Five common diseases and insect pests of Michelia mollissima

In fact, the cultivation of Michelia mollissima is not very difficult, but in the process of conservation, some insect pests and diseases often occur. If it is not dealt with in time, it will not only affect the ornamental value of Michelia mollissima, but also prone to death. The editor will introduce to you five common diseases and insect pests and their prevention and control methods. Friends in need can learn together.

Smiley flower

1. Scale insects

Michelia is often damaged by shell insects, which absorb plant sap and harm new shoots and leaf veins, which usually appear on the branches and the back of the leaves. Solution: can be brushed with a small brush, or sprayed with No. 20 petroleum emulsion with 150 times water.

Second, coal pollution disease of Michelia mollissima

Coal fouling disease harms the leaves of Michelia mollissima, which is not conducive to the growth of Michelia mollissima. Solution: the solution can be scrubbed with clean water or sprayed with 500 / 1000 times carbendazim aqueous solution.

Third, smiling leaf blight

Leaf blight mostly occurs at the edge of the leaf, and there are many black particles on the leaf. When the disease is serious, the leaf dies and falls. Solution: remove diseased leaves and spray 50% topiramine wettable powder 800-1000 times when diseased plants are found.

4. Anthracnose of Michelia mollissima

Anthracnose is also a common disease of Michelia mollissima, which harms the stems and twigs of Michelia mollissima, reduces the ornamental value of plants, and even causes plant death. Solution: during the onset period, 0.5% Bordeaux solution or 5% Baiyinqing wettable powder 600mur750 times can be sprayed, once every 10 days.

Fifth, smiling yellow leaf disease

Yellow leaf disease is mainly caused by chlorosis of young leaves at the tip of Michelia mollissima, the mesophyll turns yellow or yellowish, and the plant grows weak and dies slowly. Solution: appropriate supplement of soluble iron.

Common diseases and insect pests of flowers and their treatment methods

Common diseases of flowers: harm of cold in late spring

This is a non-infectious disease, which mainly occurs in some areas south of the Yangtze River and between the Yangtze and Huaihe Rivers. by the end of March, the daytime temperature has reached more than 20 ℃. Many people are eager to move their potted ornamental plants outside for conditioning and maintenance. At this time, there is often cold air to the south, there is a "late spring cold" reverse weather, and the lowest temperature in the early morning often drops below 4 ℃, resulting in the "freezing" of new shoots and leaves of some tropical flowers.

Common such as Magnolia, Milan, jasmine, gentleman orchid, Dai powder leaf, fruit taro, inverted golden bell, bamboo taro, Anthurium andraeanum, poinsettia, etc., will seriously affect the normal growth of that spring.

Solution method

Timely grasp the weather forecast of local meteorological stations and meet the special weather of "late spring cold". For a small number of potted plants that have moved outdoors, they can be moved back to the greenhouse or indoors; if more potted plants are moved outdoors, they can be gathered together and covered with double-layer plastic film.

In the Yangtze River basin and its northern areas, it is generally necessary to wait until after the Qingming Festival or the end of the "final frost period" before moving outdoors. The doors and windows can be cooled down by opening doors and windows and installing electric fans, and the doors and windows will be closed at night. Make it have a process of gradually adapting to the outdoor environment.

Common diseases of flowers and plants: harm of powdery mildew

It mainly harms the ornamental plants such as rose, crape myrtle, ten meritorious works, big leaf yellow poplar, bamboo Polygonum and so on. It mainly harms leaves, petioles, pedicels, flower buds and tender shoots, and the damaged parts are covered with a layer of white powder. In severe cases, the leaves turn yellow, the tender leaves curl, wrinkle and thicken, the buds die, deformed flowers appear, and the tender shoots are bent and shortened.

Solution method

Sulfur powder fumigation in March, an electric fumigator was used in the greenhouse with built-in sulfur powder to carry out sealed fumigation, which had a good control effect.

Common diseases of flowers and plants: anthrax harm

It mainly harms camellia, tea plum, Yemeni iron, eight immortal flowers, gentleman orchids, evergreen, orchids, spider eggs, epiphyllum, rubber trees, cyclamen and so on. It mainly harms leaves, tender shoots and fruits, and the disease spot is nearly round and grayish brown. In the later stage, the disease spot turns gray-white, with obvious concentric patterns and small black spots.

Solution method

The density of flowers in the whole pot and the planting plants and row spacing in the ground can improve the ventilation and ventilation conditions. The pot soil should be properly watered when it is dry to increase the resistance of the plant.

At the initial stage of the disease, 80% of anthrax Fumei wettable powder 500 times, or 50% polysulfide suspension 800 times, alternately sprayed once every 10 days, 2 times in a row for 3 times.

Common diseases of flowers: harm of Botrytis cinerea

With the recovery of gas, excessive humidity and poor ventilation, Botrytis cinerea is still one of the main diseases of indoor flowers. It is harmful to African chrysanthemum, rubber tree, melon and leaf chrysanthemum, cyclamen, poinsettia, geranium, Rieger begonia, green apple, dragon boat flower, mulberry, Anthurium andraeanum and other potted flowers, especially leaves and petals.

Solution method

After March, it is necessary to strengthen ventilation and light penetration, reduce indoor air humidity, and prohibit spraying water on the leaf surface in the evening to prevent moisture from remaining on the leaf surface for a long time.

For the plants in the early stage of the disease, 65% of Dysen zinc wettable powder or 50% carbendazim 1000 times of wettable powder can be sprayed alternately every 10 days for 2 consecutive times.

Common diseases of flowers 5: harm of coal fouling disease

In March, due to poor indoor ventilation and high humidity, scale insects, aphids, whiteflies and other prickly mouthparts pests could not be completely eliminated. Coal fouling disease still occurs on the leaf flowers and fruits of citrus, Milan, Fusang, Magnolia, Michelia, fishtail sunflower, banyan, camellia, palm bamboo, rhododendron, gardenia, bone holly, Fujian tea and other plants.

Solution method

Strengthen indoor ventilation and timely kill the insect vectors of coal pollution caused by aphids, scale insects, whitefly and so on.

A small number of leaves on individual plants are infected with coal fouling disease, so the coal dirt layer can be scrubbed with wet cloth with low concentration of washing powder water.

At the initial stage of the disease, the branches and leaves of infected plants can be sprayed with 50% of methyl sulfur suspension 500 times or 75% of chlorothalonil wettable powder 500 times, once every 15 days for 2 consecutive times.

Common insect pests in flowers and plants VI: damage of scale insects

For the potted ornamental plants placed in the greenhouse, scale insects are still the main pest species due to the restriction of ventilation, lack of light and high humidity.

Such as green woolly scale on kumquat, gray pink scale on yew, pink scale on Fusang, chaff scale on magnolia, tortoise wax scale and red wax scale on camellia, horned wax scale on holly, black helmet scale and oyster shield scale on cycad, wheel shield scale on rose, Koch's white shield scale on smile and bran shield scale on Magnolia, giant tumor oyster scale on orchid, white shield scale on brown bamboo, round shield scale on ivy The coconut shield scale on the loose-tailed sunflower, the sagittal shield scale on the four seasons cinnamon and so on. The species of scale insects on each kind of flower are very different.

Prevention and cure method

Scale insects on a small number of plants in the family can be wiped out with 75% sprinkling essence of cotton wool, or with laundry powder. For small scale insects, such as sagittal scale scale, Koch's white shield scale, etc., the live insect body can be stained with transparent tape.

Or spray with 2000 times of chlorpromazine wettable powder, once every 15 days, twice in a row.

Common insect pests in flowers 7: the harm of aphids

As the temperature increases and the amount of water poured increases, the harm of aphids on indoor ornamental plants will be more serious. Aphids suck the sap of newly drawn branches and leaves, which will affect the normal growth of the plant after the beginning of spring.

Prevention and cure method

For aphids on a small number of plants, you can first sprinkle tobacco dust, plant ash or slag ash on the insect body and leaves, about 1-2 hours later, and then rinse with clean water to kill most of the aphids.

Common insect pests of flowers and plants: harm of whitefly

Mainly greenhouse whitefly, harming melon and leaf chrysanthemum, Fusang, rose, dry golden lotus, lantern flower, etc., followed by orange thorn whitefly, harming kumquat, golden bean, daidai, bergamot, rose, Bailan, Milan and so on, their harmfulness should not be underestimated.

Prevention and cure method

In severe cases, 10% imidacloprid wettable powder 2000 times or 25% chlorpromazine 2500 times can be used.

Diagnosis and prescription of common diseases and insect pests of flowers in June

Case 1: orchid blight

Diagnosis

That is, black rot is a destructive disease of orchids, which can be infected at all stages of orchid development. leaves, flowers, stems and roots can all be killed. National orchids and foreign orchids also suffer from the disease. They began to find that the base of the leaves turned a little yellow, and the base of the leaves turned brown a few days later, and the base of the leaves was dry and scorched, and the diseased leaves were basically cyan at the top and brown at the base. The pathogens are Phytophthora and Pythium, which can occur all the year round, but the disease is the most serious in summer with high temperature and humidity (6N August), or in the case of poor ventilation and excessive watering, which can damage the seedlings and seedlings of orchids, and the heart leaves are the most vulnerable. Once the disease occurs, if it is not controlled in time, it will quickly spread to the root system and pseudo-bulb, causing root rot and quenching, and even completely destroy the seedling; usually, the susceptible part first produces brown disease spot, and then expands rapidly in case of high temperature and humidity, showing large brown spot, and finally dark brown, defoliation, stem rot, or even death of the whole plant; yellowing to Cymbidium and Cymbidium, but does not cause soft rot. The main way of transmission is that the spores spread and spread through the water droplets splashed during watering; the water film on the leaves and stems of orchid plants, or too much water in the cultivation substrate, are conducive to the growth and invasion of Phytophthora; if there are wounds, it provides a shortcut for pathogen invasion. Although the leaves of orchid plants can be infected with Phytophthora blight, they mainly invade through the wounds of roots, stems and petioles, resulting in root rot (orchid) and leaf shedding.

a formula

① avoids excessive watering or high air humidity, improves ventilation and increases light, and prevents snails, slugs and insects from causing wounds that can infect Phytophthora.

② can effectively inhibit the occurrence and spread of many orchid diseases by using fully mature sheep manure as fertilizer.

③ wound protection is the primary goal, do not hurt the fleshy roots and leaves when changing plants, and the incisions should be strictly disinfected.

When ④ seedlings are infected, the diseased plants should be removed immediately, and the diseased seedlings and cultivation media should be sealed, discarded, burned or buried deeply. If the basin soil is to be used in the second year, it must be strictly sterilized by high temperature or medicine.

If the adult plant of ⑤ is sick, the susceptible part, uninfected part, plant material, basin, etc., can be removed at the initial stage of the disease. Soak for 10 minutes with 300x solution of copper sulfate or 600x solution of 75% chlorothalonil wettable powder For non-susceptible plants with the same liquid spray prevention: for the cut of the diseased plant, it can also be smeared with 70% mancozeb wettable powder, and then placed in a dry place without watering for a week to prevent the spread of the disease.

⑥ has only a small number of diseased leaves. After removing the diseased leaves with a sterilized blade, the seedlings are sprayed once a week with 50% Phytophthora, and the seedlings are sprayed once a week, and the adult plants are sprayed once a month. In peacetime, you can use Bordeaux solution of 11Dreza 200 or 70% mancozeb wettable powder 500x solution, every two weeks, once a week in the rainy season.

Other pesticides used for the prevention and treatment of the disease by ⑦ are metalaxyl 800x solution, 58% metalaxyl ·manganese-zinc wettable powder and 72% metalaxyl ·manganese-zinc wettable powder, sprayed once a month for more than 3 times.

Case 2: White silk disease

Diagnosis

It is mainly harmful to the seedlings of incense, brocade flower, golden peach leaf coral, safflower mahogany, hairpin flower, safflower grass, white clover, magnolia, white orchid, carnation and so on, often leading to the death of damaged plants. The damaged part was at the junction of the rhizome, and there was a white mycelium bundle wrapped in the stem near the ground, and produced a white or yellowish-brown sclerotia, which was rapeseed-shaped. The aboveground leaves gradually turned yellow, wilted and drooped, and finally turned reddish brown. It overwinters with sclerotia in the soil or on diseased remains or weeds. When the soil temperature is suitable in the coming year, the mycelium germinates and produces new mycelium, which invades the base of the stem or rhizome of the plant. In the Yangtze River basin, the disease usually begins in early June. From July to August, when the temperature rises to about 30 ℃, the disease enters the peak period, and the disease basically stops in October. The disease is more serious in the soil with high relative humidity.

a formula

Timely removal of withered grass layer, improvement of soil permeability, deep turning and exposure of soil by ① are beneficial to reduce the occurrence of white silk disease.

In the early stage of ②, the rhizome and surrounding soil were sprayed every 10-15 days with 3000 times of 25% dichloromethyl EC, 1000 times of Shigao water dispersible granules, or 50 times of Sukeling wettable powder, for 2-3 consecutive times.

Case 3: sunburn

Diagnosis

It is a physiological disease. The hot sun at the end of spring and the beginning of summer, the hot light in midsummer, and the indoor potted flowers were moved to the outdoor open field for a long time. These three situations are the most frequent and serious environment of sunburn, which will not only affect the normal growth and development of plants, but also greatly reduce the ornamental and commercial value of cultivated flowers and trees. Sunburn can occur in fruits, trunks and leaves, especially in leaves. The main types prone to leaf sunburn are: green emperor, gentleman orchid, camellia, cycad, bamboo taro, ash wood, rhododendron, national orchid, magnolia, eight immortal flowers, plum blossom, white orchid, hanging orchid, pearl orchid, sprinkled peach leaf coral, star anise gold plate, hairpin, ivy, palm bamboo, canna, Michelia (seedlings), crane orchid and so on. The difference between it and infectious disease is that, first, it is related to the special environment, such as appearing in high temperature and strong light; second, the disease spot of burned leaves and shoots is larger, and there is no obvious boundary with healthy tissue, and there is no pathogen on it in a short time: third, disease spots appear on the new leaves and shoots of the same kind of flowers and trees together at the same time, which do not expand or spread. Some of the burned leaves turn yellow to brown, or the new leaves turn black and necrotic, or the edges of the leaves turn brown and curl, or the new leaves all dye brown and necrosis. although there are thousands of differences, the absence of pathogens on sunburn spots is the most fundamental identification sign: there are usually three types of leaf tip, leaf margin and tender leaf burn.

a formula

Cutting off the necrotic branches and leaves of ① can avoid the occurrence of other infectious diseases; move it to the shade shed in time and spray low concentration of plant growth regulators to promote the plant to recover as soon as possible.

② regulates the light intensity and moves the potted ornamental plants to the semi-shady place in time when it is rainy and sunny.

During the hot summer of ③, control the light intensity, increase the spraying of water on leaves and environment, strengthen ventilation measures to avoid burns of leaves and new shoots.

Potted flowers on the ④ balcony can be kept indoors from 10:00 to 4 p.m., away from hours of hot sun around noon. Spraying copper sulfate and lime water can increase the heat resistance of ornamental plants by spraying 0.1% copper sulfate solution to egg flowers, rubber trees, magnolia, etc., in the high temperature season.

Case 4: red-brown weevil

Diagnosis

Red-brown weevil, also known as rust-colored brown weevil, belongs to the family Coleoptera. It is an exotic high-risk quarantine pest that seriously damages palm plants such as coconuts and oil palms in Southeast Asia. In the last one or two years, in Hangzhou, Nanjing, Hefei, Wenzhou and other places, it has been found to be harmful to Canadian jujube, Middle East jujube and other epidemic situations. It uses larvae to eat the interior and growth point of the stem, feed on soft tissue, cause tunnel, cause necrosis and decay of the damaged tissue, and produce special smell, and cause hollow stem in serious cases. The adult has a reddish-brown body, a hard body wall, a long 30mm-34mm, a tubular head, chewable mouthparts, which are born at the apex of the head canal, and antennae geniculate, with several inflated end segments, born at the front and side of the head canal. The egg is oblong and the head is dark red. The larvae are fat and curved and have no feet. The body length of the mature larvae is 50mm-60mm and the pupae are isolated pupae. The female lays 100 eggs at a time. The larval stage is 1-N28 days, and the newly emerged adults stay in the pupa for 8-14 days before they come out to feed and reproduce. The peak period of insect pests is from April to October every year, and the larvae invade from the wound or growing point after hatching. the adults have the characteristics of migration, gregariousness and pseudo-death, and often come out in the morning or evening. At the beginning of the injured plant, the leaves around the crown were yellow, and then extended to the middle leaves. If the plant is damaged, the tree will be weak: if it is heavy, the whole plant will die.

a formula

① strengthens plant quarantine and carefully checks whether the stems are eaten by red palm weevil before purchasing palm plants to prevent the purchase of insecticidal plants.

② artificial capture, for the morning or evening activity of the adult, can make use of its false death, knock on the stem to shake it down and kill it.

③ coating holes, according to the habit of adults like to lay eggs in the holes or wounds on the plant, can be coated with asphalt or mud to prevent adults from spawning.

When ④ clears the damaged plants and finds the seriously damaged plants, it should be dug up immediately to prevent the adults from spreading and breeding after Eclosion.

For ⑤ drug control, the feces or tree chips blocked in the wormhole of the damaged plant were hooked out with a long iron hook, and the whole plant was irrigated with 500x solution of dimethoate or cypermethrin, and the solution was soaked into the stem to kill the pest once every 7 days. Then place 5-8 sponge bags soaked in 200 times 40% dimethoate EC on the leaf sheath and heart buds, and re-soak them every 15 days. Or place 15g carbofuran packets at the growing point of palm plants to prevent pests from invading from the growing point. For adults damaging in the stem, the pesticide solution is injected from the wormhole and then sealed with mud. Carbofuran is applied to the root to make the plant absorb enough carbofuran to achieve the preventive effect.

Case 5: rose leaf wasp

Diagnosis

That is, rose three-leaf wasp, rose leaf wasp. The main damage to rose, ten sisters, yellow thorn rose and other rose flowers and trees, occurred in Shanghai, Hubei, Beijing, Shandong, Anhui, Jiangsu, Zhejiang, Jiangxi and other places. The leaves and shoots are eaten by the larvae, and in serious cases, the leaves of the whole plant can be eaten up. The body length of the larva is about 20mm. It is light green at first hatching and yellowish brown when it is mature. There are two generations a year, and the mature larvae live through the winter with thin cocoons in the grass or shallow soil layer near the killed plants. From May to June of the following year, the adults were active during the day and perched on the leaves at night. Most of the eggs are scattered in the epidermis of new leaves and tender shoots, and the ovipositor can also be used to longitudinally cut the outer skin of the branches to reach the xylem to form a longitudinal fissure and lay eggs inside. The number of eggs laid in each place is to dozens, the place where the eggs are laid is black, and each female lays 30-40 eggs. The egg period is about one week, the first generation larvae appear in the middle of July, the second generation larvae are in the peak stage in mid-late August, and the larvae enter the soil one after another to survive the winter at the end of October. The low instar larvae are clustered, and the larval period is about 1 month.

a formula

A small number of potted plants in ① family can be used to remove and destroy the leaves with a large number of larvae.

② loosening soil and weeding can eliminate part of the cocoons in the soil.

③ can strengthen the control of the first generation larvae by spraying the larvae with 2000 times of 25% thiazuron 3, 1000 times of 0.36% matrine, 4000 times of 5% cyhalothrin EC, or 1000 times of trichlorfon crystals.

Case 6: stinging moths

Diagnosis

June is the frenzied damage period for the larvae of Spodoptera litura, in which the second generation larvae of Spodoptera litura began to harm the leaves of cherry blossoms, crape myrtle, sweet-scented osmanthus, Magnolia, elm, green peach, plum blossoms and other flowers and trees. The first generation larvae of mulberry brown diamondback moth began to harm flowers and trees such as cherry, peach, persimmon, tallow, ginkgo and coral trees at the end of June: the larvae of flat diamondback moth hatched at the end of June and began to harm flowers and trees such as plum blossom, maple, sweet-scented osmanthus, begonia, bauhinia, rose, peony, gardenia, pomegranate, big-leaf yellow poplar, coral tree and so on. In addition, there are brown-edged green diamondback moth, beautiful green diamondback moth, jujube moth and other larvae, which can harm the leaves, shoots and fruits of many flowers and trees.

a formula

① green diamondback moth, brown edge green diamondback moth and other newly hatched larvae have the characteristics of feeding in groups. The white or translucent leaves with obvious damage are taken as the focus of inspection, and the leaves with a large number of larvae are picked as early as possible to trample on the larvae.

② set up black light to trap and kill adults during Eclosion.

③ sprayed the larvae with 1.2% diflubenzuron 1 8000 times, or 25% trichlorfon crystals 1000 times, or 25% trichlorfon 3 2000 times.