What pests and diseases affect rice in the late stage? A single article explains the control methods clearly
What pests and diseases affect rice in the late stage? How to control them? Please explain in detail. The main pests and diseases in the late stage of rice are: 1. Sheath blight: the disease has recently risen faster, with an average diseased-hill rate of 13.7% and a diseased-plant rate of 3.3%. The rise in disease severity is noticeably faster than in the previous period, especially for the Wuyunjing series varieties, where sheath blight is generally quite severe...
What pests and diseases affect rice in the late stage? How to control them? Please explain in detailThe main pests and diseases in the late stage of rice are:
1. Sheath blight: the disease has recently risen faster, with an average diseased-hill rate of 13.7% and a diseased-plant rate of 3.3%. The rise in disease severity is noticeably faster than in the previous period, especially for the Wuyunjing series varieties, where sheath blight is generally quite severe. Based on the current temperature and the rice growth stage, the diseased-hill rate and diseased-plant rate will continue to rise in the near future.
2. Fifth-generation small brown planthopper: this year the population density of the small brown planthopper has remained high. The average number of insects per 100 hills is 20.6, and the field population is relatively high. To reduce the base population, lessen the damage in the late stage of rice, and reduce the source base for next year's insects, chemical control must be applied.
3. Fourth-generation brown planthopper: the occurrence level of the second and third generations of brown planthopper in this city was moderate, but the threat of the fourth generation still exists. On September 10, the fixed monitoring field of the plant protection station had 24.6 insects per 100 hills, and on September 9, a general survey in each town found an average of 7.9 insects per 100 hills. In particular, some fields that were not treated according to the recommended formula had higher insect numbers, bringing serious effects on the late growth of rice.
4. Fourth-generation rice leaf roller: the number of insects and eggs of the fourth-generation rice leaf roller in the field is still relatively high. A survey of 35 fields in each town found an average of 170.4 eggs and insects per 100 hills, with 20.4 larvae and 150 eggs. In particular, some late-planted direct-seeded rice may still be eaten white.
5. The rice seedling condition is extremely favorable for the occurrence of pests and diseases. The rice varieties planted are all large-panicle, round-stem types, with tender green growth, large growth volume, and a high degree of field closure, which is favorable for rice planthoppers to feed and lay eggs; especially for the Wuyunjing series varieties, sheath blight rises very quickly in the late stage; for late-heading varieties such as direct-seeded rice, the leaf color is tender green, the upper functional leaves are long, and the growth stage is late, which is extremely favorable for the occurrence and damage of the rice leaf roller.
6. Abnormal temperature is favorable for major outbreaks of pests and diseases. Since September, the temperature has been on the high side. The average temperature in early September was 26.0, noticeably higher than in normal years. In addition, according to forecasts by the meteorological department, the temperature in mid-September will still be relatively high, creating very favorable conditions for the massive reproduction of the fourth-generation brown planthopper and fifth-generation small brown planthopper, and for sheath blight in the late stage.
For pests and diseases in the late stage of rice, the following methods can be used for control:
1. Application time: around ten in the morning and around three in the afternoon.
2. Application method: provide classified guidance according to local cultivation forms, main planted varieties, and growth progress to ensure control effectiveness. (1) Large-area conventional rice. Use 20 grams of 25% pymetrozine suspension concentrate plus 400 milliliters of 5% jinggangmycin per mu, targeting rice planthoppers and sheath blight; (2) direct-seeded rice, tender green conventional rice fields, and fields with a late growth stage, use 20 grams of 25% pymetrozine suspension concentrate plus 80 milliliters of 40% diazinon.phoxim plus 400 milliliters of 5% jinggangmycin per mu, targeting rice planthoppers, rice leaf roller, and sheath blight. For some extremely late fields, add 100 grams of 20% Dingfeng jinggang.tricyclazole suspension concentrate to control ear neck blast. For the above formulas, dilute with 50-60 kg of water per mu for small-machine spraying, or dilute with 150 kg of water and spray with "Gongnong 36". In particular, fields treated on August 22-23 and those where pymetrozine was not used in the heading-stage application should be the focus of this application.
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