Symptoms and prevention methods of 9 major diseases and pests of succulents

First place: scale insects

I often see tiny scale insects parasitizing on leaves. They are usually white, don't move much, and hide in the center of the leaves, making them hard to find. How can I get rid of them and prevent them from multiplying in large numbers?

The white bugs in the picture above are scale insects

Scale insects are protected by hard shells, so it is not easy to kill them after they become ill. Scale insects are most common on succulents of the Cactaceae, Euphorbiaceae, Liliaceae, Aizoaceae, and Jasmine families.

Scale insects reproduce quickly, with each adult laying nearly a hundred eggs twice a year. The eggs are powdery and after drying and cracking, they are blown away by the wind and scattered on the stems and leaves of plants. When the temperature is high and they encounter water, they hatch into adults. At this time, the outer shell has not yet been formed, so it is the best time to eliminate them.

There are also many types of scale insects, which are covered with a waxy hard shell and are round or oval in shape. The former are about 3 to 3.5 mm in diameter, and the latter are about 2 mm long and 1 mm wide. When there are small numbers, they parasitize near the areoles of plants or on the back of leaves and in leaf sheaths. When there are large numbers, they parasitize everywhere on stems, branches, and leaves, absorbing nutrients from plants.

Treatment method: When the number is small, you should immediately pick it out with a bamboo stick or toothbrush, isolate the pots of the infested plants to avoid infection, and use a brush dipped in a diluted solution of Aphid or high-concentration alcohol to wash and kill the larvae and eggs.

Note: Recommendation of the most suitable medicine

1. Flower Guardian

Dilute it 500 times, spray the stems and leaves once a week, and it can be eradicated after 2 to 3 times. It is generally toxic, but it should not be sprayed facing the wind when used. Good ventilation should be ensured, and a mask and gloves should be worn. After work, be sure to take a shower and change clothes.

2. Add white wine to water in a ratio of 1:2.

When treating insects, water the surface of the potting soil thoroughly. Scale insects begin to move when the room temperature reaches 7°C in spring. You can water it once in mid-April, and then once every half a month or so after that. The effect will be seen after 4 consecutive waterings.

3. Vinegar (rice vinegar)

50 ml of vinegar, soak a small cotton ball in it, then use the wet cotton ball to gently wipe the affected stems and leaves of flowers and trees to wipe off and kill the scale insects. This method is convenient and safe. It can not only achieve the purpose of insect removal, but also make the damaged leaves green and shiny again.

4. Alcohol

Simply wipe the diseased plants gently and repeatedly to remove the scale insects, and do it very cleanly and thoroughly. If you use alcohol to wipe the diseased leaves of orchids, it will not only remove the scale insects, but also kill the larvae that are too invisible to the naked eye. In the second year, scale insects will rarely be found. This method is simple, safe and effective.

5. Diesel, washing powder, water

Mix the mother liquor in the ratio of 10:0.6:6. At this time, the mother liquor contains 60% oil and is in milky form. After diluting the 30% oil-containing solution with water, spray it carefully on the scale insects on Milan, kumquat, and cycads. After a week, most of the scale insects had changed from their original fresh orange color to a shriveled state, indicating that this method has a good preventive and control effect on scale insects.

2. Anthrax

There are small black spots on the leaves. What disease is causing this?

The black spots in the picture above are anthrax

Causes of illness:

It usually occurs in areas of over-crowding, poor ventilation or injury. The main affected areas are the stems, where small water-soaked light brown spots appear on the nodes or near the edges, and then expand into round to oval or semicircular to irregular brown spots.

Treatment:

In the early stages of the disease, brown depressions and spots appear. In severe cases, gangrene occurs in the center of the spots and it is difficult to cure. When purchasing, you should pay attention to whether the plant has this disease and avoid purchasing it. When the disease occurs, be sure to cut off and burn the affected area, and then use special medicines such as anthrax and fulami.

3. Rust

A flower friend asked: Rusty spots like rust appear on the leaves. What disease is it?

The above picture shows rust

Causes of illness:

It is mainly caused by improper cultivation and management, such as the potting soil is too poor, lack of nutrients, or the potting is poorly ventilated for a long time, watering directly on the top of the plant, and unsuitable environmental factors that cause rust infection.

This disease occurs on the epidermis of plants. In the early stage, small swollen spots appear on the stem epidermis, which are yellow or reddish brown in the center. Then they slowly expand to the surrounding areas. In severe cases, the spots will sink to form ulcers, the tissue will turn black, and even death may occur.

Treatment:

In addition to paying attention to management, ventilation should be strengthened to avoid watering on the top of the plant. You can use 2000-3000 times diluted 12.5% ​​diniconazole wettable powder for spraying or 1500-2000 times diluted ammonium pyraclostrobin, spray once a week.

Fourth place: root mealybugs

White cotton and filamentous diseases appear on the roots of plants. What is the disease and how to solve it?

The picture above shows the root mealybug

When the plant is dormant, the soil in the pot is dry. At this time, the root mealybugs have strong reproductive capacity and will crawl out from the bottom of the pot and invade other pots. In severe cases, the soil near the roots of the flowers turns white and water cannot enter.

Pest identification:

This pest mostly parasitizes on the roots of plants. It is about several millimeters long and covered with white powder. The parasitic area forms a lump.

Treatment:

Mix water with Flower Protector and pour it into the culture soil, or use "Guoguang Jiebiji". Both of them are less harmful and have a preventive effect. If the plant has been parasitized, you can take out the plant, wash it, cut off the parasitic part of the root lice, and replace it with new soil.

You can also use dimethoate, which can eliminate most pests. It can only be used occasionally on non-edible plants, and cannot be used on edible plants. Be sure to carefully read the usage and dilution multiples.

Fifth place: Red Spider

Red spiders appear in potted plants at home, and if you don't pay attention, they will spread to nearby plants. How can you prevent and cure them?

The picture above shows Red Spider

Red spider mites reproduce rapidly during dry periods, and spraying water on the leaves can help prevent damage. The flowers that are most commonly harmed are from the Cactaceae, Aizoaceae, Euphorbiaceae and Liliaceae families.

Red spider mites are about 0.5 mm in diameter, crawl fast, are small in size, and are not easy to spot. They often gather in groups and gnaw on the epidermal tissue of stems and leaves, making the affected areas appear mottled and rough, and an unsightly white or yellow color.

Treatment:

Red spider mites tend to develop drug resistance, and using the same drug for a long time will reduce its effectiveness. The drugs currently used include imidacloprid, nicotinamide, and furadan. Pyrethroid insecticides have very poor effects on it. Insecticides such as radar on the market have little effect on it. The above drugs are easier to buy, but furadan is highly toxic and should be used with caution.

Flower lovers can also use mosquito coils to seal the smoke, 30 to 60 minutes each time.

PS: The method of making homemade chili water is simple. Just crush raw chili peppers and garlic, then add water and mix them. However, the effect is not as good as pesticides, so it is only suitable for preventive use beforehand.

6. Aphids

A flower friend asked: How can I eliminate the densely packed aphids that gather on the plants?

The picture above shows aphids

Species that are prone to insect pests include succulents such as Crassulaceae, Asteraceae, and Opuntia species of Cactaceae, which are relatively common.

Pest and disease damage:

Aphids can reproduce 5 to 10 larvae a day. When they first grow out, they are generally gray-green pests, about 1 to 2 mm long. They live in groups on plants near branches or on new buds, and use their needle-like mouths to pierce plant tissues to absorb nutrients. Young leaves often curl up into tubes as a result, so flower lovers cannot see the aphids, which is really disappointing.

Treatment:

Use a 500ml cola bottle to mix a bottle of flower protector pesticide, fill it into a spray bottle, and then spray it evenly on the plants. The spraying must be comprehensive and meticulous; remove the surrounding weeds and ensure the environment is clean, which also has a preventive effect.

6. Snails and Slugs

The leaves are obviously bitten around. What pests are causing this? How can I solve this problem?

Causes of pests:

When the climate is warm and humid, snails and slugs will increase in number and reproduce quickly. These soft-bodied insects can be found in both cities and rural areas, and you can find them when there are more plants planted.

Generally speaking, these soft-bodied insects are usually snails and slugs. Many flower lovers say that they cannot find them because they hide in damp and dark places during the day and come out to find food at night. They not only gnaw on young branches and tender leaves, but also do not let go of old stems and leaves.

Treatment:

Removing weeds, garbage, bricks and tiles and other accumulations around potted plants and keeping them clean can effectively prevent snails. In addition, you can install gauze around the potted plants, or buy special medicine to kill snails. You can also sprinkle lime or salt next to the pots, not in the soil.

7. Ants

A flower friend asked: Ants don’t bite plants directly, so will it harm the health of plants?

Of course they are very harmful, and they are the biggest accomplices in harming succulents.

The picture above shows ants

Cause of damage:

Because ants like to eat the secretions of aphids, cottonworms, scale insects, etc., they often move these pests from diseased succulents to other succulents. This is really hateful. These ants not only protect the survival of pests, but also eat the nectar secreted by the pests. They collude with each other and are the biggest accomplices in harming plants.

Prevention and treatment measures:

When purchasing potted plants, carefully check the surrounding area and the bottom of the pot to see if there are any ants, because once ants are present, it means that other pests may be present; when ant infestation occurs, use general pesticides.

8. Big Caterpillar

A flower friend asked: What should I do if I see fat caterpillars in my potted plants?

The picture above shows a caterpillar

Pest and disease damage:

Some succulents that are close to small shrubs and trees are prone to this kind of caterpillars. Some are blown onto flower plants by the wind, and some crawl onto succulents from dark places at night. The most hateful one is a black night robber lurking in the soil. It feeds on the young stems and leaves of plants, and mainly feeds on succulents.

Treatment:

Clear weeds around potted plants and set up screens. Generally, oil-based insecticides available on the market are very effective against caterpillars, but you must be careful with the plants when using them, otherwise the plants will easily be harmed by the pesticide. If you find one or two, just catch them and kill them.

9. Black Fly

The black fly is something similar to mosquito larvae, but it does not live in water and can fly. It can be found in warm and humid environments and reproduces very quickly. It is really annoying!

The picture above shows a small black fly

Pest and disease damage:

In fact, the main harm to plants is that they leave scars after feeding, and they reproduce very quickly, which looks very bad.

Treatment:

It can be killed mainly with household pyrethroid insecticides. You can use flower protector to irrigate and spray the plants in the soil, or bury furadan in the soil. Pay attention to using a small amount of medicine. Using only one medicine will easily make the insects resistant to disease. You can also use a short mosquito coil to fumigate, which is effective for adult insects, and the larvae hidden in the soil cannot be killed!