Pest and Disease Control Techniques for Common Garden Flowers
Many people in daily life enjoy growing plants and flowers to cultivate their spirits, and many also cultivate flowers on a large scale to meet market demand. Although flowers are beautiful when in bloom, many problems can be encountered during the growing process, which requires careful maintenance from us flower growers. The greatest threat to flower growth is pests and diseases! So how should flower pests and diseases be controlled? Cherry Gal teaches you a few tricks on common garden flower pests and diseases and their control techniques!
I: Common Diseases of Garden Flowers and Their Control Techniques
1. Damping-off
After flowers in the growing period are infected with damping-off, root rot will directly occur. In the early stage of infection, these flowers show brown patches on the roots, and the epidermis will also appear withered. In the late stage of infection, the most prominent manifestation is the death of the entire flower plant, and some flowers infected with damping-off even show lignification of plant tissues. The water-retention function in the tissues is gradually lost, causing the flowers to be unable to obtain nutrients or water through normal channels, directly resulting in upright wilting.
Control methods:When plant care personnel handle the planting of flowers, the first thing to do is to soak the seeds of flowers susceptible to infection in a medicinal solution. According to the weight of the seeds, mix in Ceresan at a ratio of 1:500 before sowing. At this time, staff should note that after this treatment step is completed, water must be supplied to the plants that have been sown, to prevent death from lack of water due to untimely water supply.
2. Powdery mildew
Flower species easily infected with powdery mildew mainly include cineraria (Senecio cruentus) and fuchsia (Fuchsia hybrida). In the early stage of powdery mildew infection, these flower varieties mainly show a light gray color on the leaf surface. Usually, a layer of white flocculent material appears on the infected parts. When this white flocculent material spreads across the entire leaf surface, the newly growing branches and leaves of the flowers will stop growing. This ultimately causes the entire flower plant to wilt. The conditions allowing powdery mildew to spread widely are a stuffy, hot, and poorly ventilated environment.
Control methods:In response to the causes of powdery mildew, staff need to create a dry and ventilated environment for flower growth during the planting process to meet the growth needs of the flowers. Some chemical control methods can be used. The use of phosphorus and potassium fertilizers can improve the disease resistance of flowers and enhance their immunity. If the flowers have already been infected with powdery mildew at this time, care personnel need to remove the infected stems and leaves to prevent the spread of pathogens. Treating the pathogen-infected parts at the source can prevent the disease from threatening the life and health of the entire flower plant.
3. Black mold
When flowers are infected with black mold, brown mold spots generally form on the leaves. As the infection deepens, black mold layers gradually form, which greatly affects leaf photosynthesis, also has a tremendous impact on the ornamental value of the flowers, and can even cause flower death.
Control methods: The control of flower black mold is generally carried out during indoor flower cultivation. For example, the light transmittance and ventilation of the indoor environment can be improved, and indoor temperature and humidity can be well controlled. In addition, Bordeaux mixture can be sprayed on already infected plants.
II: Common Insect Pests of Garden Flowers and Their Control Techniques
1. Aphids
Aphids, also called plant lice, are a very common type of pest in flower cultivation. Generally speaking, aphid species include chrysanthemum aphids, rose long-tube aphids, and green peach aphids. Aphids have strong reproductive capacity and often gather on the undersides of flower leaves, inside tender buds, and in flower buds. Aphid damage causes flower leaves to dry up, and in severe cases causes flower death.
Control methods: Insecticides such as derris extract or pyrethrum can be selected for spray control. A 1:1000 laundry detergent aqueous solution can also be used for spraying. In particular, the enzyme components in enzyme-added laundry detergent can cause significant damage to the epidermal tissues of aphids, thereby achieving a good killing effect. Generally speaking, the spraying cycle is 1 week.
2. Red spider mites
Red spider mites are also one of the common insect pests of flowers. Compared with aphids, red spider mites can harm many flowers, such as Chinese roses, jasmine, salvia, and azaleas. Generally speaking, summer is the period with the highest damage rate from red spider mites. These pests often spin webs on the undersides of leaves and then use their piercing-sucking mouthparts to suck plant sap and nutrients. Flowers damaged by red spider mites grow abnormally slowly, and in severe cases may wither and die.
Control methods:Select a 1500-fold dilution of dimethoate or an 800-fold dilution of 25% chlordimeform for mist spraying, with a spraying cycle of generally half a month. Note that indoor ventilation must be ensured for a period after spraying.
In summary, for the control of common garden flower pests and diseases, first, select targeted control methods and carry out control work according to the type of pesticide and the type of pest or disease infection; second, accurately grasp the occurrence patterns of different pest and disease problems and choose the best control period, deeply analyzing the occurrence time and patterns of various common pest and disease problems, so as to find the best entry point for control; third, properly master the dosage of pesticides and accurately understand the sensitivity of flowers to drugs, implementing differentiated spraying for different flower types; finally, use chemical pesticides scientifically and regularly rotate pesticide types to prevent resistance.
What are the common pests and diseases of garden flowers? Introduction to common garden flower pests and diseases and their integrated control methods
Beautiful flowers are certainly dazzling, but charming garden flowers also suffer interference from various diseases. Today, the editor of Huinong Network brings you an introduction to common garden flower pests and diseases and their integrated control methods. If you love garden flowers, you definitely should not miss it!
1 Common Diseases of Garden Flowers and Their Control Techniques
1.1 Damping-off
After flowers in the growing period are infected with damping-off, root rot will directly occur. In the early stage of infection, these flowers show brown patches on the roots, and at the same time, the epidermis will also appear withered. In the late stage of infection, the most prominent manifestation is the death of the entire flower plant, and some flowers infected with damping-off even show lignification of plant tissues. The water-retention function in the tissues is gradually lost, causing the flowers to be unable to obtain nutrients or water through normal channels, directly resulting in upright wilting.
Control methods: When plant care personnel handle the planting of flowers, the first thing to do is to soak the seeds of flowers susceptible to infection in a medicinal solution. According to the weight of the seeds, mix in Ceresan at a ratio of 1:500 before sowing. At this time, staff should note that after this treatment step is completed, water must be supplied to the plants that have been sown, to prevent death from lack of water due to untimely water supply.
1.2 Powdery mildew
Flower species easily infected with powdery mildew mainly include cineraria (Senecio cruentus) and fuchsia (Fuchsia hybrida). In the early stage of powdery mildew infection, these flower varieties mainly show a light gray color on the leaf surface. Usually, a layer of white flocculent material appears on the infected parts. When this white flocculent material spreads across the entire leaf surface, the newly growing branches and leaves of the flowers will stop growing. This ultimately causes the entire flower plant to wilt. The conditions allowing powdery mildew to spread widely are a stuffy, hot, and poorly ventilated environment.
Control methods: In response to the causes of powdery mildew, staff need to create a dry and ventilated environment for flower growth during the planting process to meet the growth needs of the flowers. Some chemical control methods can be used. The use of phosphorus and potassium fertilizers can improve the disease resistance of flowers and enhance their immunity. If the flowers have already been infected with powdery mildew at this time, care personnel need to remove the infected stems and leaves to prevent the spread of pathogens. Treating the pathogen-infected parts at the source can prevent the disease from threatening the life and health of the entire flower plant.
1.3 Black mold
When flowers are infected with black mold, brown mold spots generally form on the leaves. As the infection deepens, black mold layers gradually form, which greatly affects leaf photosynthesis. At the same time, it also has a tremendous impact on the ornamental value of the flowers, and can even cause flower death.
Control methods: The control of flower black mold is generally carried out during indoor flower cultivation. For example, the light transmittance and ventilation of the indoor environment can be improved, and indoor temperature and humidity can be well controlled. In addition, Bordeaux mixture can be sprayed on already infected plants.
2 Common Insect Pests of Garden Flowers and Their Control Techniques
2.1 Aphids
Aphids, also called plant lice, are a very common type of pest in flower cultivation. Generally speaking, aphid species include chrysanthemum aphids, rose long-tube aphids, and green peach aphids. Aphids have strong reproductive capacity and often gather on the undersides of flower leaves, inside tender buds, and in flower buds. Aphid damage causes flower leaves to dry up, and in severe cases causes flower death.
Control methods: Insecticides such as derris extract or pyrethrum can be selected for spray control. A 1:1000 laundry detergent aqueous solution can also be used for spraying. In particular, with enzyme-added laundry detergent, the enzyme components can cause significant damage to the epidermal tissues of aphids, thereby achieving a good killing effect. Generally speaking, the spraying cycle is 1 week.
2.2 Red spider mites
Red spider mites are also one of the common insect pests of flowers. Compared with aphids, red spider mites can harm many flowers, such as Chinese roses, jasmine, salvia, and azaleas. Generally speaking, summer is the period with the highest damage rate from red spider mites. These pests often spin webs on the undersides of leaves and then use their piercing-sucking mouthparts to suck plant sap and nutrients. Flowers damaged by red spider mites grow abnormally slowly, and in severe cases may wither and die.
Control methods: Select a 1500-fold dilution of dimethoate or an 800-fold dilution of 25% chlordimeform for mist spraying, with a spraying cycle of generally half a month. Note that indoor ventilation must be ensured for a period after spraying.
Did everyone understand all of the above? In summary, for the control of common garden flower pests and diseases, first, select targeted control methods and carry out control work according to the type of pesticide and the type of pest or disease infection; second, accurately grasp the occurrence patterns of different pest and disease problems and choose the best control period, deeply analyzing the occurrence time and patterns of various common pest and disease problems, so as to find the best entry point for control; third, properly master the dosage of pesticides and accurately understand the sensitivity of flowers to drugs, implementing differentiated spraying for different flower types; finally, use chemical pesticides scientifically and regularly rotate pesticide types to prevent resistance. For more content related to garden flower knowledge, stay tuned to Huinong Network!
Integrated Pest and Disease Control Techniques for Flowers in Protected Cultivation
Aiming at the special ecological and environmental conditions of flower protected cultivation, and on the basis of sufficient investigation, this paper expounds the damage degree, occurrence conditions, affected varieties, and control techniques of major flower pests and diseases in protected cultivation. It also proposes that pest and disease control for flowers in protected cultivation should adhere to the principle of “prevention is more important than cure,” actively adopt agricultural control methods, take enhancing plant resistance as the foundation, strengthen ecological regulation, purposefully adopt biological and physical control, and combine regular chemical regulation with timely use of high-efficiency, low-toxicity pesticides, so as to achieve the goal of pest and disease control and achieve high-efficiency flower production.
Keywords: protected cultivation flowers; pests and diseases; integrated control techniques
The large-scale development of protected cultivation has provided convenient conditions for year-round production of ornamental flowers. However, its special environmental conditions of high temperature and high humidity also provide a place for the massive breeding and spread of pests and diseases. The occurrence and development of flower pests and diseases in protected cultivation have their own characteristics, different from open-field cultivation. As an ornamental product, once flowers are infected with pests or diseases, their ornamental value is partially or entirely lost, which will cause relatively large economic losses. Adopting a single control method makes it difficult to achieve satisfactory results. Therefore, pest and disease control for flowers in protected cultivation must adhere to the principle of “prevention is more important than cure,” give play to the effectiveness of integrated control, and keep pests and diseases below the level allowed by the ornamental value of the flowers. On the basis of sufficient investigation, combined with several years of production experience, this paper discusses the occurrence patterns and integrated control countermeasures of major infectious pests and diseases of flowers in protected cultivation, hoping to provide a scientific basis for integrated pest and disease control in protected cultivation.
1 Main Pests and Diseases of Flowers in Protected Cultivation and Their Occurrence Conditions
1.1 Main Diseases and Their Occurrence Conditions
(1) Gray mold is the most common and most harmful fungal disease on flowers in protected cultivation. It is extremely likely to occur under humid and low-temperature conditions. The symptoms are complex and include blight, canker, rot of organs such as corms, bulbs, and seeds, and damping-off of seedlings. It often occurs at leaf tips and leaf margins. In the early stage of disease, the affected parts are mostly water-soaked spots, and in the later stage they are often covered with gray mold layers. The host range is very wide, and it mainly damages cyclamen and begonias.
(2) Powdery mildew: It mostly damages leaves, branches, floral organs, and tender shoots. In the early stage of disease, a layer of white powdery mold grows on the affected parts, and later turns gray. In the vigorous growth season, high temperature and rain, excessive nitrogen fertilizer, high planting density, insufficient light, or poor ventilation are conducive to the occurrence of the disease. It mainly damages Chinese roses, cineraria, etc.
(3) Anthracnose: It mainly damages leaves and stems. When leaves are first affected, the diseased parts are mostly round or oval reddish-brown small spots, which later expand into dark brown lesions. In the center of the lesions, small streaked black spots are produced, and the edges are dark green. When stems are affected, round or nearly round light brown lesions are often produced. It is mainly caused by potted flowers being placed too densely, cross-infection of leaves, and high temperature, stuffiness, and poor ventilation. It mainly damages orchids, jasmine, lucky bamboo, and other foliage plants.
(4) Leaf spot disease includes black spot, brown spot, ring spot, etc. It is caused by local infection, causing local necrosis of leaves and producing lesions of various colors and shapes or perforations. Various granular bodies or mold layers grow on the lesions. It mostly occurs under conditions such as low temperature and fog, poor ventilation and light transmission, and extensive management. It mainly damages Chinese roses, clivia, camellias, and foliage plants.
(5) Mosaic virus disease is a worldwide disease and mainly damages leaves and floral organs. In the early stage of disease, leaves begin to lose green and gradually turn brown; diseased leaves become yellowed and distorted. It is mainly caused by virus carried in bulbs and seedlings. It mainly damages gladiolus, cyclamen, carnations, etc.
(6) Bacterial soft rot mostly occurs on succulent tissues, namely bulbs, corms, and tuberous roots. The diseased parts show tissue disintegration and exude foul-smelling liquid. An environment with high temperature, high humidity, and excessive nitrogen fertilizer is conducive to occurrence and epidemic spread. It mainly damages cyclamen, irises, clivia, etc.
1.2 Main Insect Pests and Their Occurrence Conditions
Aphids, whiteflies, red spider mites, and scale insects are the four major insect pests in protected cultivation[1]. (1) Aphids: Adults and nymphs gather on branch tips and the undersides of tender leaves to pierce and suck sap. Affected leaves often curl, flower buds are difficult to open, and the honeydew they secrete can also easily lead to sooty mold and virus diseases. It is likely to occur when the climate is dry and the temperature is suitable. It mainly damages lilies, cineraria, tulips, etc.
(2) Whiteflies, also called small white moths, are one of the important pests harming flowers. Adults or nymphs gather on the undersides of young host leaves to pierce and suck sap. Affected leaves fade, turn yellow, wilt, and even wither and die. In addition, the honeydew secreted by adults and larvae can easily induce sooty mold and virus diseases. They reproduce and cause damage year-round in greenhouses. They mainly damage azaleas, Chinese roses, jasmine, etc.
(3) Red spider mites mostly feed on the undersides of leaves, destroying leaf tissues and often causing leaves to lose green, appear spotted or blotchy, or curl and shrink. In severe cases, the entire leaf withers and scorches, as if roasted by fire. It is likely to occur under high temperature and dry conditions. It mainly damages Chinese roses, azaleas, etc.
(4) Scale insects are numerous in species. Nymphs and female adults suck sap at branch tips and the midrib on the undersides of leaves, easily causing leaves and branches to dry up. In addition to piercing and sucking sap and weakening growth vigor, they also induce sooty mold and cause damage year-round in greenhouses. They mainly damage Michelia figo, Pittosporum tobira, banyan trees, camellias, etc.
2 Integrated Control Techniques
2.1 Cultivating Strong Seedlings Free of Pests and Diseases
Before sowing, strictly quarantine seeds, seedlings, and bulbs, and promptly combine chemical disinfection treatment with warm water soaking to prevent pathogen carriage in the seed source; do a good job in environmental sanitation in protected cultivation areas, thoroughly remove residual plants, fallen leaves, and weeds to reduce pest and disease habitats; strengthen seedling management. When planting or placing flowers and trees, density should not be too high, and ventilation and hardening of seedlings should be carried out in a timely manner to control excessive seedling growth and improve stress resistance. Diseased plants should be pulled out at any time. Through the above measures, the number of harmful organisms can be reduced by about 50%[2].
2.2 Cultivation Control
(1) The cultivation nutrient soil should be sun-dried before planting, or the soil should be treated with chemicals such as quintozene to prevent carrying pathogens and insect eggs. At the same time, applying decomposed organic fertilizer is beneficial not only for improving microbial antagonism around the rhizosphere, but also for reducing the occurrence of fusarium wilt and damping-off; (2) Crop rotation. Rotating different types of flowers can effectively reduce the occurrence of soil-borne diseases such as fusarium wilt, anthracnose, and sclerotinia rot; (3) High-ridge cultivation can use sprinkler irrigation for watering, and covering aisles with crop straw can reduce the relative humidity in the greenhouse and improve ventilation and light transmission, thereby reducing the probability of disease occurrence; (4) Reasonable water and fertilizer management. According to different flower varieties and habits, scientifically combine fertilization, regulate flower growth vigor, enhance pest and disease resistance, and promote robust flower growth. For watering time, try to make the water temperature close to the soil temperature. In spring and autumn, choose around 10 a.m. and after 3 p.m.; in summer, choose morning or evening; in winter, choose around noon. This can also alleviate the relative humidity in protected cultivation and reduce the frequency of pest and disease occurrence. (5) Choosing drip-free film or antifog polyvinyl chloride film for greenhouse covering can reduce indoor relative humidity, increase light transmittance by 15%-20% compared with ordinary film, and improve heat preservation performance by 2-3 degrees C, reducing the occurrence of pests and diseases[3].
2.3 Ecological Regulation Control
Strengthen environmental regulation, ventilate and exchange air in a timely manner, improve temperature and humidity conditions in protected cultivation, and make flower leaves free of condensation as much as possible. Generally, a temperature of 20-25 degrees C and relative air humidity of 60%-70% can ensure no water droplets. This can reduce the occurrence of diseases such as gray mold and downy mildew[4]. Protected cultivation should adopt variable temperature management. Because the temperature variation range in protected cultivation is relatively large, strengthening regulation can prevent pathogens from germinating and invading smoothly. High-temperature greenhouse sealing, with the temperature above 28 degrees C, is unfavorable for sporulation of downy mildew and gray mold, and further increase can kill pathogens. Appropriate high temperature can also activate defensive enzyme systems in the plant body, thereby improving plant resistance. On sunny days at noon, when the greenhouse temperature reaches 35-40 degrees C, sealing the greenhouse for 2 h has a certain inhibitory effect on downy mildew and gray mold.
2.4 Biological Control
Where conditions permit, biological control methods should be actively adopted. Encarsia formosa is an endoparasitic wasp of whiteflies. When the average number of whiteflies per plant in the greenhouse is 1-2, release Encarsia formosa at 2800 insects/667 sq m, once every 7-10 days, for 2 consecutive times. The control effect can reach 80%-90%. Penicillium can also be used to control greenhouse whiteflies. When natural enemies such as hoverflies, lacewings, and ladybugs are seen, protect them, which can effectively improve the effect of biological control.
2.5 Physical Control
Heat treatment and other methods can effectively control pests and diseases. For example, gladiolus corms can be soaked in hot water at 55 degrees C for 30 min to control fusarium dry rot and other diseases. Silver-gray reflective film can be used to repel aphids. The principle of silver-white tin foil reflection can also be used to repel migrating aphids, or the yellow tropism of aphids and whiteflies can be used by setting yellow boards on one side of the greenhouse wall or 10-20 cm above the plant tops, or hanging yellow sticky strips at ventilation openings for trapping and killing, with excellent effects.
2.6 Chemical Control
Chemical control of flower pests and diseases in protected cultivation should follow the principle of “prevention is more important than cure.” For target pests and diseases, regularly alternate spraying fungicides such as chlorothalonil, thiophanate-methyl, and Yifan Junke, and insecticides such as fenvalerate, dichlorvos, and manjieke, generally spraying 2-3 times per month; smoke agents can also be used in protected cultivation in the evening when the greenhouse is closed for fumigation, which saves labor and effort, disperses evenly, and overcomes shortcomings such as uneven spraying. In winter greenhouses, disease prevention should be the main focus. A 20% chlorothalonil smoke agent can be used regularly, evenly ignited at 250 g per 667 sq m, for fumigation sterilization, which can prevent large-scale occurrence of diseases. For sudden pests and diseases, the following measures should be taken:
2.6.1 Control of Main Diseases (1) Gray mold, anthracnose, and blight: In the early stage of disease, use 75% chlorothalonil soluble powder 600-fold solution or 70% thiophanate-methyl powder 1500-fold solution for control. (2) Powdery mildew: Use agricultural antibiotic 120 or 25% triadimefon 2000-fold solution and spray continuously 2-3 times; because powdery mildew fungi are particularly sensitive to “sulfur,” use 0.25 kg sulfur powder + 0.5 kg sawdust per 250-300 sq m, ignite and fumigate overnight, with good control effect. (3) Bacterial soft rot: Use agricultural streptomycin for continuous spraying or irrigation 3-4 times, which can effectively prevent the occurrence of this disease. (4) Mosaic virus disease: Do a good job in controlling aphids, scale insects, etc., and regularly spray virus inhibitor, which has a certain effect on controlling virus diseases. (5) Leaf spot disease: Use 25% carbendazim wettable powder 300-600-fold solution once every 10 days; or use 25% triadimefon wettable powder 2000-fold solution, spraying once a month, with good effect.
2.6.2 Control of Main Insect Pests (1) Aphids: Use 20% fenvalerate 3000-fold solution or 2.5% deltamethrin 5000-fold solution for control. A 22% dichlorvos smoke agent at 0.3 kg/667 sq m or 10% aphid-killing smoke agent can also be used for closed fumigation overnight. The method is simple and has a special effect on controlling aphids. (2) Whiteflies: Use 10% imidacloprid (Yashijing) 3000-fold solution for control. Use 25% buprofezin wettable powder 1500-fold solution or 2.5% bifenthrin emulsifiable concentrate 5000-fold solution in combination. Chlorpyrifos has a special effect on controlling whiteflies. Pesticides should be sprayed in the morning or evening, with continuous control 2-3 times, which can both alleviate resistance in whiteflies and improve control effect. (3) Red spider mites and scale insects: On the basis of manually removing insect-infested branches and leaves, use 90% trichlorfon emulsifiable concentrate or 40% omethoate emulsifiable concentrate 1000-fold solution. Or use 20% pyridaben emulsifiable concentrate 3000-4000-fold solution, and add a small amount of laundry detergent to facilitate even spraying, spraying once every 7-10 days, continuously 3-4 times. Dicofol 1000-fold solution can also be used, with a control effect of over 90%. In addition, using 10% chongmanjing smoke agent at 250 g/667 sq m in protected cultivation for fumigation for 4-5 hours has a certain control effect on whiteflies, red spider mites, and scale insects.
3 Summary
The occurrence of major pests and diseases of flowers in protected cultivation is closely related to the specific environmental conditions of high temperature and high humidity in protected cultivation. Pest and disease control work should follow the principle of “prevention is more important than cure,” take cultivation prevention as the foundation, strengthen ecological environment regulation, actively adopt measures such as biological control, physical control, and regular control with low-toxicity pesticides, and follow the principle of timely control according to different types of pests and diseases, so as to control the occurrence of pests and diseases, effectively improve the ornamental value of flowers, and thereby achieve high efficiency in flower production.
References
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