Prevention and Management of 11 Common Pests and Diseases of Indoor Foliage Plants
Potted flowers and plants can decorate the home and at the same time bring people a wonderful mood. If you do not keep one or two pots of foliage plants at home, it always feels a little less like home. In the process of growing these common potted flowers and plants, it is inevitable to encounter times when they suffer from pests and diseases. Below, Huacaole introduces the pest and disease control methods for common flowers and plants.
Prevention and Management of Pests and Diseases of 11 Common Indoor Foliage Plants
1. Asparagus Fern
Asparagus fern (Asparagus setaceus) is a highly ornamental plant that can be placed in the living room or study. While purifying the air, it also adds a literary atmosphere. Its roots are used as medicine and can treat acute bronchitis, with the function of moistening the lungs and stopping cough.
Common Pest and Disease Control of Asparagus Fern
● Leaf Blight
Leaf blight is likely to occur when humidity is too high and ventilation is poor. The air humidity should be appropriately reduced, and attention should be paid to ventilation and light transmission. After the disease occurs, spray 200 times Bordeaux mixture, or 50% carbendazim wettable powder 500-600 times solution, or spray 50% thiophanate wettable powder 1000 times solution for control.
● In summer, pests such as scale insects and aphids are likely to occur, and 40% omethoate 1000 times solution can be sprayed to kill them.
2. Monstera
Monstera (Monstera deliciosa) has a peculiar leaf shape with holes and splits, very much like a turtle's back. It stays green all year round and is extremely shade-tolerant. It is a famous large indoor potted foliage plant. The amount of formaldehyde absorbed by one monstera is equivalent to that absorbed by 10 g of coconut shell activated carbon, which helps purify indoor air.
Common Pest and Disease Control of Monstera
● Leaf Spot
It is a common disease of monstera. It mainly damages the leaves. After being affected, the leaves tend to scorch and fall off.
Control method: Place it in a ventilated and bright place to promote ventilation and light exposure and reduce the incidence of disease. After it occurs, promptly spray 65% mancozeb wettable powder 600 times solution.
● Gray Spot Disease
Control measures: Same as leaf spot.
● Scale Insects
They are common pests of monstera. They mainly damage the petioles and leaves.
Control measures:
1) During home care, they can be gently brushed off with a toothbrush.
2) When the occurrence is heavy, 40% omethoate emulsifiable concentrate 1000 times solution can be sprayed during the nymph stage.
3. Aspidistra
Aspidistra (Aspidistra elatior) has upright and neat leaf shapes, and its leaves are dark green and glossy. It grows vigorously, has strong adaptability, and is extremely shade-tolerant. It is an excellent shade-loving foliage plant for indoor greening and decoration.
Common Pest and Disease Control of Aspidistra
● Anthracnose
Symptom characteristics: The diseased spots on aspidistra leaves mostly occur at the leaf margins or on the leaf surface. The spots are nearly round, gray-white to gray-brown, with the outer edge yellow-brown or red-brown, and in the later stage black small granules arranged in concentric rings appear. In addition to the leaves, the petioles and stems are also infected, producing elongated lesions.
Control measures:
1) Promptly cut off and burn diseased leaves when found to reduce the source of infection.
2) Before the rainy season arrives, spray 50% Shibaike or Shibagong wettable powder 1000 times solution, or 25% Tanteling wettable powder 500 times solution. Once every 10 days, for 3-4 treatments.
3) When necessary, spray 0.5% potassium dihydrogen phosphate or Shuangxiao microelement fertilizer 300 times solution, which helps enhance disease resistance.
● Gray Mold
Symptom characteristics: It often occurs at the leaf margins. Water-soaked lesions first appear from the leaf margins. When humidity is high, the lesions expand very quickly, causing irregular withering at the leaf margins. Generally, no gray mold layer is seen. However, after continuous overcast and rainy days, with high humidity and long duration, sparse gray mold can grow.
Control measures:
1) Careful maintenance. Choose a moist, well-drained semi-shady environment for planting. Aspidistra is a shade-tolerant plant, so the light should not be too strong; otherwise, it will cause leaf yellowing or disease. Excessive watering, especially in winter, will cause root rot and will also cause leaf yellowing.
2) If scattered diseased plants are found, spray 65% Jiameiling wettable powder 1000 times solution or 50% Sumilex wettable powder 1500 times solution, 50% iprodione wettable powder, or 50% vinclozolin wettable powder 1000 times solution.
3) For aspidistra maintained in a greenhouse, measures can be taken to raise the nighttime temperature in the greenhouse, increase ventilation time during the day, and reduce the humidity in the greenhouse and the duration of fog formation, thereby achieving disease control.
● Leaf Spot
Aspidistra leaf spot is also called black spot, brown spot, etc. First, black spots appear in the middle of the leaves, then the leaves turn yellow and fall off. The cause is mostly stuffy, unventilated, and humid environmental conditions.
Control measures:
Pay attention to improving environmental conditions. At the early stage of disease, the damaged leaves can be removed and burned. Spray 1% Bordeaux mixture for control, once every 7 days, for a total of 4-5 sprays throughout the growing period, or spray 50% carbendazim 1000 times solution for control.
4. Parlor Palm
Parlor palm (Chamaedorea elegans) is shade-tolerant, so it is very suitable as a small to medium indoor potted plant. Placed on a desk or tabletop, it is a treasured item on the stand. It is also suitable for hanging indoors to decorate the space, adding a tropical atmosphere and charm to the room.
Common Pest and Disease Control of Parlor Palm
● Yellow Leaves
Reasons for yellowing leaves of parlor palm:
1) Too strong light
Parlor palm prefers semi-shady conditions. When light is too strong, the leaves will become pale or yellow and lose ornamental value.
Solution: Keep the parlor palm in a place with plenty of scattered light, which can provide enough light for growth without causing leaf yellowing due to excessive light.
2) Too little watering
Parlor palm prefers moisture and needs sufficient water. If watered too little, the leaves will turn yellow and gradually wither and fall off.
Solution: Water frequently to keep the potting soil moist. In summer and autumn when the air is dry, frequently spray water on the plant to increase the ambient air humidity.
3) Too concentrated fertilizer
Parlor palm does not have high fertilizer requirements. If too much fertilizer is applied, fertilizer burn will occur, causing the leaves of the parlor palm to turn yellow.
Solution: During the growing season, apply liquid fertilizer 1-2 times per month to the parlor palm. In late autumn and winter, apply a little fertilizer or no fertilizer.
4) Disease infection
In high-temperature seasons, parlor palm is easily infected by root rot and other diseases. Disease infection will cause the leaves of the parlor palm to begin to turn yellow and wither, and in severe cases will cause the plant to die.
Solution: Pay attention to ventilation in the growing environment of the parlor palm and air permeability of the soil. When disease occurs, spray thiophanate and chlorothalonil. [8]
● Black Spot
Black spot is likely to occur under high temperature, high humidity, and poor ventilation, especially during the vigorous growth period from April to November. Attention must be paid to disease prevention. Once leaf tip scorching is found, promptly spray 50% thiophanate or 50% chlorothalonil 800-1000 times solution for control. At the same time, ensure indoor ventilation, coolness, and air permeability, and appropriately increase phosphorus and potassium fertilizers, such as plant ash, to promote robust growth of the plant. The soil should be well drained, not too dry, and not too wet. During the growing period, the potting soil should remain moist to facilitate plant growth and improve disease resistance.
● Scale Insects
Dry air and poor ventilation easily cause scale insect damage. Pesticides such as phosmet, dimethoate, and trichlorfon can be sprayed for control.
5. Spider Plant
Spider plant (Chlorophytum comosum) is a perennial herbaceous plant with slender, drooping stems. In summer or when temperatures are high in other seasons, it produces small white flowers. The flowers are concentrated at the ends of the drooping stems, the stamens are yellow, and the small tender leaves inside are sometimes purple. It can be grown in pots for ornament.
Common Disease Control of Spider Plant
● Scale Insects
According to the various occurrence conditions of scale insects, spray pesticide at the peak nymph stage. At this time, most nymphs have recently hatched, the body surface has not yet secreted wax, and the scale cover has not yet formed, so pesticide is still likely to kill them. Spray once every 7-10 days, for 2-3 consecutive times. Use 40% omethoate 1000 times solution, or 50% malathion 1500 times solution, or 255 phosmet 1000 times solution, or 50% dichlorvos 1000 times solution, or 2.5% deltamethrin 3000 times solution, and spray.
● Whiteflies
Drench the roots with carbendazim wettable powder 500-800 times solution, once a week, for 2-3 consecutive times.
● Aphids
Spray 1500 times omethoate to kill them.
● Mites
Mites are secondary in summer and autumn and need to be killed with 1000 times dicofol. Pay attention to ventilation and increase leaf surface humidity, which can reduce mite infection.
● Root Rot
For prevention, wettable powder can be used at 2-4 grams per sq m for root drenching, or before disease onset or at the early stage of disease, use 1500-3000 times solution for root drenching, with 200 milliliters of solution per plant. When the disease is severe, remove the diseased plants and at the same time use Gugen for root drenching.
6. Snake Plant
Snake plant (Sansevieria trifasciata) has firm, upright leaves, and the leaf surface has gray-white and dark green alternating horizontal band markings like a tiger's tail. There are many cultivars, with relatively large variations in plant shape and leaf color. It has strong adaptability to the environment and is suitable for decorating studies, living rooms, and office spaces, and can be appreciated for a relatively long time.
Common Disease Control of Snake Plant
● Bacterial Soft Rot
After infection, the leaves change from green to light yellow to gray-yellow, and water-soaked soft rot appears at the stem base near the ground. In the later stage, the affected leaves are prone to bending and breaking. When the rhizome is infected, it becomes straw-yellow soft rot, and the roots rot and die. When the root system is waterlogged, it also becomes black-rotten and dies. It is especially severe in spring and summer during high temperature and rainy, typhoon, and heavy rain weather. The pathogen is caused by bacteria.
Control measures:
In winter and spring, keep the temperature above 10°C and control watering. During high-temperature weather in midsummer, provide slight shading. In the vigorous growing periods of spring and autumn, increase phosphorus and potassium fertilizers to improve disease resistance. It is best to choose disease-free soil or burned soil or soil that has been sterilized by heat before planting. Diseased leaves found should be promptly cut off and burned.
At the early stage of disease, choose medical-grade streptomycin sulfate 2000 times solution, 47% Kasugamycin-copper wettable powder 700 times solution, or 30% Ludesuspension concentrate 500 times solution, spraying once every 5-7 days, for 2-3 consecutive sprays. [4]
● Fusarium Leaf Spot
Fusarium leaf spot, also called leaf spot, first appears on the leaves as round lesions, with a diameter that can expand to 12 mm. They are slightly sunken, light red-brown, with pale yellow edges. The lesions are scattered and cover the entire leaf. The centers of the lesions dry up and fall off, forming holes. When several lesions merge with each other and girdle the leaf, the part above the diseased area dies. The pathogen is a fungus of the order Sphaeriales in the subdivision Deuteromycotina. It is likely to occur in high-temperature and rainy seasons.
Control measures:
Reduce soil humidity. At the early stage of disease, choose Bordeaux mixture, 53.8% Kocide 2000 dry suspension concentrate 1000 times solution, or 47% Kasugamycin-copper wettable powder 700 times solution, spraying 2-3 consecutive times, once every 5-7 days.
● Anthracnose
The lesions begin at the leaf tip or leaf margin, are brown, and show obvious or unobvious concentric rings on the lesion surface. On the diseased leaves, scattered or regularly arranged small black dots form. The pathogen is a fungus of the subdivision Deuteromycotina, called Sansevieria colletotrichum. It is favored by shaded and humid conditions in the high-temperature weather of the south, and the disease is especially severe from April to June.
Control measures:
In winter and spring, cut off diseased leaf parts and withered diseased leaves, and increase phosphorus and potassium fertilizers. At the early stage of disease, promptly spray 50% anthracnose thiram wettable powder 800 times solution, or 75% chlorothalonil and 70% thiophanate wettable powder (1:1) 1000 times solution.
● Arrowhead Scale
Adults and nymphs gather on young branches and leaves to pierce and suck sap, causing the leaves to turn gray-green or yellow, and causing the whole plant to wither.
Control measures:
The best time to apply pesticide is during the dispersal and migration period of the nymphs, when the insect body has no wax powder or scale cover and has the weakest resistance to pesticides. Use 40% dimethoate emulsifiable concentrate 500-1000 times solution, or 50% malathion emulsifiable concentrate 600-800 times solution, 80% dichlorvos emulsifiable concentrate 800 times solution, 25% phosmet or insecticidejing or 30% bromophos emulsifiable concentrate 400-600 times solution, or 50% fenitrothion emulsifiable concentrate 1500-2000 times solution.
7. Baby Rubber Plant
Baby rubber plant (Peperomia obtusifolia) has glossy green leaves that are very lovely, slightly recurved, broadly elliptical or nearly round. It can be grown in pots for ornament, also has medicinal value, and can also resist radiation.
Common Disease Control of Baby Rubber Plant
This species has relatively few diseases, mainly ring spot virus disease. Affected plants become dwarfed and have distorted leaves. Bordeaux mixture at equal amounts can be sprayed. There are also root collar rot and canker disease, for which 50% carbendazim wettable powder 1000 times solution can be sprayed.
For insect pests, scale insects and slugs occasionally cause damage and should be controlled promptly.
8. Silver Queen
Silver Queen (Aglaonema commutatum) has beautiful leaf color, is especially shade-tolerant, and has a unique air-purifying ability. With potted plants placed in halls and rooms, one will feel bright and comfortable.
Common Disease Control of Silver Queen
Silver Queen has dense clumps and poor ventilation, making it susceptible to scale insect damage, so prevention should be the main approach. If scale insects occur, use 50% malathion emulsifiable concentrate 1000-1500 times solution, spraying once every 7 days, for 2-3 consecutive sprays.
9. Evergreen
In addition to potted ornament in halls and rooms, Guangdong evergreen (Aglaonema modestum) leaves can also be cut for flower arrangement foliage or used to decorate outdoor environments. Making a foliage bonsai with Guangdong evergreen is simple and easy, and can highlight the beauty of nature. According to its extremely shade-tolerant characteristics, displaying it indoors for appreciation can keep it green throughout the four seasons and lasting for a long time.
Common Pest and Disease Control of Evergreen
● Leaf Spot
The lesions are initially small brown spots, surrounded by water-soaked faded green areas, and expand in concentric rings, round to elliptical, with brown edges and gray-white centers. In the later stage, dark brown mold spots appear in the center of the lesions, and under moist conditions they become a dark brown mold layer.
Control measures:
Promptly remove diseased and residual leaves. Both at the early and late stages of disease, 0.5%-1% Bordeaux mixture (or 50% carbendazim 1000 times solution) can be sprayed.
● Anthracnose
This disease also occurs on the leaves of evergreen and can spread to the petioles in severe cases. The lesions initially appear as water-soaked small yellow spots, and after expansion become elliptical to irregular brown or yellow-brown, slightly showing concentric rings. In the later stage, the lesions connect into one piece and become dry and withered, and produce small black dots arranged in concentric rings.
Control measures:
Strengthen maintenance and increase phosphorus and potassium fertilizers. At the early stage of disease, spray 0.3%-0.5% equal-amount Bordeaux mixture (or 60% zineb 800-900 times solution, or 70% thiophanate 1500 times solution).
● Brown Soft Scale
This insect has complex feeding habits and can damage many plants, and evergreen is one of the affected flowers. When brown soft scale damages plants, it generally gathers on the leaf surface or tender leaves, pierces and sucks plant sap, and at the same time excretes sticky liquid. Its excrement easily causes mass reproduction of sooty mold fungi, making stems and leaves turn black, affecting the plant's photosynthesis, causing weak growth and yellow, withered leaves, and hindering ornament. When the occurrence is severe, the branches and stems are covered with insect bodies, causing the plant to become yellow and withered and affecting growth.
Control measures:
1) If there are few affected plants or not many insects, generally use a bamboo strip or similar object to scrape off the insect bodies.
2) During the nymph hatching period, spray with 40% dimethoate emulsifiable concentrate at 1000 times dilution (or 40% omethoate emulsifiable concentrate at 1000 times dilution); spraying with 5% phosmet emulsifiable concentrate at 1000 times dilution can also eliminate them.
10. Pothos
Pothos survives as soon as it meets water, and because of its tenacious vitality, it is called the “flower of life.” The flower language of pothos is “watching over happiness.” Placing one or two pots of pothos at home brings bright colors and abundant vitality, and it can both decorate the room and purify the air.
Common disease control for pothos
● Anthracnose
This pathogen mostly harms the middle section of leaves, and can also harm flowers. At first, small pustule-like spots of a moist reddish-brown or dark brown appear on the diseased part, with a faded green halo around the spots. After expanding, they form oblong or elongated patches, with dark brown edges and a yellow-brown interior, and with ring-like markings formed by dark spots converging together. Because its spots are dark brown, it is also called black spot disease or dark brown disease. It can repeatedly infect the plant during the growing period.
Control measures:
1) There are many pesticides that can control anthracnose, such as mancozeb, carbendazim, thiophanate, and charcoal-specific fungicide, all of which have a certain control effect.
2) The German-made “Sporgon” at 1500 times dilution is a specific remedy for treating anthracnose.
● Root rot
During the onset period, spray 50% carbendazim wettable powder at 500 times dilution, or use 5% carbofuran granules, and it can also be applied as a root drench.
● Leaf spot
Remove diseased leaves and pay attention to ventilation. Spray 95% amobam at 500 times dilution, or 80% carbendazim wettable powder at 1000 times dilution, and so on for control.
11. Lucky bamboo
Lucky bamboo symbolizes blooming prosperity, bamboo reporting peace, great fortune and prosperity, and a lifetime of wealth, and its name comes from this; moreover, the stems and leaves of lucky bamboo are slender and graceful, elegant and refined, and full of bamboo charm.
Common pest and disease control for lucky bamboo
● Anthracnose
Anthracnose is a serious disease harming lucky bamboo in the south. It occurs severely when the soil is too sticky, not breathable, and poorly drained, and under conditions of overly dense plants and high temperature and high humidity. In the early stage of the disease, gray-brown lesions appear at the leaf tips or leaf margins; the lesions are irregular or semicircular, with a grayish-white center, dark brown edges, and a yellow halo outside; the concentric rings on the lesions are obvious or not obvious, and small black dots are scattered on them.
Control
1) In winter and spring, remove diseased and residual material and burn it centrally, and spread quicklime once to sterilize and disinfect the soil.
2) Improve the permeability of the garden or nursery; for open-field cultivation, pay attention to clearing ditches and draining water after rain to reduce field humidity, and avoid over-application of nitrogen fertilizer.
3) Spray pesticides in time to control the disease. Alternately spray 25% charcoal-specific fungicide wettable powder at 500 times dilution, or 60% Duofu wettable powder at 600 times dilution, or 50% Sporgon wettable powder at 1000 times dilution, or 69% Anke mancozeb plus 75% chlorothalonil (1:1) at 1500 times dilution, spraying 3~4 times in succession, once every 10 days.
● Stem rot
Stem rot causes the death of lucky bamboo and reduces its ornamental value. It occurs more often from May to September under high temperature and high humidity, and mainly harms leaves and stems. The leaves at the base of the stem of seedlings turn yellow; the stem base rots, turns yellow and softens; the inside of the stem turns red; the pathogen gradually harms upward from the lower cut.
Control measures:
1) Cultivate robust seedlings with full tissue; remove diseased plants and burn them centrally; dig deep drainage ditches and plant on raised beds 25 cm high.
2) Soak the lower cut of the seedlings for 24 hours with 42% Kejunjing powder at 3000 times dilution, or 88% oxytetracycline at 1000 times dilution.
● Leaf spot
The leaf spot pathogen mainly spreads through wounds, and the disease is severe under humid conditions. The disease is highly contagious and can cause the leaves and stems of the plant to rot. In the early stage, the lesions are brown spots with yellow edges; after expansion, the lesions are nearly round, with a gray center, dark brown edges, and yellow surroundings; under humid conditions, black granular substances appear on the lesions.
Control measures:
1) Prevent plants from being too dense and maintain ventilation and light transmission.
2) In the early stage of the disease, use 42% Kejunjing powder at 3000 times dilution, or 88% oxytetracycline at 1000 times dilution, or 25% copper ammonia complex at 800 times dilution, spraying once every 5~7 days, 2~3 times in succession.
● Root rot
Root rot occurs from December to March. The pathogen mainly enters through cuts, and secondarily through the vascular bundles of seedlings carrying the pathogen. After harvesting bamboo, the head becomes soft and rots, no basal shoots emerge or the shoots emerge unevenly, the seedling emergence rate is low, or it occurs at the base of the plant stem.
Control measures:
1) Select seedlings free of pathogens, do not harvest bamboo in the rain or when the rain has not dried, and carry out rational fertilization combining organic fertilizer and inorganic fertilizer.
2) Spray pesticides promptly after cutting bamboo. First use 70% thiophanate-methyl at 1000 times dilution, then after 5~7 days use 58% metalaxyl mancozeb at 1000 times dilution, and after another 5~7 days use 75% chlorothalonil at 1000 times dilution. Add 1.8% Aiduoshou at 3000 times dilution to the pesticide solution, which is beneficial for the healing of the cuts and promotes the growth of basal shoots.