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Researchs On Occurrence And Sowing Dates Control Technique Of Laodelphax Striatellus (Fallen) In Corn Fields

Posted on:2013-02-10Degree:MasterType:Thesis
Country:ChinaCandidate:L WangFull Text:PDF
GTID:2233330374993805Subject:Agricultural Entomology and Pest Control
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Maize rough dwarf disease (MRDD) is the main disease in the corn production areas in China from the1970s. Its pathogenic bacteria is Rice black-streaked dwarf virus (RBSDV), which is carried and caused by Laodelphax striatellas (Fallen). Its piercing-sucking effect causes less damage to crops, but it can spread virus disease of the rice, wheat, corn and other crops, and caused a pandemic virus.China first found MRDD in southern Xinjiang and western Gansu Province at1954.The MRDD was lagre popular in Hebei and Beijing at the middle of1970s, which caused large area destroyed or cut production and serious influence on corn production. Recently, with climate changing and planting structure adjustment, maize rough dwarf disease began to rise in China, especially in Hebei, Shanxi, Shandong, Jiangsu, Zhejiang, Shanghai and other regions take place much more seriously. Since2005, it has been for many years serious occurrence in Shandong Province, morbidity of10%-70%.The area caused by the disease up to4ten thousand acres in2008. At present, MRDD has become the important disease in corn production fields and breeding fields, and the key to prevention MRDD is prevention Laodelphax striatellas.From2009to2011, the occurrence of small brown planthopper, the incidence of maize rough dwarf disease and the corn yield under different sowing dates were investigated. We also comprehensive understand the field population dynamics of Laodelphax striatellas in Tai’an. Study and formulate the Laodelphax striatellas population dynamics monitoring the main line, the broadcast of regulation, combined with chemical control, select resistant varieties of maize rough dwarf disease prevention and control technology system. Not only can provide the prediction of the Laodelphax striatellas (Fallen) reference, but also can be directly guide com production1. The studys of Laodelphax striatellas populations happen dynamic The population dynamics of Laodelphax striatellas adult was essentially the same from April25n to June19th every4d during3years, since mid-May found Laodelphax striatellas on, the pests increased rapidly, in June arrived at the peak and fell rapidly, in late July field has not found traces of Laodelphax striatellas.2. Different sowing dates on maize rough dwarf disease and yields effects Before April30th and after June19th was the safe sowing date in Tai’an. The morbidity of maize rough dwarf disease sowing during incident peak of small brown planthopper was the highest, and from May20th to May30th the losses of corn yield seeding was the greatest. Therefore, sowing date is the key factors affecting the occurrence of maize rough dwarf disease.It is effective to avoid the peak of mass poisoning meet planthopper by appropriate early sowing and late sowing, which can prevent the outbreak of maize rough dwarf disease.3. The control effect of seven pesticides to the Laodelphax striatellas in fieldsThis study make use of seven kinds of pesticides on the selection of the prevention and control of Laodelphax striatellas test.By the way of investigation to the field efficacy trial, The result showed that, medicine after1d (day after treatment), the field efficacies of imidacloprid and abamectin were over95%, and the control effect was significant better than any others. After7days, the field efficacies of imidacloprid, Abamectin and Diflufenican were97.58%,92.97%, and94.95%, respectively. The field efficacies of other pesticides were at a low level.4. The resistance evaluation of different corn varietiesThe comparative test about the disease resistance were carried out among32corn varieties. The result showed that there were significant differece in resistance of different varieties. The rate of diseased plant and disease index of Luyu14, Denghai3, Denghai3622, and Ludan6018were low, the resistances were strong, and the yields (430kg/667m2) were very large. The rate of diseased plant and disease index of Jinyu2, Qidan6, Liansheng15. Tianta5. Xianxing5,9002, Xingquan2101, Denongzheng008and984were high, which were not suitable for cultivation.5. The isolation and identification of intestinal bacteria of the adult of Laodelphax striatellasEight bacteria strains were isolated from the intestine of the adult of Laodelphax striatellas by bacterial modality, dyeing reaction, cultural characteristics, physiological characteristics and biochemical reactions. The result showed the8bacteria strains belong to Bacillus lichenifomis、Citrob acter、Bacillus larvae、Salmonella、Bacillus megaterium、 Cellulomonas sp.、Propionibacterium、Brachybacterium,.
Keywords/Search Tags:Laodelphax striatellas (Fallen), Maize rough dwarf disease, Occurrence, Integrated control
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