Evaluation of oil formulations of Nomuraea rileyi (Farlow) Samson against Spodoptera litura under laboratory conditions

Sharmila, T.; Manjula, K.; Krishna, T. Murali

doi:10.15740/has/ijps/10.1/29-32

Cited by 3 publications

(3 citation statements)

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“…The larval mortality due to oil based formulations of N. rileyi was expressed as per cent mortality before subjecting to statistical analysis by using the formula (Sharmila et al, 2015).…”

Section: Analysis Of the Datamentioning

confidence: 99%

“…At the end of 10 th day, the highest cumulative mortality of 95 per cent was obtained in oil formulations whereas 83.10 and 77 per cent mortalities were recorded with WP and crude N. rileyi respectively. Sharmila et al, (2015) evaluated oil formulations of N. rileyi against S. litura under laboratory conditions and reported more than 70 % larval mortalities of S. litura in case of groundnut and sunflower oil based formulations with concentrations above 1x 10 6 spores per ml and mortality reduced with concentrations showing least with 1x 10 2 spores per ml. Prior et al, (1988) who reported that laboratory studies primarily with grasshopper have shown that oil formulation of aerial conidia of M. anisopliae are more efficacious than aqueous formulation under various temperature and moisture conditions.…”

Section: Plate1mentioning

confidence: 99%

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Efficacy of Oil Based Formulations of Nomuraea rileyi (Farlow) Samson against Spodoptera litura in vitro

Bhargavi¹,

Manjula²,

Rao³

et al. 2018

Int.J.Curr.Microbiol.App.Sci

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“…The larval mortality due to oil based formulations of N. rileyi was expressed as per cent mortality before subjecting to statistical analysis by using the formula (Sharmila et al, 2015).…”

Section: Analysis Of the Datamentioning

confidence: 99%

Section: Plate1mentioning

confidence: 99%

Efficacy of Oil Based Formulations of Nomuraea rileyi (Farlow) Samson against Spodoptera litura in vitro

Bhargavi¹,

Manjula²,

Rao³

et al. 2018

Int.J.Curr.Microbiol.App.Sci

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“…Simple formulations may protect conidia from abiotic stressors, as previously reported for species in the Metarhizium anisopliae complex [15][16][17], including the negative effects of some chemical fungicides [18]. For the fungus M. rileyi, only experimental low-cost formulations have been tested under laboratory conditions [19][20][21], greenhouse [22], and field conditions [9,23]. However, information on how these formulations may protect M. rileyi conidia from the negative effects of the chemical fungicides used in soybean crops is unavailable.…”

Section: Introductionmentioning

confidence: 99%

Potential Impact of Chemical Fungicides on the Efficacy of Metarhizium rileyi and the Occurrence of Pandora gammae on Caterpillars in Soybean Crops

et al. 2022

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Entomopathogenic fungi may play a crucial role in the regulation of caterpillar populations in soybean crops, either through natural occurrences or applied as mycopesticides. In the present work, we reported the naturally occurring entomopathogenic fungus Pandora gammae attacking the caterpillar Chrysodeixis includens, with infection rates in field trials ran in two consecutive years in the 10-35% range. As many chemicals are potentially harmful to entomopathogenic fungi, this work aimed to investigate the potential impact of two chemical fungicides (azoxystrobin + benzovindiflupyr and trifloxistrobina + prothioconazole) used to control soybean rust (Phakopsora pachyrhizi) on the natural occurrence of P. gammae and Metarhizium rileyi, as well as the efficacy of the latter fungus applied as different formulations against the soybean caterpillars Anticarsia gemmatalis and C. includens. Under laboratory conditions, fungicides used at field-recommended rates had a considerable negative impact on the germinability of M. riley on the medium surface, and all tested formulations did not protect conidia from damage by these chemicals. This harmful effect also impacted host infectivity, as the larval mortality owing to this fungus was reduced by 30-40% compared to that of the fungicide-free treatments. In field trials conducted in two subsequent years, unformulated and formulated M. rileyi conidia applied to soybean plants produced primary infection sites in caterpillar populations after a single spray. Spraying unformulated or formulated M. rileyi conidia following fungicide application on plants did not affect host infection rates over time. Moreover, the use of M. rileyi-based formulations or chemical fungicide did not interfere with the natural infection rates by P. gammae on its host, C. includens. Although a higher degree of exposure to non-selective fungicides can negatively affect fungal entomopathogens, a single foliar application of fungicides may be harmless to both M. rileyi and P. gammae in soybean fields. Additionally, this work showed that naturally occurring wasps and tachnids also play an important role in the regulation of A. gemmatalis and, notably, C. includens, with parasitism rates above 40-50% in some cases.

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Pathogenicity and in vivo Development of Metarhizium rileyi Against Spodoptera litura (Lepidoptera: Noctuidae) Larvae

Liu

Zhao

et al. 2019

Journal of Economic Entomology

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Metarhizium rileyi, a well-known entomopathogenic fungus, could open up new vistas in biological control of insect pests; however, due to its intrinsic shortcomings, such as long pathogenic process, its application is largely limited. To explore which process, the invasion or the following in vivo development, is the main factor responsible for the long pathogenic process, the lethal effect of M. rileyi against Spodoptera litura (Fabricius) was determined by conidial topical application and hyphae body injection, and the host immune response was also monitored. Results showed when larvae were inoculated by conidial topical application, the pathogenicity of M. rileyi varied greatly depending on the larval instar and conidia concentration, and LC50 values ranged from 6.24 × 106 to 6.06 × 109 conidia/ml while LT50 values fluctuated from 4.35 to 9.43 d. However, in vivo study showed when hyphal bodies (Hbs) of M. rileyi were injected into host hemocoel, they would not be recognized by the host’s immune system as invaders. There were no significant differences in the hemocytes and phenoloxidase activity between the infected and control larvae at the initial 44 h, indicated that the fungus was able to successfully avoid the attack from the cellular and humoral immune systems, therefore, it could multiply freely in the hemocoel. The in vivo development time of M. rileyi tended to remain constant for 2–3 d regardless of the initial inoculated numbers. Considering no detectable defense response was observed during in vivo development, it can be concluded that host nonself-recognition system does not respond to the hemolymph borne-Hbs.

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Evaluation of oil formulations of Nomuraea rileyi (Farlow) Samson against Spodoptera litura under laboratory conditions

Cited by 3 publications

References 0 publications

Efficacy of Oil Based Formulations of Nomuraea rileyi (Farlow) Samson against Spodoptera litura in vitro

Efficacy of Oil Based Formulations of Nomuraea rileyi (Farlow) Samson against Spodoptera litura in vitro

Potential Impact of Chemical Fungicides on the Efficacy of Metarhizium rileyi and the Occurrence of Pandora gammae on Caterpillars in Soybean Crops

Pathogenicity and in vivo Development of Metarhizium rileyi Against Spodoptera litura (Lepidoptera: Noctuidae) Larvae

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