苜蓿锈病危害损失的相关分析及其经济阈值模型初探

在田间调查苜蓿锈病病情的基础上，分析了病情指数与产量损失率之间的线性关系，并据此建立了苜蓿锈病防治的经济阈值。     

Harmful and economic thresholds for rodent pests in the Alxa desert area under different grassland utilization patterns北大核心CSCD

The rodent damage threshold and the rodent economic threshold are indicators that must be clearly defined in the practice of grassland rodent prevention and control. Different grassland types or different utilization methods of the same grassland type have completely different values for these two indicators. The damage threshold is the population density of pests at which the grassland is obviously compromised, and the economic threshold is the population density at which further pest population increases will cause economic losses. The Alxa desert region is ecologically fragile, and rodents are endemic. This study selected continuous grazing areas and prohibited grazing areas in the desert area of Alxa Left Banner and from 2015 to 2019 to investigated the species and density of pests using the ‘mark and recapture’ method, together with sampling to investigate the aboveground plant biomass in the sample area in August. The measured rodent unit densities and their daily food intakes were used to estimate the amount of forage loss, and a regression equation was used to obtain a fitted relationship between the rodent density and the ratio of forage loss. It was found that: 1) The fitted curves for the ratio of pest density and forage loss in the continuous and prohibited grazing areas took the form of logistic three-parameter, S-shaped curves. 2) According to the regression equation, the damage threshold in continuous grazing areas was 26 standard rodent units·ha-1 and the economic threshold was 39.3 standard rodent units·ha-1. In prohibited grazing areas, the damage threshold was 33.2 standard rodent units·ha-1 and the economic threshold was 30.2 standard rodent units·ha-1. Thus, the economic threshold pest density of continuous grazing areas was slightly higher than that of prohibiting grazing areas. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

螺旋粉虱为害对四季豆产量的影响及其防治指标研究

通过设置田间笼罩试验,确定了螺旋粉虱不同种群发生密度对四季豆产量的影响。研究结果表明,随着螺旋粉虱虫口密度的增加,四季豆平均荚果长度、平均最粗处周长、平均单果质量、每株豆荚数量和质量均显著下降,虫口密度与豆荚质量呈显著负相关。在研究产量损失的基础上,确定了不同产量水平下四季豆的经济允许损害水平和螺旋粉虱防治的经济阈值。当产量为1 500 kg/667 m~2时,四季豆的经济允许损害水平为9.80%,螺旋粉虱防治的经济阈值为11对成虫。     

板栗病虫综合防治技术

危害板栗的病虫害主要有．板栗疫病、早期落叶病、金龟子、栗大蚜、红蜘蛛、桃蛀螟、象鼻虫等，只要采取综合措施，可以将病虫危害控制在经济阈值以下。主要措施是：     

蔬菜斑潜蝇经济阈值研究

对斑潜蝇在豇豆上的为害损失及其经济阈值进行研究,据此制定豇豆防治指标(经济阈值)是虫道达7条,旨在通过对斑潜蝇造成的豇豆产量损失进行定量分析,确立经济危害允许水平,确定防治指标,为其防治决策提供科学依据。     

十字花科蔬菜虫害经济阈值研究概况及其分析

通过对国内、外十字花科蔬菜虫害损失率及经济阈值研究情况分析及蔬菜害虫幼虫食叶试验、功能叶剪叶试验和不同条件下虫害动态观察,结果表明:十字花科蔬菜缓苗期及结球始期对虫害敏感,莲座期及菜球充实期耐虫性强;菜球减质量与剪外叶减质量对产量影响趋于相同;莲座期外叶受损,有超补偿能力,可放宽防治指标;莲座期防治指标为菜青虫每株5头,斜纹夜蛾每株1.5头,甜菜夜娥每株7.5头等.     

黏虫虫口密度与春玉米产量损失关系及经济阈值研究

黏虫[Mythimna separata(Walker)]是黑龙江省春玉米田最重要食叶性害虫,对玉米生产造成极大威胁.为明确黑龙江省春玉米田黏虫不同虫口密度与玉米产量损失关系,确定玉米田黏虫经济阈值,采取人工饲养黏虫和田间接种不同虫口密度幼虫方法,模拟自然条件下黏虫发生情况,研究黑龙江省春玉米田二代和三代黏虫经济阈值....     

瓜实蝇经济阈值的研究

通过田间防治试验与系统诱捕调查相结合的方法,探明苦瓜地诱捕瓜实蝇雄成虫的数量动态和瓜实蝇对苦瓜的危害损失率,测定苦瓜的经济允许损失率分别为2.85%~3.09%。通过回归分析,建立苦瓜损失率与瓜实蝇雄成虫的诱捕数量的关系模型,测定瓜实蝇的经济阈值为每个诱捕器5.3~5.8只。     

杨树细菌溃疡病损失估计的研究

在杨树细菌溃疡病严重发生的吉林省抚余市，分别不同林龄和立地条件，选设具有代表性的样地，对高度感病的树种美×青，采用野外均匀分布，典型整群抽样调查和树干解析的方法，获得２０块样地６０株解析木的调查数据，确定了病情指数与材积损失率的相关效率。