scholarly journals Alterations in the expression of certain midgut genes of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) larvae and midgut histopathology in response to Bacillus thuringiensis Cry1C toxin

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Hager Khalil ◽  
Saad Moussa ◽  
Haggag S. Zein ◽  
Dalia S. Ahmed ◽  
El-Sayed H. Shaurub ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Spodoptera Littoralis ◽  
Biological Control Agent ◽  
Mrna Level ◽  
Regulatory Elements ◽  
Control Agent ◽  
Peritrophic Membrane ◽  
Cotton Leaf ◽  
Pest Species ◽  
Tolerant Strain

Abstract Background Bacillus thuringiensis (Bt) utilization as a biological control agent is highly recommended due to its safety, specificity, and efficiency. Importance of the entomocidal Cry proteins secreted by Bt is dramatically increased subsequent Cry genes transformation into a number of economic crops, rendering them protection against insect attack. In the last decade, insect resistance against transgenic Bt crops is gradually raised in several lepidopteran pests. A better understanding of the processing of Bt Cry1C toxin in the larval midgut of the lepidopteran pest species, the cotton leaf worm, Spodoptera littoralis (Boisd.), is very important to characterize the main regulatory elements of Bt tolerance. Results The present study aimed to define factors that are involved in insect tolerance toward Bt Cry1C through evaluating the mRNA level of trypsin (Try), aminopeptidase N (APN), alkaline phosphatase (ALP), cadherin (Cad), and cytochrome P450 (CYP) in both susceptible and cry1C tolerant strains of S. littoralis. Total RNAs were extracted from susceptible and tolerant strains to construct cDNAs. Quantitative real-time polymerase chain reaction (qPCR) showed a significant upregulation of CYP gene in tolerant strain. In contrast, the levels of expression of Try, ALP, and Cad were significantly downregulated in tolerant strain. APN relative mRNA expression did not show significant differences between susceptible and tolerant strains. Histologically, the midgut of late third-instar larvae of tolerant population S. littoralis showed vacuolization of the epithelium and disruption of both the peritrophic membrane and the striated boarder compared to the susceptible strain. Conclusions Obtained data indicated a relationship between exposing to Bt Cry1C toxin and alteration of CYP, Try, ALP, and Cad expression in midgut of S. littoralis. These results may be an evidence for the important roles of CYP, Try, ALP, and Cad in the resistance development and toxicity to Bt Cry1C. The results are useful for further illustrating of Bt Cry1C processing and S. littoralis tolerance.

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

2022 ◽  
Vol 32 (1) ◽  
Author(s):  
Amany M. Abd El Azim
Keyword(s):  
Spodoptera Littoralis ◽  
Insect Pests ◽  
Biological Control Agent ◽  
Entomopathogenic Nematode ◽  
Control Agent ◽  
Local Alignment ◽  
Cotton Leaf ◽  
Internal Transcribed Spacer Region ◽  
Control Programs ◽  
Lepidoptera Noctuidae

Abstract Background Entomopathogenic nematodes (EPNs) are promising alternatives since they have many characteristics as a biological control agent against insect pests. Results Among 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. Conclusions The present study indicated that the native isolate of EPN could be recommended against S. littoralis as an efficient tool in its control programs.

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

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Funda Şahin ◽  
Yusuf Yanar
Keyword(s):  
Biological Control ◽  
Entomopathogenic Fungi ◽  
Entomopathogenic Fungus ◽  
Spodoptera Littoralis ◽  
Biological Control Agent ◽  
Mortality Rates ◽  
Control Agent ◽  
Soil Samples ◽  
Cotton Leaf ◽  
Lepidoptera Noctuidae

Abstract Background Pathogenicity 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. Results Firstly, 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. Conclusions Accordingly, 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.

scholarly journals Dissecting the Environmental Consequences of Bacillus thuringiensis Application for Natural Ecosystems

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 355
Author(s):  
Maria E. Belousova ◽  
Yury V. Malovichko ◽  
Anton E. Shikov ◽  
Anton A. Nizhnikov ◽  
Kirill S. Antonets
Keyword(s):  
Bacillus Thuringiensis ◽  
Biological Control Agent ◽  
Control Agent ◽  
Plant Colonization ◽  
Natural Ecosystems ◽  
Terrestrial Invertebrates ◽  
Environmental Consequences ◽  
Local Plants ◽  
Complex Relationships ◽  
Bacteria And Fungi

Bacillus thuringiensis (Bt), a natural pathogen of different invertebrates, primarily insects, is widely used as a biological control agent. While Bt-based preparations are claimed to be safe for non-target organisms due to the immense host specificity of the bacterium, the growing evidence witnesses the distant consequences of their application for natural communities. For instance, upon introduction to soil habitats, Bt strains can affect indigenous microorganisms, such as bacteria and fungi, and further establish complex relationships with local plants, ranging from a mostly beneficial demeanor, to pathogenesis-like plant colonization. By exerting a direct effect on target insects, Bt can indirectly affect other organisms in the food chain. Furthermore, they can also exert an off-target activity on various soil and terrestrial invertebrates, and the frequent acquisition of virulence factors unrelated to major insecticidal toxins can extend the Bt host range to vertebrates, including humans. Even in the absence of direct detrimental effects, the exposure to Bt treatment may affect non-target organisms by reducing prey base and its nutritional value, resulting in delayed alleviation of their viability. The immense phenotypic plasticity of Bt strains, coupled with the complexity of ecological relationships they can engage in, indicates that further assessment of future Bt-based pesticides’ safety should consider multiple levels of ecosystem organization and extend to a wide variety of their inhabitants.

Ichneumon promissorius (Erichson) (Hymenoptera: Ichneumonidae): Factors Affecting Fecundity, Oviposition, and Longevity

1995 ◽  
Vol 30 (2) ◽  
pp. 279-286 ◽  
Author(s):  
J. E. Carpenter
Keyword(s):  
Helicoverpa Zea ◽  
Biological Control Agent ◽  
Soil Surface ◽  
The United States ◽  
Control Agent ◽  
Pest Species ◽  
Laboratory Rearing ◽  
Factors Affecting ◽  
Preoviposition Period ◽  
Host Pupa

Ichneumon (=Pterocormus) promissorius (Erichson) (Hymenoptera: Ichneumomidae), a native of Australia, is a pupal parasitoid which searches the soil surface for host pupation sites, burrows into a pupal gallery, and oviposits in the host pupa. Fecundity and rate of oviposition were influenced by the mating status of females, the host from which females developed, and the frequency in which females were exposed to hosts. Virgin females continued laying eggs many days after mated females had stopped. A preoviposition period of 17 d in mated females did not affect the oviposition curve or the number of eggs laid, suggesting that the oogenesis is arrested until female wasps are exposed to host pupae. Female wasps exposed to pupae for 24 h every fifth day lived longer than female wasps continuously exposed to pupae. However, females that were continuously exposed to pupae laid more eggs. Virgin females reared on Spodoptera exigua (Hübner) pupae laid fewer eggs than virgin females reared on Helicoverpa zea (Boddie) pupae. These data will be important in evaluating the potential of I. promissorius as a biological control agent for pest species in the United States and will be useful in developing laboratory rearing procedures for I. promissorius.

Evaluation of a formulation of Bacillus thuringiensis against waxmoths in stored honeycombs

1991 ◽  
Vol 31 (5) ◽  
pp. 709 ◽  
Author(s):  
SC McKillup ◽  
DG Brown
Keyword(s):  
Biological Control ◽  
Apis Mellifera ◽  
Bacillus Thuringiensis ◽  
Field Experiment ◽  
Biological Control Agent ◽  
Control Agent ◽  
Control Methods ◽  
Commercial Formulation ◽  
Significant Damage ◽  
The Cost

Waxmoths cause significant damage to stored honeycombs of the Western honeybee Apis mellifera in Australia. A field experiment was designed to evaluate the effectiveness of a commercial formulation (Certan) of the biological control agent Bacillus thuringiensis in preventing this damage.Treatment applied at the manufacturer's recommended rate of 855 units per cm2 of honeycomb almost completely prevented damage, while untreated combs showed an average of 76% damage. The cost and practicality of applying the formulation of B. thuringiensis are discussed, together with the recommendation that new control methods for waxmoths should be researched.

scholarly journals Bacillus thuringiensis Cry1C resistance development and its processing pattern in Egyptian cotton leaf worm: Spodoptera littoralis (Boisd.) (Lepidoptera:Noctuidae)

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Saad Moussa ◽  
Fatian Biaomy ◽  
Kahled Aiad ◽  
Hager Khalil ◽  
Ashraf Oukasha Abd El-latif
Keyword(s):  
Bacillus Thuringiensis ◽  
Spodoptera Littoralis ◽  
Cotton Leaf ◽  
Resistance Development ◽  
Egyptian Cotton

scholarly journals Evaluating the efficacy of Trichoderma harzianum and Bacillus thuringiensis on induce the plant growth and resistance of local variety patchouli under covered and uncovered seedlings methods

2022 ◽  
Vol 951 (1) ◽  
pp. 012106
Author(s):  
R Sriwati ◽  
T Chamzurni ◽  
F Razi ◽  
Syaifullah ◽  
Yunita ◽  
...  
Keyword(s):  
Biological Control ◽  
Bacillus Thuringiensis ◽  
Plant Growth ◽  
Biological Control Agent ◽  
Dose Range ◽  
Morphological Characters ◽  
Control Agent ◽  
Plant Diseases ◽  
Biological Control Agents ◽  
Pests And Diseases

Abstract To increase plant resistance from an early age, it is necessary to introduce biological control agents from groups of fungi and bacteria. This study aims to determine the effect of Trichoderma harziaunum and Bacillus thuringiensis Aceh isolates in increasing the superiority of Aceh patchouli plants that are resistant to pests and plant diseases. The study used non-factorial RAL method with cover and uncovered seedling methods. Both series were treated with the same biological control agent, the control without any treatment, the treatment of T. harzianum and B. thuringiensis while the observations were made when the seedling covered was opened. Observations included plant morphological characters, plant growth development and peroxidase enzymes. The results showed that morphologically the original patchouli growing in Lhoong district had similar morphological characters to the Lhokseumawe variety. The application of biological control agents of the T. harzianum and B. thuringiensis groups was more effective in increasing plant growth in the closed seedling treatment compared to the uncovered seedling. T. harzianum gave the best effect at a dose range of 1-1.5 while B. thuringensis showed a better effect at a concentration of 10-15 ml. Both treatments increased the growth of patchouli seedlings as indicated by the better plant height and number of shoots. Furthermore, higher peroxidation enzymes were found in the closed seedling treatment with 1.5 g T harzianum and 15 ml B. thuringiensis. The high peroxidase enzyme as an indicator of the more resistant plants have been induced to pests and diseases. From the screen house experiment, T. harzianum and B. thuringiensis were more efficient in inducing plant growth and disease resistance of local varieties of patchouli using the closed seedling method.

Sign in / Sign up

Export Citation Format

Share Document