Maize rough dwarf disease (MRDV) is a virus disease transmitted by the planthopper, commonly known as "evergreen" and "clivia". Shanghe County has suffered various degrees of damage each year since 1994, especially in spring corn and early wheat corn. For example, in the spring of 1996, all the corn fields were affected, more than 95% of them were destroyed, and almost no production was destroyed; in wheat and corn intercropping, the diseased plant rate was generally 20-30%, and the serious diseased plant rate was over 60%; Tian, ​​the general disease rate is 10-15%, and the serious diseased plant rate is 20-30%. In recent years, there has been a tendency of rising and spreading. Now it has become one of the major diseases affecting corn production.
First, the symptoms
The infected Laodelphax striatus sucks leaf juice, and the plants become infected. After the corn gets sick, the leaves are dark green, and the leaves are stiff, thickened and shortened. The back veins produce a waxy white pulse, the internode shortening is clustered and the plants are severely short. The growth is hindered. 5-6 leaves before the disease, serious plant height is only 50-80cm that is to stop growing, although the lighter can grow taller, generally can not be heading and fruiting, resulting in deadly; 8 leaves after the disease even if the heading and fruiting, However, the ear is small, deformed, and the quality is severely reduced, which can reduce production by more than 60%.
Second, the factors that affect the incidence
(A) A variety of grass-root crops and weeds are the host plants of maize rough dwarf disease. In recent years, although chemical weeding in corn fields has been vigorously promoted, due to the neglect of the control of weeds along the fields, roadsides, ditches, and ditches, it has provided a good place for the propagation of poisonous Sphaeropsis farinae and accumulated a large number of poisons. source. In the production, there are many weeds, and the corn fields with extensive management are more severe than those with fine management and less weeds. Former crops are wheat and the mass of the plots in the occurrence of bushy dwarf disease is heavy. This is due to the fact that although maize rough dwarf disease and wheat bush dwarf disease are not caused by the same virus, they are all caused by the virus of maize rough dwarf disease in wheat bush dwarf strains. Caused by poisoning.
(II) Sowing period According to the statistics of many years of investigation, the incidence of different sowing dates varies significantly. The severity of the disease was as follows: spring sowing field was more important than wheat field, and wheat field was heavier than wheat field. This is due to the law of occurrence of the planthoppers. In the Shanghe County, Sphaeropsis sinensis occurs five generations a year, and the overwintering generation carries toxic hazards to wheat. The first generation of adults spreads and harms corn. In Shanghe County, spring sowing of corn is generally planted in the upper and middle stages of May. Intercropping of corn in wheat and wheat is mostly planted in late May. The seedling stage of maize coincides with the first generation of adult migratory larvae during the peak period of transmission. The corn sown after the harvesting has not yet emerged, then escaped the peak of transmission infestation, which is the reason why spring sowing corn and wheat covered corn are serious, and the reason why live corn is lighter.
(III) Maize inbred lines are not resistant to disease Currently, corn inbred lines with high resistance or immune rough shrinkage have not been cultivated.
(d) Meteorological conditions are suitable In recent years, the temperatures in autumn and winter are high, and the time for the transmission of poisoning by Laodelphax striatellus has been prolonged, resulting in an increase in the number of host poisoning sites during overwintering. In spring drought, early corn in spring corn and wheat fields grow slowly, grow weakly, and their disease resistance declines. Drought is more conducive to the growth and development of Laodelphax striatellus, and promotes the spread of a large number of migratory and transmissible viruses.
(V) Impact of the farming system Shanghe County is a two-year-cropping area, in which the area of ​​spring corn is very small, the intercropping area of ​​wheat in previous years is larger, and the symbiotic period of wheat and corn is gradually extended. This cultivation system, maize seedling stage It is happening that Sphaerotheca sinensis migrates to the poisonous period and is extremely conducive to the occurrence of corn rough dwarf disease.
Third, comprehensive control measures
(I) Improve the farming system to eliminate small spring maize crops. Avoid summer wheat crops as early as possible in summer sowing maize. Even if interplanting, the symbiosis of wheat and corn should not exceed 7 days. Vigorously promote the method of planting crops after live broadcasting or harvesting. A few years of practice has proved that this can effectively avoid the peak period of transmission of poisoning of Laodelphax striatellus, reduce the occurrence of corn rough dwarf disease, and ensure the normal maturation of corn.
(II) Environment for improving the growth of corn fields Gramineous weeds are the source of corn rough dwarf diseases. They can eradicate weeds in corn fields and landsides, destroy suitable habitats for SBPH, and reduce the number of their populations. Growth creates a good environment to reduce the risk of this disease.
(3) Doing a good job of seed chemical treatment Before sowing, use 5% antimony net emulsifiable concentrate to coat 2% of the seed amount or coat with a special corn coating agent, which can effectively eradicate poisonous insects - Laodelphax striatellus, Significantly reduce the incidence and reduce the degree of morbidity.
(IV) Chemical control of Laodelphax striatellus Intercropping maize and direct-seeding corn must be sprayed in the field and around the field to prevent and control the planthopper in the 3-4 leaf stage. The agent can be sprayed with 10% imidacloprid 1500 times or 50% omethoate EC 1000 times. The sprayer strives to be even and thoughtful to ensure the control effect.
(V) Strengthen cultivation and management, do a good job in prevention and cure of the soil, strengthen the field management of maize seedlings, promote early-onset seedling growth, and plant seedlings and seedlings in time; find diseased plants in a timely manner, remove them from the field, reduce the source of poisons, and increase organic fertilizers; , Nitrogen, phosphorus, potassium, micro-fertilizer reasonable match, timely watering, cultivating loose soil, etc.; when the corn grows to 5-6 leaves, timely spraying foliar treasure, spray Shi Bao, Wan Jiabao, plant power 2003, etc. Growth regulators and fungicides, such as phytophthora, virus A, and mycotoxin, promote the robust growth of corn, increase the plant's own disease resistance and tolerance after induction, and effectively control the occurrence of the disease.
Anqiu Ginger is famous for its bright yellow skin, good fruity shape, compact structure and strong ginger flavor. In addition to containing a large number of carbohydrates, proteins, vitamins and minerals, it also contains a large number of gingerol, gingerolone, gingerol and gingerol, etc., which has high edible value and medicinal value.
Fresh Ginger To Ground Ginger,Storing Fresh Ginger,Ground Ginger To Fresh Ginger,Fresh Ginger To Ground
Jining Yuanheng International Trading Co.,Ltd , https://www.china-garlic-exporter.com