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 Biological activities of spores and metabolites of some fungal isolates on certain aspects of the spiny bollworms Earias insulana (Boisd.) (Lepidoptera: Noctuidae)

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Eman Mohammed Abd-ElAzeem ◽  
Warda Ahmed Zaki El-Medany ◽  
Hend Mohammed Sabry
Keyword(s):  
Biological Activities ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Pupal Weight ◽  
Earias Insulana ◽  
Dead Larva ◽  
Fungal Isolates ◽  
Protease Enzyme ◽  
Newly Hatched Larvae ◽  
Lepidoptera Noctuidae

AbstractBiological activities of spores and metabolites of some fungi isolated from dead larva of the spiny bollworms (SBW), Earias insulana (Boisd.) (Lepidoptera: Noctuidae), against the newly hatched larvae of the pest were carried out. Results showed that the fungi Metarhizium anisopliae, Acremonium sp., and Paecilomyces variotii had affected the newly hatched larvae of (SBW). Acremonium sp. was the most potent one as it had the highest newly hatched larval mortality percentage (65 and 58.33%) for its spore suspension and metabolites, respectively, while the lowest one (41%) was for P. variotii metabolites. Also, spore suspensions of the all fungal isolates had the highest larval mortality than fungal metabolites. Studying the enzymatic activity showed that Acremonium sp. produced protease enzyme on media containing gelatin, which caused the highest larval mortality (72.22%).These isolates showed different effects on all stages of the pest and decreased pupal weight, adult emergence percentages, deposited eggs, and hatchability percentages than the control. Identification of Acremonium sp. EZ1 was confirmed using 18 s rRNA and its accession number MN25101.

scholarly journals Differential side-effects of Bacillus thuringiensis bioinsecticide on non-target Drosophila flies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aurélie Babin ◽  
Marie-Paule Nawrot-Esposito ◽  
Armel Gallet ◽  
Jean-Luc Gatti ◽  
Marylène Poirié
Keyword(s):  
Side Effects ◽  
Bacillus Thuringiensis ◽  
Insect Pests ◽  
Larval Mortality ◽  
Specific Effect ◽  
Adult Emergence ◽  
Developmental Time ◽  
Field Application ◽  
Dependent Manner ◽  
Offspring Number

Abstract Bioinsecticides based on Bacillus thuringiensis (Bt) spores and toxins are increasingly popular alternative solutions to control insect pests, with potential impact of their accumulation in the environment on non-target organisms. Here, we tested the effects of chronic exposure to commercial Bt formulations (Bt var. kurstaki and israelensis) on eight non-target Drosophila species present in Bt-treated areas, including D. melanogaster (four strains). Doses up to those recommended for field application (~ 106 Colony Forming Unit (CFU)/g fly medium) did not impact fly development, while no fly emerged at ≥ 1000-fold this dose. Doses between 10- to 100-fold the recommended one increased developmental time and decreased adult emergence rates in a dose-dependent manner, with species-and strain-specific effect amplitudes. Focusing on D. melanogaster, development alterations were due to instar-dependent larval mortality, and the longevity and offspring number of adult flies exposed to bioinsecticide throughout their development were moderately influenced. Our data also suggest a synergy between the formulation compounds (spores, cleaved toxins, additives) might induce the bioinsecticide effects on larval development. Although recommended doses had no impact on non-target Drosophila species, misuse or local environmental accumulation of Bt bioinsecticides could have side-effects on fly populations with potential implications for their associated communities.

Population fluctuations of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), in Outdoor Cages in Kenya

1981 ◽  
Vol 71 (2) ◽  
pp. 289-297 ◽  
Author(s):  
B. Persson
Keyword(s):  
Cynodon Dactylon ◽  
Lake Victoria ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Developmental Time ◽  
Egg Laying ◽  
Spodoptera Exempta ◽  
Population Fluctuations ◽  
One Year ◽  
Nuclear Polyhedrosis

AbstractSpodoptera exempta (Wlk.) was reared for one year at three locations in Kenya: Msabaha on the coast, Nairobi, and Mbita Point on Lake Victoria. The potential yearly number of generations was 15·8 at Msabaha, 6·6 at Nairobi and 13·1 at Mbita Point. Average developmental time from egg deposition to adult emergence was 23·1, 54·9 and 27·8 days, respectively. The longest, 77·3 days, was recorded in Nairobi and the shortest, 19·4 days, at Msabaha. The survival rate varied little seasonally at the coast but was erratic inland, with some generations failing and others very successful. Larvae offered a choice of maize and stargrass (Cynodon dactylon) showed a preference for stargrass. Survival was higher on stargrass than on maize but the developmental time was longer. Mortality was highest in the larval stage. In all generations and at all locations, death was usually caused by a nuclear polyhedrosis virus. There was a positive relationship between larval mortality and rainfall, and a negative one between larval mortality and sunshine. Mating was restricted to after midnight. Females oviposited and then mated during the same night. Peak egg-laying took place before midnight, with a smaller peak at about 02·00–04·00 h.

scholarly journals Effect of Bacillus safensis NBRC 100820 isolated from cotton plant against the spiny bollworm, Earias insulana (Boisduval)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Ali Ahmed El-Sayed ◽  
Mohammed Farouk Ghaly ◽  
Ahmed Adel Amer
Keyword(s):  
Toxic Effect ◽  
Cotton Plant ◽  
Biological Effects ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Field Studies ◽  
Pupal Weight ◽  
Earias Insulana ◽  
Bacillus Safensis ◽  
Spiny Bollworm

Abstract Background Toxic effect of some local bacterial isolates, isolated from the Egyptian cotton plant (Gossypium barbadance L.), on larvae of the spiny bollworm (SBW), Earias insulana (Boisduval) (Lepidoptera: Nolidae) was studied as well as the biological effects of the most toxic isolate. Results Bacillus safensis NBRC 100820 had the most toxic effect on the SBW larvae compared to other isolates. Larval mortality percentages were 100, 90, 50, 50 and 30% for newly hatched, 3, 5, 7 and 10-day’s old larvae, respectively, after 2 days from treatment. Moreover, B. safensis NBRC 100820 caused latent effects on different stages of SBW. It decreased the larval and pupal weight, percentages of adult emergence and hatchability as well as number of deposited eggs/female more than the control. Using 16s rRNA confirmed the identification of B. safensis NBRC 100820 and its accession number is MW281809. Conclusions Use of B. safensis NBRC 100820 can be recommended for biological control of E. insulana. Further field studies are needed.

Development and Reproductive Behavior of Mantispa viridis Walker (Neuroptera: Mantispidae)

1995 ◽  
Vol 30 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Jeffrey R. Brushwein ◽  
Joseph D. Culin ◽  
Kevin M. Hoffman
Keyword(s):  
South Carolina ◽  
Mating Behavior ◽  
Reproductive Behavior ◽  
Developmental Stages ◽  
Adult Emergence ◽  
Developmental Time ◽  
Adult Longevity ◽  
Black Widow ◽  
Latrodectus Mactans

The development and reproductive behavior of Mantispa viridis Walker was examined in northwestern South Carolina. Campodeiform first instars actively searched spider egg sacs and halted the development of spider eggs that had advanced to the prelarval or larval developmental stages. M. viridis utilized both viable and inviable spider eggs and completed development on as few as five black widow, Latrodectus mactans (F.), eggs. Developmental time from eclosion to adult emergence averaged slightly less than 24 d. Both mated and unmated females produced egg clutches. However, viable clutches were only produced by mated females. Mated females produced a greater number of clutches each containing more eggs than unmated females. Unmated females produced a small number of eggs that embryonated, and in which a mantispid larva developed. However, larvae in these eggs did not eclose. Males were found to have the intertergal membranes between abdominal segments 3 and 4, and 4 and 5 expanded. These membranes were everted during courtship and apparently emitted a mating or recognition pheromone. Mating behavior and adult longevity are also described.

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.

scholarly journals Plant Growth Promoting Rhizobacteria of Cotton Affecting the Developmental Stages of Helicoverpa Armigera

2009 ◽  
Vol 49 (3) ◽  
pp. 239-243 ◽  
Author(s):  
Ayyathurai Vijayasamundeeswari ◽  
Duraisamy Ladhalakshmi ◽  
Ambalavanan Sankaralingam ◽  
Ramasamy Samiyappan
Keyword(s):  
Plant Growth ◽  
Helicoverpa Armigera ◽  
Developmental Stages ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Plant Growth Promoting Rhizobacteria ◽  
Broth Culture ◽  
Helicoverpa Armígera ◽  
Plant Growth Promoting ◽  
Growth Promoting

Plant Growth Promoting Rhizobacteria of Cotton Affecting the Developmental Stages ofHelicoverpa ArmigeraRhizobacteria isolated from cotton roots exhibiting antagonism towards seedling blight and leaf blight of cotton were tested for their efficiency against the insect pest American bollworm (Helicoverpa armigera). The bioformulation developed usingBacillus subtilis(isolate DGL9) + chitin was found to be detrimental to the developmental stages ofH. armigera(larva, pupa and adult) by causing larval mortality, pupal and adult malformation with reduced adult emergence. Generally, the larvae exhibited antifeeding behaviour when fed on bolls collected from rhizobacterial treatments. Hence, the developmental stages were altered leading to early pupation. Further, the efficacy of the isolate DGL9 was confirmed by culturing the bacteria in a suitable medium and incorporating the cell suspension and supernatant obtained form the broth culture in larval diet. The larvae fed to the diet exhibited defective developmental stages which was more significant in case of diet incorporated with supernatant. The percentage of pupal malformation, adult emergence and adult malformation was high at 96 h of incubation with the supernatant.

scholarly journals Toxicological, biological and biochemical effects of two nanocomposites on cotton leaf worm, Spodoptera littoralis (Boisduval, 1833)

2020 ◽  
Vol 89 (2) ◽  
pp. 101-112
Author(s):  
Soheir F. Abd El-Rahman ◽  
Sayeda S. Ahmed ◽  
Mahmoud H. Abdel Kader
Keyword(s):  
Graphene Oxide ◽  
Mortality Rate ◽  
Spodoptera Littoralis ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Pupal Weight ◽  
Cotton Leaf ◽  
Biochemical Effects ◽  
Total Carbohydrates ◽  
Biological Aspects

Cotton leaf worm, Spodoptera littoralis (Boisduval, 1833), is one of the most dangerous pests in Egypt, causing economically significant losses of different crops. The present study was aimed to evaluate toxicological, biological and biochemical effects of two nanocomposites, Silver (Ag) and graphene oxide (GO) nanomaterials over magnesium chlorophillin (Mg-Chl/Ag and Mg-Chl/GO) at three concentrations (1, 10, 100 ml/L) against 2nd instar larvae of S. littoralis. The results showed that larval mortality rate was positively correlated with the increase of concentrations of the tested nanocomposites and time after exposure. The mortality rate in nanographene oxide composite were higher than nano silver. LC50 (lethal concentration of 50% of a group of test larvae) values were 10.27 and 16.14 mg/L at Mg-Chl/Ag and Mg-Chl/GO compound at 2 h exposure to light. Some biological aspects of S. littoralis resulted from the treated 2nd instars larvae with two nanocomposites were recorded. Larval, pupal durations, pupation, adult emergence rate and pupal weight were significantly lower in all concentrations compared to untreated larvae. All tested samples showed decrease in total carbohydrates, total proteins and total lipids. Obtained results suggest that using silver and graphene oxide nanomaterials over the magnesium chlorophillin would be a useful component for controlling S. littoralis.

scholarly journals Effects of larval diet on the life-history traits and phenotypic expression of pyrethroid resistance in the major malaria vector Anopheles gambiae s.s.

2022 ◽  
Author(s):  
Pierre Marie Sovegnon ◽  
Marie Joelle Fanou ◽  
Romaric Akoton ◽  
Oswald Yédjinnavênan Djihinto ◽  
Hamirath Odée Lagnika ◽  
...  
Keyword(s):  
Life History ◽  
Insecticide Resistance ◽  
Life History Traits ◽  
Wing Length ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Developmental Time ◽  
Larval Diet ◽  
Anopheles Gambiae S.S ◽  
Permanet 3.0

The success achieved in reducing malaria transmission by vector control is threatened by insecticide resistance. To strengthen the current vector control programmes, the non-genetic factors underlying the emergence of insecticide resistance in Anopheles vectors and its widespread need to be explored. This study aimed to assess the effects of larval diet on some life-history traits and pyrethroid-insecticide susceptibility of Anopheles gambiae s.s. Three (3) An. gambiae strains, namely Kisumu (insecticide susceptible), AcerKis (homozygous ace-1 R G119S resistant) and KisKdr (homozygous kdr R L1014F resistant) were fed with three different diets (low, medium, and high) of TetraMin ® Baby fish food. Pre-imaginal developmental time, larval mortality, adult emergence rate and female wing length were measured. Mosquito females were exposed to insecticide-treated net (ITN) PermaNet 2.0 and PermaNet 3.0. In the three An. gambiae strains, significant differences in adult emergence rates ( F = 1054.2; df = 2; p <0.01), mosquito wing length ( F = 970.5; df = 2; p <0.01) and adult survival post insecticide exposure ( χ2 = 173; df = 2; p <0.01), were noticed among the three larval diets. Larvae fed with the low food diets took more time to develop, were smaller at emergence and displayed a short lifespan, while the specimens fed with a high regime developed faster and into big adults. Although being fed with a high diet, none of An. gambiae strain harbouring the kdr R and ace-1 R allele survived 24 hours after exposure against PermaNet 3.0. This study showed that variation in the larval diet significantly impacts An. gambiae life-history traits such as larval mortality and developmental time, adult wing length, and female susceptibility to pyrethroid insecticides. Further investigations through field-based studies would allow an in-depth understanding of the implications of these non-genetic parameters on the physiological traits of malaria vectors and consequently improve resistance management.

Development of Spodoptera exigua and Helicoverpa zea (Lepidoptera: Noctuidae) on Transgenic Cotton Containing CrylAc Insecticidal Protein

2000 ◽  
Vol 35 (4) ◽  
pp. 360-372 ◽  
Author(s):  
Muhammad Ashfaq ◽  
S. Y. Young ◽  
R. W. McNew
Keyword(s):  
Helicoverpa Zea ◽  
Spodoptera Exigua ◽  
Larval Mortality ◽  
Transgenic Cotton ◽  
Larval Period ◽  
Pupal Weight ◽  
Feeding Time ◽  
Bt Cotton ◽  
Cotton Pests ◽  
Lepidoptera Noctuidae

The effects of transgenic Bacillus thuringiensis (Bt)-cotton on three instars of Spodoptera exigua (Hübner) and Helicoverpa zea (Boddie) were studied. First, third and fifth instars were fed field-collected Bt-cotton leaves for 1, 2, 3, 4 and 7 d or until pupation, and then transferred to artificial diet. Larval mortality at pupation, length of larval and pupal periods, pupal weights and survival time from hatch to adult were recorded for regular and Bt-cotton. Larval mortality at pupation in S. exigua fed Bt-cotton was low for all instars exposed and feeding periods on Bt-cotton. The mortality in H. zea was high for first and third instars and significantly increased with the increase in feeding period on Bt-cotton (P &lt; 0.05). The length of larval period increased in both species when first and third instars but not fifth instars were fed Bt-cotton. In H. zea, the larval period increased when larvae were on Bt-cotton leaves for only 2 d. Pupal weight was reduced with an increase in feeding time on Bt-cotton in all three instars in both species. An increase in length of feeding time on Bt-cotton reduced survival to adults in both species on Bt-cotton in first and third instars but not in fifth instars. Survival to adults was much lower in H. zea than S. exigua for all instars exposed and feeding periods on Bt-cotton. These results demonstrate the large differences in effectiveness of Bt-cotton against lepidopteran cotton pests, as well as the adverse effects on larvae developing on Bt-cotton.

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