Resumo
O objetivo do presente trabalho foi identificar a diversidade da micobiota parasitária e o tempo decorrido até o início do parasitismo de escleródios de Sclerotinia sclerotiorum em solos da fronteira oeste do Rio Grande do Sul (RS). Foram coletados solos agrícolas e não agrícolas de cinco localidades na fronteira oeste do Rio Grande do Sul. O isolamento dos fungos foi realizado por meio do teste de iscas, sendo que as iscas foram os escleródios do fitopatógeno, os quais permaneceram enterrados no solo durante 15, 30 e 60 dias. Os fungos foram identificados em nível de gênero. Os gêneros fúngicos encontrados parasitando escleródios foram: Trichoderma, Penicillium, Aspergillus, Fusarium, Pythium (Cromista), Clonostachys rosea (Gliocladium), Chaetomium, Curvularia, Phytophthora (Cromista), Rhizopus, Lichtheimia (Absidia), Mucor, Acremonium, Periconia e Isaria.Observou-se que os escleródios foram parasitados pelos fungos até 15 dias depois de serem enterrados, e deste período em diante apenas a frequência de ocorrência dos fungos mudou. Concluiu-se que os gêneros fúngicos Isaria, Periconia, Acremonium, Lichtheimia (Absidia), Phytophthora, Curvularia e Chaetomium são encontrados em solos agrícolas e não agrícolas na fronteira oeste do RS, e não foram citados anteriormente em outros trabalhos. Existe diversidade de fungos parasitários de escleródios de S. sclerotiorum nos solos da fronteira oeste do RS, os quais podem ser utilizados em experimentos para compor um programa de controle biológico desse fitopatógeno. Os escleródios são parasitados pelos fungos durante até 15 dias, após os mesmos serem enterrados no solo.(AU)
The aim of this study was to identify the diversity of the parasitic mycoflora and to identify the necessary time until the beginning of the parasitism of sclerotia of Sclerotinia sclerotiorum in soils of the western frontier of the state of Rio Grande do Sul (RS), Brazil. Agricultural and non agricultural soils of five locations in the western frontier of Rio Grande do Sul were collected. The fungi isolation was performed by testing baits, and baits were the sclerotia of the phytopathogen, which remained buried in the soil for 15, 30 and 60 days. The fungi were identified at the genus level. The following fungal genera were found parasitizing sclerotia: Trichoderma, Penicillium, Aspergillus, Fusarium, Pythium (Cromista) Clonostachys rosea (Gliocladium), Chaetomium, Curvularia, Phytophthora (Cromista), Rhizopus, Lichtheimia (Absidia), Mucor, Acremonium, Periconia and Isaria. It was observed that the sclerotia were parasitized by fungi until 15 days after they had been buried. And after this period, only the frequency of occurrence of fungi has changed. It was concluded that the fungal genera Isaria, Periconia, Acremonium, Lichtheimia (Absidia), Phytophthora, Curvularia and Chaetomium are found both in agricultural and non-agricultural soils on the western frontier of RS, but they were not previously cited in other works. There is diversity of parasitic fungi of sclerotia of S. sclerotiorum in the soils of the western frontier of the RS, which can be used in experiments to compose biological control programs for this pathogen. The sclerotia are parasitized by fungi until 15 days after being buried underground.(AU)
Assuntos
Ascomicetos , Análise do Solo , Micobioma , Controle Biológico de VetoresResumo
O objetivo do presente trabalho foi identificar a diversidade da micobiota parasitária e o tempo decorrido até o início do parasitismo de escleródios de Sclerotinia sclerotiorum em solos da fronteira oeste do Rio Grande do Sul (RS). Foram coletados solos agrícolas e não agrícolas de cinco localidades na fronteira oeste do Rio Grande do Sul. O isolamento dos fungos foi realizado por meio do teste de iscas, sendo que as iscas foram os escleródios do fitopatógeno, os quais permaneceram enterrados no solo durante 15, 30 e 60 dias. Os fungos foram identificados em nível de gênero. Os gêneros fúngicos encontrados parasitando escleródios foram: Trichoderma, Penicillium, Aspergillus, Fusarium, Pythium (Cromista), Clonostachys rosea (Gliocladium), Chaetomium, Curvularia, Phytophthora (Cromista), Rhizopus, Lichtheimia (Absidia), Mucor, Acremonium, Periconia e Isaria.Observou-se que os escleródios foram parasitados pelos fungos até 15 dias depois de serem enterrados, e deste período em diante apenas a frequência de ocorrência dos fungos mudou. Concluiu-se que os gêneros fúngicos Isaria, Periconia, Acremonium, Lichtheimia (Absidia), Phytophthora, Curvularia e Chaetomium são encontrados em solos agrícolas e não agrícolas na fronteira oeste do RS, e não foram citados anteriormente em outros trabalhos. Existe diversidade de fungos parasitários de escleródios de S. sclerotiorum nos solos da fronteira oeste do RS, os quais podem ser utilizados em experimentos para compor um programa de controle biológico desse fitopatógeno. Os escleródios são parasitados pelos fungos durante até 15 dias, após os mesmos serem enterrados no solo.(AU)
The aim of this study was to identify the diversity of the parasitic mycoflora and to identify the necessary time until the beginning of the parasitism of sclerotia of Sclerotinia sclerotiorum in soils of the western frontier of the state of Rio Grande do Sul (RS), Brazil. Agricultural and non agricultural soils of five locations in the western frontier of Rio Grande do Sul were collected. The fungi isolation was performed by testing baits, and baits were the sclerotia of the phytopathogen, which remained buried in the soil for 15, 30 and 60 days. The fungi were identified at the genus level. The following fungal genera were found parasitizing sclerotia: Trichoderma, Penicillium, Aspergillus, Fusarium, Pythium (Cromista) Clonostachys rosea (Gliocladium), Chaetomium, Curvularia, Phytophthora (Cromista), Rhizopus, Lichtheimia (Absidia), Mucor, Acremonium, Periconia and Isaria. It was observed that the sclerotia were parasitized by fungi until 15 days after they had been buried. And after this period, only the frequency of occurrence of fungi has changed. It was concluded that the fungal genera Isaria, Periconia, Acremonium, Lichtheimia (Absidia), Phytophthora, Curvularia and Chaetomium are found both in agricultural and non-agricultural soils on the western frontier of RS, but they were not previously cited in other works. There is diversity of parasitic fungi of sclerotia of S. sclerotiorum in the soils of the western frontier of the RS, which can be used in experiments to compose biological control programs for this pathogen. The sclerotia are parasitized by fungi until 15 days after being buried underground.(AU)
Assuntos
Ascomicetos , Análise do Solo , Micobioma , Controle Biológico de VetoresResumo
ABSTRACT The coffee root mealybug Dysmicoccus texensis (Tinsley) attacks the roots of this plant and can cause serious damage to crops, and consequent losses in production. The entomopathogenic nematodes (EPNs) are effective agents in controlling pests found in soil, which suggests a likely effectiveness in controlling the coffee root mealybug. Therefore, this study aimed to evaluate the pathogenicity of some strains of EPNs against the coffee root mealybug through selection tests of isolates, determination of the maximum lethal concentration (LC99) and the pathogenicity of crypts collected in the field. The isolated Heterorhabditis sp. CCA, Heterorhabditis bacteriophora, Heterorhabditis sp. JPM3.1 and Heterorhabditis sp. JPM3 presented higher virulence, reaching maximum mortality values of 100, 94, 94 and 82% respectively at the highest concentration that was tested (100 infective juveniles IJ/insect). The LC99 determined for Heterorhabditis sp. CCA was estimated at 530 IJ/plate. A similar value was found for Heterorhabditis sp. JPM3, which had the LC99 equal to 560 IJ/plate. Estimating the concentration by area, the value obtained for Heterorhabditis sp. CCA and Heterorhabditis sp. JPM3 was 28 and 29 IJ/cm2, respectively. In the test conducted with crypts, both isolated from EPNs were pathogenic to insects.
RESUMO A cochonilha-da-raiz-do-cafeeiro Dysmicoccus texensis (Tinsley) ataca as raízes desta planta, podendo causar sérios danos às plantações e conseqüentes perdas na produção. Os nematóides entomopatogênicos (NEPs) são agentes eficientes no controle de várias pragas encontradas no solo, o que sugere provável eficiência no controle da cochonilha-da-raiz-do-cafeeiro. Dessa forma, este trabalho teve por objetivo avaliar a patogenicidade de alguns isolados de NEPs à cochonilhada-raíz-do-cafeeiro através de testes de seleção de isolados, determinação da concentração letal máxima (CLM99) e patogenicidade a criptas coletadas no campo. Os isolados Heterorhabditis sp. CCA, Heterorhabditis bacteriophora, Heterorhabditis sp. JPM3.1 e Heterorhabditis sp. JPM3 foram os que apresentaram maior virulência, alcançando valores máximos de mortalidade de 100, 94, 94 e 82%, respectivamente, na maior concentração testada (100 juvenis infectantes (JI)/inseto). A CL99 determinada para Heterorhabditis sp. CCA foi estimada em 530 JI/placa. Valor semelhante foi encontrado para Heterorhabditis sp. JPM3 que teve a CL99 igual a 560 JI/placa. Estimando a concentração por área, o valor obtido para Heterorhabditis sp. CCA e Heterorhabditis sp. JPM3 foi de 28 e 29 JI/cm2, respectivamente. No teste realizado com criptas, ambos os isolados de NEPs foram patogênicos aos insetos.
Resumo
El picudo, Conotrachelus dubiae O'Brien 1995, es una de las plagas mas importantes del camu camu Myrciaria dubia H.B.K. Mc Vaugh en la Amazonía Peruana. El objetivo del presente estudio fue determinar el ciclo biológico de este insecto bajo condiciones de laboratorio y describir su comportamiento y fluctuación en condiciones de campo en Pucallpa, Ucayali, Perú. El porcentaje de eclosión de larvas fue de 87%, la duración del periodo de incubación de los huevos fue de 5,5±0,9 (4 a 7) días, del estado larval en el fruto 22,2±1,9 (20 a 25) días y en el suelo (fase pre-pupa), 54,4±5,5 (46 a 67) días, del periodo pupal 11,8±0,9 (9 a 13) días y la longevidad del adulto fue de 51,8±18,9 (9 a 75) días. Los adultos se alimentaron de frutos de diferentes diámetros y estados de maduración y de botones florales, ramas tiernas y flores. No se registró la presencia de adultos de C. dubiae en frutos secos, ni en la base del tallo, sino en ritidomas. La mayor actividad de alimentación y de reproducción de los adultos fue entre 18:30 a 22:00 h. Los adultos fueron observados en el cultivo durante todo el año, encontrándose con mayor frecuencia en los meses de enero a marzo en pisos bajos inundables y entre octubre a diciembre en tierra firme no inundable, coincidiendo con la fase de floración y fructificación de la planta.
Camu camu weevil Conotrachelus dubiae O'Brien, 1995 is a one of the main pests of camu camu (Myrciaria dubia H.B.K. Mc Vaugh) in Peruvian Amazonia. The aim of this study was to determine the biological cycle of this insect under laboratory conditions, to describe its behavior and population numbers under field conditions in Pucallpa, Ucayali, Peru. The percentage of hatching was 87%; the egg incubation period was 5.5±0.9 (4 to 7) days; the length of the larval stage inside the fruit was 22.2±1.9 (20 to 25) days, and the length larval stage (pre-pupa) underground was 54.4±5.5 (46 to 67) days. The length of pupal period was 11.8±0.9 (9 to 13) days, and the longevity of adults was 51.8±18.9 (9 to 75) days. Adults feed on fruits of different diameters and state of ripeness. Weevils also feed on buds, fresh branches and flowers. Adults of C. dubiae were only found in the rhizome, not in dry fruits or on the stem base.. The highest feeding and reproductive activity of adults was between 18:30 to 22:00 h. Adults were observed during the whole year, with the highest frequency between January and March in low seasonally flooded soils and between October to December in upland unflooded soils, coinciding with flowering and fruiting plant phenology.