Effects of Entomopathogenic Fungi on the Biology of Spodoptera litura (Lepidoptera: Noctuidae) and its Reduviid Predator, Rhynocoris marginatus (Heteroptera: Reduviidae) (original) (raw)
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Journal of Animal and Plant Sciences, 2013
Susceptibility of different biological stages of Spodoptera litura to various strains of entomopathogenic fungi was evaluated under laboratory conditions at Department of Entomology University of Agriculture, Faisalabad using the insect immersion method. Virulence potential of the entomopathogenic fungi varied with different biological stages of the insect pest. Eggs and larvae were comparatively more susceptible to infections by ent omopathogenic fungi, while pupae were less susceptible. The susceptibility of the insect to entomopathogenic fungi decreased with the advancement in age of larvae of the insect . The LC50 values for eggs were 1.13×10 6 , 4.82×10 6 and 2.45×10 7 conidia ml -1 in M. anisopliae L6, I. fumosorosea 32 and B. bassiana 25, respectively. The median lethal concentration (LC50) for 3 rd instar larvae was 1.11×10 7 conidia ml -1 in B. bassiana 25 and 2.17×10 7 conidia ml -1 in I. fumosorosea 32. Mortality of the larvae
2019
Spodoptera litura (Fabricius) (Noctuidae: Lepidoptera) is one of the notorious and polyphagous insect pest with broad host range of more than one hundred plants including 40 plant families. This pest flourishes under favorable conditions causing 70 to 100% yield losses to crops at their blossoming and vegetative stages. Many species of insect pests have significantly developed resistance to different group of chemical insecticides. Subsequently controlling insect pests by the usage of synthetic chemicals is expensive and ecologically harmful, so there has been a developing hunt for naturally arising with integration, economical and more globally safe means. Presently B. bassiana (1.3 × 10 spores/ml) and three new chemistry insecticides [emamectin benzoate (Timer), flubendiamide (Belt) and chlorantraniliprole (Coragen)] alone and in mixtures at dose less than the 2 folds of recommended field dose were tested against 2 and 4 instar larvae of S. litura , under laboratory conditions usi...
Pakistan Journal of Medical and Health Sciences, 2022
Tobacco caterpillar, Spodoptera litura is destructive pest causes severe losses to various crops worldwide. The potential of different entomopathogenic fungi (EPFs) against S. litura was conducted at Institute of Plant Protection, MNS-University of Agriculture, Multan by using leaf dip method. Larvae and eggs were the most susceptible while pupae were less susceptible to the tested entomopathogenic fungal isolates. The early instar larvae were highly susceptible to EPFs as compared to the later instar larvae. The median lethal concentration (LC50) values for third instar larvae were 1.13×107 conidia ml-1 and 2.16×107 conidia ml-1 for B. bassiana 25 and I. fumosorosea 32, respectively. The entomopathogenic fungi pathogenicity was increased with increase in conidial concentration and mortality rate also increased. Median lethal time (LT50) of S. litura was increased with decreased in fungus conidial concentrations. The median lethal concentration (LC50) values for eggs were 1.22×106, ...
Tobacco caterpillar, Spodoptera litura was reared in semi-synthetic diet and the different stages were maintained to conduct bioassay. Entomopathogenic fungi Beauveria bassiana was sub-cultured on Potato Dextrose Agar (PDA). Spore suspensions of four different concentrations (2.4 × 10 7 , 2.4 × 10 6 , 2.4 × 10 5 , 2.4 × 10 4 conidia/ml) were prepared from the 15 day old culture of the fungi. A preliminary study on B. bassiana against S. litura larvae was done. Cypermethrin, neem and untreated (sterile water) were used as controls. The least pupation (43.33%) was observed in larvae treated with the highest spore concentration (2.4 × 10 7 ) of B. bassiana. A sequential follow up from this assay was done on the resulting pupae and adults, if any. Further treatment of the resultant pupae caused mortality and adult malformation. The healthy moth emergence was least in (2.4 × 10 4 ) spore concentration of the treatment, while the fecundity was completely arrested in the highest concentration.
Tobacco caterpillar, Spodoptera litura was reared in semi-synthetic diet and the different stages were maintained to conduct bioassay. Entomopathogenic fungi Beauveria bassiana was sub-cultured on Potato Dextrose Agar (PDA). Spore suspensions of four different concentrations (2.4 × 10 7 , 2.4 × 10 6 , 2.4 × 10 5 , 2.4 × 10 4 conidia/ml) were prepared from the 15 day old culture of the fungi. A preliminary study on B. bassiana against S. litura larvae was done. Cypermethrin, neem and untreated (sterile water) were used as controls. The least pupation (43.33%) was observed in larvae treated with the highest spore concentration (2.4 × 10 7 ) of B. bassiana. A sequential follow up from this assay was done on the resulting pupae and adults, if any. Further treatment of the resultant pupae caused mortality and adult malformation. The healthy moth emergence was least in (2.4 × 10 4 ) spore concentration of the treatment, while the fecundity was completely arrested in the highest concentration.
SpringerPlus, 2015
Background Entomopathogenic fungi, a group of microbial pest control agents, are natural insect pathogens regulating the insect population in an environment. It has been widely employed for the control of major insect pest and currently 700 species have been reported as entomopathogenic (Suganya and Selvanarayanan 2010). There are several insect pathogens, like Beauveria bassiana, Metarhizium anisopliae, Isaria fumosorosea, Verticillium lecanii and Nomuraea rileyi have been found to be promising in the control of several agricultural insect pests (Lingappa et al. 2005). The invasion of these fungi, during pathogenesis has been facilitated by enzymes but it has been strongly defended by the insect's cellular and humoral reaction. In climax, the insect barrier has been perfectly broken by the fungi by its enzymes and they started growing inside the hemolymph, where toxins like oosporein, beauverin and destruxin were secreted. The studies on role of enzyme in pathogenicity was studied enormously, while the release of secondary soluble fungal toxin during post penetration event has been detailed very little
Insects
Maize is a major staple crop in China, and the sustainable productivity of this primary crop has been recently threatened by fall armyworm (FAW), Spodoptera frugiperda, invasion. The five fungal isolates, Aspergillus sp. BM-3 and SE-2-1, Cladosporium tenuissimum SE-10, Penicillium citrinum CTD-24, and Beauveria bassiana ZK-5 were assessed for their efficacy in causing mortality against first to sixth instar eggs and neonate larvae seven days post-treatment, and their effects on the feeding performance of sixth instar S. frugiperda larvae at 48 h post-treatment at three concentrations (1 × 106, 1 × 107, and 1 × 108 conidia mL−1) were also assessed. The six instar S. frugiperda larvae were not susceptible to the five tested fungal isolates. However, B. bassiana ZK-5 caused the highest egg mortality of 40, 70, and 85.6% at 1 × 106, 1 × 107, and 1 × 108 conidia mL−1, respectively, followed by P. citrinum CTD-24 (30.6, 50, and 75.6%) and C. tenuissimum SE-10 (25.6, 40, and 55.6%). In add...
Relative susceptibility of Spodoptera litura pupae to selected entomopathogenic fungi
Biocontrol, 2009
The pupae of Spodoptera litura (Fab.), (Lepidoptera: Noctuidae), a polyphagous pest affecting common crops in Indian subcontinent, were treated with different concentrations of conidia of four isolates of entomopathogenic fungi belonging to three species, Metarhizium anisopliae var. anisopliae (Metschnikov) Sorokin (ARSEF 7487), Lecanicillium muscarium (Petch) Zare & W Gams (two isolates ARSEF 7037 and ARSEF 6118) and Cordyceps cardinalis Sung & Spatafora (ARSEF 7193) under laboratory conditions. Suspensions (108/ml) of conidia harvested from Sabouraud dextrose agar yeast extract (SDAY) plates resulted in the highest mortality (85.8%) with M. anisopliae and the lowest mortality (57.3%) with C. cardinalis. The values of LC50 and LC90 suggested that M. anisopliae was the most virulent fungal strain followed by L. muscarium (ARSEF 7037). However, C. cardinalis was the least virulent species among the fungi used in the bioassay. In soil bioassays, drenching the soil with conidial suspensions of ARSEF 7487 and ARSEF 7037 (108 conidia/g of soil) reduced the adult emergence from pupa by 81.3% and 72.5%, respectively, while premixing the sterile soil with conidia killed lesser number of pupae (62.9% by ARSEF 7487 and 54.6% by ARSEF 7037). Our findings suggest that M. anisopliae (ARSEF 7487) and L. muscarium (ARSEF 7037) are potent entomopathogens and could be developed into biocontrol agents against rice cutworm in IPM programs.
Entomopathogenic Fungi as Effective Insect Pest Management Tactic: A Review
Entomopathogenic fungi, with its cosmopolitan existence and rich diversity, present a sustainable solution towards integrated pest management programs. These entomopathogens, due to their eco-friendliness and bio-persistence, are preferred to kill insects at various stages of its life cycle. The most important entomopathogens that have been commercially produced are Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea. These are classified into different phylums including Oomucota, Ascomycota, Chytridiomycota and Zygomocata . These entomopathogens have contact mode of action in most cases. It contacts the cuticle, forms appresoria, penetrates into the insect, proliferates, produces toxins and ultimately kills the insect. The insect host shows reaction of reduced or increased feeding, behavioral fever, aberrant mating, and changed ovipositional preferences. The spores are disseminated by the insect cadaver, air, soil and water. The factors affecting entomopathogens are high relative humidity, temperature and sunlight. These are used for all bio-control methods including inundative and classical biological control. For future prospects, improvements are needed in the research methods, mass production, formulation and the application techniques. The proper selection of strains to kill specific host range without disturbing non-target insects is another point of study. It should be possible that the best use of microbial insecticides at wider range eradicate the chemicals use to a large level.
European Journal of Entomology
Populations of herbivorous insects are considered to be primarily regulated by natural enemies. However, little is known about the ecological role of entomopathogenic fungi. There is very little data on the diversity and prevalence of fungal pathogens in natural insect populations. In this study, the percentage mortality attributable to fungal pathogens for the immature stages of three noctuid moths feeding inside the stems of the herbaceous plant, Typha latifolia, were determined. The average percentage mortality caused by fungal pathogens was around 8%, with the value never exceeding 20% at any of the studied sites. As many as ten species of fungi were identifi ed in the 52 infected larvae/pupae collected, this high diversity is consistent with the results of comparable studies. The prevalence of fungal infections did not correlate with host population density or performance of the host insects. This study contributes to the emerging generalisation that populations of insects commonly harbour diverse assemblages of pathogenic fungi, but with low overall prevalence. A signifi cant contribution of these antagonists to regulating insect populations is unlikely.