How to control cotton pests How to control cotton seedling pests and diseases? What are the tips and

Cotton aphid. It is an important pest in the seedling stage of cotton, widely distributed throughout the country, and has become one of the main pests in cotton producing areas, and is also one of the main factors affecting cotton yield and quality.

First, the characteristics of harm:

Cotton aphids use a stinging mouthpiece to pierce the back of cotton leaves or tender heads to suck the juice. The seedling stage was damaged, the cotton leaves were curled, and the flowering and boll setting stage was delayed, resulting in late maturity and reduced yield. The upper leaves were shrunk, the middle leaves were shiny, and the lower leaves were yellow and fell off. The bud bell is damaged, easy to drop buds, and affects the development of cotton plants; Some cause defoliation and reduce yields.

Second, the occurrence characteristics:

10 to 20 generations occur annually, and in cotton fields can be divided into seedling aphids and aphids according to the season. Seedling aphids occur from the beginning of seedlings to the end of June, mid-May to mid-to-late June to budding, enter the peak period of pest, and adapt to low temperatures. Aphids occur in mid-to-late July and August, adapting to higher temperatures.

Heavy rain had an obvious inhibitory effect on A. gossypi, and rainy years or rainy seasons were not conducive to its occurrence. However, the weather of sunny and rainy, cloudy and drizzly is conducive to the rapid proliferation of aphids.

3. Prevention and control indicators:

The number of aphids per 100 seedlings was 250 or the number of leaf-curling plants was used as the control index, and the average number of aphids in the upper, middle and lower three leaves of the aphid per plant was 150 200 as the control index.

Fourth, chemical control:

20 30g of 10% imidacloprid per mu, or 10 15g of 30% imidacloprid, or 4 6g of 70% imidacloprid are sprayed evenly, the control effect is 90%, and the effective period is more than 15 days.

Cotton red spider. First, the characteristics of harm:

The cotton red spider, also known as the fire dragon and the fire spider, is rampant in drought years, mainly sucking the juice on the back of cotton leaves; It occurs from seedling stage to mature stage, and if the mites and adult mites gather on the back of the leaves to absorb the juice, the damaged cotton leaves begin to appear yellow-white spots, and the leaves appear red patches when the damage is aggravated, until the whole leaf becomes brown, dry and falls off.

Second, the occurrence characteristics:

It occurs in about 10 20 generations per year, mainly in litter, wild hosts and soil crevices, and occurs in patches at first, and then spreads to the whole field. The optimal temperature is 29 31, the optimal relative humidity is 35% 55%, the temperature is above 30 and the relative humidity is more than 70%, which is not conducive to its reproduction, and the rainstorm has an inhibiting effect on its occurrence. In the high temperature and dry season, the cotton red spider is rampant, the light cotton seedlings stop growing, the bud bells fall off, and the later stage is early; In the heavy, the leaves are red, dry and fall off, and the cotton turns into a bare stalk.

In recent years, with the widespread planting of insect-resistant cotton and the reduction of drug use, the population structure of pests in cotton fields has changed accordingly, and the cotton blind bug has risen to become the main pest, and the degree of damage has increased year by year. Adults and nymphs suck the sap of cotton plants, causing a large number of bud bells to fall off, break head leaves and branches and leaves. Killed at the cotyledonous stage, manifested as withered top; If the apical bud is punctured at the true leaf stage, the head will break the head; If the young leaves are killed, it will form leaf-breaking madness; The young buds turned from yellow to black when they were killed, and fell off after 2 to 3 days; The top heart or side heart is damaged, forming a broom cotton.

The damage to cotton is very long, from the seedling to the flocculation stage. Adult eggs are usually laid on cotton petioles, tender tissues, and even tender stalks. It likes to be warm and humid, with a temperature of 25 30 and a relative humidity of about 80%, which is most suitable for breeding.

Generally, the rainy year in June and August is conducive to the occurrence of cotton blind bugs; Cotton grows luxuriantly, and cotton fields with more buds occur heavier.

Cotton bollworm belongs to the order Lepidoptera, Noctuidae. It is the main pest of cotton bud stage. The larvae are the pests of cotton tender tips, flower buds, flowers and green bells, which can bite the top of short tender stems to form headless cotton.

After the young buds are killed, the bracts turn yellow and open, and fall off after two or three days. The larvae prefer to feed on pollen and stigma. After the green bell is damaged, it can form rotten boll or stiff spots, which seriously affects the yield and quality of cotton.

Cotton bollworm is a temperature-loving and moisture-loving pest, and the adult eggs are laid at a temperature of more than 23, and rarely eggs are laid below 20. Larval development is optimal at 25 28 and 75 90% relative humidity. When there are 5 larvae of more than 3 instars in 100 insect-resistant cotton fields, 100 eggs or 5 8 young larvae in non-insect-resistant cotton fields.

China is a big cotton producer, and everyone knows that we can't do without cotton, which is mainly used to make all kinds of clothes and many household items. However, in the process of cotton growth, many diseases will be encountered, so diseases will have an impact on the quality and yield of cotton.

1.Cotton wilt

Cotton wilt disease is a common and major disease of cotton, which has serious harm to cotton production and causes large losses. Cotton wilt disease mainly affects cotton seedlings, and the disease forms are various, some leaves appear yellow reticulated, and after the leaves wilt, some leaves turn yellow or purple, but the outcome is leaf wilting and plant death.

Prevention and control methods:Fusarium wilt can safely overwinter in soil and fertilizer, and as new plants continue to spread the following year, seeds, soil, fertilizer, etc. should be disinfected before planting. Reasonable dense planting, fertilization, polymyxin agents can be used to dilute root irrigation or spraying in the early stage of the disease.

2. Cotton verticillium wilt

There is only one word difference between cotton verticillium wilt and wilt, we can get from the name, cotton verticillium wilt occurs when the leaves lose water, the leaves are yellow and blocked, and with the spread of the disease, the disease gradually expands. After a long period of drought and heavy rainfall, the leaves suddenly withered and then fell off.

Prevention and control methods:Choose varieties with strong disease resistance, avoid continuous cropping, good cropping and other crop rotation, can reduce the occurrence of diseases, spray growth regulators such as shrinkage at the current budding stage, and regularly spray daidzein manganese-zinc or methyl mercaptan and other agents, which has a preventive effect.

3. Cotton aphid

Cotton aphid mainly harms cotton seedlings, aphids suck the sap of seedling leaves, causing seedling leaf curl, resulting in normal growth and development, affecting the flowering boll stage, resulting in late maturity and reduced yield of plants.

Prevention and control methods:Spray is used with pesticides that are less harmful to plants.

4. Cotton bollworm

Cotton bollworm mainly affects the budding stage of cotton. Cotton bollworm feeds on cotton buds, bolls and young stems, resulting in flowering failure, boll leaf shedding and boll rot, which ultimately affects the quality and yield of cotton.

Prevention and control methods:Spray the same insecticide that is less harmful to plants.

Diseases and insect pests at the seedling stage of cotton are important factors restricting the early emergence of strong seedlings in cotton fields. There are two main types of seedling diseases: root diseases and leaf diseases. Field management should be strengthened, and cotton should be cultivated in depth and diligently after emergence, so as to increase soil temperature, reduce soil moisture, and aerate the soil to facilitate root development.

For insect pests, only drugs can be used**, for example, the control of cotton aphid can be sprayed on cotton leaves and stems with imidacloprid or acetamiprid.

Improving soil fertility and soil fertility can effectively control the occurrence of seedling diseases by increasing agricultural measures such as increasing farm fertilizer, vigorously promoting straw returning to the field, and intensive cultivation, so as to fertilize the soil, improve the soil, and increase soil permeability. The selection of disease-resistant varieties and the selection of disease-resistant varieties with excellent seed coating agents is the fundamental measure to prevent diseases. Years of trials have shown that Syngenta's Ready-to-Eat seed coatings are effective in controlling cotton seedling diseases.

When planting cotton, spray some pesticides on the cotton, so that it can be prevented. Spray some pesticides, renovate the soil, clean the surrounding area, prune the branches, and put more fertilizer.

It is necessary to do a good job of prevention, to ensure soil fertility, to do a good job of watering and fertilization, but also to prune branches and leaves in a timely manner, use pesticides and fertilizers, and do a good job of ventilation and loosening the soil.

Cotton worm is a common pest and disease of crops, which will make crops grow poorly and reduce their yield, so it is necessary to strengthen ventilation management, and need to cut off the diseased branches and leaves, and then spray it every other week with diluted avermectin, thiobenone, pyridafen, spirodifen and other pests and diseases, and timely apply fertilizer to breed so that it can grow well.

1. Strengthen ventilation

As the name suggests, cotton insect is a kind of insect disease that harms crops, which will make crops grow poorly, and may wilt, yellow, etc., for how to kill cotton insects, first of all, we need to strengthen environmental ventilation, and use shade nets to shade crops and protect them from the sun, so that they can grow well in the soil.

2. Pruning

First of all, it is necessary to disinfect the sharp scissors with alcohol, carbendazim solution, etc., and then cut off the harmful branches and leaves in time.

3. Spray the agent

For how to kill cotton insects, in addition to strengthening ventilation and pruning, it is also necessary to spray diluted avermectin, thiamethone, pyridafenalin, spirodifen and other pests and diseases every other week, so that its crops can gradually recover their vitality and avoid a decline in yield.

4. Water and fertilizer management

Cotton worm is mainly caused by high temperature, so it needs to be watered in time, sprayed with water to reduce the temperature, and timely fertilizer to crops, which can increase the disease resistance of crops, promote their good growth, and recover their vitality faster, but it is not suitable to apply a large amount of fertilizer.