Symptoms and control methods of common diseases and insect pests in horticultural plants

In the process of cultivation, horticultural plants will encounter mildew, powdery mildew, virus disease, tomato spot miner, melon aphid and so on, which will not only affect the beauty of horticultural plants, but also affect the planting efficiency of horticultural plants. therefore, horticulturists should master the common symptoms and control methods of diseases and insect pests.

1. Common diseases and insect pests of horticultural plants

1.1 mildew frost disease

In general, melons, fruits and vegetables are easy to be infected with mildew and frost disease. Mildew disease comes rapidly and spreads very fast. Once vegetables are infected with other vegetables, it is also easy to spread. Mildew mainly infects the leaves of plants and spreads through them. In general, light yellow spots appear on the leaves of plants at the initial stage after infection. With the passage of time, the spots gradually spread and the shape becomes irregular. The color also changes gradually from the initial green to dark brown when the yellow is serious.

1.2 powdery mildew

Powdery mildew is a disease with long duration and uncertain onset time. In general, powdery mildew will appear in any link of melon, fruit and vegetable production, and it is the most serious in the middle and later stage of vegetable production. Powdery mildew also occurs on the leaves of fruits and vegetables, initially forming irregular spots on the front or back of the leaves, and forming white spots that cover the whole leaf in severe cases as it spreads gradually. In the early stage of the disease, the leaves of plants infected with the disease change from green to yellow, and in the later stage, they will produce many small brown spots, and the leaves will gradually die. Serious ones will lead to reduced production or even death of melons, fruits and vegetables.

1.3 virus disease

Virus disease is also a disease that occurs on vegetables, melons and fruits, but it is caused by a variety of viruses. Melons, fruits and vegetables infected with viral diseases grow slowly at first and seriously affect plant yield. Once the melon, fruit and vegetable are infected with the disease, the symptoms are mainly reflected in the flowers and leaves, and green spots with different colors will appear on the leaves. With the infection of the disease, the leaves will gradually become smaller, yellow or even wither, resulting in the plant withering and dying.

1.4 Liriomyza sinensis

Liriomyza huidobrensis is a kind of pest which has a very serious effect on plant growth. The serious damage of Liriomyza sinensis will lead to the death of a large area of leaves, which will lead to the reduction of plant production or even death. Liriomyza huidobrensis is a kind of small flies that sneak into the plant leaves in the process of plant growth, and lurk on the plant until the larvae grow and pierce the leaves, suck the sap of the leaves and lay eggs on the leaves to make secondary damage to the plants. Liriomyza huidobrensis has a very strong reproductive ability, so it can have an impact on plants all the year round, especially in Rain Water Festival.

1.5 melon aphid

Melon aphid, also known as cotton aphid, is a common and harmful pest in melons, fruits and vegetables. Melon aphids basically occur on the back of the leaves and on the stems and leaves in the form of clusters, using their needle-like mouths to pierce into the stems and leaves to absorb juice, resulting in leaf curling or even withering, and in serious cases leading to the death of plants. Melon aphid has a strong reproductive ability, so it can reproduce one generation at regular intervals and spread very rapidly. In the north, the melon aphid overwinters on plants in the form of eggs and the pest also begins to reproduce after the plants recover in spring. In the warm south, melon aphids multiply and damage plants all the year round.

2. Effective methods for prevention and control of horticultural plant diseases and insect pests.

2.1 breeding excellent varieties with strong resistance from a genetic point of view

At present, plants use sexual hybridization, artificial mutagenesis, bioengineering and other new techniques and means to change genes for genetic variation. Prevention should be carried out from the root causes so as to improve the disease resistance of the variety. For example, the leaves of some trees contain resin ingredients to control pests, even if the pests lurk eggs or larvae in the leaves of the plant, they will be blocked to death by the resin components secreted by the plant. In addition, neem tree trunk, leaves and fruits have azadirachtin, so pests do not like to eat, in some countries in India to make full use of this ingredient to make pesticides.

2.2 suitable for planting and reasonable planting

Some plants like a dry environment, so putting plants in a wet environment is not conducive to plant growth and is more likely to be infected with insect pests. On the contrary, plants that like to be wet are also susceptible to insect pests in a dry environment. Therefore, first, we should plant and arrange reasonably according to the growth habits of plants; second, we should carry out reasonable rotation: because plant diseases and insect pests are parasitic in the shallow soil, planting the same species in a piece of land for a long time also provides a habitat and overwintering environment for diseases and insect pests. In addition, planting the same plants on a piece of land for a long time will destroy the structure of the land and lead to the decline of soil fertility, which will also affect the growth of plants and promote the reproduction of diseases and insect pests. Reasonable rotation can change the soil structure of the land, improve fertility, enhance plant growth, so that diseases and insect pests can not find suitable hosts, thus reducing the occurrence of diseases and insect pests.

2.3 pay attention to the rational allocation of fertilizers

When planting trees scientifically, we should choose inorganic fertilizer and organic fertilizer reasonably. Generally speaking, livestock and poultry manure can be used as organic fertilizer to improve soil and ensure soil quality. Long-term use of inorganic fertilizer will lead to a decline in the quality of the soil. Therefore, it is necessary to use trace elements while making a reasonable combination of organic and inorganic fertilizers. Because the lack of trace elements in flowers and trees will lead to the deformation and discoloration of flowers and leaves, stems and vines will reduce the ornamental value of flowers and trees.

2.4 clear the garden in time

In the cultivation of green plants, it is necessary to timely remove the diseased and diseased branches, so as to reduce the root causes of diseases and insect pests. In addition, pests like to lurk in withered leaves and weeds in the park, so it is necessary to clean up litter in time to reduce the incidence of diseases and insect pests. Special attention should be paid to the work of clearing the garden in winter, and the withered branches and leaves of weeds should be thoroughly removed.

2.5 protect and introduce natural enemies, effectively control pests and maintain ecological balance

All kinds of pests have their own natural enemies, such as ladybugs and birds, which can be effectively controlled by the natural enemies of insect pests. In order to eliminate pests, we can not only protect the natural enemies of pests, but also introduce a large number of natural enemies of pests. In large nurseries, not only artificial reproduction can be carried out, but also the species can be introduced. In some places due to misuse of pesticides, although poisoning pests correspondingly harms other species. In contemporary society, people's awareness of protecting animals is weak, and some people like to hunt birds and dig out their nests. These practices have brought a fatal blow to the natural enemies of insect pests, so that the mass reproduction of insect pests has destroyed the ecological balance of nature.

To sum up, priority should be given to biological means in the prevention and control of horticultural plant diseases and insect pests. In order to avoid the reproduction of pests, the genetic variation of plants can be improved, or natural laws can be used to artificially cultivate the natural enemies of pests for pest management, which can not only save costs but also protect the environment.

Common diseases and insect pests of horticultural flowers and their control techniques

In life, many people like to raise flowers and plants to cultivate sentiment, and there are also many people who plant a large number of flowers to provide market demand. Although flowers are delicious when they are open, they will encounter a lot of problems in the process of planting. This requires the careful maintenance of our flower-growing friends, and the greatest harm to flower growth is diseases and insect pests! So how to prevent and control the diseases and insect pests of flowers? Cherry little sister to teach you a few horticultural flowers common diseases and insect pests and their control techniques!  

1. Common diseases of horticultural flowers and their control techniques   

1. Fusarium wilt   

After the growing flowers are infected with Rhizoctonia solani, root festering will occur directly. The expression of these flowers in the early stage of infection is brown spots on the roots and wilting of the epidermis. The most prominent manifestation in the later stage of infection is the phenomenon of death of the whole flower, and even the Lignification of plant tissue will occur after some flowers are infected with bacterial blight. The function of water locking in the tissue is gradually lost, resulting in flowers can not get nutrients or water through normal channels, and directly appear upright withering.   

Prevention and control measures: when planting flowers, the first thing the plant nurses should do is to soak the easily infected flower seeds and mix them with Sailisan in the proportion of 1 ∶ 500 according to the seed weight before sowing. At this time, the staff should pay attention to the fact that after the implementation of this treatment step, it is necessary to replenish water to the plants that have completed the sowing step, so as to prevent water shortage and death due to the lack of timely water supply.

two。 Powdery mildew   

The flower species which are easy to be infected with powdery mildew mainly include melon leaf lotus, inverted golden bell and so on. in the early stage of being infected with powdery mildew, the main situation is that the leaves of flowers are light gray. Usually there will be a layer of white floc in the infected area, and when these white flocs extend to the entire leaf surface, the growth of the new branches and leaves of flowers will be suspended. Finally, it leads to the phenomenon of wilting of flowers as a whole, and the condition under which powdery mildew can spread wantonly is a stuffy and airtight environment.   

Prevention and control measures: in view of the causes of powdery mildew, staff need to create a dry and ventilated environment for the growth of flowers to meet the growth needs of flowers in the process of flower planting. Some drug prevention and control methods can be used for treatment, and the use of phosphorus and potassium fertilizer can improve the disease resistance and enhance the immunity of flowers. If the flowers have been infected with powdery mildew at this time, nurses need to remove the infected stems and leaves to prevent the spread of germs. Dealing with the infected parts at the source can prevent the disease from threatening the life and health of the whole flower.   

3. Black mildew   

When flowers are infected with black mildew, brown mildew spots are generally formed on the flowers and leaves, and with the deepening of the degree of infection, black mildew layers are gradually formed, which will affect the photosynthesis of leaves to a great extent, and have a great impact on the beauty of flowers, and even cause the death of flowers.   

Prevention and control measures: the prevention and control of black mold of flowers is generally carried out in the process of indoor cultivation of flowers, such as improving the light transmittance and ventilation of the indoor environment and controlling the indoor temperature and humidity. In addition, Bordeaux solution can be sprayed on infected plants.

Second, common insect pests of horticultural flowers and their control techniques   

1. Aphid   

Aphids, also known as dense insects, are very common pests in the process of flower cultivation. Generally speaking, the species of aphids include chrysanthemum aphid, rose long tube aphid, peach powder aphid and so on. Aphids have strong fecundity and are often concentrated in the back of flower leaves, inside buds and medium buds. The harm of aphids will lead to the dryness of flower leaves and, in serious cases, the death of flowers.   

Control measures: you can choose rotenin or pyrethrum and other chemicals for spraying, or you can choose 1 ∶ 1000 washing powder aqueous solution to spray, especially the enzyme components in the enzyme detergent can cause great damage to the epidermis of aphids, thus playing a good killing effect, usually the spraying cycle is 1 week.   

two。 Red spider

Red spiders are also one of the common pests in flowers. Compared with aphids, red spiders do harm to many flowers, such as rose, jasmine, red flowers and azaleas. Generally speaking, summer is the stage with the highest damage rate of red spiders. These pests often web on the back of flowers and leaves, and then use their piercing mouthparts to absorb the sap and nutrients of the plant. Flowers harmed by red spiders grow unusually slowly and die in severe cases.   

Control methods: choose dimethoate 1500 times dilution or 25% chlordimeform 800 times dilution for fog spraying, the spraying period is generally half a month. It is important to pay attention to ensuring indoor ventilation for a period of time after spraying.   

To sum up, for the prevention and control of common diseases and insect pests in horticultural flowers, first of all, targeted control methods should be selected, and the prevention and control work should be carried out according to the types of pesticides and infection types of diseases and insect pests; secondly, we should accurately grasp the occurrence rules of different diseases and insect pests, select the best control period, and deeply analyze the occurrence time and rules of various common diseases and insect pests, so as to find the best cut-in point for prevention and control. Thirdly, we should grasp the amount of chemicals used, accurately understand the sensitivity of flowers to drugs, and spray differently for different kinds of flowers; finally, we should use chemicals scientifically and change the types of chemicals regularly to prevent drug resistance.

Common plant diseases and insect pests-blight control

Blight is a soil-borne disease in horticulture, with about 224 genera and 301 hosts.

Species, including citrus, passion fruit, Luoshenkui, guava fruit, eggplant, lily, Caryophyllaceae flowers, Araceae flowers and other foliage plants.

Symptoms: the disease can be divided into black because of its different location and different symptoms.

Rot, heart rot, stem rot, broken disease and so on. The most common symptom of black rot is the early stage of the disease site.

It is immersed in water, but the tissue in the later stage is black and rotten, dark brown or dark brown. The disease infects most of the leaves.

The middle and lateral end of the piece occurs, and some start from the leaf base or leaf end. The initial leaf color fades to green or

There are water stains, and then gradually expand to light brown or dark brown, until the plant dries up and dies. Also

In some cases, the roots, stems, leaves and flowers were completely damaged. In the early stage of the damage, the color of the leaves remained the same and the affected parts were affected.

Like scraped, wet it, dark green, turned black after drying, without direct damage

Some of the tissues withered and turned black due to the destruction of the conducting tissue.

Disease conditions: too high temperature, too much watering, poor ventilation, lack of sunlight, soil

Epidemic disease is easy to occur under the condition of poor air permeability. Application of unripe organic fertilizer with diseased residue

And partial application of nitrogen fertilizer, especially available nitrogen fertilizer. Snails, clams and other insects feed

Transmission can also cause a serious epidemic of the disease. Trimming with unsterilized knives and scissors, etc.

It is easy to cause cross infection. The peak period of epidemic disease is from June to August every year. Epidemic disease passed through

Wind, rain, watering and unsterilized tools spread, resulting in repeated infection. When it rains a lot,

The disease is serious in years with high humidity.

Prevention and control methods: in order to prevent and cure the epidemic disease, we should choose places with good ventilation and good lighting to maintain flowers.

To avoid partial application of nitrogen fertilizer, more organic matter with low nitrogen and high potassium should be applied to enhance plant disease resistance.

If you find an infected plant, remove the diseased tissue immediately and apply methyl topiramate or thiophanate methyl to the wound.

Disinfect and isolate diseased plants by carbendazim, and avoid spraying water from top to bottom when watering, so as not to spread the disease.

Exhibition, if the damage is serious, remove the whole plant; wash hands before daily operation, operating tools such as scissors, etc.

Appliances should be strictly disinfected; 25% metalaxyl wettable powder and 40% Fu can be used for chemical control.

Meishuang wettable powder 500-800 times, 70% Dexon 400 times, 70% Dyson

Manganese and zinc 600-800 times solution, 70% methyl topiramate 1 500.mur2000 times solution, etc.

It was sprayed every 7-10 days for 3-4 consecutive times.