Hoya Cultivation and Management Techniques and Pest and Disease Control Methods

How to grow hoya? There are many hoya varieties with strong ornamental appeal. Nowadays many households like to keep one or two hoya plants at home. Below, the editor of Huinong Network will bring you the propagation and pest and disease control cultivation techniques for Hoya genus plants.

1. Cultivation and Care

1.1 Environmental Regulation

Hoya genus plants are mainly found in tropical and subtropical regions, growing epiphytically on tree trunks and rock walls. They prefer warmth and tolerate dryness. In artificial cultivation, the ambient temperature should not be too high; if it is too high, good ventilation is required, and a high-humidity, semi-shaded environment is suitable. In summer and autumn, relatively high air humidity should be maintained, and direct sun exposure should be avoided. The suitable temperature for growth is 20°C-25°C. In winter, the temperature should not drop below 5°C; if conditions permit, keep it above 10°C. In summer, shading is needed, along with water-curtain cooling and humidification, with the temperature controlled at around 25°C.

1.2 Medium Ratio

The cultivation medium for Hoya genus plants should be fertile, breathable and well-draining. Domestic hoya growers often use a mixed medium of peat, garden soil and perlite (5:2:3). Based on their own environmental characteristics and growing experience, the author's team chose a mixed medium of peat, bark and orchid stone (2:2:1). At the same time, the medium ratio is appropriately adjusted according to different growth stages and the special requirements of different species. For example, at the seedling stage of hoya, because the root system is fine, a larger proportion of peat can be used while reducing the proportions of bark and orchid stone, so as to reduce soil porosity, allow the fine roots to bind better with the soil, and promote root growth.

2. Water and Fertilizer

Hoya genus plants are epiphytes that prefer relatively high air humidity but do not tolerate waterlogging. During daily care, attention should be paid to observing and controlling moisture. Before each watering, the water shortage of the potting soil must be checked, following the principle of "water when dry, stop when wet." Under normal circumstances, sufficient water will make hoya grow vigorously vegetatively but bloom less. Its roots have a weak ability to absorb fertilizer, so slow-release fertilizer should be used during cultivation, preferably with a fertilizer effect lasting 3 months. For seedlings, a granular slow-release fertilizer with an N:P:K ratio of 1:1:1 (such as Osmocote) can be applied. As the seedlings gradually grow, the P content in the fertilizer should be increased, and some foliar fertilizer such as monopotassium phosphate can also be applied. From November each year to March of the following year, fertilization should be reduced as much as possible or stopped entirely, because Hoya genus plants originate from the tropics, and in winter with low light and low temperature, they are basically in a dormant state.

3. Propagation

For most species in the Hoya genus, seed pods are rarely seen developing, especially in plants cultivated in greenhouses. This is because hoya flowers require special insects to assist pollination, such as butterflies and ants. If seed pods are produced on indoor-cultivated plants, they must be harvested only after they are fully mature. Since Hoya genus seeds have a pappus and are easily dispersed by wind, it is recommended to place a mesh bag or nylon stocking around the seed pod to collect mature seeds when the pod splits. Seeds should be sown immediately after collection; collected seeds should not be stored, because after a few weeks the germination rate drops sharply. In addition, the seeds are sensitive to fungi and are highly prone to rotting under unsuitable conditions.

When sowing, a drainage layer should be placed at the base, using small-grade orchid stone or kanuma soil (3-6mm). For the sowing layer, a mixed medium of peat, perlite and vermiculite (1:1:1) can be used. One to two weeks after sowing, seedlings will emerge one after another. When the roots of the seedlings extend out of the container, repot them. The author suggests planting several plants together when repotting, to facilitate later care and management.

In addition, hoya can also be propagated by layering and cuttings. When taking cuttings, attention should be paid to the size and age of the cuttings. Cuttings retaining two nodes are more likely to sprout new shoots than cuttings with only one node; the maturity state of the cutting is also crucial. Cuttings from the tip of a shoot often have a very low survival rate, because their tissue is very tender and tends to rot. The lower-middle part of the stem is better used as a cutting, because the tissue there is relatively mature but has not yet become woody. The cutting medium should mainly be loose and sandy; use fine peat or vermiculite as the medium, or increase the proportion of perlite. In experiments, the author usually lays a layer of large-particle medium with good drainage at the base of the cutting medium, such as expanded clay pebbles or orchid stone, and uses a mixed medium of peat, perlite and vermiculite to increase breathability.

4. Pests and Diseases and Their Control

Under environments such as high temperature and poor ventilation, Hoya genus plants can be infected by certain pests and diseases. These are mainly summarized into two major categories: insect pests and diseases.

4.1 Insect Pests

4.1.1 Mealybugs

They generally occur on the undersides of leaves, leaf axils, peduncles and other positions, and tend to affect Hoya genus plants that have hairs, fragrance and nectar. The secretions of mealybugs can also lead to sooty mold, which requires attention. Usually, when the number of mealybugs is small, they can be manually removed with a brush. If the number is large, a 2,000-fold dilution of methidathion (using a 1,000-fold dilution tends to cause phytotoxicity such as bud abortion and dropping of inflorescences) can be used once a week for 3 consecutive times, with relatively good results.

4.1.2 Aphids

They mainly gather on tender leaves or the tips of young branches. When the infestation is small, the leaves can be washed with clean water or soapy water, or the affected parts can be removed. For chemical control, use a 1,000-fold dilution of imidacloprid or a 1,000-1,500-fold dilution of deltamethrin once a week for 3 consecutive times, with relatively good results.

4.1.3 Scale Insects

Most Hoya genus plants have a certain scent, and different species have different scents, such as citrus scent and creamy scent. Some species can also secrete a certain amount of nectar. This nectar easily attracts scale insect infestation. Especially in summer, with higher temperatures and poor ventilation, scale insects are very likely to occur. When a small number of scale insects is found, they can be brushed off with a brush. When the infestation occurs on a large scale, spraying a 2,000-fold dilution of methidathion is generally used to kill scale insects. When spraying, try to avoid spraying the inflorescences, as some species will show phytotoxicity. Spray once a week for 3 consecutive times, which has a relatively good control effect.

4.2 Diseases

4.2.1 Sooty Mold

It generally occurs on leaves and branches. The symptoms are that small black mold spots first form, then expand and merge into patches, covering the entire leaf surface and tender shoots with a black mold layer.

Control methods:

(1) Plants should not be planted or placed too densely; ensure good ventilation and carry out appropriate pruning;

(2) Use fungicides for prevention in the early stage of the disease;

(3) The occurrence of this disease is closely related to insect secretions, such as those of mealybugs and aphids, so timely insect control is the best approach;

(4) Use a 1,000-fold dilution of mancozeb for spraying during the period when pests occur, for regular prevention.

4.2.2 Soft Rot

In high-temperature and high-humidity environments, Hoya genus plants are prone to soft rot. In the early stage of the disease, hoya leaves appear wilted, and the affected site is mostly at the base of the plant. After infection at the base, it rapidly spreads to the whole plant. Infected leaves become yellow and soft-rotted, with brown liquid oozing out and a special foul odor. The control method is: once the plant becomes diseased, promptly cut off the diseased leaves, apply sulfur powder or mancozeb powder to the wounds, pay attention to watering and maintaining ventilation, and regularly spray a 1,000-fold dilution of thiophanate-methyl or a 5,000-fold dilution of agricultural streptomycin.

That is all for today's content. The editor of Huinong Network reminds everyone that pest and disease control is very important when growing hoya.

How to grow hoya; hoya pest and disease control

Hoya flowers are brightly colored with peculiar flower shapes, and can be enjoyed for both foliage and flowers. They are highly ornamental and can be placed in the home for decoration. Next, we will introduce relevant knowledge about hoya cultivation.

How to grow hoya

1. Soil: For hoya cultivation, humus-rich loam is best, and drainage must be good.

2. Watering: Hoya is a succulent plant, and its leaves contain relatively much water. During the growing season, watering should follow the principle of "water when dry, stop when wet." Too much watering easily causes root rot, but in summer watering should be sufficient. Because it likes moisture, attention should be paid to frequently spraying water on the leaf surface to increase air humidity.

3. Sunlight: When grown at home, in spring and autumn hoya is best placed on a south-facing windowsill or near a south-facing indoor window in a bright spot, which can keep the leaves green and glossy and allow good flowering. But in summer it should be moved to a shaded place to prevent direct strong light, otherwise the leaves easily turn yellow. If it is kept in a place with insufficient light for a long time, the leaf color becomes lighter, and the flowers are fewer and less vivid.

4. Temperature: Hoya is not cold-tolerant. The suitable growth temperature is 15°C-25°C. In winter, room temperature should be kept above 10°C. If it is below 5°C, it is easily damaged by cold, causing leaf drop and even death of the whole plant.

5. Fertilization: Hoya fertilization is mainly based on organic fertilizer or compound fertilizer; during the peak growing season, apply dilute cake fertilizer water combining nitrogen and phosphorus 1-2 times a month. At other times, because growth is slow, fertilization should be stopped to avoid wasting fertilizer or causing fertilizer damage.

6. Pruning: Young hoya plants should be pinched early to promote the sprouting of new branches, and supports should be set up in time so that they can climb upward. After the flowers fade, let them wither and drop naturally. Do not cut off the flower stems, because most of the flower buds for the second year will still sprout at the same place. If you do not understand this habit and cut them off, it will affect the number of flowers the following year.

7. Flowering period management: Before the flowering period, some liquid fertilizer can be applied. At the same time, hoya needs 3-5 hours of light every day to bloom, so when it is flowering, the flowerpot should not be moved at will. Its flowering period is generally about 10 days, after which the flowers will automatically drop and then grow new flowers again, continuing until mid-October.

Hoya pest and disease control

Hoya is generally prone to pests and diseases such as powdery mildew, anthracnose, soft rot, scale insects and aphids.

1. Hoya powdery mildew

In the early stages of leaf spot disease and powdery mildew, spray with a 1,000-fold dilution of 50% carbendazim wettable powder or a 700-fold dilution of 70% mancozeb wettable powder.

Anthracnose: It generally infects through wounds, and the common symptom is black spots on the leaves. It can be regularly sprayed and killed with a 600-fold dilution of 80% anthracnose thiram or a 1,000-fold dilution of 70% thiophanate-methyl.

Prevention methods: Strengthen ventilation, and pay attention to watering and plant wounds in ordinary care.

Soft rot: It is prone to occur in high-temperature and high-humidity environments. In the early stage, spots generally appear on the leaf surface, and then the plant wilts and droops, losing ornamental value. It can be controlled by spraying with a 5,000-fold dilution of agricultural streptomycin or a 1,000-fold dilution of methyl parathion, etc.

Prevention methods: Once the plant becomes diseased, promptly cut off the diseased leaves, and apply M-45 Topsin powder to the wounds to prevent reinfection.

2. Hoya anthracnose

Hoya anthracnose generally infects through wounds and manifests as black spots on the leaves. At first, several light yellow, dark brown or light gray small areas appear on the leaf surface, sometimes gathering into several black bands. When the lesions expand, the surrounding tissue turns yellow or grayish green and sinks, and in severe cases it can lead to the death of the whole plant.

Control methods: Strengthen management, do not plant too densely, maintain good light transmission and ventilation, and water from the edge of the pot when watering. If there are damaged leaves, promptly cut off the diseased leaves, avoid sunburn, cold damage, fertilizer damage and phytotoxicity, and reduce the occurrence of anthracnose. For routine prevention, regularly spray and kill with a 600-fold dilution of 80% anthracnose thiram or a 1,000-fold dilution of 70% thiophanate-methyl.

3. Hoya soft rot

Hoya soft rot is prone to occur in high-temperature and high-humidity environments. It is most likely to occur in the rainy season in early summer and less in winter. In the early stage, water-soaked spots appear on the leaf surface and petioles, and then the plant wilts and droops, losing ornamental value. It generally affects the whole plant. When leaves are damaged, dark green water-soaked small spots appear, rapidly expanding into yellow-brown soft rot, with brown water droplets oozing out and a special foul odor.

Control methods: Once the plant becomes diseased, promptly cut off the diseased leaves, and apply M-45 Topsin powder to the wounds to prevent reinfection. Use a 5,000-fold dilution of agricultural streptomycin or a 1,000-fold dilution of methyl parathion for spraying control.

4. Scale insects:

They generally parasitize leaf sheaths and stems, sucking plant nutrients.

Prevention methods: Maintain a ventilated environment, detect insects in time, and at the same time use a small brush to brush off the insect bodies, and spray pesticides 1-3 times. For example, use a 1,000-fold dilution of 80% dichlorvos emulsifiable concentrate or 3% pyrethrin and spray once every 7-10 days for 3 consecutive times.

5. Aphids

There are many kinds of aphids. They are common small, soft-bodied insects that often gather on the tender stem tips of branches and leaves to suck nutrients, causing affected plants to stagnate in growth and leaves to turn yellow. Their secretions often lead to the parasitism of various molds, especially easily causing sooty mold.

Control methods: When the infestation is small, wash the leaves with water or soapy water, or remove the affected parts. For chemical control, spray with a 1,000-1,500-fold dilution of deltamethrin, a 2,000-fold dilution of 40% omethoate or a 1,000-fold dilution of trichlorfon. Spray once every 5-7 days for 3 consecutive times, with relatively good control results.

The above is the relevant knowledge about hoya cultivation introduced to everyone. We hope it can help you. For more home knowledge, please keep following.

Hoya pest and disease control