Larvae Of Cotton Leafworm Research Articles

Synthesis, Insecticide Evaluation & Molecular Docking Studies of Some New Functionalized Pyrazole Derivatives Against the Cotton Leafworm, Spodoptera littoralis.

5-(Cyanomethyl)-3-((5,5-dimethyl-3-oxocyclohex-1-en-1-yl)amino)-1H-pyrazole-4-carbonitrile (3) is used as a key for the synthesis of arylidenes 5 a-fvia its reaction with some aldehydes 4 a-f. 5-[(5,5-Dimethyl-3-oxocyclohex-1-en-1-yl)amino]-3-(2-imino-2H-chromen-3-yl)-1H-pyrazole-4-carbonitrile (7) was synthesized via the reaction of compound (3) with 2-Hydroxybenzaldehyde in EtOH/piperidine. The target compounds were tested against cotton leafworm larvae in their second and fourth instar. The available data demonstrated that the LC50 values for commercial phenylpyrazole were 3.37 mg/L and 4.55 mg/L for the most affected synthesized compound, 5 b. The chemical structure of compound 5 bhas two cyano moieties, a pyrazole ring and a chlorophenyl, which may be increasing it efficiency. Evaluation of the latent effects of the examined synthesized compounds on various biological parameters, including adult longevity, pupal weight, proportion of normal, deformed pupae, adult emergency, fecundity, and egg hatchability, was done in an additional effort to slightly improve insecticidal compounds. Seven target synthesized compounds were subjected to a molecular docking analysis against glutamate-activated chloride channels. Twelve artificial compounds with the PDB ID of 4COF were subjected to a molecular docking study against the gamma-aminobutyric acid receptor (GABA).

Insecticidal and biochemical impacts with molecular docking analysis of three essential oils against Spodoptera littoralis (Lepidoptera: Noctuidae)

As an eco-friendly alternative to chemical insecticides, essential oils (EOs), have gained recognition for their pest-control properties. In this study, the toxicity, biochemical activity and molecular docking analysis of marjoram (Origanum majorana), citronella (Cymbopogon winterianus), and rosemary (Rosmarinus officinalis) EOs were investigated against 2nd instar larvae of cotton leafworm (Spodoptera littoralis) Boisaduval. GC–MS analysis of the chemical composition of the tested EOs showed that O. majorana, C. winterianus, and R. officinalis EOs contained 12, 20, and 5 components, respectively. O. majorana was composed largely of monoterpenoid molecules (47.12%), while both C. winterianus and R. officinalis were composed mainly of monoterpenes (84.39 and 92.16%, respectively). The toxicity tests revealed that R. officinalis EO had the highest insecticidal activity (LC50 = 2526.08 mg/L) against S. littoralis larvae. In addition, the tested EOs resulted in development disruption in S. littoralis, with R. officinalis EO showing the highest potency. Cymbopogon winterianus significantly inhibited the activity of detoxifying enzymes, namely, Carboxylesterase (α- and β-esterase), Glutathione S-Transferase (GST) and Cytochrome P450 (P450s). Similarly, C. winterianus and O. majorana inhibited the activity of superoxide dismutase (SOD). However, no significant difference in CAT activity was observed between the treated larvae and the control. As a result of docking analysis, the interaction of the main constituent of the tested EOs with GST occurred in the following order terpinen-4-ol> (Z)-citral> α-pinene correspondence to their energy score of −4.7386, −4.6491, and −4.5097 kcal/mol, respectively. The obtained results demonstrate the potential use of O. majorana, C. winterianus and R. officinalis EOs in S. littoralis management programs.

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.

Pesticidal Effect of Leaves Extract of Different Plants on the Larvae of Cotton Leaf Worm, Spodoptera littoralis.

<b>Background and Objective:</b> The cotton leafworm, <i>Spodoptera littoralis</i> (Boisd.) (Lepidoptera: Noctuidae), represents the worst lepidopterous pest on most vegetable crops. Moreover, its host range is extensive because it is a polyphagous and cosmopolitan pest that can cause an estimated loss of nearly 25.8 to 100% of crop production. Natural controls have replaced pesticides due to the environmental damage that chemical pesticides cause. Eggplant, tomato, okra and pepper are Egypt's most significant vegetable crops and the leaves of these plants are cheap and can act as botanical and nontoxic pesticides. <b>Materials and Methods:</b> <i>Spodoptera littoralis </i>larvae were reared in the laboratory and plant leaves of eggplant, tomato, okra and pepper were extracted in the laboratory with organic solvents. Then, these extracts were applied to the larvae. Therefore, the histological sectors in larvae bodies were prepared and the changes were observed compared with the control. <b>Results:</b> This study proved the efficiency of all plant leaf extracts, especially those of eggplant and tomato leaves (LC<sub>50</sub> of 1191.9 and 1582.7 ppm, respectively). In contrast, okra and pepper leaf extracts had the highest LC<sub>50</sub> (3904.8 and 5431.6 ppm, respectively). Also, the abnormalities in the midgut and internal tissues were evident in the larvae treated with eggplant leaf extracts, followed by tomato leaf extracts and okra leaf extracts. Larvae treated with pepper leaf extracts were as normal as the control. <b>Conclusion:</b> The current study opens horizons to new plant extracts that are cheap and unused plant parts and make them helpful as new and good insecticides.

Biological activity of tannins extracts from processed Camellia sinensis (black and green tea), Vicia faba and Urtica dioica and Allium cepa essential oil on three economic insects

Nowadays to move toward a more sustainable agriculture, use of pesticide alternatives that have positive effects and play critical roles toward reducing the use of pesticides should be used. Laboratory bioassays were carried out to analyze the bioactivity of tannins isolated from urtica weed leaves (U), bean hull (B), black tea (BT) and green tea (GT) against larvae of cotton leafworm Spodoptera littoralis (Boisduval) using food mixing technique and essential oil isolated from onion against larvae of cotton leafworm, adults of rice weevil and houseflies using fumigation technique. The results showed that during the first week of treatment, tannins extracted from U had the strongest antifeedant activity with an EC50 of 33.034 μg/g followed by tannins extracted from B (EC50 = 47.839 μg/g). In the second and third week, tannins isolated from B depicted highest antifeedant activity (EC50 = 37.733 and 84.828, respectively). Furthermore, the isolated tannins induced notable larval growth inhibition on S littoralis. On the other hand, mortality percentage of onion essential oil on tested insects clearly increased with both increased concentration and exposure time. The LC50 (μg/cm3) at 30 min reflected that the essential oil had a greater toxicity to cotton leafworm with a LC50 = 2.15 μg/cm3 while least toxic to house flies (LC50 = 16.09). The repellency action based on LT50 values was seen to be highly effective in houseflies (LT50 = 1.85 min). The results demonstrated that tannins and essential oil could be applicable in the management of insect pests to decrease ecologically detrimental effects of synthetic insecticides.

EVALUATION OF YIELD AND RESISTANCE TO COTTON LEAF WORM FOR SOME NEW GENOTYPES OF SOYBEAN UNDER OLD LANDS AND NEWLY RECLAIMED LANDS CONDITIONS IN EL-BEHEIRA GOVERNORATE

A field traial allowed in completely randomized design with three replications were conducted in the research farm of the agricultural research station of Etay Al-Baroud (old land) and the research farm of the Faculty of Agriculture, Damanhur University, in El-Bostan region, El-Beheira Governorate (newly reclaimed lands) during 2018 and 2019 seasons to evaluate the performance of twelve new genotypes of soybean compared with the three commercial varieties Giza 111, Giza 22 and Crawford. The resistance of genotypes to cotton leaf worm was estimated in the laboratory by raising a fourth instar larvae of cotton leaf worm and leaving them for feeding on the middle leaflet of the third upper trifoliate leaf of the plant for 24 hours, after that the areas that the insect fed on were measured as a percentage of the total area of the leaf (leaf area consumed). The resistance to cotton leaf worm in the field was estimated by vision according to the Smith and Brim 1979 method (defoliation %). The results confirmed that mean square due to genotypes, locations and genotypes x location were highly significant for all studied traits except the locations mean square for number of hairs under binocular field area and branches number /plant in the first season and genotypes x location mean square of number of hairs under binocular field area, branches number /plant, maturity date and 100-seed weight in both seasons as well as number of pods/plant in the second season. All tested genotypes significantly differ in their performances in all studied traits across the two locations and the four genotypes Line 3, Line 105, Line 127 and Line 129 seemed to excellent genotypes for yield and resistance to cotton leaf worm across the two locations. The consumed leaf area caused by cotton leaf worm and oil percentage negatively associated with pubescence density while seed yield positively associated with pubescence density. Seed yield and oil percentage negatively associated with the defoliation value. In general, it can be said that the four soybean genotypes, Line 3, Line 105, Line 127 and Line 129 are promising genotypes that could be sowing in newly reclaimed lands to expand soybean cultivation in Egypt.

Development of imidacloprid and indoxacarb formulations to nanoformulations and their efficacy against Spodoptera littoralis (Boisd)

BackgroundThe conventional pesticide formulations have many side effects on environmental. These effects were due to the huge quantity of pesticides used. Using of nanopesticide formulations can be reduced the quantity of pesticides used and subsequently decreased the cost of pest control and environment contamination.ResultsIndoxacarb and imidacloprid nanoparticles were developed. The size of nanoparticles ranged between 200 and 400 nm. The obtained results showed that the percentage of mortalities in second instar larvae of Egyptian cotton leafworm, Spodoptera littoralis were 95 and 75% in indoxacarb and imidacloprid nanoparticles, respectively. On the other hand, these percentages were 76.7 and 91.7%, respectively, with conventional formulations. In spite of one fifth of pesticide concentrations were used in nanoformulations, the LC50, s in nanoformulations were 2.9 and 15.9 ppm for indoxacarb and imidacloprid, respectively, compared to 34.3 and 66.5 in conventional formulation. The loading capacity in both indoxacarb nanoparticle and imidacloprid nanoparticle were 60.7 and 52.0%, respectively.ConclusionThese results found that indoxacarb and imidacloprid nanoparticles were 12 and 4 times, respectively, more effective than indoxacarb and imidacloprid conventional formulations against the second instar larvae of S. littoralis. These results also showed that indoxacarb and imidacloprid nanoparticles can be used as effective formulations against the cotton leafworm larvae instead of the conventional formulation to reduce the environment contamination, control cost and pest population.

Yeast Volatomes Differentially Affect Larval Feeding in an Insect Herbivore.

Yeasts form mutualistic interactions with insects. Hallmarks of this interaction include provision of essential nutrients, while insects facilitate yeast dispersal and growth on plant substrates. A phylogenetically ancient chemical dialogue coordinates this interaction, where the vocabulary, the volatile chemicals that mediate the insect response, remains largely unknown. Here, we used gas chromatography-mass spectrometry, followed by hierarchical cluster and orthogonal partial least-squares discriminant analyses, to profile the volatomes of six Metschnikowia spp., Cryptococcus nemorosus, and brewer's yeast (Saccharomyces cerevisiae). The yeasts, which are all found in association with insects feeding on foliage or fruit, emit characteristic, species-specific volatile blends that reflect the phylogenetic context. Species specificity of these volatome profiles aligned with differential feeding of cotton leafworm (Spodoptera littoralis) larvae on these yeasts. Bioactivity correlates with yeast ecology; phylloplane species elicited a stronger response than fruit yeasts, and larval discrimination may provide a mechanism for establishment of insect-yeast associations. The yeast volatomes contained a suite of insect attractants known from plant and especially floral headspace, including (Z)-hexenyl acetate, ethyl (2E,4Z)-deca-2,4-dienoate (pear ester), (3E)-4,8-dimethylnona-1,3,7-triene (DMNT), linalool, α-terpineol, β-myrcene, or (E,E)-α-farnesene. A wide overlap of yeast and plant volatiles, notably floral scents, further emphasizes the prominent role of yeasts in plant-microbe-insect relationships, including pollination. The knowledge of insect-yeast interactions can be readily brought to practical application, as live yeasts or yeast metabolites mediating insect attraction provide an ample toolbox for the development of sustainable insect management.IMPORTANCE Yeasts interface insect herbivores with their food plants. Communication depends on volatile metabolites, and decoding this chemical dialogue is key to understanding the ecology of insect-yeast interactions. This study explores the volatomes of eight yeast species which have been isolated from foliage, from flowers or fruit, and from plant-feeding insects. These yeasts each release a rich bouquet of volatile metabolites, including a suite of known insect attractants from plant and floral scent. This overlap underlines the phylogenetic dimension of insect-yeast associations, which according to the fossil record long predate the appearance of flowering plants. Volatome composition is characteristic for each species, aligns with yeast taxonomy, and is further reflected by a differential behavioral response of cotton leafworm larvae, which naturally feed on foliage of a wide spectrum of broad-leaved plants. Larval discrimination may establish and maintain associations with yeasts and is also a substrate for designing sustainable insect management techniques.

Biochemical characterization of spiromesifen and spirotetramat as lipid synthesis inhibitors on cotton leaf worm, Spodoptera littoralis

BackgroundTwo lipid synthesis inhibitors compounds (spiromesifen SPM and spirotetramat SPT) were used against the second instar larvae of cotton leaf worm, Spodoptera littoralis under laboratory condition. Toxicity of both compounds was tested. Effect of these insecticides on total lipid also was determined.ResultsThe obtained results showed that both compounds were moderately toxic against the second instar larvae of S. littoralis. The mortality percentages caused by the field rate of spiromesifen and spirotetramat were 51.7 and 60.0%, respectively. The lethal concentrations for 50% of tested insect population (LC50) were 170.1 and 42.2 ppm, respectively. The total lipid content was determined in treated larvae and compared with the untreated. The percentage of total lipid in spiromesifen- and spirotetramat-treated larvae was 2.17 and 2.21%, respectively, compared with 2.42% in untreated larvae. GC/MS also was used in identification of fatty acids composition of S. littoralis larvae.ConclusionThe results cleared that 13 fatty acids were identified in S. littoralis larvae. The obtained results showed significant difference in percentages of fatty acids with both treated and untreated larvae and also, between tested compounds. Some fatty acids were existed in untreated larvae but not existed in treated larvae.

Impact of nanosilver-profenofos on cotton leafworm, Spodoptera littoralis (Boisd.) larvae

BackgroundThe cotton leafworm, Spodoptera littoralis (Boisd.), is one of the most dangerous pests in Egypt and Africa, causing significant economic loss of cotton crop yield. The frequent use of insecticides to control this insect has led to the development of a generation’s resistance to them. The need of a new, safe control method and effective insecticides has become necessary after the recent increases in environmental pollution and insect resistance. This study is devoted to developing a novel synthetic scheme to produce a pesticide nanocomposite of very high efficiency compared to the originals. The nature of its chemical binding has been investigated via Fourier transform-infrared (FT-IR) and transmission electron microscopy (TEM) techniques.ResultsIn this work, the method is based on using silver nanoparticles (AgNPS) as a pesticide carrier by loading the organophosphorus pesticide profenofos on to their surface. The profenofos, AgNPS alone and nanocomposite profenofos (AgNPS@P) have been tested against second- and fourth-instar larvae of laboratory and field cotton leafworm. Our findings indicate that the AgNPS@P is more effective on cotton leafworm larvae than each of profenofos and nanosilver alone. The activity of AgNPS@P (LC50 = 0.94 and 5.15 ppm) was increased to 85 and 69 times more than that of profenofos (LC50 = 79.52 and 356.97 ppm) against second- and fourth-instar larvae of field cotton leafworm.ConclusionsThis method may be successful for reducing environmental pollution and the resistance of this pest to many pesticides.

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.

ANTIBACTERIAL, ANTIVIRAL AND CYTOTOXIC ACTIVITIES OF RHYNCHOPHORUS FERRUGINEUS (COLEOPTERA: DRYOPHTHORIDAE) AND SPODOPTERA LITTORALIS (LEPIDOPTERA: NOCTUIDAE) LARVAL EXTRACTS

The present study dealt with evaluating the effect of different crude extracts from the larvae of palm weevil, Rhynchophorus ferrugineus and cotton leaf worm, Spodoptera littoralis on different pathogenic strains of bacteria and viruses. The results revealed that, ethyl acetate extracts of R. ferrugineus and S. littoralis larvae were more effective against different pathogenic bacterial strains tested than petroleum ether, chloroform, methanol and ethanol extract. Also,The MICs’ determination showed that all different extracts of R. ferrugineus and S. littoralis larvae were active against tested bacterial strains. Minimum Inhibitory Concentration (MIC) values were ranged from 25 to 6.25mg/ml depended on tested species. Ethyl acetate extract from R. ferrugineus and S. littoralis larvae exhibited antiviral activity against hepatitis A virus (HAV) and Herpes simplex virus (HSV-1) cell lines at 625 & 312.5mg/ml. Ethyl acetate extract from R. ferrugineus and S. littoralis larvae recorded 5.19 & 4.07% antiviral activity against HAV at 625 & 312.5mg/ml, respectively; while, antiviral activity percentage was 12.42 & 26.17 at 625 and 312.5mg/ml, respectively against HSV-1. Tested extracts exhibited no antiviral activity against Coxsackie B virus (Cox B4) cell lines. Crude extracts of R. ferrugineus & S. littoralis were not cytotoxic to Vero (CCL-81) cells at 312.5 and/or 625μg/ml.

Toxicological and Biological Effects of some Synthetic Organic Compounds on Pink Bollworm, Pectinophora gossypiella (Sound.) and Cotton Leafworm, Spodoptera littoralis ((Boisd.) Laboratory Strains

Laboratory experiments have been conducted in the Plant Protection Research Institute (Sharkia Branch) Bollworms Research Department to evaluate the effect of to study the toxic and biological effects of three synthetic organic compounds, pyrazole: (A= 3-amino-5-hydrazino-4- phenyl azo -1H-pyrazole, B= 3-hydrazino-4- phenyl azo -5-hydroxy-1H-pyrazole and C= 1-(5-hydroxy-4- phenyl azo -1H-pyrazole-3-yl ) 3, 5-dimethylpyrazole) against the 1st instar larvae of pink bollworm, Pectinophora gossypiella (Sound.) and 2nd, 4th instar larvae of cotton leafworm, Spodoptera littoralis (Boisd.) under constant conditions of (26± 1oC. and 70 ± 5% R.H.). Data revealed that syntheticpyrazole compounds had highly toxic effect against newly hatched larvae of pink bollworm followed by 2nd and 4th instar larvae of S. littoralis. On the other hand, the latent effects of the pyrazoles compounds on the two insects species were presented in increasing the duration of larval and pupal stages, Significantly decreased on larval and pupal weight of the two insects, male and female longevities and also reduced the fecundity, While the highest reduction in laid eggs recorded 103.83 eggs/female in pink bollworm followed by 123.33 eggs/female for 2nd and 4th instar larvae of S. littoralis as compared with 287.25 egg/female for pink bollworm and 503.33 & 663.33 egg/female with untreated control, Also, results showed the tested chemical compounds on the hatchability rate caused decreased significantly with P. gossypiella recorded 61.48 % with compound (A) & 55.57 ,68.21 % reduction in 2nd, 4th instar larvae of S. littoralis compared 88.00% for untreated moths of P. gossypiella and 63.00 , 97.47 % in 2nd, and 4th instar larvae for untreated moths of S. littoralis, respectively

Toxicological and Biochemical Effects of Jojoba, Simmondsia chinensis Extract on Cotton Leafworm, Spodoptera littoralis (Boisd.)

This study was conducted to evaluate the toxicity and biological effects of ethanolic leaf extract of Simmondsia chinensis on 2nd and 4th instar larvae of cotton leafworm, Spodoptera littoralis, as well as the effect on total protein content and the activity some enzymes of S. littoralis larvae after 48 and 72 hr of treatment. The obtained results indicated that the extract was more effective on the second instar larvae than the fourth one. The LC50 of the jojoba extract on the 2nd instar larvae was less than that on the 4th instar larvae , as well as it was decreased by increasing the period after treatment indicated that the larval mortality was higher on 2nd instars than 4th ones. Larval duration was shortened at all treatments of the 2nd instars compared with control. Pupae mortality was high on the 2nd instar treatments comparing with that of the 4th instars, also, the pupae duration was shortened at all treatments of the 2nd and 4th instars compared with control. The percentages of emerged moths were decreased by increasing the extract concentrations.There were significant differences in the egg laid per female between treatments and control. Total protein after 48 hr. of treating was decreased from 32 mg/ g b wt. in control to 31.8 mg/ g b wt. at treated larvae with – 0.36 % change, while it was 19.5 mg/g b wt. at control compared to 14 mg/ g b wt. after 72 hr. with –28.21 % change. As for the enzymes activity it was observed that nearly all enzyme activities were decreased in comparison with control except α-esterase activity which was decreased to 15.3µg-a-naphthal/min/mg protein after 48 hr. from treatment compared with control 27.7 µg-a-naphthal/min/mg protein and increased to 23.2 µg-a-naphthal/min/mg proteinafter72 hr. from treatment compared with control 19.5 µg-a-naphthal/min/mg protein. Also, AkP activity which increased to 20.5 U x 103/mg protein after 48hr. of treatment, compared with control7.9 U x 103/mg protein and decreased to 3.7U x 103/mg protein compared with control 5.8 U x 103/mg protein after72 hr. of treatment. Jojoba is suggested as a safe product with a potential for use as a bioinsecticide in integrated pest management especially in urban localities where use of chemical insecticides are discouraged.

An endophytic Beauveria bassiana strain increases spike production in bread and durum wheat plants and effectively controls cotton leafworm (Spodoptera littoralis) larvae

Entomopathogenic fungi have traditionally been assumed to help regulate insect populations. However, some hypocrealean ascomycetes, such as Beauveria bassiana, play other, poorly understood ecological roles that might be useful in developing novel strategies for both increased crop production and crop protection. The primary aims of this work were (a) to assess endophytic colonization of bread wheat and durum wheat plants by the applied fungus B. bassiana strain EABb 04/01-Tip; (b) to examine the impact of various B. bassiana inoculation methods on growth, yield, phytohormone levels and nutrient uptake in the plants, and (c) to quantify mortality of cotton leafworm (Spodoptera littoralis) larvae fed with leaves from inoculated plants. Three experiments involving different inoculation methods (viz., ‘soil treatment’, ‘seed dressing’ and ‘leaf spraying’), and a fourth experiment to assess mortality in S. littoralis larvae fed with leaves from endophytically-colonized plants, and were conducted according to a completely randomized design. Beauveria bassiana successfully established within, and colonized, bread wheat and durum wheat plants. The fungus was, for the first time, re-isolated from grains produced by plants inoculated using the ‘seed dressing’ and ‘soil treatment’ methods. The fungus boosted spike production in bread wheat inoculated using the ‘seed dressing’ and ‘soil treatment’ methods, and also in durum wheat but only using the ‘soil treatment’ method. ‘Seed dressing’ increased grain yield by about 40%, and also root length, in bread wheat compared with control plants. Mortality in S. littoralis larvae fed with leaves from inoculated plants ranged from 30% using the ‘seed dressing’ method to 57% using the ‘leaf spraying’ method compared with 0% when fed the control leaves. However, no fungal outgrowth was detected in larval cadavers. The sustainability of crop production and crop protection strategies based on B. bassiana therefore depends on the effectiveness of the inoculation method and on the particular host plant.

Enhancing the efficacy of entomopathogenic nematodes by gamma radiation in controlling Spodoptera littoralis larvae

Nowadays, finding a safe control program is the aim of all researchers. The goal of this work is to investigate the effect of gamma radiation on the Entomopathogenic nematodes, Steinernema scapterisci and Heterorhabditis bacteriophora Poinar (HP88) efficacy were tested against larvae of cotton leaf worm, Spodoptera littoralis (Boisd.) under laboratory conditions. Results showed that 2 Gy irradiated S. scapterisci and H. bacteriophora were substantially effective in controlling S. littoralis larvae, while H. bacteriophora was more potent in controlling insect larvae. The results revealed that total protein concentration was significantly decreased (P < 0.05) after treatment with normal or irradiated H. bacteriophora or S. scapterisci. In addition, larvae infected with normal S. scapterisci or H. bacteriophora showed a significant elevation in phenoloxidase activity and represented significant reduce after treatment with 2 Gy irradiated S. scapterisci or H. bacteriophora as compared to control group. Also, lysozyme activity was significantly decreased after treatment with irradiated H. bacteriophora, but there was no significance with irradiated S. scapterisci, when compared with control. LDH activity was significantly high (p<0.05) in the haemolymph of larvae treated with normal or irradiated H. bacteriophora or S. scapterisci, as compared to control group. Furthermore among all treatments, 2 Gy irradiated H. bacteriophora was the most potent and efficient in the biomarkers changes. Therefore, it could be concluded that 2 Gy irradiated S. scapterisci and H. bacteriophora can serve within an integrated pest management (IPM) program in an agroecosystem.

Efficacy of Three Bioinsecticide and A methomyl Insecticide Against Cotton Leafworm Larvae, Spodoptera littoralis under Controlled Semi-field Conditions at El-Behara Governorate

Efficacy of Three Bioinsecticide and A methomyl Insecticide Against Cotton Leafworm Larvae, Spodoptera littoralis under Controlled Semi-field Conditions at El-Behara Governorate

A Method to Determine Lethal and Sublethal Concentrations of Recombinant Bioinsecticides Derived from Bacillus thuringiensis Against Larvae of Spodoptera litura

The increased awareness of environmental pollution have led to the growing interests of the application of biological agents to control insects such as lepidopteran family .Thus , this study aimed to produce genetically improved bioinsecticide agents to be used to control Spodoptera litura which would be useful in reducing environmental pollution ,preventing resistance to bioinsecticides and for safe food production .Four Bacillus thuringensis strains were used as recipients ' while ' Seratia marcescens was used as a doner strain in the conjugation to induce new recombinants in Bacillus thuringiensis over expressed chitinase.Four matings were conducted in this study between Serratia marcescence and the four Bacillus thuringiensis strains which having opposite genetic markers.Two efficient transconjugants based on chitin hydrolysis on agar medium were selected from each conjugation to be evaluated for toxicites against the larvae of cotton leafworm in relation to their parents .The efficient LC50 was appeared by Tr4 ( 1.93 x105 ppm ) followed by Tr6 and Tr7 ( 2x105 ppm). However , more than 995% toxicity index was recorded by Tr4,Tr6 and Tr7. Higher toxicity index observed by these transconjugants may be the related to the overexpression of chitinase genes.Therefore , the lethal concentration values obtained was necessary to kill 50% of larval population from Spodoptera litura in a certain period .The virulence of Bt strains showed that a lower concentration from Tr4 was required to kill 100% of larval population .It must be pointed out that higher toxicity index obtained by transconjugants reflected the interaction between crystal genes from Bt and chitinase genes from Seratia marcescens which enhanced the possibility of larval mortality as a genetic helpful tool in integrated pest management in cotton fields.

Impact ofBtcotton expressing cry1ac and cry2ab on cotton leaf worm,Spodoptera litura(F.)

Feeding assays with the top fully opened young, middle, and bottom leaves, squares, young green bolls and whole plant bioassays were conducted at the Agricultural Research Station, Darsi to compare the relative toxicity of commercially released single and dual toxin Bt cotton hybrids viz., Mallika BG, Mallika BGII with their non-Bt counterpart on survival and extent of damage by cotton leaf worm larvae, Spodoptera litura. Oviposition studies revealed that the number of egg masses laid, the fertile egg masses and number of neonates hatched per egg mass were not statistically different under both choice and no-choice situations. In insect feeding assays, Mallika BGII bottom leaves showed highest mortality (73.75) of neonate larvae followed by young leaves and squares (60.00) at 45 DAS and bottom leaves (81.25) followed by squares (70.00), young bolls (65.00), middle leaves (57.50) and terminal leaves (43.75) recorded at 75 DAS. At whole plant stage the degree of tolerance in Mallika BGII under choice and no-choice situations varied and the minimum leaf damage score (3.42), damage on squares (13.33%) and bolls (1.03%) was observed in no-choice situation when compared to leaf damage score of 3.00, square damage of 15.00% and boll damage of 2.86% by third instar larvae in choice situation.

Toxicity of Chlorantraniliprole and Lufenuron Against the Cotton Leafworm Larvae in Relation to Their Effects on AST, ALT and ALP Enzymes Activity

The toxicity of chlorantraniliprole (an anthranilic diamide) and lufenuron (an insect growth inhibitor) against the 2nd and 4th instar larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) was investigated. The in vivo effects of chlorantraniliprole and lufenuron on the activity of each of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatases (ALP) activities of the S. littoralis 4th larval instar were also assessed. The bioassay of the 2nd instar larvae revealed that chlorantraniliprole (LC50 = 0.009, 0.005 and 0.003 mg/l) was approximately as 234.3, 206.2 and 226.3 fold more toxic than lufenuron (LC50 = 2.019, 1.031 and 0.679 mg/l) after three different exposure periods (48, 72 and 96 hrs, respectively). Concerning the 4th instar larvae, chlorantraniliprole (LC50 = 6.645, 0.028 and 0.006 mg/l) was approximately as 2.01, 105.36 and 226.3 fold more toxic than lufenuron (LC50 = 13.37, 2.95 and 1.87 mg/l) after 48, 72 and 96 hrs of exposure, respectively. In vivo effect of chlorantraniliprole and lufenuron enhanced the activity of AST and ALT and that enhancement was concentration and time of exposure dependent. Both chlorantraniliprole and lufenuron inhibited ALP activity; which was also concentration and time of exposure dependent. Based on the obtained results, chlorantraniliprole and lufenuron would be involved within the current foliar insecticide applications used for controlling S. littoralis in cotton fields.