Effect of Baculovirus spodoptera isolates in Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) larvae and their characterization by RAPD

Abstract

Neotropical Entomology 34(1): 067-075 (2005) Efeitos de Isolados do Baculovirus spodoptera em Lagartas de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) e sua Caracterização por Meio de RAPD RESUMO -Foram utilizados 22 isolados de vírus amostrados em diferentes regiões produtoras de milho do Brasil. Os vírus foram purificados e suas suspensões fornecidas a lagartas sadias do 3º e 4º ínstar de Spodoptera frugiperda (J.E. Smith). A mortalidade foi avaliada diariamente, e as lagartas infectadas foram congeladas logo após sua morte, o que em geral ocorreu do 5 o ao 7 o dia após ingestão do vírus. Os isolados foram usados em seis concentrações (10 3 a 10 8 poliedros/ml) e uma testemunha (água). Os percentuais de mortalidade, duração do período larval e período pupal, peso de pupa e a concentração letal (CL 50 ) foram determinados para todos os isolados. Foram observadas diferenças significativas entre todos os isolados e concentrações testadas para todos os parâmetros avaliados, e também foi constatada a presença da interação isolado x concentração, exceto para período pupal. Os padrões de amplificação de 54 marcadores RAPD, sendo 41 polimórficos, foram utilizados para avaliar a distância genética e a sua correlação com os índices de mortalidade das lagartas. A divergência genética calculada pelo coeficiente Jaccard utilizando os dados moleculares permitiu dividir os isolados em dois grupos, com um elevada confiabilidade. O agrupamento não apresentou associação com a taxa de mortalidade causada pelos isolados ou com sua distribuição geográfica. No entanto, um fragmento de RAPD OPW04.2280 apresentou-se altamente associado com a mortalidade das lagartas e com a CL 50 , explicando 23% e 65% da variação fenotípica para essas características entre os isolados virais, respectivamente. PALAVRAS-CHAVE: Patologia de insetos, lagarta do cartucho do milho, PCR ABSTRACT -The total of 22 Baculovirus isolates surveyed in different corn producing regions in Brazil were used against fall armyworm, Spodoptera frugiperda (J.E. Smith). The viruses were purified and their suspensions were used to feed fall armyworm larvae from 4 th and 5 th instar. The mortality rate was checked daily and the infected larvae were frost after death, what generally occurred between the 5 th and 7 th day after virus ingestion. The 22 Baculovirus isolates were used in six concentrations (from 10 3 to 10 8 polyhedra/ml) and one check treatment with water. Mortality rate, larval period, pupal period, pupa weight and lethal concentration (LC 50 ) were determined for all isolates. Significant differences were found among all isolates and different concentrations, also interaction between isolate x virus concentration for all characteristics evaluated, except for pupal period. Amplification patterns of 54 RAPD markers, being 41 polymorphic among the isolates, were used to evaluate the genetic distance and its correlation with the fall armyworm larvae mortality rate. The genetic diversity calculated by the Jaccard's coefficient using the molecular...

Genetic and biological variation among nucleopolyhedrovirus isolates from the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

“…Many NPVs have been isolated from the fall armyworm, Spodoptera frugiperda [7][8][9][10][11][12]. The S. frugiperda NPVs isolated to date appear to be variants of the same virus species, S. frugiperda multiple nucleopolyhedrovirus (SfMNPV).…”

Molecular and Morphological characterization of multiple nucleopolyhedrovirus from Mexico and their insecticidal activity against Spodoptera frugiperda (Lepidoptera: Noctuidae)

“…A larval mortality of 100% after 8.5 days with a dose of 9.2 × 10 4 OBs/larva was observed in the present study. Barreto, Guimaraes, Teixeira, Paiva, and Valicente () evaluated the mortality of 3rd‐ and 4th‐instar FAW larvae infected with 22 baculoviruses from Brazil and observed that doses of 10 3 and 10 4 OBs/ml caused mortalities from 9% to 90.7% and from 11.5% to 94%, respectively, and doses of 10 6 OBs/ml or higher caused mortalities >72%. The mortality values were higher than those (39.6% at 168 hpi) reported by Figueroa, Coronado, Pineda, Chavarrieta, and Martínez‐Castillo (), who evaluated a SfNPV from Nicaragua at 10 6 OBs/ml.…”

In vitro infectivity of Spodoptera frugiperda multiple nucleopolyhedrovirus to different insect cell lines

“…agropec. bras., Brasília, v.53, n.1, p.1-9, Jan. 2018 DOI: 10.1590/S0100-204X2018000100001 named as SfMNPV-19 showed the lowest LC 50 and the highest mortality rate at lower concentrations, leading to intense disruption of the host integument (Barreto et al, 2005). In contrast to other reported SfMNPV isolates, however, an isolate named SfMNPV-6nd did not cause liquefaction to larvae, a very important feature for virus pesticides production.…”

“…bras., Brasília, v.53, n.1, p.1-9, Jan. 2018 DOI: 10.1590/S0100-204X2018000100001 lactalbumin hydrolysate and yeastolate), except for the UFL-AG-286 cells, which were cultivated in TC-100 (Gibco-BRL, Grand Island, NY, USA). The cells were infected with the virus isolate SfMNPV-19 (Barreto et al, 2005). Tissue culture plates (60 mm 2 ) were seeded with 1x10 6 cells and allowed to attach overnight (12-14 hours).…”