Efficacy of commercially available entomopathogenic nematodes against insect pests of canola in Alberta, Canada.

Certain entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae are among the most studied biocontrol tools, some of which are commercially available against pest insects. Their use against foliar and subterranean insect pests is largely unexplored in the Canadian Prairies. We conducted a laboratory-based study to produce baseline information on the biocontrol potential of a few commercial EPN species. Percent mortality of flea beetles, diamondback moths (DBMs), lygus, cabbage root maggots, and black cutworms (BCWs) was assessed after 72 hours exposure to Steinernema carpocapsae, S. kraussei, S. feltiae, and Heterorhabditis bacteriophora at varying concentrations (25, 50, 100, and 200 infective juveniles (IJs) per larvae, pupae, or cm2 of soil surface). Irrespective of concentration level, S. carpocapsae and S. kraussei caused significant mortality in DBM and BCW larvae compared with H. bacteriophora.S. kraussei, and S. feltiae were more efficient than S. carpocapsae in controlling root maggot larvae. H. bacteriophora caused zero mortality to root maggots at any concentration. Root maggot pupae were resistant to entry to EPN species tested, likely due to hard outer covering. Compared with root maggot pupae, a moderate level of mortality was observed in DBM pupae, suggesting differential ability of the tested EPNs in killing different life stages of certain pests. All nematode species tested caused low mortality (≤10%) in flea beetle adults. The findings of this investigation form fundamental data essential for carrying out field-based studies on canola and other related crops aimed at control and management of these pest species.

Entomopathogenic nematodes and their symbiotic bacteria: from genes to field uses.

The term "microbial control" has been used to describe the use of microbial pathogens (bacteria, viruses, or fungi) or entomopathogenic nematodes (EPNs) to control various insect pest populations. EPNs are among the best biocontrol agents, and major developments in their use have occurred in recent decades, with many surveys having been conducted all over the world to identify EPNs that may have potential in the management of insect pests. For nematodes, the term "entomopathogenic" means "causing disease to insects" and is mainly used in reference to the bacterial symbionts of Steinernema and Heterorhabditis (Xenorhabdus and Photorhabdus, respectively), which cause EPN infectivity. A compendium of our multiannual experiences on EPN surveys and on their collection, identification, characterization, and use in agro-forestry ecosystems is presented here to testify and demonstrate once again that biological control with EPNs is possible and offers many advantages over chemicals, such as end-user safety, minimal damage to natural enemies, and lack of environmental pollution, which are essential conditions for an advanced IPM strategy.

Potential of Entomopathogenic Nematode HbSD as a Candidate Biocontrol Agent against Spodoptera frugiperda.

Spodoptera frugiperda is a highly destructive and polyphagous pest that causes severe damage to various crops, especially maize. The wide use of chemical insecticides to control S. frugiperda results in resistance against commonly used chemicals and resistant mutations will expand in populations accompanied by a spread to vulnerable areas. Consequently, more effective and friendly strategies must be explored to minimize losses caused by S. frugiperda. Entomopathogenic nematodes (EPN) are good candidates for the biological control of different species of insect pests, including S. frugiperda. In the current study, the infective capabilities of the EPN species HbSD, belonging to Hetrerorhabditis bacteriophora, were evaluated against S. frugiperda under laboratory, greenhouse and field conditions. In laboratory assays, HbSD was highly virulent against 3rd/5th instar larvae, which was related to HbSD concentration and exposure durations. In greenhouse assays, spraying aqueous HbSD also showed good performance in killing larvae on maize leaves. However, the virulence of HbSD decreased in field trials where many adverse factors affecting survival and efficacy were encountered by HbSD. Overall, our study provides an alternative EPN for the biological control of S. frugiperda with the potential to be developed as a sustainable option for efficient pest management.

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)

Evaluation of Indigenous Entomopathogenic Nematodes as Potential Biocontrol Agents against Popillia japonica (Coleoptera: Scarabaeidae) in Northern Italy.

The natural presence of entomopathogenic nematodes (EPNs) has been investigated in the Piedmont region (Northern Italy) in areas infested by the Japanese beetle Popillia japonica. Thirty-nine out of 155 soil samples (25.2%) were positive for EPNs. Most of the samples contained only steinermatids (92.3%), 5.1% contained heterorhabditids, and one sample (2.6%) contained both genera. All the recovered isolates were identified at species level both morphologically and molecularly. Steinernema carpocapsae was the most abundant and it was mainly distributed in open habitats, such as perennial meadows, uncultivated soils, and cropland, characterized by sandy loam soil texture and acidic pH. Steinernema feltiae has been found associated mainly with closed habitats such as coniferous and deciduous woodland, characterized by sandy loam-texture and extremely acidic soil. The three isolates of Heterorhabditis bacteriophora were collected only in open habitats (perennial meadows and uncultivated fields) characterized by strongly acidic soils with sandy loam texture. The virulence of all EPN natural strains was evaluated by laboratory assays against P. japonica third-instar larvae collected during two different periods of the year (spring, autumn). The results showed that larval mortality was higher for pre-wintering larvae than post-wintering ones. The five more promising EPN isolates were tested in the semi-field assay in which H. bacteriophora natural strains have been shown to be more efficient in controlling P. japonica grubs. All of these results are finally discussed considering the use of these natural EPNs as biological control agents against P. japonica, within an eco-friendly perspective of management.

Susceptibility of entomopathogenic nematodes to ivermectin and thiabendazole.

The objective of the present study was to determine the susceptibility of entomopathogenic nematodes to ivermectin and thiabendazole. Soil samples collected from the municipalities of Irapuato and León, Guanajuato, Mexico, were obtained, from which the entomopathogenic nematodes (EPNs) of the Steinernematidae and Heterorhabditidae families were isolated. The samples were classified from livestock and nonlivestock soils, and the susceptibility of EPNs to anthelmintics was determined with the larval motility assay (LMA, 24 h) and the larval migration inhibition assay (LMI assay, 48 h). Sterile distilled water (T1) and treatments with 1% ivermectin diluted in 5% DMSO (dimethyl sulfoxide) (T2) and 5% thiabendazole diluted in 5% DMSO (T3) were applied to infective juvenile larvae. Analysis of variance was performed with a factorial design and Tukey's test at 0.05 probability. In addition, different concentrations of ivermectin (0.1, 0.5, 1, 1.2, 1.5, and 2 µg) and thiabendazole (1, 5, 10, 12, 15, and 20 mg) were evaluated to perform a Probit analysis to determine their LC50. All strains of EPNs were susceptible to ivermectin in both the LMA and LMI assay. The results show that EPNs are susceptible to ivermectin and thiabendazole, and the degree depends on the type of test performed, the chemical product used, and the origin of the strain of EPN.

Compatibility of Heterorhabditis amazonensis MC01 (Nematoda: rhabditida) with fertilizers and soil conditioners / Compatibilidade de Heterorhabditis amazonensis MC01 (Nematoda: Rhabditida) com fertilizantes e condicionadores de solo

Entomopathogenic nematodes are natural enemies of insect pests present in the soil; however, the intensive use of agricultural inputs can affect the action of these organisms. The objective of this study was to evaluate the effects of exposure of the nematode Heterorhabditis amazonensis MC01 to soil fertilizers containing different active ingredient, verifying their influence in the viability, infectivity and nematode production in Tenebrio molitor L. larvae. Nine products were tested, including fertilizers and soil conditioners, using the adapted IOBC/WPRS protocol. The infective juveniles were exposed to the highest concentration recommended by the manufacturer of each product for a period of 48 h. After this period, the viability, infectivity and production were evaluated and the values of mortality, infectivity reduction, production reduction and insecticide effect were obtained in order to classify the products according to IOBC criteria. In this way, the nematode H. amazonensisMC01 was compatible with most of the products under the tested conditions, so could be present in the soil at the same time. However, the product Nutriterge® Formula 3 was considered slightly harmful and Nem out® considered harmful. However, further field tests should be performed with these products to prove the deleterious effect on the nematode tested.

Nematoides entomopatogênicos são inimigos naturais de insetos-praga presentes no solo; no entanto, o uso de insumos agrícolas pode afetar a ação desses organismos. O objetivo deste estudo foi avaliar os efeitos da exposição de Heterorhabditis amazonensis MC01 com fertilizantes de solo contendo diferentes ingredientes ativos, a fim de verificar a influência na viabilidade, infectividade e produção do nematoide em larvas de Tenebrio molitor L. Foram testados nove produtos, incluindo fertilizantes e condicionadores de solo, utilizando o protocolo adaptado da IOBC/WPRS. Os juvenis infectantes foram expostos à maior concentração recomendada de cada produto por período de 48 h. Após, esse período os valores de viabilidade, infectividade, redução da produção e efeito inseticida foram obtidos e os produtos foram classificados de acordo com os critérios da IOBC. Dessa forma, o nematoide H. amazonensis MC01 foi compatível com a maioria dos produtos nas condições testadas, podendo estar presente no solo ao mesmo tempo. No entanto, o produto Nutriterge® Fórmula 3 foi considerado ligeiramente prejudicial e Nem out® foi considerado prejudicial. Outros testes de campo devem ser realizados com esses produtos para comprovar o efeito deletério sobre o nematoide testado.

Transmission Success of Entomopathogenic Nematodes Used in Pest Control.

Entomopathogenic nematodes from the two genera Steinernema and Heterorhabditis are widely used as biological agents against various insect pests and represent a promising alternative to replace pesticides. Efficacy and biocontrol success can be enhanced through improved understanding of their biology and ecology. Many endogenous and environmental factors influence the survival of nematodes following application, as well as their transmission success to the target species. The aim of this paper is to give an overview of the major topics currently considered to affect transmission success of these biological control agents, including interactions with insects, plants and other members of the soil biota including conspecifics.

Efficacy of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) on developmental stages of house fly, Musca domestica.

The housefly, Musca domestica is a major domestic, medical and veterinary pest. The management of these flies reliance on insecticide, causes environmental constraints, insecticide resistance and residues in the meat, skin. Therefore one of the eco-friendly alternate methods is by using biological agents such as entomopathogenic nematodes (EPN). In the present study evaluated the survival of EPN species Steinernema feltiae, Heterorhabditis indica, S. carpocapsae, S. glaseri and S. abbasi in poultry manure and also their efficacy against different developmental stages of house fly. After exposing to poultry manure, S. feltiae showed more survival as followed by H. indica, S. carpocapsae, S. glaseri and S. abbasi in all exposition period. When the exposition period extended to 96 h, all nematode species survivability was drastically reduced. After exposing these nematodes to poultry manure at 24 h their virulence capacity against wax moth, Galleria mellonella showed all the nematode species were able cause 100% mortality. However their progeny production was significantly reduced. Fly eggs and pupae were refractory to these nematode infection. Petri dish without artificial diet assay showed that, second and 3rd-instar larvae were highly susceptible to EPNs as compared to larvae provided with artificial diet. H. indica showed high virulence capacity compared to other nematodes tested. Poultry manure assay revealed that, H. indica and S. carpocapsae caused minimal mortality where as S. feltiae, S. glaseri and S. abbasi did not cause any mortality. This may be because of poor survival and limited movement of nematodes in poultry manure which may be due to ammonia, other toxic substances in poultry manure. The decrease in larval mortality in manure suggests that biocontrol of housefly by using EPNs is unlikely.

Variability study of entomopathogenic nematode populations (Heterorhabditidae) from Argentina / Estudo da variabilidade entomopatogênicos nematóides populações (Heterorhabditidae) da Argentina

Abstract Entomopathogenic nematodes (EPN) belonging to the Heterorhabditidae family are lethal parasites of soil-dwelling insects. Two species were reported in Argentina: Heterorhabditis argentinensis and Heterorhabditis bacteriophora characterized mainly by morphometric features. In this work a comparative and phylogenetic study between five Heterorhabditis populations from Argentina was conducted to analyze the variability between strains and to evaluate the taxonomic position of Heterorhabditis argentinensis. The PCA analyses of morphometric characters separated the larger juvenile, female and male H. argentinensis from H. bacteriophora populations. The juvenile (IJs) stage provided the clearest separation of Heterorhabditis populations presenting the least variability between strains. The variable L and MBW were highly related to H. argentinensis IJs. Three groups were separated by this stage considering PC1 and PC2: one formed by H. bacteriophora OLI, RIV and RN strains, (isolates from Córdoba and Río Negro province), one for H. bacteriophora VELI strain (Buenos Aires province) and one for H. argentinensis (Santa Fe province). Heterorhabditis bacteriophora VELI and H. argentinensis isolated from regions with more rainfalls and humidity presented larger values for morphometric features. Molecular analyses showed the Argentinian populations (H. bacteriophora VELI strain and H. argentinensis), forming a same clade, with six other H. bacteriophora populations (not from Argentina) with a genetic similarity between them of 99%. Heterorhabditis argentinensis presented one unique nucleotide that was not present in any of the other species of the clade. Considering the results of this study H. argentinensis would be conspecific to H. bacteriophora, constituting a strain with a great morphometric variation where the host and climatic conditions could have influenced on the measurements.

Resumo Nematóides entomopatogênicos (EPN) pertencentes à família Heterorhabditidae são parasitas letais de insetos que vivem no solo. Duas espécies foram relatados na Argentina: Heterorhabditis argentinensis e Heterorhabditis bacteriophora, caracterizada principalmente por características morfométricas. Neste trabalho um estudo comparativo e filogenética entre cinco populações do Heterorhabditis da Argentina foi conduzido para analisar a variabilidade entre as linhagens e avaliar a posição taxonômica das Heterorhabditis argentinensis. Características morfométricas de Heterorhabditis bacteriophora VELI e H. argentinensis isoladas de regiões com mais chuvas e umidade apresentaram dimensões maiores. Analisa o PCA de personagens morfométricas separou a maior juvenil, feminino e masculino H. argentinensis de H. bacteriophora populações. A fase juvenil (JIs) fornece a mais clara separação de populações Heterorhabditis apresentando a menor variação entre as cepas. A L variável e MBW foram altamente relacionada com H. argentinensis JIs. Três grupos foram separados por esta fase considerando PC1 e PC2: um formado por H. bacteriophora OLI, RIV e estirpes RN, (isolados de Córdoba e província de Rio Negro), um para a estirpe H. bacteriophora VELI (província de Buenos Aires) e um para H. argentinensis (província de Santa Fe). Heterorhabditis bacteriophora VELI e H. argentinensis isolado a partir de regiões com mais chuvas e umidade apresentaram maiores valores para as características morfométricas. A análise molecular mostrou as populações da Argentina (estirpe H. bacteriophora VELI e H. argentinensis), formando um mesmo subtipo, com seis outras populações H. bacteriophora (não da Argentina), com uma similaridade genética entre eles de 99%. Heterorhabditis argentinensis apresentado um único nucleótido que não estava presente em nenhum dos outros espécies do clado. Considerando os resultados deste estudo H. argentinensis seria conspecific a H. bacteriophora, constituindo uma estirpe com uma grande variação morfométrica onde o anfitrião e as condições climáticas podem ter influenciado nas medições.

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...

Biological characterization of the colombian isolate Heterorhabditis sp. SL0708 (Rhabditida: Heterorhabditidae) / Caracterização biológica do isolamento colombiano Heterorhabditis sp. SL0708 (Rhabditida: Heterorhabditidae)

Heterorhabditis sp SL0708 (Rhabditida: Heterorhabditidae) is a native entomopathogenic nematode from Alcalá, Valle del Cauca (Colombia), a natural enemy of insects that can be used for controlling Plutella xylostella L, Conotrachelus psidii Marshall and Delia platura (Meigen); however its biological characterization is unknown. In order to know about the infective capacity of the isolate, tests were made with last instar larvae of Galleria mellonella (Lepidoptera: Pyrallidae) on penetration, one by one, exposure time, dose response and foraging strategy. The average infecting juveniles (IJ) entering larvae was 3 (1.5%). In the one-on-one test, larvae mortality ranged between 8.3 and 16.7%. There was no significant difference (p < 0.05) between treatments and in number of dead larvae in the exposure time and dose response assays. Heterorhabditis sp. SL0708 presented a cruiser foraging strategy, which indicates that it can be used for sessile or cryptic hosts.

Heterorhabditis sp.SL0708, nematoide entomopatogênico nativo de Alcalá, Valle del Cauca (Colômbia), é um inimigo natural que pode ser usado para o controle de Plutella xylostella L, Conotrachelus psidii Marshall e Delia platura (Meigen), porém, a sua caracterização biológica é desconhecida. Assim, ensaios de penetração, um a um, tempo de exposição, exposição a diferentes doses e estratégia de forrageio foram realizados com lagartas de último ínstar de Galleria mellonella (Lepidoptera: Pyrallidae). A média dos juvenis infectantes (IJs) que ingressaram na lagarta foi 3 (1,5%). No ensaio um a um a mortalidade das lagartas oscilou entre 8,3 e 16,7%. Não foram encontradas diferenças significativas entre os tratamentos e o número de lagartas mortas no tempo de exposição e dose. Heterorhabditis sp., apresentou uma estratégia de forrageio de cruzeiro, o que indica que pode ser usado para hospedeiros com hábitos sésseis ou crípticos.

Ecological characterisation of the Colombian entomopathogenic nematode Heterorhabditis sp. SL0708 / Caracterização ecológica do nematoide entomopatogênico colombiano Heterorhabditis sp. SL0708

The entomopathogenic nematode Heterorhabditis sp. SL0708 (Rhabditida: Heterorhabditidae) isolated from soil in Alcalá, Valle del Cauca (Colombia) was characterised ecologically using Galleria mellonella larvae (L) (Pyralidae: Galleriinae) as hosts. The effect of temperature on the viability, infectivity and reproduction, and of moisture on infectivity and storage in liquid were evaluated in infective juveniles (IJs). Significant differences were found in the viability, infectivity and reproduction of the IJs at different temperatures. No nematodes were recovered at 5 °C and 10 °C, and at 35 °C no infectivity was observed. Average daily nematode recovery was best at 25 °C, and survival of the IJs was low in substrates presenting 13% moisture. The optimal storage temperature for Heterorhabditis sp. SL0708 was between 20 °C and 30 °C, keeping its infectivity for up to 8 weeks.

O nematoide entomopatogênico colombiano Heterorhabditis sp. SL0708, isolado do solo de Alcalá, Valle del Cauca (Colombia), foi caracterizado ecologicamente utilizando-se como hospedeiro lagartas de Galleria mellonella (L) (Pyralidae:Galleriinae). O efeito da temperatura na viabilidade, na infecção e na reprodução, e da umidade na infecção e do armazenamento em líquido foi avaliado em juvenis infectantes (JIs). Diferenças significativas na viabilidade, na infecção e na reprodução dos JIs foram observadas nas diferentes temperaturas. Não foram recuperados nematoides a 5 °C e 10 °C, e não se observou infecção a 35 °C. A maior média diária de recuperação de nematoides foi a 25 °C. Por outro lado, a sobrevivência dos JIs foi baixa nos substratos com unidades de 13% e a melhor temperatura de armazenamento para SL0708 foi entre 20 °C e 30 °C, mantendo a infecção até oito semanas.

Identification of entomopathogenic nematodes in the steinernematidae and heterorhabditidae (nemata: rhabditida).

This paper contains taxonomic keys for the identification of species of the genera Steinernema and Heterorhabditis. Morphometrics of certain life stages are presented in data tables so that the morphometrics of species identified using the keys can be checked in the tables. Additionally, SEM photographs and diagnoses of the families and genera of Steinernematidae and Heterorhabditidae are presented.

Survey of heterorhabditidae and steinernematidae (rhabditida, nematoda) in Western Canada.

A survey was done in the summer months along the Alaska Highway, in other parts of British Columbia, in northern Alberta, and in the Yukon Territory for steinernematid and heterorhabditid nematodes occurring in the top 10 cm of soil. Steinernema feltiae and Steinernema spp. were found at 18 and Heterorhabditis megidis at 7 sites of 125 sampled. Most nematodes were found where visible insect infestation occurred and where human influence on the habitat was substantial (e.g., agricultural, forested and bush-hedgerow habitats); none was found in grassland or virgin forests. Heterorhabditis megidis occurred in only the southern, warmer, drier region of British Columbia. In the laboratory some steinernematid isolates and H. megidis killed Galleria mellonella larvae at 13 and 22 C, whereas some isolates of Steinernema killed the larvae at only 13 C. Steinernema spp. from three high altitude sites with low, average July temperatures (13-14 C) are cold-active in that they produced infective juveniles at 13 C and killed G. mellonella at 6 C.