Effects of the Allelochemical, α-tomatine, on the Soybean Looper (Lepidoptera: Noctuidae)

1990 ◽  
Vol 25 (3) ◽  
pp. 376-382 ◽  
Author(s):  
F. Gallardo ◽  
D. J. Boethel
Keyword(s):  
Larval Mortality ◽  
Larval Growth ◽  
Developmental Time ◽  
Pupal Weight ◽  
Larval Weight ◽  
Wet Weight ◽  
Soybean Looper ◽  
Neonate Larvae ◽  
The Impact ◽  
The Relationship

To determine the impact of the allelochemical, α-tomatine, on the soybean looper, Pseudoplusia includens (Walker), various concentrations (0.001 to 0.10% wet weight of diet [wwt]) were added to an artificial diet. Neonate larvae were fed on the diet to determine effects on larval weight, developmental time, mortality, and pupal weight. Longer development times were observed at the higher concentrations (0.05 and 0.10% wwt). Larval mortality at 0.10% α–tomatine was signficantly greater (P ≤ 0.05) than all other concentrations. Larval weight was decreased by concentrations of α-tomatine above 0.005% wwt. A linear regression (Y = 217.8 - 2089.5 X, r2 = 0.90) described the relationship between larval growth and α-tomatine concentrations. The effective dose to reduce larval weight by 50% was calculated (ED50 = 0.048% wwt) and then validated in a subsequent experiment. In that study, a significant reduction (P ≤ 0.05) in mean body weight of 10- and 12-day-old larvae was obtained when larvae were fed diet containing the ED50 dose of α-tomatine. Percent growth relative to controls ranged from 56.1 to 52.1% at 6 and 12 days, respectively.

Bollworm (Lepidoptera: Noctuidae) Development and Movement on Bacillus thuringiensis-treated Cotton Leaves

2001 ◽  
Vol 36 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Muhammad Ashfaq ◽  
S. Y. Young ◽  
R. W. McNew
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Leaf Surface ◽  
Larval Mortality ◽  
Lethal Dose ◽  
Crop Protection ◽  
Pupal Weight ◽  
Larval Weight ◽  
Lepidoptera Noctuidae ◽  
Transfer Times

Larval mortality, survivorship and movement of the bollworm, Helicoverpa zea (Boddie), on and away from Bacillus thuringiensis-treated cotton leaves were investigated in the laboratory. Bacillus thuringiensis (Costar®, Novartis Crop Protection, Inc; Greensboro, NC) was applied to the upper surface of cotton leaves via a spray table in five concentrations, i.e., 0.0 (control), 0.14, 0.29, 0.58, and 1.15 kg/ha. Three-day-old H. zea larvae were released on treated leaves, kept at 30°C, and transferred to artificial diet after 12, 24, and 48 h. Significantly higher numbers of larvae were found on the lower than upper leaf surface after all three transfer times, but the numbers surviving in all treatments were similar to the control. Larval movement from the leaf to cup surface was significantly higher in B. thuringiensis-treated leaves than in the control. The mortality of larvae that were transferred from leaves to diet at 7 d after treatment was significantly higher in all treatments than in the control and highest at the highest rates (0.58 and 1.15 kg/ha). Data on survival of larvae at different locations suggest that for the first 24 h, the increase in the percentage of larvae on the inner cup surface in B. thuringiensis treatments was not due to larvae that had consumed a lethal dose, but an attempt to avoid the B. thuringiensis on the upper leaf surface. Highest larval weight was recorded in the control for all transfer times. The length of the larval period increased with the B. thuringiensis rate at the 12-h transfer. The pupal weight was reduced at the highest B. thuringiensis rates at the 48-h transfer.

scholarly journals Controlling of bacterial and fungal diseases that contaminating mulberry silkworm, Bombyx mori by using some plant extracts

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Mahmoud S. I. Saad ◽  
Enas M. Y. Elyamani ◽  
Walaa M. M. Helaly
Keyword(s):  
Bombyx Mori ◽  
Larval Mortality ◽  
Pupal Weight ◽  
Filament Length ◽  
Larval Weight ◽  
Shell Weight ◽  
Cocoon Production ◽  
Black Seed ◽  
Mulberry Silkworm ◽  
Silk Filament

Abstract Background Mulberry silkworm, Bombyx mori L. is one of the most economically important insect because its production of silk which interfere with many important industries. Diseases of the silkworm, B. mori such as viral, bacterial, fungal and protozoan pathogens seriously affect their cocoon production. Bacterial and fungal pathogens independently cause the highest cocoon loss, so the use of botanicals is considered an important strategy to control diseases of silkworm. Results The artificially infected silkworm, B. mori larvae with Bacillus thuriengiensis when treated with concentrations of 2 and 3% of black seed and basil leaves extracts increased significantly larval weight and decreased larval mortality. In addition, 3% basil leaves extract and 1% of black seed increased pupal weight. Cocoon weight and cocoon shell weight increased significantly by 3% basil leaves extract treatment. All tested concentrations of black seed extract increased the silk ratios of the resulted cocoons as compared to the infected control. For technological parameters, all tested extracts at 3% concentration caused the highest silk filament length; meanwhile control larvae recorded the highest silk filament weight and size. Regarding the mulberry silkworm, B. mori artificially infested with conidial solution of Beauveria bassiana when treated with all concentrations of the tested plants showed an enhancement in larval weight, pupal weight, cocoon weight, cocoon shell weight, silk filament length, and filament weight and reduced the larval mortality percentage. The highest silk filament size were recorded for the control group. Conclusions Tested concentrations of Morus alba, Ocimum basilicum leaves extracts and Nigella sativa seeds extract have suppressed the bacterial and fungal disease spread when used three times through both 4th and 5th larval instars. Moreover, the biological characters and technological traits enhanced by using of these extracts, so it can be used in sericulture for improving cocoon crop quality and quantity.

Influence of Cotton Plant Structures on Heliothine Larval Development and the Production and Infectivity of Occlusion Bodies of Nucleopolyhedrovirus in Larvae

2003 ◽  
Vol 38 (3) ◽  
pp. 368-376
Author(s):  
M. Ibrahim Ali ◽  
S. Y. Young ◽  
G. W. Felton ◽  
D. A. Streett
Keyword(s):  
Growth And Development ◽  
Helicoverpa Zea ◽  
Larval Growth ◽  
Developmental Period ◽  
Pupal Weight ◽  
Plant Structure ◽  
Larval Weight ◽  
Highest Weight ◽  
Occlusion Bodies ◽  
The Mean

Helicoverpa zea (Boddie) and Heliothis virescens (F.), reared on different cotton structures, were studied for larval growth and development, susceptibility to H. zea nucleopolyhedrovirus (HzNPV), and production of occluded virus (OBs). Larval weight of both species after 10 d of rearing differed with larvae on artificial diet having the highest weight and those on square bracts the lowest weight. In both species, pupal weight and length of pupal developmental period were positively correlated with the larval weight, but length of the larval developmental period was negatively correlated with larval weight. Mortality from virus infection of H. zea and H. virescens larvae on squares, square bracts or flowers did not differ significantly among the structures. In both species, the number of viral OBs produced was greater in larvae fed flowers than those fed other structures and was positively correlated with the weight gained by a healthy larva on that plant structure. The mean LC50 for OBs produced in H. zea or H. virescens larvae on square, square bract or flower did not differ significantly. These results indicate that dietary difference in fruiting structures of cotton plants directly affects H. zea and H. virescens larval growth and development and indirectly affects the production of virus by HzNPV-infected larvae.

scholarly journals Iflavirus Covert Infection Increases Susceptibility to Nucleopolyhedrovirus Disease in Spodoptera exigua

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 509
Author(s):  
Arkaitz Carballo ◽  
Trevor Williams ◽  
Rosa Murillo ◽  
Primitivo Caballero
Keyword(s):  
Spodoptera Exigua ◽  
Developmental Stages ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Developmental Time ◽  
Pupal Weight ◽  
Biological Pest Control ◽  
Egg Masses ◽  
Time To Death ◽  
Covert Infection

Naturally occurring covert infections in lepidopteran populations can involve multiple viruses with potentially different transmission strategies. In this study, we characterized covert infection by two RNA viruses, Spodoptera exigua iflavirus 1 (SeIV-1) and Spodoptera exigua iflavirus 2 (SeIV-2) (family Iflaviridae) that naturally infect populations of Spodoptera exigua, and examined their influence on susceptibility to patent disease by the nucleopolyhedrovirus Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) (family Baculoviridae). The abundance of SeIV-1 genomes increased up to ten-thousand-fold across insect developmental stages after surface contamination of host eggs with a mixture of SeIV-1 and SeIV-2 particles, whereas the abundance of SeIV-2 remained constant across all developmental stages. Low levels of SeIV-2 infection were detected in all groups of insects, including those that hatched from surface-decontaminated egg masses. SeIV-1 infection resulted in reduced larval weight gain, and an unbalanced sex ratio, whereas larval developmental time, pupal weight, and adult emergence and fecundity were not significantly affected in infected adults. The inoculation of S. exigua egg masses with iflavirus, followed by a subsequent infection with SeMNPV, resulted in an additive effect on larval mortality. The 50% lethal concentration (LC50) of SeMNPV was reduced nearly 4-fold and the mean time to death was faster by 12 h in iflavirus-treated insects. These results suggest that inapparent iflavirus infections may be able to modulate the host response to a new pathogen, a finding that has particular relevance to the use of SeMNPV as the basis for biological pest control products.

scholarly journals Seasonal variation in larval growth of Eri silkworm (Samia ricini Boisduval) reared on two Ailanthus species

2021 ◽  
Vol 22 (1&2) ◽  
pp. 199-204
Author(s):  
R. R. Borah ◽  
Monimala Saikia ◽  
H. Saikia ◽  
A. Borgohain ◽  
R. Borah Dutta
Keyword(s):  
Seasonal Variation ◽  
Growth Parameters ◽  
Larval Growth ◽  
Late Summer ◽  
Summer Season ◽  
Larval Duration ◽  
Larval Weight ◽  
Ailanthus Excelsa ◽  
Different Seasons ◽  
The Impact

Present study was undertaken to evaluate the impact of different seasons in larval growth of eri silkworm (Samia ricini Boisduval) reared on Ailanthus species viz., borpat (Ailanthus grandis) and borkesseru (Ailanthus excelsa). The study revealed that the larval growth parameters of eri silkworm was found better in terms of larval duration, full grown larval weight and matured larval weight on the borpat leaves as compared to the borkesseru leaves. Considering the seasons, the full grown larval weight and matured larval weight were observed significantly higher during the autumn season but the shortest larval duration was observed during the late summer season.

scholarly journals The effect of C6- to CIO- fatty acids on larval growth and survival of the olive fruit fly Bactrocera oleae (Diptera: Tephritidae)

2017 ◽  
Vol 13 ◽  
pp. 17
Author(s):  
A. G. Manoukas
Keyword(s):  
Larval Growth ◽  
Fruit Fly ◽  
Larval Survival ◽  
Bactrocera Oleae ◽  
Pupal Weight ◽  
Larval Performance ◽  
Olive Fruit Fly ◽  
Larval Weight ◽  
Olive Fruit ◽  
Egg Hatchability

The effects of caproic (C6), amino caproic (C6), caprylic (C8) and cupric (CIO) acid on larval performance of the olive fruit fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae) were investigated. The acids were added to an artificial larval diet at four different concentration levels, during the mixing of its ingredients. Eggs obtained from a colony of olive fruit flies were placed on these diets and on the control. caproic acid depressed significantly egg hatchability, larval survival and larval weight at the dietary level of 0.05 and 0.1 %. In addition, it did not permit eggs to hatch at the level of 0.2%. On the contrary, aminocaproic acid did not depress any of the parameters recorded up to the level of 0.2%. The levels of 0.4 to 1.6% depressed larval survival larval growth and pupal weight and the level of 3.2% did not permit larvae to survive. caprylic acid depressed significantly hatchability, larval survival and number of pupae/g diet at the level of 0.0125% and gave no pupae at the level of 0.1%. Finally cupric acid depressed egg hatchability, larval survival and larval weight from the level of 0.05% and gave no pupae at the level of 0.2%, Adult emergence was not affected by any of the acids tested.

scholarly journals Effect of Iron Fortified Wheat Flour on the Biology and Physiology of Red Flour Beetle, Tribolium castaneum (Herbst)

2010 ◽  
Vol 2 ◽  
pp. IJIS.S5200 ◽  
Author(s):  
Sohail Ahmed ◽  
Waqas Wakil ◽  
H.M. Salman Saleem ◽  
Mohammad Shahid ◽  
M. Usman Ghazanfar
Keyword(s):  
Tribolium Castaneum ◽  
First Generation ◽  
Larval Mortality ◽  
Developmental Time ◽  
Red Flour Beetle ◽  
Control Treatment ◽  
Larval Weight ◽  
Flour Beetle ◽  
Fortified Flour ◽  
And Control

Iron overload in the fortified flour can influence the life stages and physiology of the insects. The present study was carried out to evaluate the effect of commercially available premix iron fortified flour as well as effect of different concentrations of post-mix iron fortified flour (30–5 ppm) on biology of red flour beetle, Tribolium castaneum (Hebrst.). Larval and pupal duration, total developmental time, fecundity and larval weights in two consecutive generations of beetle were compared with control treatment. Amylase and protease activities of gut of the beetle were also measured in premix and postmix flours. Results showed that larval mortality increased in two sources of premix iron flour when compared with control. Larval weight was reduced in first generation only. The larval mortality was significantly higher in 30 ppm postmix iron fortified flour than in other postmix concentrations and control treatment. The larvae of T. castaneum fed on two sources of premix and in various concentrations of postmix iron fortified flour revealed an increase in amylases and decrease in protease activities.

scholarly journals Individual and combined impacts of sulfoxaflor and Nosema bombi on bumblebee ( Bombus terrestris ) larval growth

2020 ◽  
Vol 287 (1932) ◽  
pp. 20200935 ◽  
Author(s):  
Harry Siviter ◽  
Arran J. Folly ◽  
Mark J. F. Brown ◽  
Ellouise Leadbeater
Keyword(s):  
Reproductive Output ◽  
Bombus Terrestris ◽  
Larval Mortality ◽  
Larval Growth ◽  
Life History Stage ◽  
Nosema Bombi ◽  
Negative Effect ◽  
Negative Impacts ◽  
The Individual ◽  
The Impact

Sulfoxaflor is a globally important novel insecticide that can have negative impacts on the reproductive output of bumblebee ( Bombus terrestris ) colonies. However, it remains unclear as to which life-history stage is critically affected by exposure. One hypothesis is that sulfoxaflor exposure early in the colony's life cycle can impair larval development, reducing the number of workers produced and ultimately lowering colony reproductive output. Here we assess the influence of sulfoxaflor exposure on bumblebee larval mortality and growth both when tested in insolation and when in combination with the common fungal parasite Nosema bombi, following a pre-registered design. We found no significant impact of sulfoxaflor (5 ppb) or N. bombi exposure (50 000 spores) on larval mortality when tested in isolation but found an additive, negative effect when larvae received both stressors in combination. Individually, sulfoxaflor and N. bombi exposure each impaired larval growth, although the impact of combined exposure fell significantly short of the predicted sum of the individual effects (i.e. they interacted antagonistically). Ultimately, our results suggest that colony-level consequences of sulfoxaflor exposure for bumblebees may be mediated through direct effects on larvae. As sulfoxaflor is licensed for use globally, our findings highlight the need to understand how novel insecticides impact non-target insects at various stages of their development.

EXPERIMENTAL EVIDENCE FOR FACTORS AFFECTING THE RELATIVE EFFICIENCY OF INDIRECT TO DIRECT SELECTION IN TRIBOLIUM CASTANEUM

1969 ◽  
Vol 11 (1) ◽  
pp. 86-96 ◽  
Author(s):  
Eliyahu Scheinberg
Keyword(s):  
Random Mating ◽  
Developmental Time ◽  
Indirect Selection ◽  
Direct Selection ◽  
Pupal Weight ◽  
Larval Weight ◽  
Underlying Distribution ◽  
Factors Affecting ◽  
Genetic Gains ◽  
Different Populations

Uni-stage tandem selection was practiced for three traits in three different populations. An unselected random mating control population was also maintained. These populations, each replicated three times, were selected for ten generations. The three traits measured were: larval weight, developmental time and pupal weight. The factors affecting the genetic gains were discussed. It was demonstrated that indirect selection for larval weight, when selecting directly for pupal weight, is at least as efficient as selecting directly for larval weight. — The genetic gains obtained in the populations under study were compared to their theoretical expectations. They were found to be lower than expected in all selected populations. The results were explained on the basis of development of skewness in the underlying distribution, low realized selection differentials, overestimation of parameters before selection and biased estimates of genetic variances and covariances due to the presence of nonadditive genetic variance. — Further study of this problem, using an index for indirect selection, should be attempted.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

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