The good and bad prevention and control of the panicle neck in the production of late rice is directly related to the level of late rice production, and even related to the receipt or non-receipt. The prevention and control technology is not in place, and missed the proper control. Even the best fungicides can not recover the damage caused by the panicle neck, because the neck is the only way to transport nutrients to the ear of rice, and it is also the most susceptible to late rice plants. Part. After the initial ear, the neck is relatively young, and some susceptible varieties with poor disease resistance are easily infected with rice blast. In production, there are many misunderstandings about the control of rice blast, especially the panicle, and it must be paid enough attention, otherwise the harvest will be destroyed.
Misunderstanding 1: Only when the ear is used
The rice blast pathogen has just invaded, and the symptoms are generally invisible. The initial stage of the disease is not obvious. It takes a while to show the symptoms. When the ear of the neck is necrotic due to necrosis, it is too late to control the disease. Invading the neck and neck tissue, the nutrient transport of the ear neck is blocked. At this time, the effect of the drug is very poor. The damage caused by the neck is difficult to recover, and the white ear will also form an established loss. The medication can only be a “post-horse gunâ€. Therefore, the key to control the rice blast in late rice is the break period of late rice.
In the middle and late stages of late rice growth, rice blast is mainly re-infected by a large number of conidia produced on the lesions by airflow. As long as the conditions are appropriate, the bacteria can be repeatedly infested, causing the disease to rapidly expand and become popular. The conidia spread to the germination of the rice leaves, and the conidia at the neck of the ear germinated from the scaly lobes, and on the branches, the cells invaded from the branches near the cob branch, and the neck was young and tender. The disease is most susceptible to disease, and the disease resistance gradually increases after 6 days of heading. If there is much rainfall during the heading of late rice, the humidity in the field is large, and the temperature drops below 20 °C for about 1 week. The ability of late rice to resist rice blast is greatly reduced, which often causes the occurrence of panicle neck lice.
Therefore, we must grasp the beginning and ear of the period to carry out drug control, we must not see the white spikes when spraying, the susceptible varieties should be re-medicated once at the heading stage to ensure the prevention and treatment of the panicle.
Misunderstanding 2: Ye Wei is not serious, the head of the hill is not used for medicine.
Among the late rice varieties planted, some varieties are resistant to spider mites, but not to spikes. The occurrence of rice blast is greatly affected by the environment, and the conditions at the tillering stage are not suitable. The occurrence of leaf lice in susceptible sorghum varieties will not be serious, but if the conditions are suitable at the late rice stage, it may show serious susceptibility; if it is a disease Variety, and the rainy and humid conditions of the rainy season, regardless of the severity of leafhopper, may lead to a pandemic of the panicle.
Therefore, even if the rice blast in the early stage of late rice is not serious, when it encounters rainy days at the heading stage, when the temperature and humidity conditions are suitable, the rice blast can also occur as large as the neck. Especially in the 30-40 days after "Liuqiu", if the temperature drops below 25 °C, the minimum temperature is only about 20 °C. If you encounter more than 20 days of rainy weather conditions, the field humidity is high, although there is no The occurrence of leaf blasts also causes serious occurrence of rice blast at the ear stage. Therefore, it cannot be careless and should be closely watched.
Misunderstanding 3: The varieties with strong anti-caries ability do not need medicine
Among the cultivated rice varieties, some varieties are more resistant to rice blast, while most of the current varieties are not strong against rice blast, and the resistance level of many varieties to rice blast is generally reduced. The occurrence and damage of rice blast, the conditions of tillering period are not suitable, and the occurrence of leaf lice in susceptible sorghum is not serious. If the conditions at the ear stage are appropriate, it may show serious susceptibility.
In 2014, several late rice varieties planted in Lujiang City, Hunan Province, including two super hybrid late rice varieties, although they were proved to be highly resistant or moderately resistant to rice blast in the identification of varieties, but in late August, late autumn, late rice entered During the heading period, there were more than 10 days of rainy weather in the first ten days of this period, and the temperature was low. Even in the first half of September and the beginning of the first half of the year, the lowest temperature reached 17-19 °C. This low-temperature and high-humidity weather condition coincides with the heading period of large-area late rice. Therefore, even if the varieties with high or moderate disease resistance are promoted, in some late-season planting areas, a large number of panicle-necked ticks occur. situation.
In early September, the possibility of continuous rainy weather in the southern region exists every year, which brings inconvenience to the application of pesticides. In order to prevent the occurrence of rice blast, it is necessary to pay close attention to the weather forecast. Before the heading of late rice, it is necessary to apply before the rain. Prevent panicle neck lice. Before the rice breaks, there is no time to apply the medicine. If the rain occurs in the heading period, the rain should be applied, and the application concentration should be increased to avoid the drop of the medicine with water, which will affect the effect of controlling the late rice ear. Some varieties with strong disease resistance may occur if they are planted in places where they have been infected for a long time or if they are applied with nitrogen fertilizer, vegetative growth is too strong, and rain occurs during heading. For the perennial diseased hills, even for high-resistance varieties, attention should be paid to the prevention and treatment of panicle neck lice. Partial application of nitrogen fertilizer and vegetative growth of the hills, whether it is anti-aphid or sensation, can not ignore the prevention and control of rice blast.
Misunderstanding 4: No rain during the heading period
In recent years, it has been shown that rainy weather occurs almost every year at the heading stage, which provides favorable conditions for the occurrence of panicle neck lice, especially in places where the susceptible varieties are planted, and may cause a disease pandemic. In production, the drug should be seized at the beginning of the blasting period (10% of the whole field rice heading). In the case of continuous rainy weather in the rice heading stage, it should be re-medicated once in the heading stage (80% heading).
The agent may be selected from the group consisting of kasugamycin, rice bran, rice amide, azoxystrobin and trifloxystrobin. Tricyclazole is a protective fungicide with strong systemic absorption and can be absorbed by various parts of rice. It has a long-lasting effect. If it is mixed with benzotriazol, it has both protective and therapeutic effects. Good suction and long lasting effect.
In early September and early mid-September, large areas of late rice have entered the heading stage, which is conducive to the occurrence of various ear-stage diseases such as panicle neck lice. At the same time, the rainy rain brings inconvenience to the application of pesticides.瘟 should grasp the early application of the drug, in the 5-7 days before the break of the late rice, tricyclazole, in the rupture period, the application of benzoyl azoxystrobin, to achieve both before and after, play a role in the prevention and control of rice blast in late rice effect. When using the medicine repeatedly, different types of pesticides can be used alternately, and the medicine should be applied before the rain; in the case of continuous rainy weather, it is necessary to grasp the rain gap application and control, so as to achieve a bumper harvest.
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