The main pests of osmanthus fragrans are acaricide, mite, scale insect, whitefly, chilblain moth, marsupial, wax cicada, short-fronted negative locust and so on. Among them, mites, scale insects and whiteflies are the most serious and common.
Common diseases:
First, brown spot disease
Brown spot is caused by fungi, which harm leaves. At first it was yellow spots, and later it developed into nearly round or irregular spots, yellow-brown to taupe. The diameter of the spot is 2- 10mm, the outer edge of the spot has yellow halo, and many black mildew spots are scattered on the front of the leaf. These are conidia and conidia of fungi. After the diseased spots become large spots, the leaves will die, but they will not spread to the veins. Pathogens are spread by wind, rain, water and other means. It began to increase in March, and from April to the onset of 10, and the incidence decreased after 10.
High temperature and high humidity are beneficial to the disease, and the disease of old leaves is more serious. Generally speaking, Dangui is more resistant to the disease than Jingui and Yin Gui.
Prevention and control methods:
1. Remove the remains and leaves of diseased plants in winter and destroy them in time. The introduced seedlings should be pruned of diseased leaves. When the seedlings in seriously ill areas leave the nursery, potassium permanganate can be sprayed 1000 times. Chemical control refers to osmanthus leaf blight.
2. Strengthen the management of water and fertilizer, increase the application of humus fertilizer and potassium fertilizer, and enhance the disease resistance of plants; The environment should be ventilated and transparent, and do not spray drugs during the onset period to avoid getting wet in the rain. Never accumulate water in the soil.
3. Control sucking pests such as scale insects and aphids in time;
4. Spray 70% mancozeb wettable powder 500 times twice before entering the house in late autumn. If it happens, you can use Youlejing 1000 times solution or 50% carbendazim 500 times solution for prevention and control. During the onset period, 1: 2: 100-200 times of lime Bordeaux solution can be sprayed.
Second, leaf blight
Leaf blight, also called leaf blight, is an important disease of osmanthus fragrans. The damage of leaves mostly starts from the tip and edge of leaves, and the small spots are light brown, and then expand into round or irregular shapes. Lesions are sometimes friable and curly. Lesions can be interconnected to 1/3 to 1/2 of leaves. They are grayish brown with green edges, and small black spots are produced on the later lesions. The disease can occur all year round, resulting in large-scale dry leaves, high temperature and humidity, poor ventilation and weak plant growth. It usually occurs from July to 1 1, and it is spread by wind and rain.
Prevention and control methods:
1, in late autumn and early winter, the diseased leaves should be completely removed, burned or buried centrally to reduce overwintering bacteria, which can effectively inhibit the occurrence of diseases in the coming year;
2. Transplanted or introduced seedlings should remove diseased leaves and burn them centrally. When necessary, 500 times of 50% carbendazim wettable powder or 0. 1% potassium permanganate solution can be sprayed before the seedlings leave the nursery for disinfection.
3. Strengthen management, increase the application of phosphorus and potassium fertilizers, frequently loosen the soil to weed, prevent soil hardening or water accumulation, water and spray water in time in case of high temperature and dry weather, and increase the disease resistance of osmanthus plants;
4. In areas with serious diseases, 500-fold solution of 70% mancozeb wettable powder and 800-fold solution of leaf bank should be sprayed every half month from the end of June.
Third, anthrax.
This disease infects the leaves of osmanthus fragrans. At the early stage of the disease, small chlorosis spots appeared on the leaves, which gradually expanded to form round, semi-circular or oval lesions. The lesion is light brown to grayish white with reddish-brown ring at the edge. Under wet conditions, pink myxospore discs appear on the lesion. Anthrax occurs from April to June. Pathogenic bacteria overwinter in the diseased leaves of maple trees and spread through wind and rain.
Prevention and control methods:
1, first of all, reduce the source of infection. Thoroughly remove diseased leaves in autumn. Potted sweet-scented osmanthus should remove the diseased leaves in time.
2. Secondly, strengthen cultivation management. Choose fertile and well-drained soil or substrate to plant osmanthus fragrans; Increase the application of organic fertilizer and potassium fertilizer; Planting density should be suitable for ventilation and light transmission, reduce leaf humidity and reduce diseases.
3. Scientific use of chemicals for prevention and control. At the early stage of onset, spray 1: 2: 200 times bordeaux mixture or 1000 times charcoal.
Fourth, coal pollution spots.
The disease usually occurs in hot and humid seasons and in hot and humid, hidden and poorly ventilated environments. The main performance is that leaves and branches are covered with a layer of gray-black powder of different colors, and sometimes even a black film is formed. The reason is that when aphids, scale insects, whiteflies and other insects harm osmanthus fragrans, the excreta secreted by them cause parasitism of many fungi, thus inducing a dark gray sooty blotch. The gray-black coal pollution layer not only affects the ornamental of osmanthus fragrans plants, but also affects the photosynthesis of leaves, resulting in poor plant growth and early shedding of susceptible leaves after yellowing and wilting.
Prevention and control methods:
1, strengthen the shaping and pruning of osmanthus plants, ensure the ventilation and light transmission in the plant cavity, and promote the good growth of plants;
2. When aphids, scale insects, whiteflies and other pests are found to harm osmanthus fragrans, effective prevention and control should be carried out in time to kill them; Potted plants, often spraying water to wash leaves;
3. At the early stage of the disease, spraying 500 times of sulfur suspension, or 800 times of 50% carbendazim wettable powder and 500 times of royal forest bacteria on the branches and leaves has a good control effect.
Verb (abbreviation of verb) yellowing disease
This disease is iron deficiency chlorosis. Due to the imbalance of PH value in soil, alkaline soil and incomplete cleaning of building residues, iron in soil exists in the form of insoluble iron hydroxide, which cannot be absorbed by osmanthus fragrans roots, thus making osmanthus fragrans lack of iron. If it is mild iron deficiency, it means that the veins of young leaves turn green and yellow, and the vein tissue is still green; If the iron deficiency is serious, the new and old leaves will turn yellow, the young leaves will stop growing slowly, some old leaves will appear yellow-brown spots, and the plants will not grow and bloom normally, which will seriously affect the ornamental effect and the harvest of flowers.
Prevention and control methods:
1, mild iron deficiency, root irrigation with 0.5% ferrous sulfate solution and foliar spraying with high iron;
2. When iron deficiency is serious, 20-40g of chelated iron [F-EDTA (EDTA)] can be applied to the soil around the rhizosphere of each osmanthus fragrans (including potted osmanthus fragrans), and 0. 1% chelated iron solution can be sprayed on the leaves at the same time;
3. Spraying leaves with 0.2% ferrous sulfate solution every half month during the growth season of new shoots in spring; When preparing potted soil, the pH value can be adjusted to below 6.5 with 0.5% ferrous sulfate solution.
Six, dry rot
It mainly occurs on newly transplanted osmanthus plants with large specifications. When landscaping or transplanting osmanthus fragrans, the trunk or branch bark of osmanthus fragrans plants is seriously damaged or large pieces of dry bark are not properly protected in time due to reasons such as bumps during digging, scratches during long-distance transportation and strangulation during hanging planting. When rain and sewage infect wounds, fungi (such as wood rot fungi, etc. ) and bacteria (such as soil wild Bacillus, etc. ) is induced to invade and parasitize, causing the wound to rot.
Prevention and control methods:
1, for small wounds on tree trunks or branches, apply wound healing agent in time;
2. For small wounds that have been partially decomposed or slightly decomposed, the wound can be partially cleaned until the fresh xylem and phloem are exposed, and then the wound healing agent can be applied to the fresh wound to promote the wound healing as soon as possible;
3. For the old big wounds with long-term phloem damage and exposed xylem for many years, the rotting exposed xylem can be cleaned up, and sulfur stone mixture can be regularly applied to prevent corrosion or decay or drying, which will have better protection effect.
4. For the thick osmanthus plants with cavities formed in the trunk, the rotten parts can be thoroughly removed first, and care should be taken not to destroy the isolation layer between rotten xylem and non-rotten xylem, and the cavities should be filled with polyurethane foaming agent.
Seven, rot disease
It mainly occurs in roots and damaged parts. After the lesion gradually expands, the plants become weak and even die. The rainy season is serious in summer and autumn.
Prevention and control methods:
1. Sprinkle a small amount of sulfur powder around the plant in early spring and coat the trunk in winter. The whitening agent is made of 25 kg of quicklime, 3 kg of salt, 0.5 kg of vegetable oil, sulfur powder 1 kg and water 100 kg.
2, after the disease spots appear, after scraping coated with rotten skin or rotten skin. You can also use Toucui Bao to spray the trunk to treat rot.
Common pests:
I. Tetranychus cinnabarinus
The mites that harm osmanthus fragrans are mainly Panonychus citri and Tetranychus cinnabarinus, which are very serious in all parts of the province in recent years.
The adult mite of Tetranychus cinnabarinus is 0.5-0.6 mm long, and the female mite is ovoid, vermilion to rust red, or dark brown to dark brown; Male mites are slightly diamond-shaped, slightly yellowish and small, with 0.3-0.4 mm eggs, round, reddish to pink. Young mites are nearly round and translucent when they are first hatched, and their bodies are dark green after feeding. If it is a mite, its body is oval and its body color is dark. It can produce 10- 15 generations a year, and adults, nymphs and eggs overwinter on host plants and weeds in the south; The next spring, when the average temperature reached above 7℃, it began to feed and breed. Adult mites, juvenile mites and nymph mites all like to gather on the back of leaves to feed, and most of the eggs are laid on both sides of veins on the back of leaves or under dense mesh. Each female mite can lay 50-500 eggs in her lifetime. The high temperature and drought season is the most favorable for its occurrence, which leads to the grayish yellow leaves of the whole plant or a piece of osmanthus forest, which seriously affects the growth, flowering and display of osmanthus. The optimum temperature for the occurrence of this insect is 25℃-30℃, and the optimum air relative humidity is 35%-55%. Strong wind and heavy rain can wash away the insect body and reduce the density of the insect population.
Control methods: Protect natural enemies, such as ladybugs, bark beetles, thrips, Chrysopa sinica, Chrysopa macrophylla, etc. In winter, weeds under trees are removed and burned, and the overwintering adult mites, nymphs and eggs are killed with lime-sulfur mixture with Baume degree of 0.3-0.5; 1000 times acarbose or 800 times avermectin.
Second, blow mites.
The scale insects that harm osmanthus fragrans are scale insects, scale insects, scale insects, scale insects, scale insects, scale insects, scale insects, scale insects, scale insects, scale insects, scale insects, scale insects. Among them, blown cotton scales, chaff scales, Japanese white scales and orange scales are more common.
Bactrocera yessoensis, adult body length is 5-7 mm, female body is oval, orange-red, abdomen is flat, and back is raised. Before spawning, white oocysts are secreted at the back of abdomen, with longitudinal stripes of 14- 16. The male worm has a thin abdomen, about 3 mm long, black chest, orange abdomen, long and narrow front wings, black and hooked rear wings. Eggs, oval, 0.7 mm long and orange, are densely packed in the oocysts of female insects. Nymphs, oval, orange, covered with yellowish wax powder on the back. Pupa, 3.5 mm long, orange-red, with light yellow-brown fine hairs scattered on the body surface and covered with white wax powder. Cocoon, long oval, white, composed of loose wax filaments, covered with white wax powder. The insect occurs 2-3 generations a year, and the generations overlap; Most of the female adults are clustered and fixed in one place, and the white waxy oocysts are secreted at the end of the abdomen, and they lay eggs while secreting wax. The spawning period is more than 30 days, and each female insect can lay hundreds to 2000 eggs. There are fewer males and more parthenogenesis; After hatching, the larvae spread out, and then moved back from the tender branches to live in groups, sucking tree juice and secreting honey dew, which induced sooty blotch. Due to the cross-harm of diseases, leaves of osmanthus plants often turn yellow and branches wither.
Prevention and control methods: use less pesticides in peacetime to protect natural enemies; Found a small number of bugs, wipe them in time and squeeze them to death; Spraying lime-sulfur mixture with Baume degree of 0.3-0.5 in winter to kill overwintering pests; At the peak of incubation, eggs are sprayed with 1000 times of culture medium, 1000 times of cockroaches, or 800 times of cockroaches.
Third, the tea bag moth
Marsupials, also known as "foodies". Bag moth pests that harm osmanthus fragrans include tea bag moth, big bag moth, small bag moth and so on. Their similarity is that insects hide in bags, and larvae and female adults eat leaves and twigs. In severe cases, the whole plant leaves can be eaten up, and the high temperature and drought last for a long time, which is more serious.
Tea bag moth, the adult is bisexual, the female adult has no wings, the body length is 12- 16 mm, it is maggot-like, fat, with a small head and a pair of spikes; Male worm, body length 1 1- 15mm, wings spread 22-30mm, body and wings are dark brown, and there is a transparent rectangular spot near the tip of the front wing and near the center of the outer edge; Oval, milky white, about 0.8 mm long; Larvae, mature larvae are 10-26 mm in length, and there are brownish yellow longitudinal bands with jade white stripes on the dorsal line of each thoracic segment and on the middle and posterior thoracic valves. Pupa, female, hammer-shaped, dark brown, small head, curved chest, body length14-18mm, male, brown, body length1-13mm, curved abdomen and a pair of hip spines; The capsule is olive-shaped, dark brown and filiform. The length of the capsule can reach 25-30mm. Branchlets and cut branches are attached outside the capsule, and the parallel longitudinal cracks are neat. This insect has 2-3 generations a year, and overwinters as mature larvae. Adult eclosion often occurs in the afternoon, and mating occurs the next night. The female insect remains in the pouch after eclosion, and the male insect flies close to the pouch for mating after eclosion; Eggs are laid in cysts, and each female lays about 500 eggs; After hatching, the larvae crawl from the drainage hole of the capsule to the branches and leaves, spin silk and droop, and spread to the surrounding hosts with the wind to feed, and the leaves and branchlets are connected with silk to form the capsule; When the larva crawls to feed, its head and chest are exposed outside the sac, and the protective sac is hung on the abdomen; Feeding time is mostly in the early morning, evening or cloudy days, and feeding is rare at noon on sunny days; In the early stage, it feeds on mesophyll, leaving transparent spots on the epidermis. With the growth of insect age, it eats leaves into holes and lacks carving. After eating for a long time, insects can eat up the whole leaf and chew bark, flowers and fruits.
Prevention and control methods: manually remove the protective capsule and destroy the larvae; Protect natural enemies; Trapping and killing adults with black lights and vibrating lights; Spraying 1000 times 2 billion/g cotton-aged nuclear polyhedrosis virus suspension at the peak of spawning; At the peak of the second instar larvae, spray control was carried out with 1.500 times abamilon, 1.2% nicotinamide, 1.000 times diflubenzuron No.3 and1.000-2,000 times diflubenzuron.
Fourth, frost moths.
Adults are 45-50 mm long, with dark gray wings mixed with creamy white powder; The wingspan is 90- 130mm, and there are brown semi-circular stripes on the chest back plate, two brown wavy horizontal lines in the middle of the front wing, two black longitudinal stripes below the middle cavity and a black curve at the top of the wing. The hind wings are brown, and the outer edges of the front and rear wings are connected by small black and white squares. Eggs, spherical, first born green, then yellow. Larvae, green, 75-96 mm long, light green head, green chest, and 8-9 rows of horizontally arranged particles on the back; The abdomen is yellow-green, with 7 white oblique bands on the side; The tail angle is brown-green, with purple-brown particles on it, and the length is12-13 mm; The valve is brown, the chest and feet are brown and the abdomen and feet are green. Pupa, reddish brown, 50-60 mm long. The insect has three generations a year in the Yangtze River valley and overwinters in the soil as pupa. The overwintering moth period is from the middle of April to the end of July, the first generation is from the middle of July to the middle of September, and the second generation is from the middle of September to the beginning of 10. Adults live in the dark places of trees, branches and leaves, weeds, crops and houses during the day, fly out at dusk, mate and lay eggs at night, and have strong flying ability and phototaxis. Most adults lay eggs on the back of leaves, and the newly hatched larvae feed on the surface of leaves. The larger ones eat leaves into notches and holes, or even eat them all, and the mature larvae are buried and pupated.
Prevention and control methods: turn over the soil in winter to kill the overwintering pupae; Trapping and killing adults with black light; A small number of osmanthus fragrans larvae appear on a single plant, which can be killed manually; The 3rd instar larvae were sprayed with 1000 times of Ye Chong net and 500 times of 1000 billion /g of Cordyceps spore powder.
Five, the beautiful green thorn moth
Spiny moths, that is, "hot peppers." The moths that harm osmanthus fragrans include yellow thorn moth, flower green thorn moth, mulberry brown thorn moth, flat thorn moth, yellow-edged green thorn moth and so on. Their larvae sometimes eat up the leaves of plants such as osmanthus fragrans, wither the damaged branches, hinder the growth of osmanthus fragrans, and reduce the ornamental value and economic value of flowers and trees.
The adult Hymenoptera viridis, with a body length of 16- 18 mm, is emerald green, with quadrangular dark brown spots at the base of the wing and light brown at the rear wing. Egg, oval, 0.9- 1 mm, yellow-green. When the larva matures, its body length is about 24 mm, its body is emerald green, its head is reddish brown, there are three blue-purple and dark green lines in the center of its back, there are blue patches and thorns on its back, there are a pair of orange thorns on the back of the first abdominal segment, and there are black fluffy spherical tufts on its belly. Pupa, ovoid, body length14-17mm, yellowish brown; Cocoon, dark brown, flat, covered with white silk, oval, long14-17mm. This insect has 2-3 generations a year in the Yangtze River valley, and overwinters on branches as mature larvae. April to May, mid-May to early June, and early August to mid-September of the following year are the emergence and spawning periods of the first and second generation adults. Adults have strong phototaxis, can mate on the night of emergence and start laying eggs the next day. A single female can lay 600-900 eggs. Eggs range from a few to more than a hundred, mostly 30-40, which are concentrated on the back of young leaves and arranged like fish scales. The newly hatched larvae only feed on mesophyll and lower epidermis, leave the upper epidermis, bite through the epidermis after the third instar and feed on the whole leaf after the fifth instar. Larvae ***7 years old, like to cluster, and gradually spread out after 5 years old. Mature larvae cocoon at bark seams and the base of trunk, and some first-generation cocoons cocoon at the back of leaves.
Prevention and control methods: check the white to translucent damaged leaves of osmanthus plants in time, pick and kill the leaves with a large number of larvae in time with gloves to avoid being stabbed by their poisonous hairs; Manual scraping of overwintering cocoons from branches can reduce the overwintering base and prevent it from recurring in the next year; Trapping and killing adults with black light to reduce the number of next generation larvae; Biological pesticides such as Bacillus thuringiensis and Penicillium are used to control larvae; Spraying 1000 times, 1.25% tobacco 1000 times and 1.2% diflubenzuron 8000 times in larval stage.
Bemisia tabaci
Whitefly pests that harm osmanthus fragrans mainly include whitefly, whitefly, whitefly, whitefly, whitefly and osmanthus fragrans (Hefei, Chuzhou and Wuhu). They mainly use the mouthparts of adults and larvae to pierce the mesophyll of leaves to absorb juice, which makes the leaves of osmanthus fragrans curl, turn green and yellow, and even dry up; A large amount of honey dew discharged from it will seriously pollute the branches and leaves of osmanthus fragrans, cause coal pollution, and lead to poor growth of osmanthus fragrans, thus affecting the normal flowering and display of plants.
Whitefly
Whitefly
Prevention and control methods: Protect natural enemies, such as Anoplophora nigripes, Aphid, Anoplophora nigripes, Lepidoptera Tenebrio molitor, Chrysopa lacewings, ladybugs, wasps, predatory mites, etc. Whitefly can be trapped and killed by yellow armyworm; Bemisia tabaci is very resistant. When selecting pesticides for control, we should pay attention to the principle of alternate use and mixing, such as alternate use of 1 1,000 times of fly-sweep, 2000 times of 10% imidacloprid wettable powder, 1 1,500 times of 40% omethoate EC and 1 1,000 times of aphid pests.
Seven, scale insects
It can occur for 2-3 generations in the Yangtze River basin, and it is seriously harmful in May-June and August-September. Living together in the shade of main branches and branches, or on branches and leaves, both adults and nymphs secrete honey dew, which leads to sooty blotch of flowers and trees. High temperature and high humidity are beneficial to the occurrence, and a small amount can be brushed off gently with a soft brush, with good effect. In summer, it is most beneficial to spray lime-sulfur mixture with Baume of 0.3-0.5, or spray 1000 times to kill scale for 800 times, and spray 1 time every 7- 10 day for 2-3 times continuously.
Eight, Starscream
High temperature and drought often occur. Control methods: When the weather is dry, pay attention to irrigation combined with fertilization to promote plant health and enhance insect resistance. Pay attention to frequent rotation when applying chemical pesticides, because some highly toxic pesticides will produce drug resistance. 65,438+0,000 times acarbose or 65,438+0,500 times 40% dimethoate EC can be sprayed, and the control effect is good.