Cotton Leafworm Spodoptera Littoralis Research Articles

Disturbance of the Main Body Metabolites in Larvae and Pupae of Spodoptera littoralis (Lepidoptera: Noctuidae) by Certain Sesquiterpene Compounds

The Egyptian cotton leafworm Spodoptera littoralis (Boisduval) is a dangerous pest of many field crops and vegetables in the world. The present study was conducted to investigate the disturbing effects of the sesquiterpene compounds, Farnesol, Nerolidol, and Bisabolol, on the main body metabolites in larvae and pupae of this insect. The newly moulted last (6th) instar larvae were treated with LC50 values of these compounds (33.67, 42.24 and 59.31 ppm, respectively) and the determination of the main metabolites was achieved in haemolymph and fat bodies of larvae and the homogenate of pupae. The most important results could be summarized as follows. The present study recorded predominant reducing effects of these compounds on the protein content in larvae and pupae with an exceptional enhancing effect of some compounds at certain ages of last instar larvae. Also, the lipid content in haemolymph and fat bodies of larvae as well as in the pupae was remarkably reduced. In addition, all compounds exhibited predominant reducing effects on the carbohydrate content in haemolymph and fat bodies of larvae and in the pupae, with two exceptions of increasing carbohydrate content in larval haemolymph (at 24 hr post-treatment) and in larval fat bodies by Nerolidol (at 72 hr post-treatment).

Efficacy of entomopathogenic nematodes against Spodoptera littoralis (Boisd.) and Agrotis ipsilon (H.) (Lepidoptera: Noctuidae)

The study aimed to evaluate the efficacy of the EPNs against the larvae of Egyptian cotton leaf worm Spodoptera littoralis (Boisduval) and the black cutworm Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) in vitro before in vivo study. The susceptibility of both larval species to the entomopathogenic nematode species, Steinernema monticolum and Heterorhabditis bacteriophora, was evaluated under laboratory conditions. The concentration of 400 IJs/dish for S. monticolum achieved up to 97.77 and 95.55% mortality rates of the 5 larval instars from 2nd to 6th instars of S. littoralis and A. ipsilon, respectively after 72 h. The concentration of 800 IJs/dish recorded larval mortality rates of 41.86 to 100% against 2nd to 6th instars of A. ipsilon larvae, after 72 h. At the lowest concentration (50 IJs/dish), the larvae of S. littoralis were more susceptible to H. bacteriophora than the larvae of A. ipsilon. The data indicated that 200 IJs/dish was the most effective concentration for all larval stages of both insect pests because the mortality percentage was 100%.

Impairing Effectiveness of Nerolidol, a Sesquiterpene Compound, on Adult Performance and Reproductive Potential of Egyptian Cotton Leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae).

Although Egyptian cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) is native in Africa, it is distributed throughout the world. It is a serious polyphagous insect damaging more than 90 host plants of economic importance. The objective of the current study was to evaluate the disruptive impact of Nerolidol, a Sesquiterpene compound, on the most important parameters of adult performance and reproductive potential of this insect. The newly moulted larvae of 5th (penultimate) or 6th (last) instar larvae fed castor bean leaves previously treated with 7 concentrations of Nerolidol(400, 200, 100, 50, 25, 12.5& 6.25 ppm) for 24 hr. The most important results could be summarized as follows. Nerolidol exhibited an adulticidal activity only at the higher concentrations. Nerolidol exerted an anti-morphogenic activity against adult moths since some malformed adults were produced at the higher concentrations. Regardless the treated larval instar, Nerolidol induced the successfully emerged adults to live remarkably shortened total longevity and oviposition period, but the pre-oviposition period was generally prolonged. Nerolidol exhibited an inhibitory effect on the oviposition efficiency since the oviposition rate was deleteriously regressed, in a dose-dependent course. Nerolidol caused a disturbance of the reproductive capacity since fecundity and fertility were dramatically prohibited. After larval treatment with Nerolidol, the successfully mated adult females laid eggs with a significantly prolonged incubation period, especially at the higher concentration levels.

Insecticide resistance and efficacy evolved in field populations of Spodoptera littoralis in Egypt cotton season

This study aimed mainly to estimate the resistance of the cotton leafworm Spodoptera littoralis to several bioinsecticides Agerine 6.5% WP, Protecto 9.4 %WP biotect 9.4 %, wp Dipel 2x 6.4% WP, Dipel Df 5.4 % WG and two other bioinsecticides, Emamectin benzoate (Radical 0.5 %) EC against Spodoptera littoralis that all field strains the tested bioinsecticides used against cotton leafworm S. littoralis were calculated for both susebtable and field strains collected from six governorates namely Sharkia, Dakahlia, Behera, kafr- Elshek, Fayuom and Beni- swef in the cotton season 2019. The resistance ratio fluctuated from very low resistance to low resistance in some governorates to others except low of governorates RR indicated high resistance. tested IGR, s used against cotton leafworm S. littoralis were calculated for both susebtable and field strains collected from six governorates namely Sharkia, Dakahlia, Behera, kafr- Elshek, Fayuom, and Beni-Swef in the cotton season 2019. showed no resistance in all tested IGR, s for all Governorates, except some Governorate in some IGR, s

Bioefficacy of Farnesol, A Common Sesquiterpene, On the Survival, Growth, Development, and Morphogenesis of Spodoptera littoralis (Lepidoptera: Noctuidae).

Egyptian cotton leafworm Spodoptera littoralis (Boisduval) is a dangerous pest of many field crops and vegetables in the world. The present study was conducted to evaluate the toxicity of Farnesol and its effects on the growth, development, and morphogenesis of this insect. The newly moulted larvae of 5th (penultimate) or 6th (last) instar larvae were fed on castor bean leaves previously treated with 7 concentrations of Farnesol (400, 200, 100, 50, 25, 12.5 & 6.25 ppm) for 24 hr. The most important results could be summarized as follows. After treatment of 5th or 6th instar larvae with Farnesol, various mortalities were recorded among larvae, pupae, and adults. Depending onLC50values, Farnesol exhibited stronger insecticidal activity after treatment of 6th instar larvae(LC50= 33.67 ppm) than after treatment of 5th instar larvae(LC50= 36.56 ppm). Farnesol caused a serious reduction of larval weight gain and deleterious regression of the growth rate. The larval and pupal durations had been remarkably prolonged, in a dose-dependent course. Disruption of the developmental program was recorded as a failure of ecdysis after treatment of 5th instar larvae and production of larval-pupal intermediates, regardless the treated larval instar. Farnesol exerted considerable suppressing action on the pupation. At higher concentrations, Farnesol interfered with the adult emergence, since eclosion was completely prevented at the highest concentration and partially blocked at other concentrations. Irrespective of the treated larval instar, some deformed pupae were developed only at higher two concentrations of Farnesol.

Biological Activity of some Synthetic Cyanoacetamide Derivatives against some Cotton Pests

The continuous searching for new compounds that more effective is very important in the pest control field. That is because of the resistance in many pests to several pesticides. In the search for new biologically active compounds, extensive research is based on the synthesis of heterocyclic molecules. In this work, three new cyanoacetamide derivatives were synthesized and confirmed by IR spectra, mass spectra and elemental analysis. These compounds were; (1): 2-cyano-N-(2-hydroxyphenyl) acetamide, (2): (E)-2-cyano-N-(2-hydroxyphenyl)-3-(methylthio)-3-(phenylamino) acrylamide and (3): 1-(2-hydroxyphenyl)-4,6-dimethyl-2-oxo-1,2-dihydropyridine-3-carbonitrile. They were tested as active ingredients against the 3rd instar larvae of cotton leafworm Spodoptera littoralis (Boisd) and the adult stage of cotton mealybug Phenacoccus solenopsis under laboratory conditions. Based on the mortality percentages and LC50 values, all compounds had high toxicity against Phenacoccus solenopsis after 48 hours of treatment. While the second compound was more toxic against Spodoptera littoralis compared with other both compounds that had a very low toxicity.

Toxic effect of Spirulina platensis and Sargassum vulgar as natural pesticides on survival and biological characteristics of cotton leaf worm Spodoptera littoralis

In a trial to explore new alternatives to chemical pesticides whose negative side effects on humans and the environment are a serious concern, natural alternatives are being addressed to discover new, cost-effective and environmentally friendly compounds.; therefore, present work aimed to evaluate the toxicity of two algal species; Spirulina platensis (blue-green micro alga) and Sargassaum vulgar (brown marine macro alga) as natural pesticides against cotton leaf worm Spodoptera littoralis (Lepidoptera: Noctuidae). Water and ethanol extracts of tested algae prepared in three concentrations (3, 5 and 7 %). S. platensis extracts exhibited higher toxicity against 2nd and 4th larval instars, 2nd instar larvae were more susceptible to all treatments. Egg hatchability was slightly affected, larval and pupal duration prolonged with increasing extracts concentration. Ethanol extracts were more toxic especially at 7% concentration. Pupal malformation of 2nd larval stage was more affected than 4th one, similarly moth malformation of 2nd larval instar reached 59 and 43 % when treated with alcohol extract (7%) of S. platensis and S. vulgar respectively, while for 4th larval instar, adult malformation reached 33 and 29 % respectively. Female fecundity decreased with increasing concentration of algae extracts. Abnormal morphological changes observed during insect development. To evaluate insecticidal activity of examined algae, certain phytochemicals were screened in algae biomass including, total phenols, total tannins and total alkaloids; the highest percentages were recorded for total phenols followed by total tannins then total alkaloids in both algae, with more elevated levels in S. platensis biomass. Further investigations on phenolic constituents in S. platensis were done through HPLC analysis, indicating the occurrence of four phenolic compounds; quercetin (214.06 ppm), kaempferol (126.45 ppm), resorcinol (27.02 ppm) and Naphthaline (2.42 ppm). Study results revealed the efficacy of tested algae especially S. platensis as a potential source of natural pesticides to control mentioned pest.

Exploring essential oils of Slovak medicinal plants for insecticidal activity: The case of Thymus alternans and Teucrium montanum subsp. jailae

Thymus alternans and Teucrium montanum subsp. jailae are medicinal and aromatic plants, typical of Slovakian flora, producing bioactive essential oils. In the present study, we evaluated the insecticidal potential of the essential oils, obtained by hydrodistillation from the plant aerial parts and analysed by GC-MS, as insecticidal agents. For the purpose, they were assayed against three insect species acting as agricultural pests or vectors of medical relevance, such as the common housefly, Musca domestica L., the lymphatic filariasis vector, Culex quinquefasciatus and the Egyptian cotton leafworm Spodoptera littoralis; α-cypermethrin was tested as positive control. The two essential oils exhibited a different chemical profile, with monoterpenes and sesquiterpenes being the main fractions in the essential oils from Th. alternans and T. montanum subsp. jailae, respectively. Insecticidal tests showed that the T. montanum essential oil was effective against S. littoralis (LD50(90) = 56.7 (170.0) μg larva−1) and Cx. quinquefasciatus larvae (LC50(90) = 180.5 (268.7) mg L−1), whereas T. alternans essential oil displayed good toxicity against M. domestica adults (LD50(90) = 103.7 (223.9) μg adult−1). Overall, our results add useful knowledge about the potential of Slovakian flora as a source of botanicals for the eco-friendly management of insect pests and vectors.

Increasing the efficacy of the cotton leaf worm Spodoptera littoralis nucleopolyhedrosis virus using certain essential oils

Baculoviruses inactivation by UV sunlight is considered one of the most important factors that reduce their potential use in insect management programs. The three antioxidant essential oils, marjoram, orange, and tea tree were tested as protective additives to the multiple nucleopolyhedrosis virus (SpliMNPV) against UV. The results revealed that the orange oil was promising for virus protection, while the tea tree oil and marjoram oil did not protect the virus. The results also showed that the pathogenicity of the combination treatment of SpliMNPV and orange oil was increased drastically by adding the LC50 (1.0%) concentration of the oil to the virus concentrations. Consequently, the LC50 of the mixture was reduced to 5.3 × 103 PIB/ml compared to 3.2 × 105 PIB/ml concentration of virus alone. Concomitantly, the ovicidal and larvicidal effects of orange oils were determined. The results suggested that the combination treatment of orange oil and SpliMNPV could be used as an effective method for the cotton leaf worm, Spodoptera littoralis (Boisd.), management.

Study the Toxicity of Three Benzothiazole Compounds Formulated as 10 % Suspension Concentrate against Cotton Leafworm Spodoptera littoralis (Boisd)

Three compounds of benzothiazole were synthetized as active ingredient and prepared as 10 % suspensions concentrate (SC). They were evaluated against the second and fourth instar larvae of the cotton leafworm S. littoralis (Boisd.), under laboratory conditions. LC50 values showed that formulation (1) gave the highest toxic effect against 2nd and 4th instar larvae after 48 hrs from treatment and gave the best effect as antifeedant followed by formulation (3) and formulation (2). Semi field experiment was done to evaluate the initial and latent effects of the formulated compounds compared with commercial insecticide chlorpyrifos 48% EC (Dursban), the results showed that formulation (1) gave 100 % prevention of adult emergency due to the high initial and latent effects and lowest pupation percentage as the same as chlorpyrifos followed by formulation (3) and formulation (2) with the 2nd and the 4th instar larvae. Whereas Formulation (1) at 1 % is already as the same of recommended insecticide chlorpyrifos, therefore it could be recommended to use the new formulations as alternative of hazard conventional insecticides in controlling cotton leafworm in different crops after conducting the other necessary open field experiments.

Complex patterns in tolerance and resistance to pests and diseases underpin the domestication of tomato.

A frequent hypothesis explaining the high susceptibility of many crops to pests and diseases is that, in the process of domestication, crops have lost defensive genes and traits against pests and diseases. Ecological theory predicts trade-offs whereby resistance and tolerance go at the cost of each other. We used wild relatives, early domesticated varieties, traditional local landraces and cultivars of tomato (Solanum lycopersicum) to test whether resistance and tolerance trade-offs were phylogenetically structured or varied according to degree of domestication. We exposed tomato genotypes to the aphid Macrosiphum euphorbiae, the cotton leafworm Spodoptera littoralis, the root knot nematode Meloidogyne incognita and two common insect-transmitted plant viruses, and reconstructed their phylogenetic relationships using Genotyping-by-Sequencing. We found differences in the performance and effect of pest and diseases but such differences were not related with domestication degree nor genetic relatedness, which probably underlie a complex genetic basis for resistance and indicate that resistance traits appeared at different stages and in unrelated genetic lineages. Still, wild and early domesticated accessions showed greater resistance to aphids and tolerance to caterpillars, nematodes and diseases than modern cultivars. Our findings help to understand how domestication affects plant-pest interactions and underline the importance of tolerance in crop breeding.

A novel lineage of candidate pheromone receptors for sex communication in moths.

Sex pheromone receptors (PRs) are key players in chemical communication between mating partners in insects. In the highly diversified insect order Lepidoptera, male PRs tuned to female-emitted type I pheromones (which make up the vast majority of pheromones identified) form a dedicated subfamily of odorant receptors (ORs). Here, using a combination of heterologous expression and in vivo genome editing methods, we bring functional evidence that at least one moth PR does not belong to this subfamily but to a distantly related OR lineage. This PR, identified in the cotton leafworm Spodoptera littoralis, is highly expressed in male antennae and is specifically tuned to the major sex pheromone component emitted by females. Together with a comprehensive phylogenetic analysis of moth ORs, our functional data suggest two independent apparitions of PRs tuned to type I pheromones in Lepidoptera, opening up a new path for studying the evolution of moth pheromone communication.

Suitability of Host Plants and Insect Preys to the Zoophytophagous Tomato Bug Nesidiocoris tenuis (Reuter) (Heteroptera :Miridae)

The tomato bug Nesidiocoris tenuis (Reuter) (Miridae, Heteroptera)is one of the mirid bugs that can feed on plants and preys on different insect pests. It’s generally appears with large numbers in greenhouses and open fields of tomato crop in Egypt. It can complete the development of immature stages and survive on solanaceous plants with no choice feed. Tomato plants found to be the suitable host plant with survival rate 42.5%, followed by eggplant and pepper and represented by 21.7 and 10.0 %, respectively. Meanwhile, the duration of the total immature stage found to be the shortest duration when it reared on pepper plants and represented by 7.3 ±0.33days, followed by eggplant and pepper and represented by 8.3±0.3 and 7.7 ±0.3 days, respectively. In addition tomato bug can develop and survive when the immature stage feed on different insects as prey with no choice feed. The survival rate increased by feeding the immature stages insects as prey, the highest survival rate recorded when the tomato bug reared with the tomato borer, Tuta absoluta Meyrick. ranged between 80.8%, meanwhile the lowest survival rate record when reared immature stages on the cotton leafworm Spodoptera littoralis Bosid.,and ranged 63.3%, respectively .On other hand the duration found to be short with 6.33±0.33 days on the cotton whitefly Bemisia tabaci Genn., and T.absoluta followed by the cotton worm and plant hoppers Empoasca spp., and represented by 6.33±0.33 days, respectively. When tomato plants and insects as prey introduced to the immature stages with choice feed, the highest survivals rate were record and ranged 95.8 % on tomato with B. tabaci followed by tomato plants with T.absoluta ,S.littoralis and Empoasca spp.and represented by 92.9 , 90.8 and 89.2 ,respectively.

Effect of Oxymatrine 2.4% in some Biological Aspects of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

This study was conducted to evaluate the biological effects and the antifeedant effect of pesticide Oxymatrine 2.4% on the larval stage of cotton leaf worm Spodoptera littoralis when the second and fourth instar larvae fed on food treated with concentration 0.5 ,0.75 and 1 ml.Lˉ¹ of pesticide. The results of second larvae instar showed the highest mortality percentage which reached 76% when 1 ml.Lˉ¹ conc. was used. The lowest mortality percentage was 28.3% at the conc. 0.5 ml.Lˉ¹ The mortality percentage reached 34.3% at 1 ml.Lˉ¹ for fourth larvae instar. The results also indicated that the period of larvae growth and pupae were prolonged and decrease in the rate of adult age and the number of eggs laid of adults emerged from treated stages larvae. This study showed that Oxymatrine 2.4% had antifeedant effect against cotton leaf worm and the second instar larvae were the most susceptible, the effect of the pesticide was 70% for the second instar larvae while reached 29.9% for fourth instar larvae at ml.Lˉ¹.

Comparative Study of the Use of Insect Meal from Spodoptera littoralis and Bactrocera zonata for Feeding Japanese Quail Chicks.

Simple SummaryWith the increasing world population and rising meat consumption, sustainable high-quality feed is urgently needed. It was proposed that insects could be a promising alternative feed source, since they have high protein contents and can be reared sustainably on food production residues. Caterpillars of the African cotton leafworm Spodoptera littoralis can be cultivated on different residues of crops and vegetables and larvae of the peach fruit fly Bactrocera zonata can be reared on fruit and vegetable residues. In addition, mass rearing expertise of these two insect species already exists thanks to the sterile insect technique, a method of biological pest control. The nutrient composition of meals from these two insect species was determined and the impact of their meals as feed ingredients for Japanese quail chicks in comparison to soybean meal was investigated. In the feeding trials, 50% of the soybean protein was replaced with B. zonata meal and S. littoralis meal, respectively. For chicks fed with insect meal containing diets, improved growth, feed performance parameters, carcass characteristics and biochemical indices were observed in comparison to a soybean meal-based diet. Consequently, both insect meals represent a promising alternative to soy in the feed of Japanese quail chicks.A transformation of current livestock production towards a more sustainable operation is crucial to face nutritional and environmental challenges. There is an urgent demand for more sustainable high-quality feed sources to reduce environmental costs. Insects pose a potential alternative since they can be reared sustainably on food and feed residues. Know-how in mass rearing already exists for insect species used in biological pest control, such as the African cotton leafworm Spodoptera littoralis and the peach fruit fly Bactrocera zonata. The impact of a replacement of 50% of soybean meal by S. littoralis and B. zonata meal, respectively, on seven-days-old Japanese quail chicks was investigated in feeding trials. Concomitantly, the chemical compositions of the two insect meals and soybean meal were determined and compared. It was observed that the insect meals had higher protein and fat contents, lower carbohydrate contents and contained more saturated fatty acids than soybean meal. They also had higher methionine, and S. littoralis had a higher lysine content. Feeding trials resulted in improved growth, feed performance parameters, carcass characteristics, and biochemical indices for both insect meals. Consequently, both insect meals represent a promising alternative to soy in the feed of Japanese quail chicks.

Effect of Lambda-Cyahalothrin as Nanopesticide on Cotton Leafworm, Spodoptera littoralis (Boisd.)

The cotton leafworm Spodoptera littoralis is the most devastating insect pests to many crop plants. The overuse of pesticides increased their resistance in all pests. This study has been devote to develop a novel synthetic scheme to produce pesticide nanocomposite of very high efficiency compared to its original ones. The method is based on using silver nanoparticles (AgNPS) as a pesticide carrier by loading the pyrethroid pesticide Lambda-cyhalothrin (L-CYN) into the surface of prepared AgNPS. The nature of binding has been investigate via TEM and FT-IR techniques. The new formulation of the pesticide nanocomposite AgNPS@L-CYN has been teste for its larvicidal activity against second instar larvae of lab and field cotton leafworm. Our findings indicate that silver lambda-cyhalothrin nanocomposite is more effective on cotton leafworm larvae than that of formulated lambda-cyhalothrin alone. The required concentration for control of cotton leafworm decreased more than 37 times. This approach might be successful ones for decreasing the resistance of this pest to pesticides and reduce environmental pollution.

Combined efficacy of insecticides and entomopathogenic nematodes in the management of cotton leaf worm Spodoptera littoralis

Combined efficacy of insecticides and entomopathogenic nematodes in the management of cotton leaf worm Spodoptera littoralis

Biocontrol Potential of some Entomopathogenic Fungi against The Cotton Leaf Worm Spodoptera littoralis in vitro

Biocontrol Potential of some Entomopathogenic Fungi against The Cotton Leaf Worm Spodoptera littoralis in vitro

Assessment of the Inhibitory Impact of Novaluron, A Recent Insect Growth Regulator, on the Reproductive Potential of Spodoptera littoralis (Boisd.)(Lepidoptera: Noctuidae).

The Egyptian cotton leafworm Spodoptera littoralis is one of the destructive pests of field crops in the tropical and subtropical areas of the world. The objective of the present study was to assess the impact of Novaluron on the reproductive potential of this pest. A series of concentrations (1.0, 0.1, 0.01, 0.001 & 0.0001ppm) was prepared and applied on the freshly molted penultimate instar larvae. Another series (0.1, 0.01, 0.001 & 0.0001 ppm) was prepared and applied on the newly molted last (6th) instar larvae. The results can be summarized as follows. The tested compound exhibited a predominantly inhibitory effect on the oviposition efficiency, regardless the concentration and time of larval treatment. Both fecundity and fertility had been drastically reduced, in a dose-dependent course, regardless the time of treatment. Irrespective of the concentration and time of treatment, Novaluron halted the embryonic development, since the incubation period of eggs was remarkably prolonged. In light of the present results, Novaluron acts as an antigonadotropic compound in S. littoralis.

Antifeedant effect of Brassica nigra seeds against cotton leafworm Spodoptera littoralis and its potential antibacterial activity

Antifeedant effect of Brassica nigra seeds against cotton leafworm Spodoptera littoralis and its potential antibacterial activity