虫口密度

碎麦诱捕器在不同虫口密度下诱捕效果明显不同。

Lure effects of trap with creaked wheat depend on different population density .

本文采用平均虫口密度、拥挤度和被害株率作为标准地的指标，对杨树蛀干害虫的危害状况作动态分析。

Dynamic analysis of poplar stem borer was done with population density , crowded level and percentage of damaged trees on sample plots .

该线虫在胡萝卜的生长期内，以10～11月份虫口密度最大，主要分布于0～15cm土壤层。

It distributed mostly in the soil depth from 0 to 15cm .

试验区诱蛾量为CK区的20%，虫口密度下降73.6%，寄生蜂存活率高达81.7%。

The number of moth tempted in experimental zone is 20 % of the one in CK zone . The population is 73.6 % less than the one in CK zone . The survival rate of autoeciousness bee could reach the point of 81.7 % .

结果表明，B2菌分别在土壤pH7、25℃和60%湿度的处理中能有效降低南方根结线虫的虫口密度，其幼虫减退率分别达79.06%、83.08%和80.97%；

The results showed that bacterium B2 could effectively reduce the population density of the root-knot nematode in soil pH 7 , 25 ℃ or 60 % humidity . The larva decreased respectively by 79 . 06 % , 83 . 08 % and 80 . 97 % .

平均单果虫口密度3头左右时，虫害果较健康果相比，出种率下降2.5%，健饱种数下降18.3%，虫蛀种子率达16.2%，千粒重下降0.93g，发芽率降低28%。

Comparison of infected cones averaging 3 pests with healthy ones showed that seed amount declined by 2.5 % , full-filled seed reduced by 18.3 % ; pest damage rates 16.2 % ; thousand grain weight decreased by 0.93g and germination rate lowered by 28 % .

随着虫口密度增加，种子受害率升高，种子优良度降低，说明种实害虫危害不仅造成种子直接损失，还使种子品质下降。

The quality of the seeds declines with the posts density increases .

随着虫口密度的增大，向饲养池中央扩散。

When the density increased , they dispersed rearing pool .

在稀植、管理粗放的桑园中，一般虫口密度较高。

The density was fairly high especially in the mulberry fields without control .

单宁含量与青杨脊虎天牛虫口密度之间存在比较明显的负相关性。

Negative correlation between tannin content and larvae density of X.rusticus was obvious .

利用幼虫粪粒数推算高大树上虫口密度

Determining insect density in high and big trees by feces amount of pine caterpillar

不同种和品种的根际寄生线虫种类及虫口密度差异较大。

The sorts and densities of nematodes largely varied from different varieties and clones .

松针红蜡蚧虫口密度与针叶变黑呈正相关，受害木的材积生长率受到较大影响。

The population density shows a positive correlation to the blackening degree of the needle .

第类，虫口密度、中等被害株率、较低拥挤度；

ⅲ . Higher insect density , middle attacked trees rate , lower crowded degree ;

在大田，使用耳霉菌的分生孢子悬浊液，能在短时间内有效地降低蚜虫虫口密度。

The conidial aquatic spray in field can effectively decrease aphid population trends in relative short time .

调查结果表明，木本花卉和多年生草本花卉根部线虫群体结构比较复杂，虫口密度较高。

There were more complicated population structures and higher population level in the rhizosphere of wood-plants and perennial herbaceous plants .

主要危害嫩梢、花芽、雌雄花、球果、种子等，使球果产量降低。采用营林措施和辅以佳多频振式杀虫灯进行防治，可有效地降低虫口密度，达到防治效果。

This article presents that silvicultural and biological control could effectively reduce the density of larva to increase the cone yield .

实验结果表明：虫口密度大于20头蚜虫的，其取食量之间存在显著的差异。

The result shows : the density is over 20 aphids , and the consumptions take on remarkable difference . 5 .

虫口密度由38头／株下降为21头／株，幼虫化学防治效果达83%。

Population density fell from 38 to 21 per tree , the chemical control effect of the larva reached 83 % .

本文研究了不同虫口密度下，对苞菜外观品质和营养品质的影响。

The influence of appearance and chemical components of cabbage injured by different population of the B.tabaci was studied in this paper .

相关性分析的结果表明上一代的虫口密度可以影响下一代害虫卵期的寄生性天敌的数量。

The result of correlation analysis showed that the caterpillar densities of previous generation could affect the parasitism rates of following generation .

茶树受害程度与虫口密度的相关性密切，制定了受害允许密度及防治指标计算公式。

Another formula for calculating economical threshold and control index was founded because of the damage of tea was close relative to insect population .

下层虫口密度通常为上层的2倍以上，最多可达3.2倍。

The average density of larvae on lower crown was twice as much as on uper crown , with the maximum of 3.2 times .

以生物多样性指数、马尾松毛虫虫口密度和成本投入作为指标，用灰色决策理论对不同放菌量和不同放菌频度的12种接种式放菌方案作局势决策，以确定最佳放菌方案。

With biodiversity , caterpillar population density and control cost as indices , optimal inoculating frequency and dosage were determined based on grey decision-making method .

在此基础上，建立了不同虫口密度与茶鲜叶经济损失率线性回归方程。

Based on the results , the linear correlation equation was obtained for analysis on pest densities and economic loss rate of fresh tea leaves .

漆标记和隔离试验表明，4区蛴螬虫口密度显著性差异是果岭外部蛴螬迁入的结果；

Lacquer mark and isolating tests showed that difference of grubs population among green 4 areas was result of grubs moving from out of green ⅰ .

利用网罩法测定了假眼小绿叶蝉不同虫口密度对茶鲜叶产量及受害指数的影响。

Effect of different densities of Empoasca vitis on the yield loss rate and the damage indexes of fresh tea leaves was evaluated with the net method .

植株中部虫口密度较上部和下部大，差异显著，而上部和下部的虫口密度无显著差异。

The larvae density on the middle position was higher than the upper as well as the lower position of the tree , and was remarkable difference between them .

利用美国白蛾性信息素诱捕美国白蛾可有效监测成虫发生期，调查成虫虫口密度，为防治下一代白蛾提供准确的防治时间。

Trapping Hyphantria cunea with its sex pheromone can effectively monitor the occurrence and population density of adults , thus provide the exact control time for the next generation .

采用人工控制虫口密度，研究小麦生育期蚜虫密度对小麦产量的影响。

The effects of the population density of wheat aphids at different growth stages on wheat yield were investigated under controlled conditions with the density of the pest regulated .