Symptoms of injury: Maize can be affected during the whole growing period, with heavy seedling damage and obvious symptoms at the 5-6 leaf stage. Firstly, transparent dotted spots appear on both sides of the midrib of the base of the heart leaf, and then gradually spread to the entire leaf. The leaf veins, leaf sheaths, and temporal lobes of the diseased plants have waxy white sticks on the veins, and there is a noticeable rough and uneven feeling by hand. The leaves are short and wide, thick and stiff and stiff, with dark green leaves and clusters of top leaves. The growth of diseased plants was inhibited, internode swelling and shortening, and severe dwarfing. The roots of the diseased plants are few and short, less than half of the healthy plants, and they are easy to pull out of the soil. The mildly diseased plants have poorly developed tassels, less loose powder, shorter ears, less filaments, and less strong seeds. Severely diseased tassels cannot be extracted or can be extracted but with few branches, no pollen, and false or abnormal grains.
Occurrence pattern: The cause of corn rough dwarf disease is corn thickening virus. The seedling stage is the most susceptible. The disease is an insect-borne disease, and the host virus is very widespread. It is mainly transmitted by Laodelphax striatellus in a persistent manner. Once it is poisoned, it will be poisoned. The virus can live over winter perennial grasses and weeds and other virus mediators. Toxic sources, mediators, and maize susceptible varieties are three essential conditions for the occurrence of corn rough dwarf diseases. First, the amount of toxic sources: perennial grass crops and weeds are the host plants of the corn roughage virus, so management of coarse, weedy corn fields than the fine management, weeds less severe disease incidence. Second, the resistance of maize varieties: At present, most of the varieties cultivated have a high or middle sense of viral disease, few disease-resistant varieties and fewer highly resistant varieties. Therefore, once the number of viral mediators increases, it will promote the epidemic. The third is the maize cultivation model: The difference in the degree of susceptibility of the maize at different growth stages is relatively large. The earlier the disease is, the heavier the disease is.
Prevention and control measures: The prevention and control of the disease should be based on comprehensive prevention and control strategies based on agricultural control and supplemented by chemical control.
The first is cultivation and management measures. (1) Use anti-resistant varieties and sow for appropriate period. According to the local conditions can choose to use relatively good varieties. (2) Removal of weeds, control of poisons, removal of diseased plants, and strengthening of field management. Timely eradication of weeds in corn fields and land and destruction of suitable habitats for SBPH. Combining seedlings with seedlings, timely removal of diseased plants in the field, brought out of the field burned or buried. Rational fertilization and watering, strengthen field management, promote robust growth of corn, shorten the period of disease, reduce the chance of transmission, and enhance the resistance of corn to disease resistance.
The second is chemical control. (1) Seed dressing or coating. Insecticides or coating agents used for dressing or coating can effectively control the planthopper stage and reduce disease transmission. (2) Insecticide spraying at seedling stage. Before and after corn sowing and during the seedling stage, controlling spraying of corn plants in the corn field and nearby weeds has a certain effect on reducing disease. Can use 10% imidacloprid wettable powder, 20 grams per acre plus water spray, comprehensive control of field lice, land, weeds in the ditch on the planthoppers and aphids. Corn three-leaf period timely with omethoate plus 25% buprofezin WP spray prevention, spray once every 7-10 days, and even spray 2-3 times. When the control effect is unsatisfactory, 25% morpholinium zinc soluble powder or mycotoxin spray is used to treat pests and prevent disease. (3) In the early stage of corn rough disease, the use of 1.5% sulfur copper alkyl alkyl alcohol emulsion can be used for prevention and treatment, and the effect is also ideal.
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