Introduction to the damage symptoms and control methods of cotton aphids

Cotton aphid is one of the main pests of cotton. Five kinds of aphids have been found, including cotton aphid, cotton long tube aphid, alfalfa aphid, jujube aphid and bean root aphid. Cotton aphid is one of the most important pests in cotton in China. The cotton area in the Yellow River valley and Liaohe River valley is the most harmful, followed by the Yangtze River valley cotton area. Let's take a look at the control methods of cotton aphids.

Symptoms of cotton aphids

Cotton aphids occur 20-30 generations a year in southern China and 10-20 generations a year in northern cotton areas. In most parts of the country, eggs overwinter on hibiscus, pomegranate, prickly ash and holly, insert the back or tender part of cotton leaves with piercing mouthparts, suck the juice, the damaged leaves curl to the back, and there is honeydew excreted by aphids on the leaf surface, which often breeds mold, and the plants become dwarf, leaves become smaller and the number of leaves decreases after damage. The appearance of bud is late, the number of buds and bolls is reduced, and so on.

Agricultural control of cotton aphids

1. Planting insect-resistant varieties is an effective measure to control cotton aphids, such as planting 372 and so on.

2. Intercropping can increase the species and number of natural enemies and control the damage of aphids, such as cotton-wheat intercropping, cotton intercropping with mung bean and green manure, flower arrangement and trapping crops such as corn, rape, sorghum and so on.

3. Flood-drought rotation can reduce the occurrence of cotton aphid, and cotton and rice rotation can be carried out where conditions permit.

4. Deal with the overwintering host, reduce the source of aphids in early spring, and generally remove weeds inside and outside the cotton field before the cotton seedlings are unearthed. It is possible to control the overwintering hosts of Zanthoxylum bungeanum, pomegranate, hibiscus and holly, which can reduce the number of aphids in cotton field.

Chemical Control of Cotton aphids

1. Seed dressing: before sowing, cotton seeds per mu and 3% furan granule 1.5-2kg, mix evenly, or mix seeds with Tiemike (also known as aldicarb), with 50 grams of active ingredients per mu, aphid damage can be controlled for 40 days. Seed dressing with 3911 (methamidophos) emulsion or granule or seed coating agent has a good effect.

2. Spray: dilute 1000-1500 times spray with 50% monocrotophos, 50% phoxim, 40% omethoate, 40% aphids, 35% aphids, 50% phosphoramines and so on.

3. Heart dripping: 80% 100 times diluted with 40% omethoate emulsion or 40% monocrotophos or 50% methamidophos emulsion, and the aphid damage can be controlled by dropping the solution on the top of cotton seedlings with a sprayer.

4. Stalk coating: the stem coating agent is prepared with 40% omethoate emulsion or 40% monocrotophos or 50% methamidophos emulsion, polyvinyl alcohol and water according to the proportion of 1-0. 1-1-5. With a device similar to a brush, the solution is applied to the purple-green part of the cotton stem, and the aphid prevention effect is more than 90%.

Agricultural Control methods of Cotton Verticillium Wilt

The agricultural control methods of cotton Verticillium wilt are mainly from a series of management measures after cotton seed selection, sowing, growth, harvest and harvest, which are introduced in detail below.

Agricultural prevention and control methods:

(1) before sowing and after harvest, remove weeds and crop disease and residue in the field and around, concentrate on burning or retting fertilizer; turn the ground deeply to kill stubble, promote the decomposition of disease and residue, and reduce pathogens and pathogens.

(2) and non-undergraduate crop rotation, flood-drought rotation is the best.

(3) selecting fields with convenient drainage and irrigation, opening good drainage ditches, lowering the groundwater level, so that there is no stagnant water in the rain; cleaning up the ditch system in time after heavy rain to prevent moisture retention and reduce field humidity is an important measure to prevent disease.

(4) the fields with many soil germs or serious underground pests should be sprinkled or ditched with sterilized and insecticidal soil before sowing or transplanting.

(5) selection of disease-resistant varieties, disease-free, coated seeds, if uncoated, seeds should be sterilized with seed dressing agent or seed soaking agent.

(6) Seedling and transplanting, covering seeds with medicinal soil after sowing, and spraying insecticide and fungicide before transplanting, which is the key to disease prevention.

(7) for direct seeding in the field, it is necessary to sow early at the right time, early seedling, early soil cultivation, early fertilization, timely ploughing and soil cultivation to cultivate strong seedlings, and the seedlings should be sprayed with a mixture of insecticides and sterilization before closing.

(8) compost retted by enzyme bacteria or rotten organic fertilizer shall not be used with bacteria, and the organic fertilizer shall not contain plant disease residues. The use of soil testing formula fertilization technology, appropriate application of phosphorus and potassium fertilizer, strengthening field management, cultivating strong seedlings, and timely topdressing after typhoon and heavy rain to enhance plant disease resistance is helpful to reduce the disease.

(9) timely control of insect pests, reduction of plant wounds, reduction of pathogen transmission; timely removal of diseased leaves and diseased plants, and burning out of the field, application of medicine or quicklime at disease points.

(10) reasonable close planting, timely pruning, timely removal of 2-3 leaves at the lowest part of the stem, timely cutting of empty branches, beating old leaves, pulling out diseased plants, concentrated burning, application of diseased points, and increase ventilation and transparency in the field.

(11) Scientific irrigation should be applied during high temperature and drought in order to increase field humidity and reduce the harm and transmission of aphids and gray planthoppers. Continuous irrigation and flood irrigation are strictly prohibited.

(12) protect disease-free areas. Do a good job in quarantine and strictly prevent the expansion of the disease area.

(13) selecting and breeding disease-resistant varieties.

Agricultural control methods of cotton mosaic virus disease

In the agricultural control of cotton mosaic virus disease, disease-resistant varieties should be selected at the beginning, the main force should be planted in close planting reasonably, the spacing should be increased appropriately, and attention should be paid to the amount of fertilizer applied.

Agricultural control of cotton mosaic virus disease:

(1) before sowing or after harvest, remove weeds, dodder and crop residues in and around the field, concentrate on burning or retting fertilizer; turn the ground deeply to kill stubble, promote the decomposition of disease residues and reduce pathogens and pathogens.

(2) and non-undergraduate crop rotation, flood-drought rotation is the best.

(3) selecting fields with convenient drainage and irrigation, opening good drainage ditches, lowering the groundwater level, so that there is no stagnant water in the rain; cleaning up the ditch system in time after heavy rain to prevent moisture retention and reduce field humidity is an important measure to prevent disease.

(4) the fields with many soil germs or serious underground pests should be sprinkled or ditched with sterilized and insecticidal soil before sowing or transplanting.

(5) selection of disease-resistant varieties, disease-free, coated seeds, if uncoated, seeds should be sterilized with seed dressing agent or seed soaking agent.

(6) Seedling and transplanting, covering seeds with medicinal soil after sowing, and spraying insecticide and fungicide before transplanting, which is the key to disease prevention.

(7) for direct seeding in the field, it is necessary to sow early at the right time, early seedling, early soil cultivation, early fertilization, timely ploughing and soil cultivation to cultivate strong seedlings, and the seedlings should be sprayed with a mixture of insecticides and sterilization before closing.

(8) compost retted by enzyme bacteria or rotten organic fertilizer shall not be used with bacteria, and the organic fertilizer shall not contain plant disease residues. The use of soil testing formula fertilization technology, appropriate application of phosphorus and potassium fertilizer, strengthening field management, cultivating strong seedlings, and timely topdressing after typhoon and heavy rain to enhance plant disease resistance is helpful to reduce the disease.

(9) timely control of insect pests, reduction of plant wounds, reduction of pathogen transmission; timely removal of diseased leaves and diseased plants, and burning out of the field, application of medicine or quicklime at disease points.

(10) reasonable close planting, timely pruning, timely removal of 2-3 leaves at the lowest part of the stem, timely cutting of empty branches, beating old leaves, pulling out diseased plants, concentrated burning, application of diseased points, and increase ventilation and transparency in the field.

(11) Scientific irrigation should be applied during high temperature and drought in order to increase field humidity and reduce the harm and transmission of aphids and gray planthoppers. Continuous irrigation and flood irrigation are strictly prohibited.