What are the five common pests and diseases of banana shrub?
Cultivating banana shrub is actually not very difficult, but during its care, pests and diseases often occur. If not dealt with in time, they will not only affect the ornamental value of the banana shrub, but in severe cases can even cause the plant to die. The editor will now introduce five common pests and diseases of banana shrub and their control methods; friends who need this information can study along.
Banana shrub
I. Scale insects
Banana shrub commonly suffers from scale insect damage; they suck the plant's sap and harm new shoots and leaf veins, and generally appear mostly at branch forks and on the undersides of leaves. Solution: they can be brushed off with a small brush, or killed by spraying with No. 20 petroleum emulsion diluted 150 times with water.
II. Banana shrub sooty mold
Sooty mold harms banana shrub leaves and is detrimental to its growth. Solution: it can be controlled by wiping with clean water or spraying with a carbendazim aqueous solution diluted 500-1000 times with water.
III. Banana shrub leaf blight
Leaf blight occurs mostly at the leaf margins; many small black dots densely cover the leaves, and when the disease is severe, the leaves wither and fall. Solution: remove diseased leaves, and upon discovering diseased plants, promptly spray with a 50% thiophanate-methyl wettable powder solution diluted 800-1000 times.
IV. Banana shrub anthracnose
Anthracnose is also a common disease of banana shrub; it harms the stems and tender branches, reduces the ornamental value of the plant, and can even cause plant death. Solution: during the disease period, spray with 0.5% Bordeaux mixture or a 5% carbendazim wettable powder solution diluted 600-750 times, once about every 10 days.
V. Banana shrub yellow leaf disease
In yellow leaf disease, the young tender leaves at the tips of the banana shrub's branches first lose their green color, and the leaf mesophyll turns yellow or pale yellow; the plant gradually weakens in growth and dies. Solution: appropriately supplement with soluble iron.
Common pests and diseases of flowers and their treatment methods
Common flower disease one: late spring cold
Harm
This is a non-infectious disease that mainly occurs in the areas south of the Yangtze River and parts of the region between the Yangtze and Huai rivers. By the end of March, daytime temperatures have already reached above 20°C, and many people are eager to move their indoor potted ornamental plants outdoors for conditioning and care; but at this time cold air often moves southward, bringing a reversal weather pattern known as "late spring cold," when the lowest temperature in the early morning often drops below 4°C, causing the newly emerged shoots and tender leaves of some flowers native to the tropics to be "frozen" and damaged.
Common examples such as white michelia (Michelia alba), Aglaia odorata, jasmine, clivia, Dieffenbachia, Syngonium, fuchsia, Calathea, Anthurium, and poinsettia will have their normal growth that spring seriously affected.
Solution
Keep timely track of the weather forecast from the local meteorological station. When the special "late spring cold" weather occurs, for the small number of potted plants already moved outdoors, they can be moved back into the greenhouse or indoors; if there are many potted plants moved outdoors, they can be gathered together and covered with a double layer of plastic film.
In the Yangtze River basin and areas to its north, generally one must wait until after Qingming or after the "last frost period" ends before moving plants outdoors. You can lower the temperature by opening doors and windows and adding electric fans, then close the doors and windows well at night, so that the plants have a process of gradually adapting to the outdoor environment.
Common flower disease two: powdery mildew
Harm
It mainly harms ornamental plants such as Chinese rose, crape myrtle, Mahonia, large-leaf boxwood, and Polygonum chinense. It mainly harms leaves, petioles, flower stalks, flower buds and tender shoots; the affected parts are covered with a layer of white powdery substance, and in severe cases the leaves turn yellow, the tender leaves curl, shrink and thicken, the flower buds wither and die, deformed flowers appear, and the tender shoots bend and shorten.
Solution
Sulfur powder fumigation: in March, use an electric heating fumigator in the greenhouse or shed, place sulfur powder inside, and carry out sealed fumigation, which has a good control effect.
Common flower disease three: anthracnose
Harm
It mainly harms Camellia, sasanqua, Yucca (Yemen iron), hydrangea, clivia, Rohdea japonica, orchids, Aspidistra, Epiphyllum, rubber tree, and cyclamen in the greenhouse. It mainly harms leaves, tender shoots and fruits; the lesions are nearly round and grayish brown, and later the lesions turn grayish white, with obvious concentric rings and whorled (or scattered) small black dots.
Solution
Adjust the placement density of potted flowers and the planting spacing and row spacing of ground-planted plants to improve ventilation and air permeability. Water appropriately when the potting soil dries out to increase the plant's resistance.
In the early stage of the disease, alternately spray with an 80% anthracnose thiram wettable powder solution diluted 500 times, or a 50% carbendazim-sulfur suspension concentrate diluted 800 times, once every 10 days, 2-3 times in succession.
Common flower disease four: gray mold
Harm
As temperatures rise, with excessive humidity and poor ventilation, gray mold remains one of the main diseases of indoor flowers. It harms potted flowers such as Gerbera, rubber tree, cineraria, cyclamen, poinsettia, geranium, Rieger begonia, pothos, Ixora, hibiscus, and Anthurium, with leaves and petals being especially severely affected.
Solution
After March, strengthen ventilation and light transmission, reduce indoor air humidity, prohibit spraying water on leaf surfaces in the evening, and prevent moisture from lingering on leaf surfaces for long periods.
For plants in the early stage of the disease, alternately spray with a 65% zineb wettable powder solution diluted 500 times, or a 50% hymexazol wettable powder solution diluted 1000 times, around midday, once every 10 days, 2-3 times in succession.
Common flower disease five: sooty mold
Harm
In March, due to poor indoor ventilation and air permeability and high humidity, piercing-sucking pests such as scale insects, aphids and whiteflies cannot be completely eliminated, and sooty mold can still occur on the leaves, flowers and fruits of plants such as citrus, Aglaia odorata, hibiscus, white michelia, banana shrub, Areca palm, banyan, Camellia, Rhapis, azalea, gardenia, Ilex cornuta, and Fujian tea.
Solution
Strengthen indoor ventilation and air permeability, and promptly kill aphids, scale insects, whiteflies and other insect vectors that induce sooty mold.
If a small number of leaves on individual plants are infected with sooty mold, the sooty layer can be wiped off with a damp cloth dipped in low-concentration laundry detergent water.
In the early stage of the disease, spray the branches and leaves of infected plants with a 50% carbendazim-sulfur suspension concentrate diluted 500 times, or a 75% chlorothalonil wettable powder solution diluted 500 times, once every 15 days, 2-3 times in succession.
Common flower pest six: scale insects
Harm
For potted ornamental plants placed in a shed, due to limited ventilation, insufficient light and relatively high humidity, scale insects remain the main type of pest.
For example, the green soft scale on kumquat, the gray mealybug on yew, the mango mealybug on hibiscus, the rice grain-shaped mealybug on clivia, the tortoise wax scale and red wax scale on Camellia, the horned wax scale on holly, the black helmet scale and oyster shell scale on cycad, the wheel scale on Chinese rose, the Pseudaulacaspis cockerelli on banana shrub and white michelia, the rice grain-shaped scale on fingered citron, the giant tubercled oyster shell scale on orchids, the white scale on Rhapis, the round scale on ivy, the coconut round scale on Areca palm, and the arrowhead scale on four-season osmanthus. The species of scale insects on each kind of flower vary greatly.
Control methods
For scale insects appearing on a small number of household plants, you can use absorbent cotton dipped in 75% alcohol to wipe off the live insect bodies, or dip it in laundry detergent solution to wipe off the insect bodies. For smaller scale insects such as the arrowhead scale and Pseudaulacaspis cockerelli, you can use transparent adhesive tape to stick off the live insect bodies.
Or spray with a 25% buprofezin wettable powder solution diluted 2000 times, once every 15 days, 2 times in succession.
Common flower pest seven: aphids
Harm
As temperatures rise and watering increases, aphid damage on indoor ornamental plants also becomes more severe. Aphids suck the sap of newly emerged branches and leaves, which affects the plant's normal growth after spring begins.
Control methods
For aphids on a small number of plants, you can first sprinkle tobacco powder, plant ash or cinder ash on the insect bodies and leaves, and after about 1-2 hours, rinse clean with water, which can kill the vast majority of aphids.
Common flower pest eight: whiteflies
Harm
The main one is the greenhouse whitefly, which harms cineraria, hibiscus, Chinese rose, nasturtium, and lantern flower; the second is the citrus spiny whitefly, which harms kumquat, golden bean, bitter orange, fingered citron, Chinese rose, white michelia, and Aglaia odorata. Their harmfulness must not be underestimated.
Control methods
When the outbreak is severe, use a 10% imidacloprid wettable powder solution diluted 2000 times, or a 25% buprofezin wettable powder solution diluted 2500 times.
Case diagnosis and prescriptions for common flower pests and diseases in June
Case one:Orchid blight
Diagnosis
Also known as black rot, it is a devastating disease of orchids. It can infect orchids at all stages of development; leaves, flowers, stems and roots may all be affected. Chinese orchids and Western orchids are equally susceptible. At first, the leaf base is found to turn slightly yellow; a few days later, the leaf base turns coffee-colored and breaks off at a touch, and the leaf base has dried out and scorched. Diseased leaves basically all have a green upper part and a coffee-colored base. The pathogens are Phytophthora nicotianae and Pythium ultimum. It can occur throughout the year, but is most severe in the hot, humid summer (June to August), or under poor ventilation and excessive watering. It can attack orchid seedlings and mature plants, and the heart leaves are most easily harmed. Once the disease occurs, if not controlled in time, it will quickly spread to the root system and pseudobulbs, causing root rot and damping-off, and can even completely destroy the seedlings and plants; it usually manifests as brown lesions first appearing at the infected site, which rapidly expand under high temperature and high humidity into large brown spots, finally turning dark brown, with leaf loss, stem rot, and even death of the whole plant; on Cymbidium and Chinese orchids it shows yellowing, but does not cause soft rot. The main route of transmission is that spores spread and diffuse through water droplets splashing during watering; a water film on the surface of orchid leaves and stems, or excessive water in the growing medium, both favor the breeding and invasion of Phytophthora; if wounds are present, this provides an even more direct route for pathogen invasion. Although orchid leaves can be infected by blight, it mainly invades through wounds at the roots, stems and petioles, causing root rot (in Western orchids) and leaf drop.
Prescription
① Avoid excessive watering or air humidity that is too high; improve ventilation, increase light; preventsnails, slugs, insectsand other pests from causing wounds that can serve as entry points for Phytophthora infection.
② Use fully decomposed sheep manure as fertilizer, which can effectively inhibit the occurrence and spread of many orchid diseases.
③ Protecting wounds is the primary goal; when repotting and dividing, do not damage the fleshy root system or leaves, and strictlydisinfect。
④ If seedlings are infected, immediately pull out the diseased plants, and seal and discard, burn or deeply bury the diseased seedlings and growing medium; if the potting soil is to be used the following year, it must undergo strict high-temperature or chemical sterilization and disinfection.
⑤ If mature plants are infected, in the early stage of disease, cut off the infected parts; disinfect the uninfected parts, growing medium and pots by soaking for 10 minutes in a copper sulfate solution diluted 300 times or a 75% chlorothalonil wettable powder solution diluted 600 times; for uninfected plants, spray the same solution for prevention; for the wounds on the cut parts of diseased plants, you can also smear with a 70% mancozeb wettable powder, then place in a dry place and do not water for one week, which can prevent the spread of this disease.
⑥ For large clumps of orchids with only a small number of diseased leaves, after cutting off the diseased leaves with a sterilized blade, use a 50% metalaxyl wettable powder solution diluted 500 times; spray seedlings once a week and mature plants once every half month; for routine prevention, use a 1:1:200 Bordeaux mixture or a 70% mancozeb wettable powder solution diluted 500 times, once every two weeks, and once a week during the rainy season.
⑦ Other pesticides used to control this disease include: a 25% metalaxyl wettable powder solution diluted 800 times, a 58% metalaxyl · mancozeb wettable powder solution diluted 600 times, and a 72% cymoxanil · mancozeb wettable powder solution diluted 600 times, sprayed once a month, 3 times in succession or more.
Case two:Southern blight
Diagnosis
It mainly harmsthe seedlings of edgeworthia, weigela, Aucuba japonica 'Variegata', Chinese loropetalum, hosta, red wood sorrel, white clover, clivia, white michelia, and fringed pink,etc., and often causes the affected plants to die. The affected part is the junction of root and stem; white mycelial strands wrap around the stem near the ground, and white or yellowish-brown sclerotia are produced, with the sclerotia resembling rapeseeds. The aboveground leaves gradually turn yellow, wilt and droop, and finally turn reddish brown. It overwinters in the soil as sclerotia, and can also overwinter on diseased residues or weeds. When the soil temperature is suitable the following year, the mycelium germinates and produces new mycelium, which invades the stem base or rhizome of the plant and causes damage. In the Yangtze River basin, the disease generally begins in early June; by July-August, when the temperature rises to around 30°C, the disease enters its peak period, and by October the disease basically stops. Soil with high relative humidity tends to have more severe outbreaks.
Prescription
① Promptly remove the thatch layer and improvesoilpermeability; deep plowing and sun-exposing the soil are both beneficial for reducing the occurrence of southern blight.
② In the early stage of disease, use a 25% propiconazole emulsifiable concentrate diluted 3000 times, or a 10% difenoconazole water-dispersible granule diluted 1000 times, or a 50% procymidone wettable powder solution diluted 700 times, and spray the root-stem area and surrounding soil once every 10-15 days, 2-3 times in succession.
Case three:Sunscald
Diagnosis
It is a physiological disease. The intense sun after long rain clears in late spring and early summer, the scorching heat and strong light of midsummer, and moving potted flowers kept indoors for a long time out to open ground - these three situations are the environments in which sunscald is most frequent and severe. It will not only affect the plant's normal growth and development and flowering and fruiting, but will also greatly reduce the ornamental and commercial value of the cultivated flowers and trees. Sunscald can occur on fruits, trunks and leaves, with leaves being especially severe. The types prone to leaf sunscald mainly include: Philodendron 'Imperial Green', clivia, Camellia, cycad, Calathea, Fagraea ceilanica, azalea, Chinese orchids, Cymbidium, hydrangea, plum blossom, white michelia, spider plant, Chloranthus, Aucuba japonica 'Variegata', Fatsia japonica, hosta, ivy, Rhapis, Canna, banana shrub (seedlings), and Strelitzia. Its differences from infectious diseases are: first, it is related to special environments, such as appearing under high temperature and strong light; second, the lesions on scorched leaves and tender shoots are relatively large, with no obvious boundary from healthy tissue, and no pathogens appear on them within a short time; third, on the same kind of flower and tree placed together, new leaves and tender shoots show lesions at the same time, without expanding or spreading. Scorched leaves may be partially yellowed and browned, or new leaves may turn black and necrotic, or leaf margins may turn brown and then curl, or all new leaves may turn brown and necrotic. Although the manifestations vary widely, the most fundamental identifying marker is that there are no pathogens on the sunscald spots. There are usually three types: leaf tip, leaf margin, and tender leaf scorch.
Prescription
① Cut off the necrotic branches and leaves to avoid causing the occurrence of other infectious diseases; promptly move it under a shade shed and spray a low-concentration plant growth regulator to promote the plant's rapid recovery of vitality.
② Regulate light intensity; when the weather clears after long rain, promptly move potted ornamental plants to a semi-shaded place.
③ During the scorching heat of midsummer, control light intensity, increase spraying on leaf surfaces and the environment, and strengthen ventilation measures to avoid scorching of leaves and new shoots.
④ For potted flowers on the balcony, place them indoors from after 10 a.m. to before 4 p.m. to avoid the scorching sun for several hours around noon. Spraying copper sulfate, lime water, etc. onfrangipani, rubber tree, and Strelitziaetc., spraying a 0.1% copper sulfate solution during the hot season can increase the heat resistance of ornamental plants.
Case four:Red palm weevil
Diagnosis
The red palm weevil, also known as the rust-colored palm weevil, belongs to the order Coleoptera, family Curculionidae. It is an invasive high-risk quarantine pest that severely harms coconut, oil palm and other palm family plants in Southeast Asia; in the past one to two years, in Hangzhou, Nanjing, Hefei, Wenzhou and other places, outbreaks of its damage to Canary Island date palm and Middle East date palm have been discovered one after another. Its larvae bore into and feed on the interior of the stem and the growing point, eating the soft tissue, creating tunnels, causing the affected tissue to necrose and rot and producing a special odor, and in severe cases causing the stem to become hollow. The adult is reddish brown in body color with a hard body wall, 30mm-34mm long, with the head extended into a tube shape, chewing mouthparts, with the mouthparts borne at the tip of the head tube; the antennae are geniculate, with several enlarged segments at the end, borne at the front lateral end of the head tube. The egg is oblong, with a dark red head end. The larva is plump and curved, legless; the mature larva is 50mm-60mm long; the pupa is a free pupa. The female lays a hundred eggs each time. The larval stage is 1-N28 days; newly emerged adults first stay inside the pupa for 8-14 days before drilling out to feed and reproduce the next generation. From April to October each year is the peak period of the pest; after hatching, the larvae invade from wounds or the growing point; adults are migratory, gregarious and feign death, and often come out to activity in the morning or evening. Affected plants initially show yellowing and wilting of leaves around the crown, then this extends to the middle leaves turning yellow and withered. When a plant is affected, it ranges from weakened tree vigor in mild cases to death of the whole plant in severe cases.
Prescription
①Strengthenplant quarantine; before purchasing palm family plants, carefully inspect whether the stems have been bored by the red palm weevil to prevent buying plants with insects.
② Manual capture: for adults that come out to activity in the morning or evening, you can take advantage of their feign-death behavior and tap the stems to shake them off and kill them.
③ Seal the holes: in view of the habit of adults preferring to lay eggs in holes or wounds on plants, you can seal them with asphalt or smear them with mud slurry to prevent adults from laying eggs.
④ Remove affected plants: upon discovering severely affected plants, they should be dug out immediately to avoid adults emerging and spreading to reproduce.
⑤ Chemical control: first use a long iron hook to hook out the frass or wood shavings blocking the insect holes in affected plants, then use a dimethoate or cypermethrin solution diluted 500 times to drench and irrigate the whole plant, allowing the solution to penetrate into the stem to kill the pests, once every 7 days. Then place 5-8 sponge pesticide bags soaked in a 40% dimethoate emulsifiable concentrate solution diluted 200 times at the leaf sheaths and heart buds, and re-soak and replace them every 15 days. Or place a 15-gram small packet of carbofuran at the growing point of palm family plants to prevent pests from invading from the growing point. For adults causing damage in the stem, inject the pesticide stock solution from the insect hole, then seal it with mud. Bury carbofuran at the roots so that the plant absorbs sufficient carbofuran to achieve a preventive effect.
Case five:Rose sawfly
Diagnosis
Namely the rose three-section sawfly and the rose sawfly. It mainly harms Chinese rose, rose, Rosa rugosa, Rosa multiflora 'Grevillei', Rosa xanthina and other Rosa genus flowers and trees, and occurs in Shanghai, Hubei, Beijing, Shandong, Anhui, Jiangsu, Zhejiang, Jiangxi and other places. Its larvae gnaw on leaves and tender shoots, and in severe cases can eat all the leaves of the whole plant. Its larvae are about 20mm long, light green when newly hatched, and turn yellowish brown when mature. It has 2 generations a year, and overwinters as mature larvae in thin cocoons in grass or shallow soil near the affected plants. They emerge the following May-June; adults are active during the day and rest quietly on leaves at night. Eggs are mostly laid scattered within the epidermis of new leaves and tender shoots; the female can also use her ovipositor to cut a longitudinal slit through the outer bark of the branch down to the xylem, and lay eggs inside. Several to several dozen eggs are laid at each site; the egg-laying site turns black; each female lays 30-40 eggs. The egg stage is about 1 week; the first-generation larvae appear in mid-July, and mid-to-late August is the peak period of damage by the second-generation larvae; by the end of October the larvae successively enter the soil to overwinter. Young larvae are gregarious, and the larval stage is about 1 month.
Prescription
① For a small number of household potted plants, you can take advantage of the larvae's gregarious damage behavior and remove and destroy leaves on which many larvae have gathered.
② Loosening the soil and weeding can eliminate some of the cocoons in the soil.
③ Strengthen control of the first-generation larvae; you can use a 25% chlorbenzuron No. 3 solution diluted 2000 times, or a 0.36% matrine aqueous solution diluted 1000 times, or a 5% cyfluthrin emulsifiable concentrate diluted 4000 times, or a 90% trichlorfon crystal solution diluted 1000 times to spray and kill the larvae.
Case Six:Slug moths
Diagnosis
June is the period of frantic damage by slug moth larvae (stinging caterpillars). Among them, the second-generation larvae of the yellow slug moth (Cnidocampa flavescens) begin damaging the leaves of flowering trees and shrubs such as flowering cherry, crape myrtle, osmanthus, white magnolia, Chinese elm (Ulmus parvifolia), ornamental peach, and Japanese apricot; the first-generation larvae of the mulberry brown slug moth (Thosea sinensis) begin damaging flowering trees and shrubs such as cherry, peach, persimmon, Chinese tallow tree, ginkgo, and coral tree at the end of June; the larvae of the flattened slug moth (Thosea sinensis) hatch at the end of June and begin damaging flowering trees and shrubs such as Japanese apricot, maples, osmanthus, crabapples, redbud, Chinese rose, tree peony, gardenia, pomegranate, large-leaf boxwood, and coral tree; in addition, the larvae of the brown-edged green slug moth (Latoia lepida), the beautiful green slug moth (Latoia lepida), and the jujube stinging moth can all damage the leaves, tender shoots, and fruits of many flowering trees and shrubs.
Prescription
① The newly hatched larvae of the beautiful green slug moth, the brown-edged green slug moth, and others have gregarious feeding habits. Focus inspection on leaves at the damaged sites that show obvious white or semi-transparent damage. For leaves with large numbers of gregarious larvae, pick them off early and crush the larvae underfoot.
② Set up black light traps during the adult emergence period to trap and kill them.
③ Spray to kill the larvae with 1.2% diflubenzuron No. 1 at 8000 times dilution, or 25% diflubenzuron No. 3 at 2000 times dilution, or 90% trichlorfon crystals at 1000 times dilution.