Abstract:

The spatial distribution pattern and sampling technique of the small brown planthopper, Laodelphax striatellus, in maize field in the Northwestern of Zhejiang province were studied by the methods of the aggregated indices method, Iwao method and Taylor power law method, in order to improve the monitoring, prediction and the sustained control system for this pest in maize field. All of three methods shown that: the distribution pattern of L. striatellus was the assemble distribution type, with the assemble distribution index increasing along with their population density. It was tested by Blackith’s method, when m<1.8072 insect per plant, their aggregation was caused by some environmental factors, such as climate, the growth period and growth vigor; when m≥1.8072 insect per plant, the gathering was caused by the interaction of their life habit and environment factor. Based on this distribution pattern, the model for determining the optimum theoretical sampling number and the optimum sequential sampling were proposed. These results provided scientific basis for sampling investigating precisely and controlling effectively the field populations of L. striatellus.