scholarly journals Impact of resistance to fenitrotion and esfenvalerate on the control of Rhyzopertha dominica (Coleoptera: Bostrichidae) in stored wheat

2020 ◽  
Vol 46 (2) ◽  
pp. e7612
Author(s):  
Javier Alberto Vásquez-Castro ◽  
Gilberto Casadei De Baptista ◽  
Casimiro Dias Gadanha Jr. ◽  
Julio Cesar Bracho-Pérez
Keyword(s):  
Rhyzopertha Dominica ◽  
Application System ◽  
Stored Wheat ◽  
Control Programs ◽  
Insecticidal Effect ◽  
Factors Influencing ◽  
Number Of Individuals ◽  
Residual Action ◽  
Brazilian Populations

Insecticides resistance can significantly compromise the control programs of Rhyzopertha dominica (Coleoptera: Bostrichidae), one of the main wheat pests in warehouses. The objectives of this work were to study the occurrence of resistance to fenitrothion and esfenvalerate in two Brazilian populations of R. dominica from Santa Rosa (SR lineage) and Campo Grande (CG lineage), as well as the insecticidal effect and residual action of these insecticides when used alone or as a mixture in stored wheat. The application system was calibrated to provide grain treatment at theoretical concentrations of 10 and/or 0.5 mg kg-1 fenitrothion and esfenvalerate, respectively. By comparing the fitted mortality curves for lineages within insecticides, as well as insecticides within lineages significant differences were observed in all cases. Esfenvalerate was ineffective in controlling R. dominica. The SR lineage of R. dominica was more resistant to the insecticides tested than the CG lineage. The number of individuals in the F1 offspring of R. dominica was dependent on the lineage, insecticide, and on the time after the application of insecticide. In the untreated grains (control), the CG lineage had a greater number of progeny than the SR lineage, while the opposite was verified in the grains treated. Fenitrothion and esfenvalerate are not useful for the control of R. dominica. Factors influencing control of R. dominica are discussed in this work.

scholarly journals Efecto insecticida del extracto de semillas de Neem (Azadirachta indica) sobre Collaria scenica, Stal (Hemiptera: Miridae)

2012 ◽  
Vol 5 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Daniel Antonio Villamil Montero ◽  
Natalia Naranjo ◽  
Mario Andres Van Strahlen
Keyword(s):  
Thin Layer ◽  
Azadirachta Indica ◽  
Seed Extract ◽  
Neem Seed ◽  
Insecticidal Effect ◽  
Negative Effect ◽  
Number Of Individuals ◽  
Layer Chromatography ◽  
Mortality Percentage ◽  
Neem Seed Extract

El presente trabajo se desarrollo con el objetivo de evaluar o efeito insecticida del extracto etanólico de semillas de Neem (Azadirachta indica A. Juss) sobre ninfas de la chinche de los pastos Collaria scenica Stal. Para eso, se elaboró un extracto a partir de frutos inmaduros de Neem mediante rotaevaporación. El extracto fue diluido en tres concentraciones de ppm que corresponden a los tratamientos. Por medio de cromatografías en capa delgada se determinó la presencia de Azaridactina. Se realizó un experimento DCA de 4 tratamientos y 5 repeticiones que incluyó las tres concentraciones del extracto y un control. En cada repeticion se usaron 15 ninfas, colocadas aleatoriamente en cajas plásticas herméticas con alimento y la concentración correspondiente. Diariamente se realizó una aplicación del extracto y se registró porcentaje de mortalidad, número de exuvia y número de individuos que llegaron al estado adulto en cada tratamiento. Los resultados fueron analizados con prueba Kruskal-wallis y Games-Howell para cada variable. Las tres concentraciones del extracto de semillas de Neem presentaron un efecto negativo sobre el desarrollo de las chinches. El tratamiento más concentrado (250ppm) fue el más eficaz presentando una mortalidad del 97%, menor número de exubias y menor número adultos al final del ensayo. Insecticide Effect of Neem (Azadirachta indica A. Juss) Seed Extract against Collaria scenica Stal (Hemiptera: Miridae) Abstract. This work was developed with the objetive to evaluate the insecticidal effect of the Neem (Azadirachta indica A. Juss) seeds against grass bug nymphs Collaria scenica Stal. For that, an extract was prepared from green fruits of Neem by rotaevaporación. The extract was diluted in three ppm concentrations corresponding to treatments. Using thin-layer chromatography we identified the presence of Azaridactina. DCA essay was carried out with 4 treatments and 5 repetitions that included the three extract concentrations and a control. In each repetition were used 15 nymphs, randomly placed in plastic boxes with food and the corresponding concentration. Every day an extract application was made and recorded mortality percentage, number of exuviae and number of individuals who came to adulthood in each treatment. The results were analyzed using Kruskal-Wallis and Games-Howell for each variable. The three concentrations of Neem seed extract had a negative effect on the development of the bugs. The more concentrated treatment (250 ppm) was the most effective, showing a 97% mortality, fewer exuvias and and fewer adults in the end of the experiment.

On the subsistence practices of the Shi’erqiao Culture: focused on zooarchaeology

2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Kunyu He
Keyword(s):  
Early Stage ◽  
Subsistence Strategies ◽  
Chengdu Plain ◽  
Factors Influencing ◽  
Animal Remains ◽  
Different Types ◽  
Minimum Number ◽  
Minimum Number Of Individuals ◽  
Archaeological Cultures ◽  
Number Of Individuals

AbstractThrough the analyses of the number of identified specimens (NISP), minimum number of individuals (MNI) and estimation of meat available from the animal remains unearthed from representative sites of the Chengdu Plain Type and Eastern Chongqing Type of the Shi’erqiao Culture, this paper discusses the subsistence strategy of this culture. The results show that the meat resources of the Chengdu Plain Type were mainly domesticated animals, while those of the Eastern Chongqing Type were mainly hunted animals. This paper draws the conclusion that in the early stage of human civilization, the subsistence strategies of different types of the same archaeological culture might be different, while those of different archaeological cultures might be similar; the factors influencing the subsistence strategies are mainly the natural environment, regional economic traditions, and population pressures.

1. Ageing, a brief history

2016 ◽  
pp. 1-21
Author(s):  
Nancy A. Pachana
Keyword(s):  
Life Expectancy ◽  
Developing World ◽  
Ancient World ◽  
Human Beings ◽  
Historical Trends ◽  
Factors Influencing ◽  
Number Of Individuals ◽  
Over Time

How has the construct of ageing, and attitudes towards it, changed over time? How have human beings from various historical epochs, cultures, and perspectives viewed ageing? What impact have these views about ageing had on individuals and our broader society? ‘Ageing, a brief history’ considers these questions and shows that from the ancient world to the modern there have been conflicting views on ageing. It examines historical trends in longevity and lifespan, and factors influencing life expectancy and ageing. We are now at a point in history where the number of individuals over the age of 65 will surpass those aged 5 and under, across the developed and developing world.

Factors influencing invertebrate drift in small forest streams, south-eastern Queensland

1995 ◽  
Vol 46 (8) ◽  
pp. 1101 ◽  
Author(s):  
BM Kerby ◽  
SE Bunn ◽  
JM Hughes
Keyword(s):  
Invertebrate Drift ◽  
Chironomid Larvae ◽  
South Eastern ◽  
Factors Influencing ◽  
Gut Fullness ◽  
Disproportionate Number ◽  
Forest Streams ◽  
Number Of Individuals ◽  
Low Drift ◽  
Small Forest

Aspects of invertebrate drift were investigated in four small rainforest streams in south-eastern Queensland. Hourly sampling in two streams revealed low drift rates and no distinct diel patterns. This may have been a consequence of the low flows experienced during the study period. The drift was dominated by Simuliidae, Chironomidae and to a lesser extent Tasmanocoenis sp. (Caenidae) and Cheumatopsyche sp. 6 (Hydropsychidae). Additional studies were undertaken to examine why some individuals of particular taxa drift while others (of the same taxa) remain in or on the substratum. Analysis of the relative gut fullness of simuliid and chironomid larvae showed that a higher proportion of non-drifting individuals had full or nearly full guts compared with those in the drift. Hungrier individuals of these two taxa may enter the drift as a food searching mechanism. An analysis of limb loss of hexapod nymphs indicated that a disproportionate number of individuals in the drift had one or more limbs missing compared with those that remained in the benthos. These data support the hypothesis that invertebrates present in the drift are less fit than non-drifters.

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