Common Pests and Diseases of the Yellow Allamanda Orchid and Their Control Methods

Growing Techniques Jan 1, 1970 0 views

Overview of Southern Blight: Southern blight mostly occurs during the plum rain season. In the early stage of the disease, the leaf bases of the yellow allamanda orchid become covered with white mycelium. This mycelium gradually causes the rhizomes of the yellow allamanda orchid to rot. Control method: Remove all the infected potting soil from the pot of the yellow allamanda orchid.

Southern Blight

Overview of the disease: Southern blight mostly occurs during the plum rain season. In the early stage of the disease, the leaf bases of the yellow allamanda orchid become covered with white mycelium. This mycelium gradually causes the rhizomes of the yellow allamanda orchid to rot.

Control method: Remove all the infected potting soil from the pot of the yellow allamanda orchid, and sprinkle pentachloronitrobenzene powder or lime on the remaining potting soil.

Radical treatment: Place the yellow allamanda orchid in a well-ventilated, well-lit spot, and always check whether the drainage of its potting soil is good. Severely diseased plants that cannot be saved must be removed from the potting soil and burned.

Anthracnose

Overview of the disease: Anthracnose is a disease that the yellow allamanda orchid can contract all year round, and it is especially prone to anthracnose during hot and rainy seasons. The lesions of anthracnose first spread from the leaf tips down to the rhizomes. The lesions are initially brown; as they gradually expand and increase, many dry black spots appear on the stems of the yellow allamanda orchid, and in severe cases the disease can cause the entire plant to die.

Control method: First, the cultivation environment of the yellow allamanda orchid should be actively improved. Second, during the disease period of the yellow allamanda orchid, first spray with a 800-1500 times dilution of 50% thiophanate-methyl wettable powder once a week, then supplement with 1% Bordeaux mixture of equal parts, twice a month; spraying continuously 3-5 times can treat this disease.

Scale Insects

Overview of the disease: Scale insects often multiply rapidly under conditions of high temperature, high humidity and poor air circulation, harming the plants.

Control method: During the hatching period of scale insects, spray with 1% omethoate or a 1500 times dilution of 50% malathion. If there are not many yellow allamanda orchids at home, you can also use a small, soft brush to brush off the eggs yourself.

Now that you understand the pests and diseases of the yellow allamanda orchid and their control methods, do you feel a bit more confident about taking good care of your flowers? Then let us also take a look at the propagation methods of the yellow allamanda orchid!

Pests and Diseases of the Yellow Allamanda and Their Control Methods

Diseases of the Yellow Allamanda and Their Control Methods

Sooty Mold

The pathogens are fungi of the subphylum Ascomycota, including various species such as Capnodium and Neocapnodium. Their asexual stage is mostly scattered sooty mold. The pathogen overwinters as epiphytic mycelium on diseased parts or diseased residues, and reproduces using the honeydew secreted by scale insects as nutrients, spreading through wind and rain and the activity of scale insects.

In the early stage, part or most of the branches and trunk of the affected plant turn black, and the diseased areas are covered with black mold that feels sticky to the touch.

In the later stage of the disease, the black mold on the leaf surface can partially peel off, leaving the leaves mottled black and white. Severely infected plants have their photosynthesis hindered, grow poorly, and their leaves drop early, greatly reducing their ornamental value.

Control Methods

The plants should be kept in a ventilated environment to maintain air circulation.

Once infected, spray with a 1000-3000 times dilution of 40% profenofos EC, or a 1000 times dilution of 40% chlorpyrifos EC, or a 2000 times dilution of 25% buprofezin EC (for scale insects, spray the dilute solution during the nymph stage), or spray a 2000-3000 times dilution of 50% pirimicarb EC.

Pests of the Yellow Allamanda and Their Control Methods

Red Wax Scale

The red wax scale of the yellow allamanda belongs to the order Homoptera, family Coccidae (also called wax scale family). It has a very wide host range and is one of the main pests harming the yellow allamanda. Female adults and nymphs pierce and suck the sap of the branches and leaves of the yellow allamanda, causing malnutrition, weakened growth, and hindered flowering and fruiting, and in severe cases can cause the branches of the yellow allamanda to die.

The red wax scale of the yellow allamanda has 1 generation per year, overwintering as fertilized female adults on the branches and trunk. May and June of the following year are the peak egg-laying period for the overwintering females. The eggs are laid beneath the body, and the egg-laying period lasts more than a month.

After crawling for a certain period, the newly hatched nymphs fix themselves on the host to feed. They generally begin secreting wax after fixing for 6 hours, and after 15 days can form a star-shaped wax covering. Once the waxy layer has formed, control efforts will not achieve ideal results.

Control Methods

Manual control: In the early stage of red wax scale occurrence, promptly remove the insects, or prune off the branches and leaves with many insects and destroy them together.

Horticultural control: Strengthen pruning of the yellow allamanda to improve air circulation and light conditions, which will reduce the damage by the red wax scale.

Control Applications for Common Pests and Diseases of the White Magnolia

Pest Prevention and Control

Common pests and diseases of the white magnolia: anthracnose, leaf spot disease, cicadas, red wax scale, cottony cushion scale, red spider mites, bagworms, longhorn beetles, etc. Once discovered, they can be sprayed with chemicals to kill them. However, longhorn beetles bore into the branches, trunk and rhizomes, and can sometimes kill the tree. If sawdust-like frass is found, search for the insect holes, use a cotton ball dipped in undiluted dichlorvos to plug the holes, then seal them with mud to fumigate and kill the pests. 1. Cicadas. The nymphs of this pest suck the sap of the roots of flowers in the soil, and the adults, besides piercing and sucking the sap of the main leaves, the females also insert their ovipositors into the branches to lay eggs, causing the branches to die. 2. Promptly search for and kill the mature nymphs that have just emerged from the soil. 3. If they occur in large numbers, on hot summer nights you can light a fire near the tree trunk, shake the branches to make the cicadas fall into the fire and die, and kill the cicadas that fall outside the fire. 4. Use boiled sticky tung oil or a sticky ball made of kneaded spider webs applied to the end of a pole to catch the adults. 5. From April to August, promptly inspect and prune off the egg-laying branches. 6. Red wax scale. The nymphs and adults of this pest pierce and suck the sap of flowers, and their excrement often induces sooty mold, causing a layer of black mold or a relatively thick black film to form on the leaves, turning the whole plant into a black tree, weakening the plant, making the tree shape haggard, and causing it to bloom rarely or not at all. 7. In winter and early spring, remove some of the branches with many insects while pruning. 8. If the affected flower plants are few and short, they can be scraped off manually in winter and spring. 9. During the peak hatching period of the nymphs, spray a 1000 times dilution of 25% phosmet EC, or a 1500 times dilution of 40% omethoate EC, spraying once every 4-6 days; 3 sprays will show results. 10. When introducing flower seedlings, they should be carefully inspected to prevent bringing in insects.

Disease Control

Anthracnose control method: Strengthen water and fertilizer management, enhance tree vigor, and improve disease resistance; promptly remove diseased leaves, and in late autumn clear away fallen leaves and burn them together; if the disease occurs, spray with a 800 times dilution of 75% chlorothalonil wettable granules or a 500 times dilution of 70% thiophanate-methyl, once every 10 days; spraying continuously 3 to 4 times can effectively control the disease. Yellowing disease control method: Yellowing disease is a physiological disease, mainly caused by soil that is too sticky, pH exceeding the standard, and insufficient iron supply. You can use a 0.2% ferrous sulfate solution to drench the roots, or use a 0.1% ferrous sulfate solution for foliar spraying, and should apply more farmyard manure. Leaf scorch control method: Increase the frequency of watering to keep the soil moist; apply more organic fertilizer to enhance tree vigor and improve the plant's resistance; whitewash the tree trunk or wrap it.