Biological activity of entomopathogenic nematodes on Anastrepha fraterculus (Diptera: Tephritidae)

Anastrepha fraterculus (Wiedemann) is one of the main pests of fruit farming, and entomopathogenic nematodes (EPNs) represent an important control tool of this species. Thus, the objective of this study was to evaluate the biological activity of different isolate against A. fraterculus larvae and adults. Bioassays were performed using a suspension of three isolates of Heterorhabditis amazonensis IBCB 24, Steinernema carpocapsae IBCB 02 and Steinernema feltiae IBCB 47 at six concentrations (control - without nematodes), 50, 150, 300, 500, 1000 and 1500 infective juveniles (IJs)/mL of water per 3º instar larvae. It was verified the susceptibility of larvae of A. fraterculus to isolates of EPNs and a significant increase of the pupal mortality in the function of the concentration of IJs inoculated by larva (above 75%). After the dissection of pupae and adults of A. fraterculus from infected larvae, the concentration of 1500 IJs/mL of EPNs provided the highest rate of multiplication of IJs by insect, equating to maximum concentration tested 1500 IJs/mL. Adults of A. fraterculus from larvae infected with EPNs longevity of five days, being less than adults from uninfected larvae by IJs (135 days). H. amazonensis IBCB 24, S. carpocapsae IBCB 02, and S. feltiae IBCB 47 proved to be promising as agents of biological control of A. fraterculus.

Entomopathogenic nematodes for the control of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) pupae

Helicoverpa armigera (Hübner) is a polyphagous insect of difficult control and maize is an important host crop of this insect. Entomopathogenic nematodes (EPNs) are control agents of soil pests. This study aimed to verify the action of EPNs for the control of H. armigera pupae. Laboratory and greenhouse bioassays were conducted to select the concentration of nematode application and subsequently field test were conducted. It was obtained that Heterorhabditis amazonensis MC01 at the concentration of 400 infective juveniles (IJs) ·pupa-1 caused the highest mortality in a lower concentration, whereas for H. amazonensis JPM4, concentrations of both 200 and 400 IJs ·pupa-1 were similar causing pupae mortality. In the greenhouse, H. amazonensis MC01 caused mortality reached values of 80% after 10 days, at concentrations of 600 and 800 IJs ·pupa-1. The highest mortality caused by Steinernema carpocapsae was observed at eight days after the juvenile application, at a concentration of 600 IJs ·pupa-1, also reaching 80% mortality. In the field test, both forms of application were considered appropriate for H. amazonensis MC01, causing mortality rates of up to 80%.(AU)

Entomopathogenic nematodes for the control of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) pupae

Helicoverpa armigera (Hübner) is a polyphagous insect of difficult control and maize is an important host crop of this insect. Entomopathogenic nematodes (EPNs) are control agents of soil pests. This study aimed to verify the action of EPNs for the control of H. armigera pupae. Laboratory and greenhouse bioassays were conducted to select the concentration of nematode application and subsequently field test were conducted. It was obtained that Heterorhabditis amazonensis MC01 at the concentration of 400 infective juveniles (IJs) ·pupa-1 caused the highest mortality in a lower concentration, whereas for H. amazonensis JPM4, concentrations of both 200 and 400 IJs ·pupa-1 were similar causing pupae mortality. In the greenhouse, H. amazonensis MC01 caused mortality reached values of 80% after 10 days, at concentrations of 600 and 800 IJs ·pupa-1. The highest mortality caused by Steinernema carpocapsae was observed at eight days after the juvenile application, at a concentration of 600 IJs ·pupa-1, also reaching 80% mortality. In the field test, both forms of application were considered appropriate for H. amazonensis MC01, causing mortality rates of up to 80%.(AU)

Susceptibility variation to different entomopathogenic nematodes in Strategus aloeus L (Coleoptera: Scarabaeidae).

Strategus aloeus L (Coleoptera: Scarabaeidae), known as "Little bull" or oil palm "chiza" is a limiting pest in palm plantation in Cesar Colombia. Its management is based on pesticide use or old palm removal in renewal lots. Therefore, other alternatives are being sought out. Entomopathogenic nematodes isolated from the Colombian Andean region were evaluated. Under laboratory conditions S. aloeus third instar larvae exposure to 160 infective juveniles (IJs) per/cm(2) Steinernema sp3 JCL027, S. feltiae SCT125, S. websteri JCL006, S. colombiense SNI0198, Heterorhabditis bacteriophora HNI0100, H. bacteriophora HASA702, H. indica SL0708 (n = 20) was evaluated under a completely randomized design. The experiment was repeated three times on different dates. Significant differences were observed (F = 11.127, df = 7. 24, p = 0.0054), registering mortality between 3 and 14 days. Steinernema sp3 JCL027 was the strain producing the highest mortality rate (19.3 ± 8 %), followed by H. bacteriophora HNI0100 (5.2 ± 9 %). Thus, we evaluated Steinernema sp3 JCL0270 using a randomized design at 0, 160, 290, 420, 550, 680, 810 IJs/cm(2) (n = 12). The experiment was repeated three times on different dates. Significant differences were found among treatments (44 ± 5 %, F = 14.676; df = 6. 21, p = 0.001), with 680 IJs/cm(2) producing the highest mortality followed by 810 IJs/cm(2) (22 ± 5 %). In conclusion, this alternative must be further explored in search of pesticide use and cost reduction, in addition to young palm loss in a plantation.

Susceptibility of Delia platura to seven entomopathogenic nematode isolates from the Central Andes region of Colombia

La mosca de la semilla, Delia platura, es una delas principales plagas en los cultivos de espinaca en la sabanade Bogotá. En Colombia la plaga es controlada mediante laaplicación de insecticidas. Sin embargo, la información sobreel control específico en cultivos de espinaca es desconocida;dado que no se realiza manejo integrado. Con el fin debuscar alternativas para control de plagas en espinaca, seevaluó: 1. La susceptibilidad de D. platura a siete especies denematodos entomopatógenos de la zona Central Andina deColombia y 2. Diferentes dosis y producción de juvenilesinfectivos (JIs) de la especie más virulenta, bajo condicionesde laboratorio. Para obtener larvas de tercer instar en ellaboratorio, se estableció la cría en papa amarilla (Solanumphureja), y se expusieron a 2500 JIs/especie. Seleccionada laespecie más virulenta, se expuso D. platura a 500, 1000, 2000,4000 y 8000 JIs/larva. Los resultados con mortalidad entreel 75 a 88% se encontraron con Steinernema sp.3 en las dosisde 4000 y 8000 JIs, encontrando que la DL50 es de 1314JIs/larva y 15259 JIs/larva para la DL95. Así mismo, se establecióque Steinernema sp.3 se reproduce exitosamente en D. platura,encontrando un promedio de producción 670±7.67 JIs/larva durante un periodo de dieciocho días. La mosca dela semilla es altamente susceptible a Steinernema sp.3, el cualpuede ser un agente potencial para el control de esta plaga...

The seed maggot, Delia platura, is a major pest of spinach crops in the savanna of Bogotá. In Colombia, chemical insecticides are used to manage the pest; however, because its management is not integrated, information about pest management in spinach is still undetermined. Here, we evaluated the susceptibility of D. platura to seven species of entomopathogenic nematodes from the central Andean region of Colombia. Additionally, under laboratory conditions, we produced and evaluated different doses of infective juveniles (IJs) of the most virulent species. In the laboratory, we used yellow potatoes (Solanum phureja) for breeding to obtain third instar larvae; we then exposed them to infective IJs 2500/species. Once we selected the most virulent species, we exposed D. platura to 500, 1000, 2000, 4000 and 8000 IJs/larvae. We obtained the best results with Steinernema sp.3 with mortality of 75-88% at doses of 4000-8000 IJs, and found that LD50 is 1314 JIs/larvae and LD95 is 15259 JIs/larva. We also evidenced the successful reproduction of Steinernema sp.3 in D. platura, with a mean production of 670±7.67 JIs/larvae for eighteen days. Thus, the seed fly is highly susceptible to Steinernema sp.3 making this species a potential controlling agent for this pest...

A mosca das sementes, Delia platura, é uma dasprincipais pragas das culturas de espinafre na savana deBogotá. Na Colômbia, a praga é controlada através daaplicação de inseticidas mas a informação sobre o controleespecífico é desconhecida. Assim, o objetivo deste estudofoi avaliar a suscetibilidade de D. platura a sete espécies denematoides entomopatogênicos na Zona Central andina daColômbia, além de avaliar as diferentes doses e produçãodos juvenis infectantes (JIs) das espécies mais virulentas, emcondições de laboratório. No laboratório foi estabelecida areprodução do inseto em batata amarela (Solanum phureja)para larvas de terceiro instar, que foram expostos a 2500 JIsespécies. Foi selecionada a espécie mais virulenta e expostaa D. platura a 500, 1000, 2000, 4000 e 8000 JIs/larva. Osmelhores resultados foram encontrados com Steinernemasp.3 com uma mortalidade de 75-88% nas doses de 4000e 8000 JIs, encontrando que a DL50 é 1314 JIs /larva e aDL95 é 15259 JIs/larva. Além disso, foi estabelecido queSteinernema sp.3 reproduz-se com sucesso em D. platura,encontrando uma média de 670±7,67 de produção de JIs/larva por um período de 18 dias. A mosca da semente éaltamente susceptível a Steinernema sp.3, e pode ser umpotencial agente para o controle desta praga...