Studies On Effect Of Host Plants On Population Of Laodelphax Striatellus And Mechanism Of Wing Dimorphism

Rice yield and economic loss were resulted in due to the serious outbreak of Laodelphax striatellus (Fallen) which transmits rice stripe virus in Jiangsu province in recent years. In order to explore outbreak mechanism and disaster regulation of the fluctuation dynamic of Laodelphax striatellus was investigated systemically in fields. Effect of different host plants on population and factors of wing dimorphism were researched in this paper. The main results were as following.1. The life historic of Laodelphax striatellus was studied based on scheduled sampling in field of fluctuation dynamic. There were 5-6 generations of Laodelphax striatellus in Yangzhou area. They overwintered in 3-4 instar nympha in the soil, root of wheat, stubble, fallen leaves, weeds and other places. The overwintering nymphae of Laodelphax striatellus began to move freely when it was warm in March. The adults occurred from early in April and the peak from middle in April to late in April. The overwintering nymphae and the first generation mainly injuried wheat. The adults emergence peak of the first generation occurred from middle in May to early in June which was also the peak of Laodelphax striatellus moving out from wheat field. Most adults spread to the field of weeds and maize. Then they migrated to seedling field of rice. After seedling transplanting they migrated to rice field. The second generation occurred from late in May to middle in July and the third generation from late in June to late in August. The peak period of Laodelphax striatellus occurrence was middle in July in paddy field. The 3-4 instar nymphae of Laodelphax striatellus began to overwinter in November.2. Effect of different host plants on population of Laodelphax striatellus was researched in this paper. The results indicated that the development durations and mortality of nymphae, longevity and fecundity of adult had significant difference in different host plants. The index of population growth on Wujing 15, Echinochloa...