Cotton Leafworm Research Articles

Efficacy of the entomopathogenic nematode isolate Heterorhabditis taysearae to control the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

BackgroundEntomopathogenic nematodes (EPNs) are promising alternatives since they have many characteristics as a biological control agent against insect pests.ResultsAmong indigenous EPN isolated, adapted to local environmental conditions by employing the Galleria baiting strategy, only one sample was positive for the presence of EPNs. The new isolate was identified at the species level using DNA sequencing of the internal transcribed spacer region and the Basic Local Alignment Search Tool search of GenBank showed that the isolate had a high similarity (99%) with that sequence available for Heterorhabditis taysearae. The pathogenicity of the EPN isolate was tested against the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae), using different concentrations (60, 90, 120 and 150 IJs/larvae). Data showed that 150 IJs/larvae caused 100% mortality rate, followed by 120 IJs/larvae (90%), while 60 IJs/larvae showed the lowest rate (60%) after 72 h.ConclusionsThe present study indicated that the native isolate of EPN could be recommended against S. littoralis as an efficient tool in its control programs.

Photosensitizing Effect of Rose Bengal, Methylene Blue and Rhodamine on Cotton Leaf worm, Spodoptera littoralis Larvae

Photosensitizing Effect of Rose Bengal, Methylene Blue and Rhodamine on Cotton Leaf worm, Spodoptera littoralis Larvae

Potential Insecticidal Effect of a Wasp (<i>Polistes dominulus</i>) and a Bee (<i>Apis mellifera</i>) Venoms in Controlling <i>Spodoptera littoralis</i>

Cotton leaf worm, Spodoptera littoralis, is considered one of the most common arthropod pests that contribute to crop devastation of cotton. Previously, agricultural pests were controlled through the application of chemical insecticides. However, insecticide-resistant insect populations emergence, as well as increasing concerns about the environmental and human health risks. Venomous animals introduce valuable sources of bioactive compounds which are employed for defence. Some of these toxins have high phyletic specificity, making them appropriate for use in IPM programs. This study aims to test the insecticidal effects of Polistes dominulus and Apis mellifera venoms. Crude venoms were examined for their insecticidal effect against cotton leaf worms by four different application methods including: leaf dipping, integument dropping, spraying, and injection. The data demonstrated a strong response to purified (Polistes dominulus) venom at an initial time than that of honey bee (Apis mellifera) which increases response with increasing the dose and the time interval. A dosage of 0.015 - 0.16 ml of both venoms had notably varied in LD50 values on Spodoptera littoralis that showed higher wasp venom toxicity. Cotton leaf worms showed more susceptibility and mortality to the Polistes sp. venom than that of honey bees.

Entomotoxic effects of calcium-based materials derived from bio-waste eggshells as alternative inorganic insecticides against cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae)

Recycling agricultural waste and changing it into value-added products is considered one of the most important issues. In this context, waste eggshells were utilized as an alternative bio-calcium source for preparing calcium-based materials. The prepared materials were characterized by using Fourier transform-infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Their entomotoxic effects were estimated against Spodoptera littorals. Calcium-based materials provide an alternative inorganic insecticide for Spodoptera littorals besides their role in reducing the pollutant effects on the environment.

Synthesis and characterization of some new tebufenozide analogues and study their toxicological effect against Spodoptera littoralis (Boisd.)

Many of mimic analogues synthesized before depending on the change in the structure of aromatic rings. In this work, the carbonyl group in the structure of compounds 1-4 converted to thiocarbonyl group, and then studying the toxicological activity due to chemical change in the active center of mimic analogues was performed for compounds N-tert-butyl-2,4-dichloro-N'-(2,4-dichlorobenzoyl)benzohydrazide (2) and N-tert-butyl-2,4-dichloro-N'-[(2,4-dichlorophenyl)carbonothioyl]benzenecarbothiohydrazide (6). The toxicological study was done by using 2nd and 4th instar larvae of the cotton leaf worm, Spodoptera littoralis (Boisd.). Five concentration levels (600, 300, 150, 75 and 37.5 ppm) of compounds (2) and (6) were applied on the fresh plant food to the newly grown (2nd and 4th) instar larvae.

Evaluation of tea tree oil formulations contact and stomach toxicity against the Egyptian cotton leafworm, Spodoptera littoralis (Boisduval, 1883) (Lepidoptera: Noctuidae)

The insecticidal potential of tea tree oil formulations was tested for contact and stomach poison toxicities against various stages of the Spodoptera littoralis ((Boisduval, 1883) (Lepidoptera: Noctuidae) larvae under laboratory conditions. The study was carried out at Yozgat Bozok University Faculty of Agriculture between 2020 and 2021. In the contact toxicity test, the formulations were tested at different stages of larvae by topical application. Among the tested formulations, TTO (100%), F14 (91.72%), and F15 (89.20%) formulations caused the highest mortality in the S. littoralis 3rd stage larvae after 72 h. Dose-response bioassay with the most promising formulations (TTO, F14 and F15) revealed that LD50 values were 0.016, 0.046, and 0.076 μg/larvae for TTO, F14, and F15, respectively. The stomach poison effects of the formulations were tested by applying a 0.16 μg/cm$^{2}$ dose to lettuce leaf discs. The F17 and F18 formulations produced the highest mortality with mortality rates of 75% and 65% after 10 days of incubation, respectively. The calculated LC$_{50}$ values for these formulations were 0.027 and 0.042 μg/cm$^{2}$ for F17 and F18 formulations after 10 days of incubation, respectively. These results revealed that tea tree oil and its main components containing formulations have the potential in controlling this destructive lepidopteran pest species.

Efficacy and Biochemical Evaluation of Two Nano materials in Control of Cotton Leafworm, Spodopetra littoralis

Efficacy and Biochemical Evaluation of Two Nano materials in Control of Cotton Leafworm, Spodopetra littoralis

Effect of Exogenously Field Application of Jojoba Oil and Methomyl on Biochemical Constituents of Broad Bean (Vicia faba L.) Against Cotton Leafworm (Spodoptera littoralis Boisd.)

Effect of Exogenously Field Application of Jojoba Oil and Methomyl on Biochemical Constituents of Broad Bean (Vicia faba L.) Against Cotton Leafworm (Spodoptera littoralis Boisd.)

Comparative Effect of Some Bio Insecticides with Chlorpyrifos on Cotton Leafworm

Comparative Effect of Some Bio Insecticides with Chlorpyrifos on Cotton Leafworm

Synthesis of Novel Phenoxyacetamide Derivatives as Potential Insecticidal Agents Against the Cotton Leafworm, Spodoptera littoralis

A number of interesting N-(4-chlorophenyl)-2-phenoxyacetamide derivatives were synthesized through interaction of N-(4-chlorophenyl)-2-(4-formylphenoxy)acetamide (1) with cyanoacetamide derivatives 2a-e, hydrazine derivatives, activated nitriles and acetophenone to yield novel acrylamide, hydrazone, acrylonitrile and chalcone derivatives, respectively. Acrylamide derivatives 3a-e were used as precursors for synthesis of 2-pyridone derivatives comprising phenoxyacetamide moiety. The structures of the newly synthesized compounds were avowed by different spectroscopic techniques such as FT-IR, 1H-NMR, 13C-NMR, and mass spectroscopy. Finally, the insecticidal efficacy of the newly synthesized phenoxyacetamide derivatives was tested using the cotton leafworm Spodoptera littoralis. Among all, compounds 12, 6 b and 6c exhibited excellent results.

The Single and Combined Effects of Two Active Ingredients Against the Cotton Leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) and Its Predators in Soybean (Glycine max L.) in Al Qalyubia Governorate

The Single and Combined Effects of Two Active Ingredients Against the Cotton Leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) and Its Predators in Soybean (Glycine max L.) in Al Qalyubia Governorate

Isolation and identification of microbiota from Egyptian common insect pests invading economically important crops

Insects bodies contain multiple distinctive microbial colonies which play key role in the metabolism, development and health of an insect. In the current study bacterial and fungal microbiota were isolated from larval feces and adult wings of two major insect pests in Egypt, the Cotton leaf worm Spodoptera littoralis and the black cutworm Agrotis ipsilon. Isolated pathogens were identified and characterized according to the scientific described methods in such cases. Two different genera of bacteria (Bacillus & Serratia) were isolated from larval feces of both insects while isolated fungus were Paecilomyces variotii and Absidia corymbifera from the feces of A. ipsilon larvae, while Rhozopus stolonifer and Penicillium chrysogenum were isolated from adults wings of the same insect. The fungus Aspergillus flavus, Aspergillus niger and Mucor circinilloides were isolated from feces of S. littoralis larvae. Numerous species of bacteria and fungi had been documented as a bio-agent against many insect pests, and most of them exhibited disruption in life-cycle of different species of Lepidopterous pests. The obtained data sheds light on microbial colonies associated with two major insect pests, however further studies are required to involve the isolated microbiota in the biological control programs of insect pests.

Pathogenicity of some local entomopathogenic fungus isolates on the cotton leafworm larvae, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

BackgroundPathogenicity of the entomopathogenic fungi (EPF), isolated from soil samples collected from Ordu Province, Turkey, was evaluated on the second-instar larvae of the cotton leaf worm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions.ResultsFirstly, single-concentration response tests were conducted in order to determine the efficacy of the 64 isolates on S. littoralis larvae at the concentration of 1 × 108 conidia/ml. The five isolates displaying the highest mortality rates in single-concentration response tests, ORU-50, ORM-40, ORP-13, ORP-27 and ORM-48 (which included Beauveria bassiana, Metarhizium brunneum and Clonostachys rogersoniana), were subjected to concentration–response tests at the concentrations of 1 × 105–1 × 109 conidia/ml. The lowest LC50 and LC90 values were recorded at ORP-27 with 1.68 × 107 and 4.60 × 108 conidia/ml, respectively, followed by ORP-13 and ORM-40.ConclusionsAccordingly, it was found that M. brunneum isolates were more effective than B. bassiana and C. rogersoniana against S. littoralis larvae. ORP-27, ORP-13 and ORM-40 of M. brunneum isolates can be a potential biological control agent used against S. littoralis larvae.

Insecticidal Activity of seed extracts of Annona squamosa L., against the cotton leafworm Spodoptera littoralis (Boisd.)

The apple sugar, Annona squamosa have been reported to have toxic and biological activities against various insect pests. Twelve natural chemical compounds were identified from A. squamosa seeds extract. Acetone and methanol extracts of A. squamosa seeds were laboratory prepared to investigate their toxicity and other biological effects against Spodoptera littoralis larvae. Toxicity of acetone and methanol seed extracts of A. squamosa against 2nd and 4th instar larvae of S. littoralis were tested at different w/v concentrations using the leaf dipping bioassay technique. The results showed that, the acetone extract was more effective against the 2nd instar larvae of S. littoralis, LC50 values were 1.9, 1.7 and 1.1%, compared with the methanol extract, LC50 values were 2.8, 2.4 and 1.6% on 8, 11 and 14 exposure days, respectively. Regarding the efficiency of both A. squamosa seeds extracts against the 4th instar larvae, the acetone extract was again more toxic than the methanol one. The LC50 values of the acetone extract were 2.9, 2.1, and 0.97%, while the LC50 values of the methanol extract were 3.2, 2.1 and 1.7% on 8, 11 and 14 exposure days, respectively. In addition, the data exhibited that, the treatment of the 2nd instars larvae of S. Littoralis with acetone seed extract of A. squamosa at LC25 and LC50 prolonged the larval and pupal duration and reduced the pupal weight. Malformations of pupae and adults were recorded.

Herbivore feeding preference corroborates optimal defense theory for specialized metabolites within plants

Significance The “optimal defense theory” is a long-standing theoretical framework that is still controversially discussed. The central hypothesis of the optimal defense theory predicts that plant defenses are concentrated at the highest level in tissues and in organs that are the most valuable for survival and fitness. In this paper, we use the herbivore-deterrent defense compounds glucosinolates in the reference plant Arabidopsis thaliana as a model to test this central aspect of the optimal defense theory. We eliminated the gradient of glucosinolate distribution across tissues by the mutation of genes encoding transporters and thereby altered the feeding preference of the African cotton leafworm, Spodoptera littoralis , which is a devastating pest of many economically important crop plants including cotton, tomato, and maize.

What You Eat Matters: Nutrient Inputs Alter the Metabolism and Neuropeptide Expression in Egyptian Cotton Leaf Worm, Spodoptera littoralis (Lepidoptera: Noctuidae).

Lipids and carbohydrates are the two primary energy sources for both animals and insects. Energy homeostasis is under strict control by the neuroendocrine system, and disruption of energy homeostasis leads to the development of various disorders, such as obesity, diabetes, fatty liver syndrome, and cardiac dysfunction. One critical factor in this respect is feeding habits and diet composition. Insects are good models to study the physiological and biochemical background of the effect of diet on energy homeostasis and related disorders; however, most studies are based on a single model species, Drosophila melanogaster. In the current study, we examined the effects of four different diets, high fat (HFD), high sugar (HSD), calcium-rich (CRD), and a plant-based (PBD) on energy homeostasis in younger (third instar) and older (fifth instar) larvae of the Egyptian cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae) in comparison to a regular artificial bean diet. Both HSD and HFD led to weight gain, while CRD had the opposite effect and PBD had no effect in fifth instar larvae and pupae. The pattern was the same for HSD and CRD in third instar larvae while a reduction in weight was detected with HFD and PBD. Larval development was shortest with the HSD, while HFD, CRD, and PBD led to retardation compared to the control. Triglyceride (TG) levels were higher with HFD, HSD, and PBD, with larger lipid droplet sizes, while CRD led to a reduction of TG levels and lipid droplet size. Trehalose levels were highest with HSD, while CRD led to a reduction at third instar larvae, and HFD and PBD had no effect. Fifth instar larvae had similar levels of trehalose with all diets. There was no difference in the expression of the genes encoding neuropeptides SpoliAKH and SpoliILP1-2 with different diets in third instar larvae, while all three genes were expressed primarily with HSD, and SpolisNPF was primarily expressed with HFD in fifth instar larvae. In summary, different diet treatments alter the development of insects, and energy and metabolic pathways through the regulation of peptide hormones.

Stage-specific expression of an odorant receptor underlies olfactory behavioral plasticity in Spodoptera littoralis larvae

BackgroundThe detection of environmental cues and signals via the sensory system directs behavioral choices in diverse organisms. Insect larvae rely on input from the chemosensory system, mainly olfaction, for locating food sources. In several lepidopteran species, foraging behavior and food preferences change across larval instars; however, the molecular mechanisms underlying such behavioral plasticity during larval development are not fully understood. Here, we hypothesize that expression patterns of odorant receptors (ORs) change during development, as a possible mechanism influencing instar-specific olfactory-guided behavior and food preferences.ResultsWe investigated the expression patterns of ORs in larvae of the cotton leafworm Spodoptera littoralis between the first and fourth instar and revealed that some of the ORs show instar-specific expression. We functionally characterized one OR expressed in the first instar, SlitOR40, as responding to the plant volatile, β-caryophyllene and its isomer α-humulene. In agreement with the proposed hypothesis, we showed that first but not fourth instar larvae responded behaviorally to β-caryophyllene and α-humulene. Moreover, knocking out this odorant receptor via CRISPR-Cas9, we confirmed that instar-specific responses towards its cognate ligands rely on the expression of SlitOR40.ConclusionOur results provide evidence that larvae of S. littoralis change their peripheral olfactory system during development. Furthermore, our data demonstrate an unprecedented instar-specific behavioral plasticity mediated by an OR, and knocking out this OR disrupts larval behavioral plasticity. The ecological relevance of such behavioral plasticity for S. littoralis remains to be elucidated, but our results demonstrate an olfactory mechanism underlying this plasticity in foraging behavior during larval development.

Improvement of expired insecticides and their effectiveness against the cotton leafworm, Spodoptera littoralis (Boisd.)

ObjectivesThis study aimed to recycle some expired insecticides and evaluate their effectiveness against the cotton leaf worm, Spodoptera littoralis (Boisd.) as a tactic to dispose of these obsolete insecticides. MethodsThe physical and chemical characteristics of chlorpyrifos (Chlorzane 48% EC), malathion (Nasr-lathion 57% EC) and cyhalothrin (Lambda-cyhalothrin 5% EC) insecticides were determined. The active ingredients of the tested compounds were estimated by gas–liquid chromatography (GLC) equipped with a flame photometric detector GC/FPD and the insecticidal efficacy against the 4th instar larvae of the cotton leafworm, S. littoralis (Boisd.) was evaluated by the leaf dipping technique. ResultsThe physical and chemical characteristics of the tested insecticides clarified that chlorpyrifos (Chlorzane 48% EC) succeeded in the stability of emulsion, while cyhalothrin (Lambda-cyhalothrin 5% EC) and malathion (Nasr-lathion 57% EC) failed the test, whether unexpired or expired. The emulsifiers, Tween 80 or Triton X-100 at a concentration of 20%, managed to improve the characterizations of the expired insecticides, cyhalothrin and malathion. Moreover, these emulsifiers investigated a promising increase in the efficiency of expired cyhalothrin against S. littoralis. ConclusionsThe emulsifiers, Tween 80 or Triton X-100 could be used to increase the efficiency of expired insecticides, especially cyhalothrin 5% EC, thus managing to apply and dispose of that outdated insecticide.

Antifungal and Insecticidal Potential of the Essential Oil from Ocimum sanctum L. against Dangerous Fungal and Insect Species and Its Safety for Non-Target Useful Soil Species Eisenia fetida (Savigny, 1826).

The antifungal and insecticidal effect of the essential oil from Ocimum sanctum L. was evaluated using a model set of harmful organisms hazardous for health and the economy. Toxigenic and plant pathogenic filamentous fungi, including causal agents of human infections, were chosen as exemplary fungal groups—Fusarium verticillioides, Penicillium expansum and Aspergillus flavus. Spodoptera littoralis (African cotton leafworm), Culex quinquefasciatus (Southern house mosquito), the lymphatic filariasis vector and potential Zika virus vector, and the common housefly, Musca domestica were chosen as model insects. Major and minor active substances were detected and quantified using GC/MS analysis. Environmental safety was verified using the non-target useful organism Eisenia fetida. Significant antifungal and insecticidal activity, as well as environmental safety, were confirmed. The essential oil showed the highest efficacy against A. flavus according to MIC50/90, and against S. littoralis larvae according to LD50/90. The monoterpenoid alcohol linalool, t-methyl cinnamate, and estragole as phenylpropanoids were detected as effective major components (85.4%). The essential oil from Ocimum sanctum L. was evaluated as universal and significantly efficient, providing a high potential for use in environmentally safe botanical pesticides.

Toward Efficient and Safe Control Strategy Against cotton leaf worm Spodoptera Littoralis (Boisd.) (Lepidoptera: Noctuidae) Applying Onion and Pepper extracts and their Oils.

Toward Efficient and Safe Control Strategy Against cotton leaf worm Spodoptera Littoralis (Boisd.) (Lepidoptera: Noctuidae) Applying Onion and Pepper extracts and their Oils.