Temperature influences the virulence of beneficial nematodes against mustard beetles

Interaction between entomopathogenic nematodes and mustard beetles- Nematodeinformation It has been demonstrated that the virulence of Heterorhabditis indica and Heterorhabditis bacteriophora against the pupae of mustard beetle, Phaedon cochleariae was high at 30^oC but the virulence of Steinernema carpocapsae and Steinernema feltiae was high at 25^oC (Mahar et al., 2012).

Literature:

Mahar, A.N., Jan, N.D. and Mahar, A.Q. 2012.  Comparative effectiveness of entomopathogenic nematodes against the pupae of mustard beetle, Phaedon cochleariae F. (Chrysomelidae: Coleoptera). Pakistan Journal of Zoology 44: 517-523.

Control sugarcane billbug, Sphenophorus levis with beneficial nematodes

Entomopathogenic nematodes and the sugarcane billbug, Sphenophorus levis- Nematode Information Sugarcane is grown as an important cash crop in many countries but insect pests like the sugarcane billbug, Sphenophorus levis can cause a tremendous yield loss to this crop. Entomopathogenic nematodes have a great potential to use as a biological control agent against the sugarcane bill bugs. Recently, Giometti et al. (2011) reported that entomopathogenic nematodes including Steinernema brazilense strain IBCB n6 and three strains of Heterorhabditis sp. (IBCB n10, IBCB n24 and IBCB n44) were highly virulent causing over 60% mortality of adults of the sugarcane billbug. Sphenophorus levis.  

Publications:

Giometti, FHC, Leite, LG., Tavares, FM., Schmit, F.S., Batista, A. and Dell'Acqua, R. 2011.  Virulence of entomopathogenic nematodes (Nematoda: Rhabditida) against Sphenophorus levis (Coleoptera: Curculionidae).   Bragantia 70: 81-86.

Virulence Mechanisms of symbiotic bacteria Photorhabdus and Xenorhabdus spp

Entomopathogenic nematodes and their symbiotic bacteria- Nematode Information

Molecular studies demonstrated that the closely related Photorhabdus, symbiotic bacteria of Heterorhabditis nematodes and Xenorhabdus, symbiotic bacteria of Steinernematid nematodes have developed totally different molecular strategies for the same objective of virulence to insects and symbiosis with the nematode.

These findings were presented by An, R. and Grewal, P.S. at the 50th annual meeting of the Society of Nematologists held in Corvallis, Oregon from July 17-20, 2011.

Entomopathogenic nematodes for the biological control of False codling moth- Nematode information

Entomopathogenic nematodes and False codling moth

• A presence of entomopathogenic nematode species including Steinernema khoisanae, Steinernema yirgalemense, Steinernema citrae, Heterorhabditis bacteriophora and Heterorhabditis zealandica have been reported in citrus orchards in the Western Cape, Eastern Cape and Mpumalanga provinces of South Africa (Malan et al., 2011).

• All the above nematode species have showed a very high virulence against false codling moth, Thaumatotibia leucotreta an economically important pest of citrus in South Africa. For example, S. yirgalemense can cause over 74% mortality of both larval and pupal mortality of false codling moth when applied at the rate of 50-200 infective juveniles/ larval or pupal stages of false codling moth.

• Two entomopathogenic nematode species including S. yirgalemense and S. citrae were reported for the first time from South Africa (Malan et al., 2011).

Read following papers on entomopathogenic nematodes from South Africa

de Waal, J.Y., Malan, A.P. and Addison, M.F. 2011.  Evaluating mulches together with Heterorhabditis zealandica (Rhabditida: Heterorhabditidae) for the control of diapausing codling moth larvae, Cydia pomonella (L.) (Lepidoptera: Tortricidae).  Biocontrol Science and Technology 21: 255-270.

de Waal, J.Y., Malan, A.P., Levings, J. and Addison, M.F. 2010.  Key elements in the successful control of diapausing codling moth, Cydia pomonella (Lepidoptera: Tortricidae) in wooden fruit bins with a South African isolate of Heterorhabditis zealandica (Rhabditida: Heterorhabditidae). Biocontrol Science and Technology. 20: 489-502.

Hatting, J., Stock, S.P. and Hazir, S.  2009. Diversity and distribution of entomopathogenic nematodes (Steinernematidae, Heterorhabditidae) in South Africa.  Journal of Invertebrate Pathology 102: 120-128.

Malan, A.P., Knoetze, R. and Moore, S.D.  2011.  Isolation and identification of entomopathogenic nematodes from citrus orchards in South Africa and their biocontrol potential against false codling moth. Journal of Invertebrate Pathology 108: 115-125.

Malan, A.P., Nguyen, K. B. and Addison, M. F. 2006.  Entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from the southwestern parts of South Africa. African Plant Protection 12: 65-69.

Malan, A.P., Nguyen, K.B., de Waal, J.Y. and Tiedt, L. 2008. Heterorhabditis safricana n. sp (Rhabditida : Heterorhabditidae), a new entomopathogenic nematode from South Africa. Nematology 10: 381-396.

Entomopathogenic nematode identification with a quantitative real-time PCR (qPCR)

Entomopathogenic nematodes and qPCR Quantitative real-time PCR (qPCR) technique can be used for the identification of entomopathogenic nematodes in the both Heterorhabditidae and Steinernematodae families directly from soil samples.

Species specific primers and TaqMan (R) probes from the ITS rDNA region for the EPNs were used for the identification of four species of entomopathogenic nematodes including Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae and Steinernema scapterisci (Campos-Herrera et al., 2011).

A publication on indentification of entomopathogenic nematodes using quantitative real-time PCR (qPCR) technique.

Campos-Herrera, R., El-Borai, F.E., Stuart, R.J., Graham, J.H. and Duncan, L.W. 2011.   Entomopathogenic nematodes, phoretic Paenibacillus spp., and the use of real time quantitative PCR to explore soil food webs in Florida citrus groves. Journal of Invertebrate Pathology 108: 30-39.

Entomopathogenic nematodes for the biological control of alfalfa weevil, Hypera postica

Heterorhabditis indica and Steinernema carpocapsae for controlling alfalfa weevil Application of Heterorhabditis indica and S. carpocapase at the rate 1 billion nematodes per hectare can reduce 72 and 50% population of alfalfa weevil, Hypera postica grubs, respectively.  Another entomopathogenic nematode, Steinemema thermophillum was also effective in killing H. postica grubs (Shah et al., 2011).

Read following paper for information on the effect of entomopathogenic nematodes on alfalfa weevil

Shah, N.K., Azmi, M.I. and Tyagi, P.K. 2011. Pathogenicity of Rhabditid nematodes (Nematoda: Heterorhabditidae and Steinernematidae) to the grubs of alfalfa weevil, Hypera postica (Coleoptera: Curculionidae). Range Management and Agroforestry 32: 64-67.

Use an entomopathogenic nematode, Heterorhabditis bacteriophora to control long-horned beetle, Dorcadion pseudopreissi infesting turf.

The application of an entomopathogenic nematode Heterorhabditis bacteriophora at the rate of 0.5 million infective juveniles per square meter can significantly reduce the population of Dorcadion pseudopreissi infesting turf grass (Lolium perenne) in the field (Susurluk et al. (2011). Read following papers for more information.

Susurluk, I.A., Kumral, N.A., Bilgili, U. and Acikgoz, E. 2011. Control of a new turf pest, Dorcadion pseudopreissi (Coleoptera: Cerambycidae), with the entomopathogenic nematode Heterorhabditis bacteriophora. Journal of Pest Science 84: 321-326.

Susurluk, I.A., Kumral, N.A., Peters, A., Bilgili, U. and Acikgoz, E. 2009.  Pathogenicity, reproduction and foraging behaviours of some entomopathogenic nematodes on a new turf pest, Dorcadion pseudopreissi (Coleoptera: Cerambycidae). Biocontrol Science and Technology 19: 585-594.

Plants can call entomopathogenic nematodes to attack their insect enemies

It has been demonstrated that entomopathogenic nematodes are attracted to herbivore-induced volatile organic compounds (VOCs) from plants when fed upon by their insect pests.   Thus these attracted nematodes can attack and kill the insects present in the vicinity of plants. Please read following papers for more information on VOCs released by plants and nematode attraction.

Ali, J.G., Alborn, H.T. and Stelinski, L.L. 2011. Constitutive and induced subterranean plant volatiles attract both entomopathogenic and plant parasitic nematodes. Journal of Ecology 99: 26-35.

Rasmann, S., Erwin, A.C., Halitschke, R. and Agrawal, A.A. 2011. Direct and indirect root defenses of milkweed (Asclepias syriaca): trophic cascades, trade-offs and novel methods for studying subterranean herbivory.  Journal of Ecology 99: 16-25.

Entomopatogenic nematodes are compatible with many insecticides

Recently, Negrisoli et al. (2010) demonstrated that entomopathogenic nematodes including Heterorhabditis indica, Steinernema carpocapsae and Steinernema glaseri were found to be compatible with many insecticides including chlorpyrifos, deltamethrin, lufenuron, deltramethrin + triazophos, diflubenzuron, gamacyhalothrin, lambdacyhalothrin, spinosad, cypermethrin, triflumuron, and permethrin under laboratory conditions. Read following paper for more information compatibility of entomopathogenic nematodes with insecticides.

Negrisoli, A.S., Garcia, M.S., Negrisoli, C.R.C.B. 2010.  Compatibility of entomopathogenic nematodes (Nematoda: Rhabditida) with registered insecticides for Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) under laboratory conditions.  Crop Protection 29: 545-549.

Biological control of fall army worm (Spodoptera frugiperda) an insect pest of corn

Recently, Andalo, et al. (2010) demonstrated that the entomopathogenic nematodes Steinernema arenarium and Heterorhabditis sp. can kill over 80% larvae of fall army worm, Spodoptera frugiperda under both laboratory and greenhouse condition. Read following paper for the information on the effect of entomopathogenic nematodes on fall army worm.

Andalo, V., Santos, V., Moreira, G.F., Moreira, C.C. and Moino, A.  2010. Evaluation of entomopathogenic nematodes under laboratory and greenhouses conditions for the control of Spodoptera frugiperda Ciencia Rural  40: 1860-1866.

Insect blood clotting can prevent infection by entomopathogenic nematodes

Recently, Hyrsl et al. (2011) demonstrated that the common fruit fly, Drosophila melanogaster as an immune response can form the blood (hemolymph) clots and protect against infection by an entomopathogenic nematode (Heterorhabditis bacteriophora) and its symbiotic bacterium (Photorhabdus luminescens). Read following papers for more information on the interaction between fruit fly and entomopathogenic nematodes.

Hyrsl, P., Dobes, P., Wang, Z., Hauling, T., Wilhelmsson, C. and Theopold, U. 2011. Clotting Factors and Eicosanoids Protect against Nematode Infections.  Journal of Innate Immunity 3: 65-70.

Quantitative real-time PCR techniques for detecting and quantifying entomopathogenic nematodes from the soil samples

Recently, a quantitative real-time PCR (qPCR) technique has been developed by Campos-Herrera et al (2011) for detecting and quantifying entomopathogenic nematodes including Steinernema diaprepesi, Steinernema riobrave, Heterorhabditis indica, Heterorhabditis zealandica, Heterorhabditis floridensis and an undescribed species in the S. glaseri group from soil samples. Read following paper for a detail protocol of quantitative real-time PCR (qPCR) technique

Campos-Herrera, R., Johnson, E. G, El-Borai, F. E., Stuart, R. J., Graham, J. H. and Duncan, L. W.2011. Long-term stability of entomopathogenic nematode spatial patterns in soil as measured by sentinel insects and real-time PCR. Annals of Applied Biology    158: 55-68.

A report of entomopathogenic nematodes from Iran

A survey conducted during 2006 and 2008 showed the presence of both heterorhabditid and steinernematid nematodes in the Arasbaran forests and rangelands, Iran.  Based on both morphological and molecular characteristics, heterorhabditid isolates were identified as Heterorhabditis bacteriophora whereas the steinernematid isolates were identified as Steinerenma carpocapsae, S. bicornutum, S. feltiae, S. glaseri, S. kraussei. For more information on the survey methodology nematode identification techniques read following paper.

Nikdel, M., Niknam, G., Griffin, C.T. and Kary, N.E. 2010. Diversity of entomopathogenic nematodes (Nematoda: Steinernematidae, Heterorhabditidae) from Arasbaran forests and rangelands in north-west Iran.  Nematology 12: 767-773.

Entomopathogenic nematodes as biological control agents for sheep lice, Bovicola ovis

Biological control of sheep lice, Bovicola ovis with entomopathogenic nematodes Four entomopathogenic nematodes including Steinernema carpocapsae, Steinernema riobrave, Steinernema feltiae and Heterorhabditis bacteriophora have showed a very high efficacy against sheep lice, Bovicola ovis when tested under laboratory conditions at different incubation temperatures (James et al., 2010).  However,  the efficacy all the four species of entomopathogenic nematodes varied with the nematode species and incubation temperature.

For more information on the interaction between entomopathogenic nematodes and sheep lice read following paper.

1. James, P. J., Hook, S.E. and Pepper, P. M. 2010. In vitro infection of sheep lice (Bovicola ovis Schrank) by Steinernematid and Heterorhabditid nematodes. Veterinary Parasitology 174: 85-91.

Use entomopathogenic nematodes to control western corn rootworm

Efficacies of two biological control agents including entomopathogenic fungus (Metarhizium anisopliae) and insect-parasitic nematode (Heterorhabditis bacteriophora) against western corn rootworm, Diabrotica virgifera virgifera was compared with two insecticides including Tefluthrin (synthetic pyrethroid compound) and clothianidin (neonicotinoid compound).  According to Pilz et al (2009), insect-parasitic nematode,  H. bacteriophora was as effective as both insecticides in reducing population of the western corn rootworm. Reference:

Pilz, C., Keller, S., Kuhlmann, U. and Toepfer, S. 2009.  Comparative efficacy assessment of fungi, nematodes and insecticides to control western corn rootworm larvae in maize.  Biocontrol. 54: 671-684.

Mode of action of entomopathogenic nematodes

When the infective juveniles of entomopathogenic nematodes are applied to the soil surface in the fields or thatch layer on golf courses, they start searching for their insect hosts. Once insect larva has been located, the nematode infective juveniles penetrate into the larval body cavity via natural openings such as mouth, anus and spiracles. Infective juveniles of Heterorhabditis nematodes can also enter through the intersegmental membranes of the grub cuticle. Once in the body cavity, infective juveniles release symbiotic bacteria (Xenorhabdus spp. for Steinernematidae and Photorhabdus spp. for Heterorhabditidae) from their gut in insect blood. In the blood, multiplying nematode-bacterium complex causes septicemia and kill their insect host usually within 48 h after infection. Nematodes feed on multiplying bacteria, mature into adults, reproduce and then emerge as infective juveniles from the host cadaver to seek new larvae in the soil.

A first report of occurrence of entomopathogenic nematodes in Nepal

Recently a survey was conducted to study the occurrence and distribution of entomopathogenic nematodes in Nepal.  Although a total of 276 soil samples were collected from various habitats, entomopathogenic nematode were found only in 29 samples.  Nematodes were isolates using the Galleria-baiting technique (Bedding and Akhurst,1975). Both heterorhabditid and steinernematid nematodes were identified at their species level using both molecular and morphological techniques.  In this survey, the occurrence of only one species of heterorhabditids including Heterorhabditis indica and four described species of steinernematids such as Steinernema abbasi, S. cholashanense, S. feltiae and S. siamkayai were reported for the first time in Nepal (Khatri-Chhetri et al., 2010). Read following literature for more information

Bedding, R.A. and R.J. Akhurst. 1975. A simple technique for detection of insect parasitic rhabditid nematodes in soil. Nematologica. 21: 109-110.

Khatri-Chhetri, H.B., Waeyenberge, L., Manandhar, H.K. and Moens, M. 2010.  Natural occurrence and distribution of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) in Nepal. Journal of Invertebrate Pathology. 103: 74-78.

How do entomopathogenic nematodes kill their insect hosts?

When the infective juveniles of entomopathogenic nematodes are applied to the soil surface in the fields or thatch layer on glf courses, they start searching for their insect hosts. Once insect larva has been located, the nematode infective juveniles penetrate into the larval body cavity via natural openings such as mouth, anus and spiracles. Infective juveniles of Heterorhabditis nematodes can also enter through the intersegmental membranes of the grub cuticle. Once in the body cavity, infective juveniles release symbiotic bacteria (Xenorhabdus spp. for Steinernematidae and Photorhabdus spp. for Heterorhabditidae) from their gut in insect blood. In the blood, multiplying nematode-bacterium complex causes septicemia and kill their insect host usually within 48 h after infection. Nematodes feed on multiplying bacteria, mature into adults, reproduce and then emerge as infective juveniles from the host cadaver to seek new larvae in the soil.