scholarly journals Bioinsecticidal Activity of some Compounds on the Cotton Leafworm, Spodoptera littoralis (Boisd.) under Laboratory Conditions.

2017 ◽  
Vol 8 (10) ◽  
pp. 525-528
Author(s):  
S. Awadalla ◽  
G. El-Mezayyen ◽  
M. Bayoumy ◽  
Nesreen EL-Mowafy
Keyword(s):  
Spodoptera Littoralis ◽  
Cotton Leafworm ◽  
Laboratory Conditions

scholarly journals Pathogenicity induced by indigenous Beauveria bassiana isolate in different life stages of the cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) under laboratory conditions

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Yasmin Adel Fergani ◽  
Elsayed Abd Elhameed Refaei
Keyword(s):  
Beauveria Bassiana ◽  
Spodoptera Littoralis ◽  
Adult Emergence ◽  
Mortality Rates ◽  
Cotton Leafworm ◽  
Control Programs ◽  
Laboratory Conditions ◽  
Ovicidal Effect ◽  
Lepidoptera Noctuidae ◽  
Mortality Percentage

Abstract Background The invincible effects of the entomopathogenic fungi (EPF) under appropriate circumstances compensate for the flaws of chemical insecticides in the control programs. Beauveria bassiana is one of the most elaborated EPF of pest control all over the world. The potential of using the B. bassiana isolate (Y-F_ITS1) was examined against different larval instars (L2, L3, L4, and L5), pupae, and eggs of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae), using different concentrations under laboratory conditions. Results In bioassay, 2nd instar larvae of S. littoralis were significantly the most susceptible stage to B. bassiana isolate at P ≤ 0.05. It is apparent from the results that the cumulative mortality percentage increased with elapsing time with typical symptoms of infection and sporulation. High efficacies ranging from 85.0 to 99.0% corrected mortality rates were recorded for 2nd instar larvae at the spore concentration (1 × 109 spores ml−1). The mortality percentage reached 90.0% for the 3rd instar larvae treated with the same concentration after 5 days. The least mortality rates results were recorded at the 5th instar larvae. B. bassiana isolate showed an ovicidal effect to the eggs of S. littoralis that reached 100% mortality when treated with 1.0 × 108 and 1.0 × 109 spores ml−1, while the concentration 1 × 107 and 1.0 × 108 caused 65.0 and 87.0%, respectively. Reduction of adult emergence reached (0%) in case of treatment with the highest concentrations (1 × 108 and 1 × 109 spores ml−1). Morphogenetic abnormalities were also recorded. Conclusion Results of mortality rates and lethal concentration values resulted from the experiments indicated that the tested Y-F_ITS1 isolate was efficient and can be recommended as a potential biocontrol agent against S. littoralis. Further field evaluations are still needed.

scholarly journals Sublethal effects of emamectin benzoate on life table parameters of the cotton leafworm, Spodoptera littoralis (Boisd.)

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
El-Sayed Mokbel ◽  
Amal Huesien
Keyword(s):  
Life Table ◽  
Spodoptera Littoralis ◽  
Sublethal Effects ◽  
Lethal Effect ◽  
Reproductive Rate ◽  
Relative Fitness ◽  
Emamectin Benzoate ◽  
Cotton Leafworm ◽  
Sublethal Concentrations ◽  
Preovipositional Period

Abstract Background The cotton leafworm, Spodoptera littoralis (Boisd.), is a serious economic pest in Egypt. Pest control depends mainly on chemical control with several pesticides include conventional and modern insecticides. Comprehensive analysis of pesticides impacts needs to investigate sublethal effects in addition to lethal effect. Results In the current study, the leaf-dip bioassay method was used to evaluate emamectin benzoate (EMB) sublethal concentrations. Results showed that EMB proved high toxicity against S. littorals with LC50 value of 0.019 mg liter−1. Life table analysis showed that treatments with LC5 and LC15 prolonged larval period, mean longevity of males and females, mean generation time (T), doubling time (DT), adult preovipositional period (APOP), and total preovipositional period (TPOP) compared with control. On the contrary, net reproduction rates (R0), intrinsic rates of increase (r), finite rate (λ), fecundity, gross reproductive rate (GRR), and relative fitness were decreased compared to control. Conclusions The current study clarified that sublethal concentrations of EMB induce adverse effects and suppress the population growth of S. littorals. Our results would be useful to assess the overall effects of EMB on S. littorals and can contribute effectively in pest management.

scholarly journals Efficacy of the parasitoid, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae) on the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) egg masses

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Hend O. Mohamed
Keyword(s):  
Spodoptera Littoralis ◽  
Insect Pests ◽  
Single Layer ◽  
Control Agent ◽  
Physical Characteristics ◽  
Great Ability ◽  
Egg Masses ◽  
Cotton Leafworm ◽  
Lepidoptera Noctuidae ◽  
Trichogrammatoidea Bactrae

Abstract Background The Egyptian cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is one of the major insect pests, causing a significant damage on different cultivated agricultural crops. Developing an alternative non-chemical tool, an effective and environmentally friendly method to suppress pest's infestation is essentially needed. Therefore, biological control by releasing the egg parasitoids could be the most promising tool for integrated pest management. Results This study was designed to evaluate the efficacy of the egg parasitoid, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae) as a bio-control agent against S. littoralis egg masses with different physical characteristics (number of egg layer and degree of scale density) in a no-choice and choice tests, under laboratory conditions. Also, the parasitoids’ fitness in terms of parasitism percentage, developmental period, adults’ emergence percentage, female offspring percentage, and longevity were investigated. The results revealed that T. bactrae wasps had a great ability to parasitize S. littoralis egg masses, but with different rates, related to their layers and scales’ thickness in both tests. The highest parasitism percentage was observed on one-layer eggs, followed by two layers. However, 3-layer eggs were the least preferable one. High numbers of adult emergencies (> 80%) were observed in all tested egg masses, except in the case of 3 layers with high scales. Furthermore, female-biased sex ratios were noticed at all examined eggs, with only the exception of high-scaly eggs with a single layer that recorded the lowest rate (≤ 45%). Besides, the survival of adult female parasitoids was not significantly affected in both tests. Conclusions T. bactrae could be used as a bio-control agent against S. littoralis egg masses with different physical characteristics based on the achieved results.

Sign in / Sign up

Export Citation Format

Share Document