Cotton Leafworm Research Articles

Synthesis and insecticide evaluation of some new oxopropylthiourea compounds as insect growth regulators against the cotton leafworm, Spodoptera littoralis

In this project we aim to share in increasing the production of the most important non-food agricultural product i.e. cotton via protection of it is plant. The usage of safe alternatives to the pesticides has become crucial due to several serious issues associated with the use of insecticides. Therefore, the families of new eco-friendly organic compounds that contain manly oxopropylthiourea scaffold will synthesis in their pure state by using green procedures. This compounds includes (i) poly functional substituted oxopropylthiourea, (ii) dihydroquinoline carboxylic acid, In second category, the structure of this compounds which may be related to the most famous insect growth regulators insecticides, will confirmed by elemental and modern spectroscopic analyses (such as IR, UV, 1HNMR and 13CNMR). In the final category, the synthesized compounds was checked toward the second & forth instar larvae of cotton leafworm, Spodoptera littoralis. The present data proved that values of LC50 of the most effected synthesized compound 8 was 2.412 ppm in which LC50 for commercial lufenuron was 2.295 ppm. Component 8 may be particularly effective due to the presence of fluorophenyl, cyanoacetamide, and carboxalic acid groups in their chemical makeup. In an additional effort to slightly improve insecticidal compounds, evaluation of the latent effects of the examined components on a number of biological parameters, such as adult longevity, pupal weight, proportion of normal, deformed pupae, & adult emergency, fecundity, & egg hatchability, was carried out.

Larvicidal activity assessment for anticholinesterase insecticides against laboratory and field strains of Egyptian cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

Larvicidal activity assessment for anticholinesterase insecticides against laboratory and field strains of Egyptian cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

Effects of phthalate and bisphenol plasticizers on the activity of glycolytic enzymes of the moth Spodoptera littoralis

Environmental plastic pollution has significantly increased in the recent decades, and severely impacts economies, human and biodiversity health. Plastics are made of several chemical additives, including bisphenol and phthalate plasticizers such as bisphenol A (BPA) and Di(2-ethylhexyl)phthalate (DEHP). In some animal species, both BPA and DEHP are known as endocrine disruptor compounds, and can alter physiological and metabolic homeostasis, reproduction, development and/or behavior. To date, the impacts of BPA and DEHP have mainly focused on vertebrates, and to a lesser extent, on aquatic invertebrates. Yet, the few studies which examined the effects of DEHP on terrestrial insects also revealed the impacts this pollutant can have on development, hormone titrations, and metabolic profiles. In particular, it has been hypothesized in the Egyptian cotton leafworm Spodoptera littoralis that the observed metabolic alterations could result from the energetic costs necessary for DEHP detoxification or to the dysregulation of hormonally-controlled enzymatic activities. To get additional insights into the physiological effects of bisphenol and phthalate plasticizers on the moth S. littoralis, larvae were fed with food contaminated by BPA, DEHP, or the mixture of both compounds. Then, activities of four glycolytic enzymes, hexokinase, phosphoglucose isomerase, phosphofructokinase, and pyruvate kinase were measured. BPA and/or DEHP had no effects on the activities of phosphofructokinase and pyruvate kinase. Conversely, BPA-contaminated larvae were characterized by a 1.9-fold increase in phosphoglucose isomerase activity, and BPA + DEHP-fed larvae had highly variable hexokinase activity. Overall, since no disruption of glycolytic enzyme was observed in DEHP-contaminated larvae, our work tended to demonstrate that exposure to bisphenol and DEHP increased the amount of oxidative stress experienced.

Biochemical alterations in cotton leafworm, Spodoptera littoralis (Boisd.) related to emamectin benzoate and fipronil compared to their joint action

Cotton leafworm, Spodoptera littoralis (Boisduval), is one of the major destructive pests of ornamental, industrial, and vegetable crops. The efficacy of technical emamectin benzoate (EMB) and fipronil (FPR) was assessed against the 4th larval instar using leaf-dip bioassay method. EMB was more efficient than FPR based on 96 h LC50 values of 0.004 and 0.023 μg/ml, respectively. Joint toxic action of the dual exposure in sequence with time interval 24 h and in mix were evaluated at LC10:LC10, LC25:LC25 and LC50:LC50 after 96 h posttreatment, as well. Their impacts on detoxification enzymes, esterases (ESTs); alkaline phosphatase (ALP); and glutathione S-transferase (GST) as well as acetylcholine esterase (AChE) were also determined. The sequential exposure of EMB after FPR (S1) produced antagonism, potentiation, and potentiation effects, respectively while sequential exposure of FPR after EMB (S2) interacted as addition, potentiation, and potentiation respectively. The rest of binary mixtures (Mix) revealed antagonistic effect regardless of concentration. Orthogonal contrast analysis showed that the highest elevations of AChE, α-EST, β- EST and ALP enzymes were obtained from Mix at LC50:LC50 (181.6%, 288.4, 229.2 and 460.9%, respectively), LC25:LC25 (131.5%, 252.8, 205.60 and 252.0, respectively) and LC10:LC10 (106.6%, 215.6%, 201.8% and 170.0%, respectively). Differently, the greatest elevation of GST activity (157.7%) resulted from S1 at LC50:LC50, while it was significantly lower at LC25:LC25 and LC10:LC10 as well as Mix and S2 at all concentrations than corresponding concentrations of FPR. These findings shed some light on the role of GST in FPR toxicity and clarified the risk of these dual exposures in elevating detoxification enzymes dangerously compared to their individual insecticides. These dual exposures should be carefully handled. Although rotational exposure at low concentrations may enhance performance and mitigate resistance risk, rotational exposure at high concentrations and Mix may indirectly contribute to the evolution of cross-resistance to other insecticides.

Biocontrol potential of native isolates of Beauveria bassiana against cotton leafworm Spodoptera litura (Fabricius)

The entomopathogenic fungus (EPF), Beauveria bassiana, is reported as the most potent biological control agent against a wide range of insect families. This study aimed to isolate and characterize the native B. bassiana from various soil habitats in Bangladesh and to evaluate the bio-efficacy of these isolates against an important vegetable insect pest, Spodoptera litura. Seven isolates from Bangladeshi soils were characterized as B. bassiana using genomic analysis. Among the isolates, TGS2.3 showed the highest mortality rate (82%) against the 2nd instar larvae of S. litura at 7 days after treatment (DAT). This isolate was further bioassayed against different stages of S. litura and found that TGS2.3 induced 81, 57, 94, 84, 75, 65, and 57% overall mortality at egg, neonatal 1st, 2nd, 3rd, 4th, and 5th instar larvae, respectively, over 7 DAT. Interestingly, treatment with B. bassiana isolate TGS2.3 resulted in pupal and adult deformities as well as decreased adult emergence of S. litura. Taken together, our results suggest that a native isolate of B. bassiana TGS2.3 is a potential biocontrol agent against the destructive insect pest S. litura. However, further studies are needed to evaluate the bio-efficacy of this promising native isolate in planta and field conditions.

Endophytic actinobacteria from wild medicinal plants are a natural source of insecticide to control the African cotton leafworm (Spodoptera littoralis)

Insecticide resistance in agricultural pests has prompted the need to discover novel compounds with new modes of action. We investigated the potency of secondary metabolites from seventy endophytic actinobacteria against laboratory and field strains of Spodoptera littoralis (fourth instar), comparable to the bioinsecticide spinetoram (Radiant SC 12%). Endophytes from Artemisia herba-alba and A. judaica were highly effective. Chemical profiling of the most potent metabolite of the strain Streptomyces sp. ES2 was investigated using LC-QTOF-MS-MS technique, and the activity was validated through molecular docking studies. Metabolic extracts from actinobacteria belonging to Streptomyces, Nocardioides, and Pseudonocardia showed immediate and latent death to the Spodoptera littoralis fourth instar larvae. The metabolite from strain ES2 has shown the most promising and significant histopathological and inhibitory effects on the fourth instar larvae. ES2 metabolite caused lesions in the body wall cuticle, indicating a different mode of action than that of Radiant. Chemical profiling of ES2 showed the presence of cyromazine (molt inhibitor), 4-nitrophenol, and diazinon as key constituents. In conclusion, these findings suggest that secondary metabolites from endophytic actinobacteria inhabiting wild medicinal plants can be a sustainable source for promising natural biocontrol agents. This is the first illustration of the insecticidal activity of Artemisia spp. microbiome, and natural cyromazine synthesis by actinobacteria.

Effect of storage temperatures on the pathogenicity of Beauveria bassiana formulations against the cottonleaf worm, Spodoptera littoralis (Boisduval) (Lepidoptera:

Effect of storage temperatures on the pathogenicity of Beauveria bassiana formulations against the cottonleaf worm, Spodoptera littoralis (Boisduval) (Lepidoptera:

Comparative Assessment of Toxicity, Persistence, and Latent Bio-Effects Post Semi-Field Treatment of Some Conventional and Non-Conventional Insecticides upon the Cotton Leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae).

Comparative Assessment of Toxicity, Persistence, and Latent Bio-Effects Post Semi-Field Treatment of Some Conventional and Non-Conventional Insecticides upon the Cotton Leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae).

Individual and combined treatments with imidacloprid and spinosad disrupt survival, life-history traits, and nutritional physiology of Spodoptera littoralis

The Egyptian cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) is a pervasive agricultural polyphagous insect pest. Because of the negative side-effects of conventional pesticides used in agricultural fields, safer alternatives for insect pest management are required. We evaluated here susceptibility, biological features, and nutritional indices of S. littoralis after treatment of 4th-instar larvae with the neonicotinoid imidacloprid and the spinosyn spinosad separately or in combination. Larvae were fed for three successive days on treated leaves of castor-bean Ricinus communis using leaf-dip technique (treatment period). In addition, in case of nutritional indices study, treated leaves were replaced by fresh untreated leaves for two successive days (recovery period). Spinosad was more toxic than imidacloprid, and their combination revealed additive effects based on the co-toxicity factor. Individual and combined treatments significantly decreased pupation rate, adult emergence rate, pupal weight, number of eggs laid per female, egg-hatch, and female longevity, compared to those of controls. Pupal and adult malformations were recorded. During the treatment period, nutritional indices were insecticide- and time-dependent. On the 2nd day of recovery, all nutritional indices of treated larvae were not significantly different, compared to those of controls. The results presented herein may help in developing more effective crop protection methodologies within integrated pest management of this insect.

Utility of 5,5′‐Methylenebis(2‐hydroxybenzaldehyde) – cyanoacetohydrazide Hybrid as Scaffold for the Synthesis of Bis‐Heterocyclic Moieties and Study of Their Insecticidal Activity

AbstractThe cotton leafworm, Spodoptera littoralis Boisd. is a serious pest attacking a wide range of ornamentals and many field crops. It is well documented that some heterocyclic systems have efficient insecticidal activities. So novel hydrazide‐hydrazone namely, N′,N′′′‐((methylenebis(6‐hydroxy‐3,1‐phenylene))bis(methanylylidene))bis(2‐cyanoacetohydrazide) 3 was exploited as a target to synthesize bis‐heterocyclic moieties such as furan, pyridone, coumarin, thiazole and isoxazole, and also some bis‐heteroarylidenes including heterocycles as indole and pyrazole. The chemical structures of the synthesized compounds were established on the basis of elemental analyses and some spectroscopic tools. All the synthesized compounds were screened for the insecticidal efficacy against the 4th larval instar of Spodoptera littoralis (cotton leafworm). Manifestly, the data showed that compounds 9 and 14 possess remarkable potency but the rest of compounds showed no pronounced activity against cotton leafworm.

Evaluation of Beauvaria bassiana metabolite pretreated with silica nanoparticles against the cotton leafworm, Spodoptera littoralis (Boisd.)

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First study on the root endophytic fungus Trichoderma hamatum as an entomopathogen: Development of a fungal bioinsecticide against cotton leafworm (Spodoptera littoralis)

Cotton leaf worm (Spodoptera littoralis) is a pest that produces important losses in horticultural and ornamental crops in greenhouse, being classified as quarantine pest A2 by EPPO. One of the strategies proposed to control agricultural pests in a health and environmentally friendly way is biological control with entomopathogenic fungi. The genus of filamentous fungi Trichoderma includes different species with direct (infection, antibiosis, anti-feeding, etc.) and indirect (systemic activation of plant defenses) insecticidal capacity, however, the species T. hamatum has never been described previously as entomopathogenic. In this work, the entomopathogenic capacity of T. hamatum on S. littoralis L3 larvae was analyzed by applying spores and fungal filtrates (topically and orally). Infection by spores was compared with the commercial entomopathogenic fungus Beauveria bassiana, obtaining similar results with respect to the production of larval mortality. Oral application of spores reported high mortality and fungal colonization of larvae, however, T. hamatum did not show chitinase activity when grown in the presence of S. littoralis tissues. Therefore, infection of S. littoralis larvae by T. hamatum is through natural openings such as mouth, anus or spiracles. With respect to the application of filtrates, only those obtained from the liquid culture of T. hamatum in contact with S. littoralis tissues reported a significant reduction in larval growth. Metabolomic analysis of the filtrates determined that the filtrate with insecticidal capacity presented the siderophore rhizoferrin in large quantities, which could be responsible for this activity. However, the production of this siderophore had never been previously described in Trichoderma and its insecticidal capacity was unknown. In conclusion, T. hamatum presents entomopathogenic capacity against S. littoralis larvae through the application of spores and filtrates, and both ways could be the basis for the development of efficient bioinsecticides against the pest.

Characterization, expression analysis and RNAi-mediated knockdown of two aquaporin genes in the cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae)

Aquaporins (AQPs) are integral membrane proteins that can transport water and small molecules across cell membranes in organisms. In a previous report, we identified an AQP (SlAQP1) gene of the cotton leafworm, Spodoptera littoralis. In the current study, we identify and characterize two more SlAQP genes and their developmental and tissues expression. Predicted amino acid sequence and phylogenetic analysis revealed that SlAQP2 is a glycerol channel belonging to the insect specific Eglp subfamily, whereas SlAQP3 is a water specific channel belonging to the Prip subfamily. SlAQP2 expression was detected mainly in the first four larval instars and adult males, whereas SlAQP3 was detected in all developmental stages. SlAQP2 gene expression was mainly detected in larval midgut and Malpighian tubules and adult male testes, whereas SlAQP3 was detected in all the tissues tested. RNAi mediated knockdown of each gene separately resulted in deleterious effects including larval and pupal mortality, deformed pupae and adults and prolonged development. Results were confirmed using qRT-PCR, which revealed downregulation of both genes after injection of larvae with gene specific dsRNA. Our results confirm the presence of Prip and Eglp AQPs in S. littoralis and suggest that Eglp has a role in male reproductive ability.

Test of Pathogenicity of Bacillus thuringensis (Berliner) in Biological Control for the Cotton Leaf Worm, Spodoptera littoralis (Boisd.)

The study was carried out to evaluate the pathogenicity of the bacteria, Bacillus thuringensis of the cotton leafworm, Spodoptera littoralis (Boisd) at the rate of 1x106 spores/ml Laboratory results revealed that egg hatching percentage, at the age of 1-2 days were 0.0, 0.0 and 8.2 % 2 and 4 days after application respectively. While the hatching percentage of the 3-4 days old eggs was 6.8% at the age of 2-4 days after 2 days' treatment. The mortality rate of larval stages (2, 4, 6 instars) was 100% 14 days after application. When pupae were treated with the bacteria adult emergence percentage was 51.3 % 15 days after treatment compared to 100% emergence for the control treatment. The results in greenhouse show that the entomopathogenic bacteria also achieved mortality rate for 2, 4, 6 larval instars of the pest were 94.4, 91.8, 100, 88.4, 85.6 and 81.3 % for the soil and plant treatments respectively, 14 days after application.
 

Application of Unused Plant Parts as Plant Extracts Against Eggs of Cotton Leafworm, Spodoptera littoralis and GC- Mass Analysis of Tested Extracts

Application of Unused Plant Parts as Plant Extracts Against Eggs of Cotton Leafworm, Spodoptera littoralis and GC- Mass Analysis of Tested Extracts

Evaluation of Some Promising Soybean Genotypes to Infestation with Cotton Leafworm (<i>Spodoptera littoralis</i>) under Field Conditions

A two-year study was carried out in Giza Agricultural Experiments and Research Station, Agricultural Research Center (ARC), Giza, Egypt in the 2020 and 2021 summer seasons to evaluate the relative tolerance of ten soybean genotypes for cotton leafworm infestation under field conditions. Soybean genotypes H11L145, H155, H113, H4L4, H15L17, H129, H30, H19L96, Giza 111, and Crawford were distributed in randomized complete blocks design with three replications. Soybean genotypes differed significantly for cotton leafworm at the 6th, 7th, and 8th week from sowing. Low values of cotton leafworm assemblages were recorded for H113, H4L4, H15L17, Giza 111, and H129. Low percentages of the larval survival number and weight, as well as the number of the survival of pupa were recorded by feeding on leaves of genotypes H4F4, H15L17, and Giza 111 under laboratory conditions. There were significant differences among the studied genotypes in most yield attributes in both seasons. Soybean genotypes H15L17, Giza 111, H113, H129, H19L96, and H4L4 gave higher seed yield per ha, meanwhile soybean genotypes H155, H19L96, H30, Giza 111, and H15L17 had higher seed oil content than the other genotypes in both seasons. The number and weight of larvae surviving, as well as the number of pupa survival, were negatively correlated with leaf total phenols and seed oil content. It can be concluded that soybean genotypes H15L17, H4L4, and Giza 111 are promising genotypes with desirable seed oil content for tolerating cotton leafworm infestation in breeding programs.

Insecticidal thioureas: Preparation and biochemical impacts of some novel thiobenzamide derivatives as potential eco-friendly insecticidal against the cotton leafworm, Spodoptera littoralis (Boisd.)

The following work could bring new insights into the application of heterocyclic N, N′-substituted thiobenzamide derivatives as novel pesticides. Insect growth regulators such as chitin synthesis inhibitors seem promising because of their specific mode of action on insects and their lower toxicity against vertebrates than conventional insecticides. Thus, a novel series of thiobenzamide derivatives have been prepared in a pure state. The structure of these synthesized compounds which related to the most famous insect growth regulator insecticides, were confirmed by elemental and modern spectroscopic analyses (IR, UV, 1HNMR and 13CNMR). Toxicological and biochemical parameters of the synthesized compounds against the cotton leafworm, Spodoptera littoralis under laboratory conditions were also investigated. Regarding the determined LC50 value for compound 2,4-Dichloro-N-[(2-methoxyphenyl)carbamothioyl]- benzamide 14 showed the most potent toxic effects than the other synthetic target compounds, with LC50 46.84 ppm of 2nd instar larvae and LC50 148.05of the 4th instar larvae.

Characterization of Bacillus thuringiensis from Cotton Fields and its Effectiveness against Spodoptera litura

Cotton is a cash crop of many countries as it serves as a source of fiber, edible oil, and seedcake. It is grown in a diverse range of environment. Bacillus thuringiensis (Bt) is a gram positive bacterium found in different habitats but mostly found in soil. This bacterium produces endotoxin which is harmful for various insects. Numerous crystal-forming strains of Bt exist in nature, but not all of them are efficient against insect pests. Bt cotton is prevalent internationally because of less insect attack. The key objective of this research was to analyze different Bacillus thuringiensis isolates residing in soil of different cotton fields of Multan and Bahawalpur districts and to identify them on the basis of morphology. To attain this, different soil samples were collected from Multan (Gup wala, Mosey Wala, Taloki Wala, Hafiz Wala, Choudary Wala, Basti Mangla Mari, Sharkha Wala, Lawain Wala, Ghulamo Wala) and Bahawalpur district (Basti Deewan Wali, Check No 8, Basti Tariqabad, Basti Khaji Wala, Basti Khandin, Basti Rammo Wali, Sultanpur, Khurampur, Jahanpur). About 178 colonies of different bacteria from eighteen soil samples appeared on Nutrient Agar plates. The screening of colonies based on morphology yielded 18 colonies of Bt. We performed endo-toxin production experiment and confirmed the presence of parasporal crystals in identified B. thuringiensis colonies. Colony forming units of soil samples collected from Multan and Bahawalpur represented statistically significant results. Based on morphology, eight colonies of B. thuringiensis were confirmed out of eighteen colonies. Results of the current study revealed that out of 18 isolates, 8 bacterial isolates that were grown on the media had an increased elevation, a round, white, slimy morphology, and smooth edges. Toxicity test for resistance to cotton leaf worm second instar larvae revealed that two strains (BtS2, BtS7) of B. thuringiensis were toxic and showed 39.25% mortality. This study will help to identify the local Bt isolates that can be used for the indigenous insect pest control.

Insecticidal and Biochemical Effects of Jatropha Oil on Cotton Leaf Worm, Spodoptera littoralis, Larvae and F1 Larvae Produced from Irradiated Parent Males

Insecticidal and Biochemical Effects of Jatropha Oil on Cotton Leaf Worm, Spodoptera littoralis, Larvae and F1 Larvae Produced from Irradiated Parent Males

Testing the effect of some pathogens and the insecticide Aktar on the severity of cotton leafworm infestation Spodoptera littoralis (Boisd) on eggplant yield

أجريت تجربة لأختبار تأثير ثلاثة معاملات ( المستحضر الحيوي للفطر Beauveria bassiana .المعزز الحيوي العراقي ومبيد أكتارا ) لخفض شدة الأصابة بدودة ورق القطن Spodoptera littoralis على محصول الباذنجان للموسم الربيعي 2013 في البيت البلاستيكي في كلية الزراعة /جامعة بغداد. اوضحت النتائج أن معاملة المعزز الحيوي العراقي أعطت أعلى نسب مئوية للأوراق المصابة وعدد الثقوب , أذ بلغت 0.44% و67.4 ثقب / نبات على التوالي . بينما أظهرت معاملة المستحضر الحيوي للفطر Beauveria bassiana أعلى نسبة مئوية للمساحة الورقية المستهلكة والثمار المصابة ,أذ بلغت %1.9 و 0.31 ثمرة /نبات على التوالي .كما أظهرت المعاملة بالمبيد أكتارا أقل نسبة مئوية للأوراق المصابة , المساحة الورقية المستهلكة وعدد الثقوب بلغت 0.4, 1.0% و 60.8 ثقب / نبات على التوالي. بينماكانت معاملة المعزز الحيوي للثمار المصابة أعطت أقل شدة أصابة بلغت 0.17 ثمرة / نبات . أوضحت النتائج أيضاً وجود فروق معنوية بين المعاملات الثلاثة, كما تفوقت هذه المعاملات عن معاملة المقارنة بفروق أحصائية واضحة .