Effects of nuclear polyhedrosis virus on various developmental stages of the cotton leafworm Spodoptera littoralis (Boisd.)

Abul-Nasr, S.; Ammar, El‐Desouky; Abul-Ela, S. M.

doi:10.1111/j.1439-0418.1979.tb02494.x

Cited by 14 publications

(2 citation statements)

References 5 publications

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“…Another advantage to the virus of being in a covert state is that it could be carried long distances during host migration (Anderson & May, 1981). Interestingly, vertical transmission appears to be frequent in more mobile insect species such as those within the genus Spodoptera (Swaine, 1966; Abul-Nasr et al , 1979; Smits & Vlak 1988; Fuxa & Richter 1991; Vilaplana et al , 2008).…”

Section: Introductionmentioning

confidence: 99%

Evidence for covert baculovirus infections in a Spodoptera exigua laboratory culture

Murillo

Hussey

Possee

2011

Journal of General Virology

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A laboratory culture of Spodoptera exigua was examined to assess covert (latent or persistent) baculovirus infections and spontaneous disease outbreaks. Two nucleopolyhedrovirus (NPV) species were found to be reactivated from a covert state in a laboratory culture of S. exigua to fully lethal forms. These were identified as S. exigua multinucleopolyhedrovirus (SeMNPV) and Mamestra brassicae NPV (MbNPV) using restriction enzyme analysis of purified viral DNA. Sequence data derived from both overtly and covertly virus-infected insects revealed highly conserved sequences for lef-8, lef-9 and polyhedrin gene sequence (98-100 % nucleotide identity to SeMNPV published sequence). By monitoring spontaneous overt infections and quantifying viral DNA (by quantitative-PCR) in asymptomatic individuals over two generations we identified fluctuating trends in viral DNA levels from covert SeMNPV and MbNPV within an S. exigua host population. Virus levels per insect life stage ranged from 3.51±0.101¾10 5 to 0.29±0.036 pg (detection limit at 0.06 pg). Bioassays performed with this culture of larvae showed a differential susceptibility to SeMNPV-like or MbNPV-like viruses, with SeMNPV superinfections being extremely virulent. The data presented has broad implications relating to our understanding of transmission patterns of baculovirus in the environment and the role of covert infections in host-pathogen interaction dynamics.

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Section: Introductionmentioning

confidence: 99%

Evidence for covert baculovirus infections in a Spodoptera exigua laboratory culture

Murillo

Hussey

Possee

2011

Journal of General Virology

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“…There are few studies where direct comparisons among species have been made, but the propensity for an NPV to be transmitted vertically as an overt infection appears to vary with diVerent hostvirus combinations (Kukan 1999). If there is any trend in patterns of vertical transmission, it would appear that higher levels are seen in more mobile (and often tropical) species, particularly those within the genus Spodoptera (Swaine 1966;Abul-Nasr et al 1979;Smits and Vlak 1988;Fuxa and Richter 1991).…”

mentioning

confidence: 95%

Density-related variation in vertical transmission of a virus in the African armyworm

et al. 2007

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Larvae of the African armyworm, Spodoptera exempta, are darker and more resistant to baculovirus infection when reared in groups (gregarious form) compared to being reared singly (solitary form). Lepidoptera that survive virus challenge as larvae could potentially retain a sublethal virus infection which is then transmitted vertically to the next generation. Here we examine whether gregarious and solitary forms of the armyworm differ in the costs of surviving virus infection and in their capacity to transmit an active baculovirus infection to their offspring. Pupae of larvae reared gregariously that survived virus challenge weighed significantly less than uninfected individuals, but this was not so for those reared solitarily. This did not, however, translate into differences in fecundity, at least under laboratory conditions. As found in previous studies, pre-oviposition period was shorter for solitary than gregarious insects, and it was also shorter for females that had been challenged with virus as larvae. Both the prevalence of egg batches containing larvae that died from nucleopolyhedrovirus (NPV) infection and the proportion of infected larvae within each egg batch were significantly increased (approximately doubled) when parental moths were previously challenged with the virus during their larval state. This demonstrates that horizontal transmission in one generation can elevate vertical transmission to the next generation. Moreover, prevalence of overt infection in the offspring generation was two to three times greater when parental moths were reared solitarily as larvae than when reared gregariously. Disease prevalence and proportional infection were both independent of the sex of the infected parent and whether or not the egg batch was surface-sterilized to remove potential contaminants. This suggests that the eggs are infected internally (transovarial) rather than externally (transovum). These results help to shed light on the observed temporal pattern of virus epizootics in eastern Africa.

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Entomopathogens for Cotton Defoliators Management

Sahayaraj

2015

Soil Biology

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Effects of nuclear polyhedrosis virus on various developmental stages of the cotton leafworm Spodoptera littoralis (Boisd.)

Cited by 14 publications

References 5 publications

Evidence for covert baculovirus infections in a Spodoptera exigua laboratory culture

Evidence for covert baculovirus infections in a Spodoptera exigua laboratory culture

Density-related variation in vertical transmission of a virus in the African armyworm

Entomopathogens for Cotton Defoliators Management

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