Prevention and Control of several Diseases of Tea Plant

1. Tea cloud leaf blight

Tea cloud leaf blight is a common and serious leaf disease of tea plant. The disease is widely distributed throughout the tea area. The injured plants often grow poorly, the new plants are not strong, the buds are thin, and the premature senescence seriously affects the yield.

Control methods for this disease:

1. Strengthen management and cultivate healthy tea plants. Rational use of pesticides to avoid phytotoxicity; timely cultivation and weeding, loose soil; do a good job in tea drainage or drought resistance, cold resistance work, create an environment conducive to tea growth, promote tea robust, improve disease resistance.

2. Clean up the countryside and reduce the source of germs. For the seriously ill tea garden, the diseased leaves should be removed in winter and spring, the dead leaves should be cleaned up or the tea garden should be cultivated in winter, and the diseased leaves should be buried deeply in the topsoil to block the source of disease. During the disease, remove the diseased leaves to prevent infection.

3. Timely spraying to control the spread of diseases. The occurrence of this disease is related to green leafhopper, mites, black rot and red rust. Therefore, the disease control should be combined with the control of the above pests. Optional spray: 0.6% lime half-dose Bordeaux mixture (picked 20 days after spraying), 70% thiophanate-methyl WP 1000 - 1500 times solution, agricultural antibiotic actinone 30 - 50ppm(picked 5 days after spraying), antibiotic limonycin lppm(picked 7 days after spraying), 80% zinc dizeb WP 600 - 800 times solution (picked 15 days after spraying), spraying dose 60 - 75 kg per mu, spraying once every 10 - 15 days, spraying twice in total. In unpicked tea gardens or nurseries, the above agents can also be sprayed. According to the actual situation, the time can be shortened appropriately and the number of spraying times can be increased to achieve better disease prevention purposes.

For tea leafhopper and mites, the following chemicals can be sprayed according to the insect situation: 40% dimethoate emulsion 500 - 1000 times solution, 90% trichlorfon crystal 500 times solution, 80% dichlorvos emulsion 500 times solution. These pesticides should not be mixed with alkaline pesticide Bordeaux mixture, otherwise it will reduce efficacy and cause phytotoxicity.

II. Tea cake disease

Tea cake disease is an important fungal disease in high mountain tea growing areas. The disease mainly affects the tender shoots of tea plants, which not only greatly affects the yield, but also the dry tea made of damaged tea leaves has bitter taste, crispy quality, many fragments and significantly reduced quality. Prevention and treatment of this disease:

1. Strengthen seedling quarantine. All diseased tea seedlings, scions and cuttings should be prohibited from being transported outside the disease area to protect tea gardens without disease areas and new areas.

2. Strengthen tea garden management. Weeds should be eliminated frequently; the type and application period of fertilizer should be adjusted; phosphorus and potassium fertilizer should be increased appropriately, and excessive application of nitrogen fertilizer should be avoided; pruning should be carried out in time, and diseased branches and leaves should be removed.

3. Reasonable tea picking. After late September, in case of cloudy and low temperature weather, it should be timely picked in batches, 1 bud 2 - 3 leaves left fish leaves, and the buds (diapause buds) will be picked clean in time.

4. Exterminate pathogenic bacteria in summer. In summer, the pathogen could not survive long sunshine and high temperature in tea garden, but could only infect and survive in shade tea plant. Therefore, strengthening the management of tea gardens, making tea gardens ventilated and transparent, in order to eliminate the summer places of germs, is an important measure to prevent the occurrence of the disease.

5. Chemical control. Available agents are: carbendazim, thiophane and thiophane methyl and other systemic organic fungicides. Spray 500 - 1000 times of the above chemicals per mu, spray 75 - 100 kg per mu, spray once every 10 days, spray 2 - 3 times in total (15 days after spraying). If there is no such agent, you can also spray 0.6% lime half-dose Bordeaux mixture, spraying 75 - 100 kg per mu, spraying once every 10 - 14 days (20 days after spraying).

III. Black rot of tea

Black rot of tea was also common in some tea growing areas, and the incidence of serious plants was as high as 52%. If the control is not good, not only will the tea yield decrease year after year, but the tea tree will gradually weaken and even die. Its prevention methods:

1. Combined with pruning, remove diseased branches and leaves, reduce bacterial sources. The tea garden with serious disease should be pruned greatly, and the pruned diseased branches and leaves should be removed and burned. After pruning, spray 0.7% lime multiple Bordeaux mixture once, spray 60 - 75kg of liquid medicine per mu.

2. Improve the surrounding environment of tea garden and enhance the permeability of tea garden. Clear the forest, shrubs and other over-dense shade trees and weeds around the tea garden to make the tea garden ventilated and transparent.

3. Strengthen inspection, early detection, timely spraying prevention and control. Check leaves frequently for disease, remove diseased leaves and branches as soon as they are found, and spray blockades to prevent spread. Spraying agents include: 0.7% lime equivalent Bordeaux mixture, spray 75 kg per mu, spray once every two weeks (pick 20 days after spraying);2% gangxin 1000 times solution, spray 60 - 100 kg per mu, or 5% Tianan 600 times solution, or 50% carbendazim WP 800 - 1000 times solution, or 70% thiophanate-methyl WP 800 - 1000 times solution, or 50% kali emulsion 800 - 1000 times solution, spray 75 - 100 kg per mu.