Common diseases and pests of jasmine and their prevention and control methods

1. Trichophyselis cretacea (Batler)

Introduction to the two-striped horn borer

The two-striped horn borer belongs to the family Pyralidae, subfamily Pyralinae. It is known to occur in low mountain plains in Japan from May to June and August to September, damaging the flowers and fruits of the plant. It was discovered in China that it harms jasmine flowers and is commonly known as the jasmine bud borer. The masses are called flower borers.

Living habits: The larvae overwinter on the young branches and dead flowers of jasmine. When the spring warms up at the end of February or the beginning of March, the insects pupate and emerge. The adult insects lay eggs on flower buds or tender leaves. After hatching, the larvae drill into the flowers and eat the flowers. When there are no flowers, they damage the leaves between leaves and can move to other places to cause damage. The larvae can also damage tender branches. More than ten generations occur each year. It has been observed that this insect causes damage throughout the entire flowering period of jasmine, with generations overlapping, and the peak period of damage is from June to September.

Control methods of jasmine double-striped horn borer

This insect mainly harms flowers, and jasmine flowers are the raw material for making scented tea, so safety requirements are particularly high. In prevention and control, we must first pay attention to not using highly toxic and highly residual pesticides during the flowering period. We should try to avoid using pesticides during the flowering period, and control the insect population density through prevention and control before and after the flowering period. Specific method:

(1) Clean the fields in winter, completely cut off dead branches, insect-damaged branches, and insect-infested branches, and burn them in a centralized location. Sweep up dead leaves and either burn or bury them. Check fields with large overwintering insect populations and apply pesticides to lower the base number of overwintering insects.

(2) Careful inspection should be carried out during the flowering period, and any damaged buds, flowers and branches should be removed promptly.

(3) Fumigating flower fields at dusk can prevent adult insects from laying eggs.

(4) Chemical control. You can choose to use 24.5% multi-worm acaricide 2000 times solution or 1.8% worm acaricide 2000 times diluted solution, or Sanle insecticide 800-1000 times solution, or other avermectin pesticides, such as: 0.9% aftodin 2000-3000 times solution, 1% worm acaricide 2500-3500 times solution, 0.6% cypermethrin 2000 times solution, or 24.5% tea cicada clean 2500-3000 times solution, or 0.5% Nonghaha 2000 times solution, you can also use 4.5% high-efficiency chlorpyrifos 3000 times solution for spraying.

2. Jasmine leaf borer (Neusinoe gemetralis Guenee)

Introduction to Jasmine Leaf Borer

Jasmine leaf borer belongs to the order Lepidoptera, family Pyralidae. The larvae mainly feed on jasmine leaves, and sometimes also damage buds and young branches. Newly hatched larvae gather on the underside of leaves, feeding on the mesophyll, leaving behind a layer of translucent epidermis. When they grow up, they eat holes or bite notches into the leaves. It can also eat the bark of twigs, causing the leaves to turn yellow and fall off, and the entire branch to die.

Living habits: There are 10 generations a year in the south, and the larvae overwinter. Adults appear between March and April, remain dormant during the day and become active at night, mating and laying eggs. The eggs are mostly laid on the leaf surface, but also on the back of leaves and twigs. The eggs are laid in masses and arranged in fish scales. Each female insect can lay 50 to 200 eggs. The larvae gather in groups at first, but spread out after the third instar, often connecting branches and leaves together, hiding in them, and feeding and causing damage. The damage is more severe in autumn.

Jasmine leaf borer control methods

1. Clean the garden in early spring, remove dead branches and leaves, and burn them to eliminate overwintering insects.

2. Biological control. Including protecting natural enemies, laying eggs of parasitic wasps, and using biological pesticides such as Bacillus thuringiensis.

3. Chemical control. When natural enemies are unable to control the damage, you can use 600-800 times diluted solution of 90% trichlorfon, 1000 times diluted solution of 50% carbofuran emulsifiable concentrate, 1500-2000 times diluted solution of 2.5% cypermethrin, or 2000-3000 times diluted solution of 20% cypermethrin. You can also use 2000 times diluted solution of 24.5% multichlorfon or 2000 times diluted solution of 1.8% cypermethrin for spraying. Please note that spraying should be done after picking the flowers. Pyrethroid pesticides can generally be used more than 5 days after application before picking.

3. Prodenia litura (Fabricius)

Introduction to Spodoptera litura

The Spodoptera litura belongs to the Lepidoptera, Noctuidae, also known as the lotus armyworm and the cutworm moth. The Spodoptera litura is a worldwide pest, mainly distributed in tropical and subtropical regions of Asia, the Mediterranean region of Europe and Africa. It is distributed throughout our country. The insect is an omnivorous, voracious leaf-feeding pest that often causes intermittent large outbreaks. There are more than 200 species of plants from 99 families known to be harmful, and at least 99 of them are the most edible plants. Among cultivated crops, it mainly harms jasmine, cotton, tobacco, sweet potatoes, peanuts, soybeans, corn, wheat, beets, taro, lotus roots, sesame, sunflowers, melons and cruciferous vegetables. The larvae mainly feed on leaves, but also on flowers, fruits and young branches. This insect occurs more frequently in warm areas south of the Huaihe River in my country, with larger populations in the middle and lower reaches of the Yangtze River and southern China, and occurs occasionally in the north.

Occurrence pattern: The number of generations of Spodoptera litura each year increases gradually from north to south. There are 4 generations in Shandong Province, 4 to 5 generations in Henan Province, 5 to 6 generations in Anhui, Hubei and Hunan Provinces, and 6 to 9 generations in Fujian, Guangdong and Yunnan Provinces.

The occurrence and damage of Spodoptera litura are affected by many factors, including temperature, humidity, soil, rainfall, host plants, natural enemies and human measures. The optimum temperature for growth and development is 25-30℃, and the optimum relative humidity is 75%-80%. In fields with good water and fertilizer conditions and dense growth, the insect density is generally higher. A soil moisture content of 20% helps the larvae to pupate and the adults to emerge. Newly hatched larvae will die in large numbers if they are washed away by heavy rain, and long-term accumulation of water in the field is also not conducive to the survival of the pupae. The temperature and humidity conditions in Guangxi are most suitable for the growth and development of Spodoptera litura. If there is no continuous heavy rain in June, it will be conducive to a large insect population.

Spodoptera litura control methods

(1) Killing adults by luring them: Take advantage of their phototaxis and chemotaxis and use black light, poplar branches, or sugar or vinegar to kill them.

(2) Manual killing: Based on the characteristics of adult insects laying eggs on the back of leaves in the middle of the plant and young larvae feeding in clusters, egg masses should be removed and adults should be killed in time during the peak egg-laying period and before the larvae spread and cause damage.

(3) Chemical control: During the peak period of infestation of young larvae, use pesticides such as 10% Dichlorvos suspension (1500 times diluted), 5% Fipronil suspension (2500 times diluted), 5.7% Bisude EC (4000 times diluted), 4.5% highly effective cis-cypermethrin EC (3000 times diluted), 52.25% Nongdile EC (1500 times diluted), 90% Trichlorfon (800 times diluted), 80% DDT (1000 times diluted), 35% Saidan EC (1000 times diluted), and 2.5% Dimethoate (3000-4000 times diluted) for spraying.

4. Citrus Gray Elephant (Sympiczomias citri Chao)

Introduction to Citrus Gray Elephant

The citrus gray elephant belongs to the order Coleoptera and the family Curculionidae. It harms jasmine flowers from March to May every year, with the adult insects feeding on tender buds, new shoots and young leaves, as well as old leaves. The tender and old leaves are eaten into notches, and in severe cases all are eaten, greatly affecting the first batch of flowers in late April and early May. According to preliminary investigations, the number of insects per acre in the sandy loam jasmine fields along the river in Hengxian County is as high as over 20,000. The citrus gray weevil is known to harm: citrus, tea, jasmine, peach, longan, lychee, etc.

Life habits of citrus gray elephant: the insect has one generation per year, and a few complete a generation in two years. Overwinters in the soil as adults and larvae. Overwintering adults emerge from the ground from mid-March to early April every year. Spawning begins in mid-April. The larvae hatch from late April to mid-July, pupate from late September to late October, emerge from the shells at the end of October, and overwinter as adults in the pupae room. The larvae hatched after late July overwinter as 3rd to 4th instar larvae that year, continue to be active in the spring of the following year, overwinter as adults after pupation and emergence in the same year, and emerge and move around in the third year. After emerging from the soil, the adults climb up the tree trunks to the treetops, eating tender buds and leaves. If there are no tender buds and leaves, they will feed on old leaves. The adults move slowly and have a strong tendency to feign death. They like to hide in hidden places such as rolled leaves and interlaced branches. It has a strong ability to withstand hunger, lasting up to 6 to 27 days. The eggs are laid between two overlapping leaves. Adults have a long lifespan, with the active period averaging 183 days for males and 130 days for females. After the eggs hatch, the larvae fall to the ground and bury themselves in the soil at a depth of 10 to 50 centimeters. They feed on young roots and humus of plants. When the larvae mature, they pupate in soil chambers.

Citrus gray weevils control methods

Artificial killing: The insect has no hind wings, cannot fly, moves slowly, and has a strong tendency to feign death. It can be killed by artificial capture.

Chemical control: It is advisable to spray during the peak period of adult insects. The following agents can be used: 1000 times of 30% pest net, 1000-2000 times of 4.5% high-efficiency cypermethrin, or 1000-2000 times of 2.5% Gongfu, and some DDT spray can be added appropriately. Highly toxic pesticides such as methyl parathion and 1605 should not be used due to their high toxicity and long residual period.

5. Aleurotuberculatus takahashii David et Subramaniam

Introduction to Gottfried's whitefly

In the past, it was reported that the whitefly mainly harmed citrus. This insect is now causing serious damage to jasmine flowers in Guangxi; it has become widespread on jasmine flowers in Hengxian County, with high insect population densities in some local plots and obvious symptoms of damage. In a severely damaged flower field in Cao Village, Fucheng Town, Hengxian County, 14 leaves with more insects were selected for inspection. It was found that there were an average of 65.3 live nymphs and 58.6 empty pupae on each leaf, that is, an average of 123.9 live nymphs and pupae on each leaf. The leaf with the largest number of insects had 152 living nymphs and 137 pupae, totaling 289. Such a high amount of insect feeding causes the leaves to turn visibly green and yellow, seriously affecting the growth of the plants. Since the Gobelins' whitefly feeds with piercing-sucking mouthparts and does not cause morphological defects in the leaves, and its body is tiny and it clusters on the underside of leaves when doing damage, the importance of this insect has not yet attracted widespread attention from flower growers. The Gouldian whitefly belongs to the Aleyrodidae family of the Homoptera order. It was first discovered in India in 1971 and is known to be distributed in Jiangxi, Fujian and Guangxi in China. Fujian Province reported that the insect mainly harms citrus and jasmine. Other known host plants include osmanthus, carambola, and cassia bark. The Goll's whitefly infests jasmine flowers by sucking sap from the back of the leaves in clusters as nymphs and adults, causing the leaves to turn green and yellow, the plants to grow poorly, and in severe cases, the branches to wither. At the same time, honeydew is secreted, which can easily induce sooty disease.

Adult insects like to gather on the back of the tender leaves on the upper part of the plant to feed and lay eggs, and often fly short distances when frightened. The adults have a certain tendency to phototaxis, like humidity, and are active under high temperature conditions. Reproduction is either sexual or parthenogenetic. The eggs are scattered on the back of the leaves. The newly hatched nymphs can crawl around on the back of the leaves, but after the second instar they become fixed. There are often dozens or even hundreds of nymphs gathered on a leaf to cause damage. The peak period of occurrence of this insect is from April to June and from September to October.

Methods for controlling Gossypium whitefly

Based on the characteristics of this insect and the results of our concurrent control of whiteflies while controlling other pests, we put forward two control suggestions for your reference.

Protect natural enemies: The predatory natural enemies of this insect include grasshoppers, ladybugs, predatory mites, spiders, etc.; the parasitic natural enemies mainly include aphid wasps. Various natural enemies have a certain control effect on pests. Therefore, when spraying pesticides to control pests in jasmine fields, you should try to avoid using highly toxic chemical pesticides.

Chemical control: During the peak period of low-age nymphs, use imidacloprid, cypermethrin and other highly effective pesticides for spraying against Homoptera pests. The insect mite light and flower maggot cleaner used by flower growers to control the double-striped horn borer have a good killing effect on the adult of Gouldian whitefly and are relatively safe against natural enemies.

6. Flower Thrips (Frankliniella intonsa)

Introduction to Flower Thrips

Flower thrips belongs to the order Thysanoptera, family Thripidae. The insect harms the corolla and stamens inside the flower, especially around the ovary, damaging the reproductive organs. When the corolla is damaged, horizontal stripes or dots will appear. In the most serious cases, the corolla may become deformed, wilted, and even dried up, which has a great impact on its ornamental value. When the leaves are damaged, silver-gray stripes often appear on the young stems and new leaves, or the base of the leaves turns silver-gray, causing leaves to fall and affecting growth.

Living habits: There are 11 to 14 generations a year, with overlapping generations. Overwinter as adults. Adults have a strong tendency to phototaxis. There may be dozens to hundreds of adults and nymphs in the slightly fragrant, larger corolla stamens. The eggs are mostly laid in the petals, filaments and young leaves. The egg-laying area is slightly swollen or raised and can be examined under light. Each female insect lays 77 to 248 eggs, and the egg-laying period lasts 20 to 50 days.

Flower thrips control methods

Use chemical control. Spray 500-800 times diluted 2.5% dernethymid emulsifiable concentrate, 800-1000 times diluted 3% pyrethroid emulsifiable concentrate, 1000 times diluted 50% cypermethrin emulsifiable concentrate, 1000-2000 times diluted 20% cypermethrin emulsifiable concentrate, 1000-1500 times diluted 25% quinalphos emulsifiable concentrate, or 3000-5000 times diluted 10% aphid-killer superfine wettable powder.

7. Cotton spider [Tetxanychus cinnabarinus (Boisduvavl)]

Introduction to Cotton Red Spider

Cotton red spider is also called two-spotted spider mite and cotton spider mite. It belongs to the order Acarina, family Tetranychidae, and is an important pest mite. Cotton red spider has a varied diet, strong reproductive ability, and spreads quickly. It can harm dozens of plants, including corn, melons, beans, vegetables, trees, and weeds. Jasmine is one of the most common plants it harms. This insect sucks the host's sap from the back of jasmine leaves or buds in the form of adult mites, young mites and nymphs, causing the affected leaves to lose their green color, turn noticeably white, turn yellow in severe cases, and even develop rust-like spots. When the flower buds are damaged, they become smaller and wrinkled, or close, greatly affecting the yield and quality of the flowers.

Cotton red spiders can be transferred with water flow, spread by wind, or spread by crawling short distances. Generally speaking, dry climate and high temperature are conducive to its reproduction. The optimum temperature for its occurrence is 29-31°C and the relative humidity is 35%-55%. If the air humidity exceeds 70%, its reproduction will be inhibited. Cotton red spiders have many natural enemies, such as lacewings, carnivorous mites, carnivorous thrips, ladybugs, etc., all of which play a good control role on cotton red spiders.

Cotton red spider control method

1. Agricultural control (1) Clearing weeds in the fields and edges, combined with pruning, removing diseased leaves, clearing fallen leaves, and burning or treating them can eliminate overwintering insect sources and reduce the risk of damage. (2) Strengthen water and fertilizer management to enhance the plant's resistance to insects. Maintaining humidity will worsen the living environment of cotton spiders.

2. For chemical control, you can choose 24.5% multi-worm acarid or 1.8% cypermethrin 2000 times diluted solution, or 50% tricyclotin wettable powder 1500 times diluted solution, or 75% cypermethrin emulsifiable concentrate 1000 times diluted solution, or 35% cypermethrin emulsifiable concentrate 3000 times diluted solution, or 50% Apollo 4000 times diluted solution for spraying, and spray again after 7 days.

8. Snail

Snail Introduction

Snails are mollusks, not insects. It is classified as Gastropoda, Stylophora, and Helicidae. Commonly known as water buffalo, sky snail, and hard-shelled insect. Common snails in farmland include Bradybaena similaris (Ferussac) and Bradybaena ravida (Benson), with Bradybaena similaris being the main species. Snails have a very diverse diet. In addition to jasmine, they will also harm vegetables, beans, hemp, tobacco, tea, cotton, green manure, bananas, fruit trees, weeds, etc. On jasmine flowers, from the newly sprouted bud tips to the growing branches, young leaves, old leaves, and even the stalks are all affected. They often gather in groups to feed, eating up all the young shoots or biting off the bark of the branches causing the entire branch to wither, or biting the leaves into notches, holes, and tatters, seriously affecting the yield.

Occurrence pattern: The same type of snail has one generation per year, with adults and juveniles hibernating in the loose soil at the roots of crops, under dead branches and leaves on the ground, or under piles of rocks and clods of earth. During the winter, they often secrete a layer of white film to seal the shell opening. In March of the following year, when the temperature turns warmer, the overwintering adult and juvenile clams begin to move, climbing to the stalks of crops and gathering to eat new shoots. Snails have two peak mating and egg-laying periods every year, the first in April and the second in September. Female adult shellfish begin laying eggs a few days after mating. They lay the eggs 1 to 2 centimeters deep in the topsoil next to the plant or under dead leaves on the ground. The eggs stick together into piles, with each pile containing dozens of eggs. Each female can lay up to 200 eggs. The eggs need shade to survive; if they are exposed to the sun and dry out, they will burst. The young clams eat very little within 4 months after hatching, but their appetite increases greatly after 6 months. They mature and become adult clams after about 8 months. Snails like humid environments. They mostly hide in shaded places under sunny conditions and come out in the morning, evening and on cloudy days. There are two peaks of damage in a year. From April to May, the overwintering young clams gradually mature and the number of adult clams in the fields increases. At this time, there is a lot of rain and high humidity, which is very suitable for their growth and the damage is serious. From June to August, the temperature rises, and there is drought and little rain, which is not conducive to their activities. Most of them lurk at the roots of crops or under soil, not eating or moving, and secrete a white film to seal their shells to survive the hot summer. The temperature drops from September to October, and when the autumn rain comes, they resume feeding activities, mate and lay eggs. After November, they gradually move to their wintering places and begin hibernation.

Snail control methods: agricultural and manual control

(1) Clean the fields regularly and sweep and burn the dead branches and leaves on the ground under the crops, especially the branches and leaves pruned before winter, which provide a place for snails to overwinter. They should not be left in the garden to overwinter.

(2) April to May and September to October are the snail-laying seasons. Combined with tillage and weeding, the topsoil at the roots of crops should be plowed and exposed to the sun to kill the eggs.

(3) During the peak activity period of snails, in the morning, evening or on cloudy days, take advantage of the large number of snails exposed to food and capture them manually.

Pesticide control: You can choose 30% snail control, use 100-500 grams per mu, use 2-3 kg of bait (corn flour, bran, peanut cake, etc.), add water and stir into small particles for application. It can be applied in strips or holes, and the control effect is very good. You can also use 300-500 grams of Snail Killer per mu, 350 grams of 6% Metha per mu, and 10% Snail Enemy per mu 1000 grams, mix with dry fine soil or fine sand, and spread evenly on the crops and the ground where snails are active in the evening, or dissolve it in warm water and then spray it or shoot it with a water barrel. Spray with 1000 times diluted 70% Bailuosha wettable powder. If it rains after applying the pesticide, apply it again. Or spread lime powder, 3 to 5 kg per mu.

There are really many common diseases and pests of jasmine, so I will just introduce them here for now! Finally, I have to sigh that it is really not easy to keep jasmine alive, and it is not easy for flower lovers who care for jasmine! Let us fight against pests to the end and protect the fragrant jasmine!