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HbSD efficacy against S. frugiperda in Petri plate bioassays. (A) Representative plates containing 3rd instar larvae of S. frugiperda treated with water and HbSD suspensions at 48 h postHbSD efficacy against S. frugiperda in Petri plate bioassays. (A) Representative plates containing 3rd instar larvae of S. frugiperda treated with water and HbSD suspensions at 48 h posttreatment. (B) The cadavers of S. frugiperda caused by HbSD infection for 48 h. (C) Observation of infective juvenile of HbSD under microscope. (D) The body contents inside the cadaver of S. frugiperda under stereomicroscope. The arrows indicate HbSD nematodes entered the insect body. (E,F) The mean control mortality (% ± SE) of 3rd (E) and 5th (F) larval stages of S. frugiperda treated with HbSD in Petri plates. The significant differences are exhibited by lowercase letters (p < 0.05) according to Tukey's HSD tests.
Source publication
Spodoptera frugiperda is a highly destructive and polyphagous pest that causes severe damage to various crops, especially maize. The wide use of chemical insecticides to control S. frugiperda results in resistance against commonly used chemicals and resistant mutations will expand in populations accompanied by a spread to vulnerable areas. Conseque...
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Background
The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a polyphagous insect pest species that travel great distances every summer to disperse. They mostly feed on maize and over 350 other crops. In this investigation, two entomopathogens: Beauveria bassiana and Heterorhabditis taysearae , were utilized to tes...
The biological control of spinach noctuids moths can be accomplished through the use of the entomopathogenic nematodes (EPNs). The nematodes are generally distributed with traditional boom sprayers, though specific references about possible damage of these living organisms due to the action of the mechanical components of the sprayer are not availa...
BACKGROUND
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Nematodes represent different trophic groups in the soil. They therefore play an important role in the soil environment: they regulate populations of other soil organisms, mineralize nutrients into plant-available forms, provide a source of food for other soil organisms and feed on pathogenic organisms and plant pests. In contrast, plant-parasitic...
Citations
... The fall armyworm (FAW), Spodoptera frugiperda, is a widely adaptable pest that poses a significant threat to maize and various cereals in tropical and subtropical areas across the globe [1]. Originating from the Americas, recent incursion of the FAW into Africa, Asia, and Oceania has resulted in substantial reductions in yields of multiple food crops [2]. ...
Spodoptera frugiperda, the fall armyworm (FAW), is a highly invasive polyphagous insect pest that is considered a source of severe economic losses to agricultural production. Currently, the majority of chemical insecticides pose tremendous threats to humans and animals besides insect resistance. Thus, there is an urgent need to develop new pest management strategies with more specificity, efficiency, and sustainability. Chitin-degrading enzymes, including chitinases, are promising agents which may contribute to FAW control. Chitinase-producing microorganisms are reported normally in bacteria and fungi. In the present study, Serratia marcescens was successfully isolated and identified from the larvae of Spodoptera frugiperda. The bacterial strain NRC408 displayed the highest chitinase enzyme activity of 250 units per milligram of protein. Subsequently, the chitinase gene was cloned and heterologously expressed in E. coli BL21 (DE3). Recombinant chitinase B was overproduced to 2.5-fold, driven by the T7 expression system. Recombinant chitinase B was evaluated for its efficacy as an insecticidal bioagent against S. frugiperda larvae, which induced significant alteration in subsequent developmental stages and conspicuous malformations. Additionally, our study highlights that in silico analyses of the anticipated protein encoded by the chitinase gene (ChiB) offered improved predictions for enzyme binding and catalytic activity. The effectiveness of (ChiB) against S. frugiperda was evaluated in laboratory and controlled field conditions. The results indicated significant mortality, disturbed development, different induced malformations, and a reduction in larval populations. Thus, the current study consequently recommends chitinase B for the first time to control FAW.
... The two known genera of EPNs used for insect control are Heterorhabditis and Steinernema (Lacey and Georgis, 2012; Guo et al. 2020). Some of the known species tested against FAW are S. carpocapsae (Fallet et al. 2022), H. indica (Shinde et al. 2022), and H. bacteriophora (Chen et al. 2022). In the field, carboxymethyl cellulose gel formulations of S. carpocapsae were found to be effective in reducing FAW population and infestations (Fallet et al. 2022). ...
The control of fall armyworm (FAW), Spodoptera frugiperda, has been a significant concern to corn and rice agroecosystems in the Philippines. As one of the strategies for FAW management, recent studies have focused on developing entomopathogen-based control tactics, of which utilization of entomopathogenic nematodes is considered as a promising option. This paper evaluated the efficacy of the Philippine isolates of Heterorhabditis indica (HiBSDS, HiMAP, HiPBCB) and Steinernema abbasi (SaMBLB) against the two strains of S. frugiperda. Results showed that all isolates are virulent to both strains 24–48 h post-infection (hpi). However, to achieve similar FAW mortality, H. indica was found to require less IJ measured through penetration percentage as compared with S. abbasi. Lower LC50 and LT50 values were also observed for H. indica isolates than SaMBLB. Among the H. indica isolates, no intraspecific variability in terms of virulence was observed. More apparent is the interspecific variability between S. abbasi and H. indica, as the latter demonstrated higher virulence activity. The FAW strains also showed similar level of sensitivity relative to each of the EPN treatments. Although this warrants further greenhouse and field efficacy study, the findings demonstrated the biocontrol potential of these local EPN isolates against FAW which can also be incorporated in integrated pest management of this insect pest in the Philippines.
... At 40 IJs/L, more than 80 % larval mortality was observed in G. mellonella. This implies that densities of insect-associated nematodes are important because when numbers of IJs are low, more time is needed to infect and multiply inside the host's body (Chen et al., 2023). The present results are in compliance with those of Park et al. (2012) Oscheius carolinensis against fifth instar larvae of G. mellonella. ...
A survey was undertaken to isolate entomopathogenic nematodes from Amritsar district of Punjab, India. Out of 20 soil samples collected, two were found positive for the presence of nematodes. 18S and ITS rDNA gene sequencing revealed their identity as Metarhabditis amsactae. To assess its biocontrol potential, Galleria mellonella larvae were treated with concentrations of 20, 40, 80 and 160 IJs/L (infective juveniles/larva) and mortality was recorded from 24h up to 96h of nematode exposure. Distilled water without nematodes was used as an untreated control. M. amsactae showed potent larvicidal activity against G. mellonella that was found to be concentration and time dependent. Nematode infection caused 93.33% larval mortality at 80 IJs/L after 72h of treatment. 100% mortality was observed after 96h. No mortality was observed in control. To evaluate the immunomodulatory effects of M. amsactae, G. mellonella larvae were infected with 100 IJs/L and activities of antioxidant and detoxifying enzymes viz., superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX), phenol oxidase (PO), glutathione-S-transferase (GST) and acetylcholine esterase (AChE) were appraised after 12, 24, 36 and 48h of nematode exposure. Malondialdehyde content was also determined. The results obtained demonstrated a significant elevation in all the enzyme activities at all time intervals in treated larvae when compared with untreated control. MDA levels were also enhanced in response to nematode infection. Thus, the present study revealed high insecticidal potential and immunomodulatory effects of M. amsactae on G. mellonella that should be further explored on other insect pests also.
... Data regarding the egg hatch inhibition and J2 mortality were corrected with Abbot Formula (Chen et al. 2023); then, percent inhibition and mortality were calculated with the help of mentioned formulae. A statistical software STATISTIX (8.0 EL USA) was used for the analysis of the data. ...
Background
Meloidogyne incognita (Kofoid and White) Chitwood is a major pest of eggplant in Pakistan. The second-stage juveniles (J2s) feed on the roots of eggplant. Damaged roots swell and the plant exhibits stunted growth. Mostly farmers rely on the use of broad-spectrum nematicides. However, due to hazardous effects on the environment and non-target species, its application is greatly criticized. Fungal biocontrol agents have been long used for curtailing root-knot nematode infections. The present study was conducted to determine the virulence of four fungal biocontrol agents against M. incognita under laboratory and greenhouse conditions.
Results
The in vitro results revealed that Trichoderma harzianum significantly caused 77.60% egg inhibition, followed by Pochonia chlamydosporium (53.0% ) at 1:1 concentration after 72 h. The maximum J2s mortality was achieved by T. harzianum (82.0%), followed by P. chlamydosporium (70.20%) at 1:1 concentration after 72 h. The in-planta examination carried out at a greenhouse demonstrated that the soil drench treatment of fungal biocontrol agents significantly suppressed M. incognita parameters and upraised the eggplant growth. The mean least number of galls (22.25) was in T. harzianum treated plants, while the control had (206.8) galls. Likewise, T. harzianum curtailed the least egg masses to 35.75 and swollen females to 21.12 than control negative (224.13 egg masses and 182.75 swollen females).
Conclusion
T. harzianum was the best agent to control M. incognita (J2s) effectively, followed by P. chlamydosporum . T. harzianum may be a contribution to the biological control of M. incognita in Pakistan.
The present study was conducted to evaluate the efficacy of entomopathogenic nematode, Steinernema carpocapsae Weiser and three entomopathogenic fungi (Metarhizium anisopliae (Metschn.) Sorokin, Trichoderma harzianum Rifai, and T. viride Pers.) against Spodoptera frugiperda (J.E. Smith) second and fourth larval instars. The results showed that S. carpocapsae caused a pronounced mortality to second and fourth larval instars of S. frugiperda using a leaf dipping method at 4 days post inoculation (dpi) with LC50 values 52.03 and 4.11 infective juveniles (IJs)/ml, respectively. On the other hand, the three tested entomopathogenic fungi caused a strong toxicity on larval instars of S. frugiperda. The fungus, T. harzianum, displayed the highest insecticidal activity on second larval instar (LC50=1.1×107 spores/ml) and M. anisopliae on fourth larval instar (LC50=1.5×107 spores/ml) after 10 dpi. Our results showed that S. carpocapsae completely inhibited pupation and adult emergence from treated larvae at 250 IJs/ml. The lethal effect of entomopathogenic nematode and fungi against S. frugiperda larval instars indicates that these biological control agents could be useful candidates in integrated pest management programs for this invasive insect.
Keywords: Fall armyworm; Steinernema carpocapsae; Metarhizium anisopliae; Trichoderma harzianum
