. However, its damage is also manageable in some areas, as it often concentrates on only a few plants; sometimes one plant is covered in scale insects while a neighboring plant is completely free.

Control methods: When the number is small, it can be driven away with a brush. Alternatively, it can be sprayed with an 800-1000 times dilution of carbofuran. Mixing a certain amount of furadan into the potting soil has a preventative effect, but its effectiveness only lasts for 3 months.

3. Whiteflies

The damage is not widespread, but it mainly occurs in shrub-like succulents of the Euphorbiaceae family, such as Euphorbia milii, Euphorbia milii, Euphorbia tirucalli, and Euphorbia tirucalli. It sucks sap from the underside of the leaves, causing the leaves to turn yellow and fall off. At the same time, it can induce sooty mold, which will leave large patches of unsightly black powder on the stems and leaves, directly affecting the ornamental value of the plant.

Control measures: In addition to improving environmental ventilation, in the early stage of the outbreak, spray with 40% dimethoate EC at a dilution of 1000-2000 times. Alternatively, spray with 500 times dilution of malathion or a mixture of dimethoate and dichlorvos at a dilution of 1000 times. Two days after spraying, use a strong stream of water to wash away the dead insects and black powder.

4. Aphids

Most succulents that harm Crassulaceae and Asteraceae plants often suck the sap from the tender parts of the plant, causing the plant to weaken and its secretions to attract ants.

Control methods: If the number is small, manual removal is possible; pinch them off as soon as you see them. In the early stages of damage, spray with a 1500-fold dilution of 80% dichlorvos emulsifiable concentrate, or consider using Bayer imidacloprid from Germany.

That concludes our introduction to pest control methods for succulent plants. Next, let's look at the prevention and control of succulent plant diseases.

1. Fusarium head blight

This is a bacterial disease and a major disease affecting succulents. It commonly affects tuberous succulents, entering through wounds on the roots and causing reddish-brown lesions on the tubers, which then rot and die within a few days.

Prevention and control measures: Before potting, spray with a 1000-fold dilution of 70% carbendazim wettable powder for prevention, and after drying, apply sulfur powder for disinfection.

2. Anthrax

This is a significant disease affecting succulents, belonging to the fungal category. It often occurs during hot and humid seasons, especially the rainy season when temperatures are high and humidity is high. Excessive application of nitrogen fertilizer can also cause it. In the early stages, small brown spots appear on the leaves, which later expand into round or oval shapes. The spots gradually dry out, and in severe cases, the entire plant is infected.

Prevention and control measures: First, open windows for ventilation to reduce indoor air temperature and humidity. Then spray with a 1000-fold dilution of 70% thiophanate-methyl wettable powder, or spray with 70% thiophanate-methyl, 60% carbendazim, or other fungicides to prevent the disease from spreading further.

3. Rust

This disease commonly occurs in succulents of the Euphorbiaceae family. Large rust-brown lesions appear on the epidermis of their stems and spread upwards from the base of the stem. In severe cases, the stem is covered with lesions.

Prevention and control methods: In conjunction with pruning, remove diseased branches to allow new branches to sprout, and then spray with a 2000-3000 times dilution of 12.5% ​​tebuconazole wettable powder.

4. Physiological disorders

Due to harsh growing conditions, such as strong sunlight exposure, insufficient light, sudden low temperatures, and long-term water shortage, the stems and leaves may suffer from scorching and browning, excessive growth at the growing point, frost damage to some tissues, and apical atrophy. The most fundamental measure is to improve the growing conditions.

Methods for controlling diseases and pests in succulent plants

Prevention is key in controlling pests and diseases in succulents. First, the environment must be kept clean. Imported succulents must be strictly inspected to ensure they are free of pests and diseases before being placed in the greenhouse. Seasonal transitions are prone to pests and diseases. Generally, the periods when the weather changes from cold to warm or from hot to cool are the times when pests and diseases are most likely to suddenly erupt. In addition, after summer, succulents have just emerged from a long dormancy period and are gradually resuming growth, but their physiological functions have not fully recovered, and their resistance is still weak, making them susceptible to pests and diseases. Concentrated spraying in the greenhouse during early winter, early spring, and before the rainy season is highly effective. Furthermore, sterilizing the potting soil has a good preventative effect.

Commonly used pesticides for succulents fall into two main categories: fungicides for disease prevention and treatment (such as carbendazim, thiophanate-methyl, chlorothalonil, and zineb) and insecticides (such as dimethoate, dicofol, malathion, pyrethroids, and abamectin). The appropriate pesticide should be applied according to the specific symptoms. The concentration of the pesticide must be strictly controlled according to the instructions, especially for insecticides. Even slightly high concentrations can cause phytotoxicity, and *Euphorbia milii* and some other succulents in the Euphorbiaceae family are particularly sensitive to this.