The leaves of pear seedlings are always eaten by insects. What medicine do you use to treat them?

1, do a good job in orchard sanitation. After eliminating the fallen leaves of overwintering bacteria, plant them before germination, thoroughly clean up the fallen leaves and diseased fruits, and bury or burn them centrally (diseased fruits cannot be buried in the soil). Cut off all kinds of dead branches on the tree and destroy them centrally. Before germination, spray the whole garden with 40% thiram 100 times solution plus 500 times solution assistant or 200 times solution of 75% sodium pentachlorophenol. So as to eradicate all kinds of overwintering bacteria remaining on the tree. In areas where pear rust occurs, completely cut off Sabina vulgaris as the host, or completely cut off before the germination of winter spore horns on Sabina vulgaris, or spray 2-3 Baume sulfur mixture or 1 Baume sulfur mixture and 75% sodium pentachlorophenol 300 times mixture on Sabina vulgaris before the spring rain to prevent the germination of winter spore horns. Thoroughly scrape off all kinds of germ fruiting bodies on wood rot trees and destroy them centrally. From the end of April to the end of May, the patrol found the diseased tip of Black Star, which was cut off in time and burned or buried deeply.

2. Strengthen cultivation management, strengthen disease prevention and rational fertilization, increase the application of organic fertilizer and avoid partial application of nitrogen fertilizer; Reasonable irrigation, pay attention to timely drainage in rainy season, timely irrigation in early spring, increase the water content of trees and improve the anti-corruption ability of trees; Reasonable fruit yield and enhanced tree potential. Orchards with serious yellow leaf disease and lobular disease should be fertilized in autumn with appropriate amount of ferrous sulfate and zinc sulfate. Pay attention to applying medicine to protect all kinds of large mechanical wounds, such as cutting, sawing and splitting wounds, to prevent the infection of wood rot fungi. Bagging after fruit setting can prevent fruit diseases.

3. The treatment of trunk diseases began in late March. Pay attention to the examination and treatment of rotten spots and apply drugs to protect them in time. See above for specific methods and effective drugs. Before germination, scrape off the ring marks in time and apply medicine. After scraping off the fruiting body of the pathogen, pay attention to taking medicine to protect the wound.

4. Timely detection and treatment of root diseases. After pear trees germinate and bloom, root diseases are found in time and treated in time.

5. The main diseases controlled by spraying chemicals before wheat harvest are scab, ring rot, black spot, rust and yellow leaf disease. Other minor illnesses can be treated at the same time. In general, scabs need to be sprayed three times, that is, at the end of April or early May, in the middle and late May and early June; When it is dry, it needs to be sprayed twice, that is, in mid-May and early June; It needs to be sprayed four times in rainy years, namely in late April, early May, late May and early June. The application time depends on the specific conditions such as climate and illness. For ring rot, it should be sprayed about 10 days after flowering, once every 15-20 days, and it needs to be sprayed 2-3 times. The specific spraying time should be timely spraying after rain, spraying more when it rains, spraying less when it rains and spraying when it doesn't rain. Black spot usually needs to be sprayed twice, that is, in the middle and late May and early June. 10- 15 spray rust once a day and twice continuously. Yellow leaf disease: spraying medicine every 7- 10 days after the leaves are unfolded until the leaves turn green. If you need to spray drugs to prevent and treat more than two diseases at the same time, you should choose drugs that are effective for both and consider treating other diseases. At the same time, try to avoid using copper preparations in the early stage to avoid phytotoxicity.

6. Spraying control in the middle growth period The diseases that need spraying control in this period mainly include scab, ring rot, black spot, epidemic rot and powdery mildew. Other minor illnesses can be treated at the same time. Generally speaking, scabs need to be sprayed 2-3 times, that is, in late June, mid-July and late July. Ring rot generally needs to be sprayed 2-3 times, that is, in late June, early July and late July. The specific spraying time and frequency still depends on the rainfall. Black spot disease generally needs to be sprayed 2-3 times, that is, in late June, mid-July and late July. The specific spraying time and frequency should be determined according to the severity of the disease and rainfall. Plague generally needs to be sprayed 1-2 times, that is, in the middle and late July. Powdery mildew generally needs to be sprayed 1-2 times, that is, in the middle and late July. Copper preparations can be used as much as possible during this period, and the treatment of different diseases should be considered.

7. Spraying before harvest to prevent and control the diseases that need spraying at this stage are mainly scab, brown spot and blight. Generally, scabs need to be sprayed 2-3 times, that is, in mid-August, late August and early September. The specific spraying time and frequency depend on the severity of the disease and rainfall, but in any case, spraying should be done on time in early September. Brown rot usually needs to be sprayed twice, that is, in the middle and late August and late September. Epidemic rot usually needs spraying 1 time, that is, in the first half of August. During this period, we should try our best to choose internal inhalation therapy drugs; At the same time, Bordeaux mixture should be avoided to avoid polluting the surface of fruit.