棉铃虫风险发生区的确定与评估

Determination and assessment for risk areas of the Helicoverpa armigera Hübne

以河北省中南部地区作为研究区 ,应用 GIS技术和地统计学方法就某一阈值的风险区、某一阈值的发生概率地图进行了探讨 ,并对该地区棉铃虫二代卵发生的历史数据 ( 1 980～ 1 997)进行了空间模拟 ,在此基础上得到风险发生区和高风险区地图。二代棉铃虫卵发生的地域特点是 ,重发生区位于研究区的西部和南部部分地区 ,而轻发生区位于东北部 ,从东北至西南 ,棉铃虫发生程度趋于加重 ,其中西部的阜平县、曲阳县、行唐县、灵寿县、平山县等地以及南部的邯郸市、磁县、临漳县、魏县等地发生最重 ,属于二代棉铃虫高风险发生地 ,而东北的遵化市、玉田县、丰润县、唐山市、丰南县等地最轻。通过对风险发生区与各个影响因子如气象、耕作制度、高程、一代蛾量等的定性和定量的分析 ,认为影响棉铃虫发生的主要因子为气象因子 ,包括温度与降雨。就二代卵而言 ,主要影响因子为 6月降雨量的大小 ,其次为耕作制度如小麦、棉花种植比例和一代蛾量。此外 ,环境因子如海拔高度、植被覆盖大小也对棉铃虫的发生有一定的影响。通过综合分析确认研究区棉铃虫高风险发生地 (重发生区及中偏重发生区 )具有一些显著特点 ,即海拔较高、多山地和高原、有较多沙土、自然植被覆盖率高、小麦种植比例较高、降雨偏少、温度较高、湿度较低、

As a rule, it is called the pest existent areas in which insect pest is present, whereas the risk areas are some places where pest population density exceeds the economic threshold. The risk areas can be divided into different regions such as low, lower, moderate, higher, high outbreak areas according to the outbreak degree. It is important to regional pest management to determine the risk areas, for example, we can use different control measures for corresponding outbreak regions.In this study, the Geographic Information System (GIS) technology and geostatistics method are used to determine the risk areas and outbreak probability for the specific economic threshold in the central and southern part of Hebei province. Moreover, the risk area and high risk area maps are acquired by modeling the historical data of the 2nd generation eggs of Helicoverpa armigera Hübne from 1980 to 1997. The distribution characteristics of the 2nd generation eggs are that the density grades are high in southwest, whereas its grades are low in northeast in the study areas. From northeast to southwest, the densities of eggs become higher and higher. The grades are the highest in Fuping, Quyang, Xingtang, Lingshou, Pingshan, Handan, Linzhang, Wei county, etc. and the lowest in Zunhua, Fengtian, Fengrun, Tangshan, Fengnan, etc..Based on the qualitative and quantitative analysis to the relation between the risk areas and impact factors such as meteorology, cropping system, elevation, the 1st generation moth quantity, etc.. We found that the meteorological factors including temperature and rainfall were the primary factors, the rainfall in the June was key factor, and the cropping system, the proportion of the wheat and cotton area to the whole area areas, the moth quantity of the 1st generation had effects remarkably to 2nd generation eggs. Besides, environmental factors such as elevation, natural vegetation abundance degree and their proportion to the whole area had some advantage to development of the eggs. The higher elevation, more mountain and tableland, more sandy soil, abundance natural plant, higher wheat plant proportion, less rainfall, higher temperature, lower humidity and higher moth quantity of the 1st generation are characteristics of the high risk areas of Helicoverpa armigera Hübne.Three kinds of risk areas have different significance and role to pest management activity. It can be acquired by analyzing the history data for potential risk areas, the aim building this kind of risk areas is to explore the key factors and pest population outbreak mechanism, moreover it is also the foundation of the prediction model. If we want to know about outbreak in the specific area and year when population density exceeds the economic threshold, it can be completed by appropriate interpolation methods and query commands in a GIS environment, and if we just want to know outbreak probability exceeding the specific economic threshold, it can be made by using the Indicator Kriging methods.We need to know about the locations of risk areas, more important to understand the outbreak mechanism and predict outbreak trends for regional pest management. And the injury can be reduced to least level just by grasping and forecasting precisely outbreak trends and risk areas. In this study, assessment and analysis synthetically to risk areas is made by relating with some impact factors such as meteorology, cropping system, population quantity, etc..