نتایج جستجو برای: percentage of larval mortality
تعداد نتایج: 21196739 فیلتر نتایج به سال:
in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...
insurers have in the past few decades faced longevity risks - the risk that annuitants survive more than expected - and therefore need a new approach to manage this new risk. in this dissertation we survey methods that hedge longevity risks. these methods use securitization to manage risk, so using modern financial and insurance pricing models, especially wang transform and actuarial concepts, ...
effect of five soybean varieties (sahar, jk, bp, williams and l17) on life cycle and fecundity of the beet armyworm, spodoptera exigua (hã¼bner) was evaluated at temperature of 25 â± 1â°c, 60 â± 5% r.h. and a photoperiod of 16: 8 (l: d) h. the preimaginal development period of males and females was longest on l17 (30.17 â± 0.28 and 29.63 â± 0.23 days) and shortest on bp and sahar. the adult lon...
The effect of fungicides on silkworm larvae was analyzed with regard to the fact that these beneficial insects are usually affected by fungicides, Daily feeding on 1 and 2g/liter of carbendazim, a systemic fungicide, did not have significant effects on larval and pupal mortality. However the weight of the treated larvae showed considerable weight decrease up to 37% weight.. All the economic tra...
The life history of Enochrus quadripunctatus Herbst was studied in the laboratory. The duration of each developmental stage, larval behavior, and preimaginal mortality rate were determined. It takes the insect a total of 43 days from hatching to reach the adult stage, with a high mortality rate in the first stadium. The mortality rate decreases as the beetle passes through the immature sta...
background: the present study was undertaken to study the larvicidal activity of different extracts of nerium ole- ander leaves, and post-treatment temperature- toxicity relationship of these extracts against culex pipiens. further, the most potent extract was used to evaluate its biological and genotoxic activities. methods: crude extracts of n. oleander leaves were prepared using water, chlor...
the population response of heliothis armigera larvae to nuclear polyhedrosis virus (npv) was investigated. the virus was introduced by permitting the larvae to feed on lettuce leaves. median lethal doses (ld50) were determined. the estimated ld50 values for the first, second, third, early, and late fourth larval instars were 5, 141, 1226, 5168 and 24553 polyhedra per larva respectively. in ...
b a ckground: development of insecticide resistance occurred due to the continuous and misuse of synthetic insecti- cides therefore, the recent study was conducted to explore eco-friendly plant extracts that have some potential to sup- press mosquito larval population. m e t hods: who recommended mosquito larval bioassay method for insecticide was used while for the analysis of cit- rus oils fo...
abstract more than %90 of natural silk in world is produced by means of mulberry silkworm (bombyx mori l.). therefore, it is important that we recognize and collect mulberry varieties which have high quantity and quality leaf performance. for this purpose, an experiment was conducted with five mulberry varieties (kenmochi, kairyonase, ichinose, shinichinose and local varieties) during two seaso...
the purpose of this study was to investigate the relationship between family functioning and marital adjustment humor couples are due to the nature and objectives of the research and application of methods for its implementation correlation was used. the study population consisted of all the couples in the city who uses random cluster sampling of 200 students were selected as sample. data from ...
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