RESUMO

The biological pest control has expanded in Brazil with the Trichogramma pretiosumas the main natural enemy. The microsatellite molecular markers Simple Sequence Repeat (SSR) have been the most used, as they are multiallelic, robust and reproducible, in several species. In order to optimize future processes of identification and analysis of the parasitoid's genetic diversity, twenty markers, isolated and characterized for the parasitoid wasp Trichogramma dendrolimi,were tested in 15 generations of T. pretiosum. Those markers, ten have been transferred and can be used to evaluate the genetic variation of T. pretiosum.(AU)

O controle biológico de pragas tem expandido no Brasil com o Trichogramma pretiosumcomo o principal inimigo natural. Os marcadores moleculares microssatélites de repetição de sequência simples (SSR) temsido os mais utilizados, por serem multialélicos, robustos e reprodutíveis, em várias espécies. No intuito de otimizar futuros processos de identificação e análise de diversidade genética do parasitoide, 20marcadores, isolados e caracterizados para a vespa parasitoide Trichogramma dendrolimi, foram testados em 15 gerações de T. pretiosum. Destes marcadores, dez foram transferidos e podem ser utilizados para avaliar a variação genética de T. pretiosum.(AU)

Assuntos

RESUMO

Entomopathogenic nematodes (EPNs) can control pests due to mutualistic association with bacteria that reproduce and kill the host from septicemia, making the environment favourable for nematode development and reproduction. The objective of this study was to identify an EPN isolate collected in eucalyptus cultivation and to determine its pathogenicity with regard to Gonipterus platensis Marelli (Coleoptera: Curculionidae). Four steel-mesh traps with two seventh-instar Galleria mellonella larvae were buried 5 cm deep in the soil in a commercial Eucalyptus plantation. After 7 days, the traps were packed in plastic bags and transported to laboratory to isolate the EPNs using White traps. The obtained nematodes were multiplied in G. mellonella larvae and identified by sequencing their D2/D3 expansion of the 28S rDNA region by polymerase chain reaction (PCR) and specific primers for ITS regions. Steinernema diaprepesi was identified and inoculated into G. platensis pupae at doses of 500, 1000 and 5000 infective juveniles (IJs) to determine its pathogenicity to this pest. At 8 days after inoculation, the mortality rate of the G. platensis pupae was 80% with the lowest concentration and 100% with the others. The emergence of nematodes and the rapid degradation of G. platensis pupae were observed in those inoculated with IJs. The pathogenicity to the G. platensis pupae indicates potential for using this nematode in the integrated management of this insect.

RESUMO

Plant parasitic nematodes have become one of the main problems in the tomato cultivation. Among these, Meloidogyne enterolobii presents great challenges to the farmer, since it is a polyphagous species and difficult to control. The entomopathogenic nematodes (EPNs) present as potential for biological control of this pathogen. The objective of the study was to evaluate the interference of EPNs S. brazilense, S. feltiae, S. rarum, H. amazonensis and H. bacteriophora on hatching and mortality of M. enterolobii. 500 eggs of this nematode and 1.000 infective juveniles of each EPN species were placed in a plastic pot totaling 25 mL of suspension and kept in an incubator at 25°C. The number of juveniles hatched in the suspension was counted every 2 days, until 10 days. After 10 days of evaluations, the remaining suspension (15 mL) containing M. enterolobii and EPNs was inoculated into Rutgers tomato seedlings. The suspension contained approximately in 300 eggs of M. enterolobii occasional juveniles and 600 IJ of each nematode species. Sixty days after inoculation were evaluated gall indexes, egg mass indexes, total number of eggs and juveniles of M. enterolobii and reproductive factor was calculated. In the mortality experiment, 500 infective juveniles of M. enterolobii and 1.000 juveniles of each EPN species were placed in a plastic pot totaling 25 mL of suspension. The evaluation of juvenile mortality was performed by counting of the mobile and immotile nematodes, by adding two drops of NaOH to the nematode suspension. It was verified that on the 10th day all ENPs provided reduction in the hatching of M. enterolobii. In the pot experiment it was found thato gall index, egg mass indexm, nematodes total number and reproduction factor were significantly reduced in treatments with all species of EPNs tested. However, in the mortality test, only EPNs S. brazilense and S. rarum provided mortality on the second day and H. bacteriophora affected mortality on the 4th day. In the other evaluations, there was no statistical difference. The results highlight the potential of the use of EPNs in programs of integrated management of M. enterolobii in tomato.

RESUMO

The black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae) is a polyphagous pest that attacks more than one hundred types of crops. The habit of being buried or underneath the cultural remains may help contact with entomopathogenic nematodes (EPNs), which are natural enemies of insects. The objective of this study was to evaluate the persistence of the pathogenicity of Steinernema carpocapsae and S. feltiae (Rhabditida: Steinernematidae) applied to the soil against A. ipsilon larvae. The EPNs were applied to vases containing soil and larvae of A. ipsilon were introduced into the vases in five periods (0, 2, 4, 6, and 8 days after treatment). The two species of EPNs caused pathogenicity in all evaluated periods. The mortality rate was over 92% in all treatments and periods evaluated. Based on the results, it is possible to indicate applications NEPs every eight days for larvae population reduction of A. ipsilon.(AU)

A lagarta rosca Agrotis ípsilon (Lepidoptera: Noctuidae) é uma praga polífaga que ataca mais de uma centena de tipos de cultivos. O hábito de ficar enterrada ou abaixo dos restos culturais pode ajudar o contato com nematoides entomopatogênicos (NEP), que são inimigos naturais de insetos. O objetivo deste estudo foi avaliar a persistência da patogenicidade de Steinernema carpocapsae e S. feltiae (Rhabditida: Steinernematidae), aplicados no solo contra lagartas de A. ipsilon. Os NEPs foram aplicados em vasos contendo solo e lagartas de A. ipsilon foram introduzidas nos vasos em cinco períodos (0, 2, 4, 6, e 8 dias após o tratamento). As duas espécies de NEPs causaram patogenicidade em todos os períodos avaliados. A taxa de mortalidade foi superior a 92% em todos os tratamentos e períodos avaliados. Com base nos resultados, é possível indicar aplicações de NEPs a cada oito dias para redução populacional de lagartas de A. ipsilon.(AU)

RESUMO

The black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae) is a polyphagous pest that attacks more than one hundred types of crops. The habit of being buried or underneath the cultural remains may help contact with entomopathogenic nematodes (EPNs), which are natural enemies of insects. The objective of this study was to evaluate the persistence of the pathogenicity of Steinernema carpocapsae and S. feltiae (Rhabditida: Steinernematidae) applied to the soil against A. ipsilon larvae. The EPNs were applied to vases containing soil and larvae of A. ipsilon were introduced into the vases in five periods (0, 2, 4, 6, and 8 days after treatment). The two species of EPNs caused pathogenicity in all evaluated periods. The mortality rate was over 92% in all treatments and periods evaluated. Based on the results, it is possible to indicate applications NEPs every eight days for larvae population reduction of A. ipsilon.

A lagarta rosca Agrotis ípsilon (Lepidoptera: Noctuidae) é uma praga polífaga que ataca mais de uma centena de tipos de cultivos. O hábito de ficar enterrada ou abaixo dos restos culturais pode ajudar o contato com nematoides entomopatogênicos (NEP), que são inimigos naturais de insetos. O objetivo deste estudo foi avaliar a persistência da patogenicidade de Steinernema carpocapsae e S. feltiae (Rhabditida: Steinernematidae), aplicados no solo contra lagartas de A. ipsilon. Os NEPs foram aplicados em vasos contendo solo e lagartas de A. ipsilon foram introduzidas nos vasos em cinco períodos (0, 2, 4, 6, e 8 dias após o tratamento). As duas espécies de NEPs causaram patogenicidade em todos os períodos avaliados. A taxa de mortalidade foi superior a 92% em todos os tratamentos e períodos avaliados. Com base nos resultados, é possível indicar aplicações de NEPs a cada oito dias para redução populacional de lagartas de A. ipsilon.