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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.

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.

Entomopathogenic nematodes- Mode of Infection

In the soil environment, infective juveniles of entomopathogenic nematodes (Figure 1.) are always searching for the insect hosts to infect, kill, feed and reproduce.  Once the infective juveniles of both Steinernematid (Steinernema spp.) and Heterorhabditid (Heterorhabditis spp.) nematodes locate any larval, pupal or adult stages of their insect host, they will rush to find any easy entry routes/points to enter into the insect host body.  As shown in Figure 2, the infective juveniles of both Steinernema spp. and Heterorhabditis spp. generally use natural openings such as mouth, anus and spiracles/breathing pores (usually one pair of spiracles per body segment located laterally along the thorax and abdomen of  insects) of their hosts as main points of entry.  However, the infective juveniles of only Heterorhabditis spp. can also enter into host’s body by puncturing the inter-segmental membranes of the cuticle (see Figure 2).  The infective juveniles that enter via mouth and anus will end up in digestive track (gut) whereas those enter through spiracles will reach in tracheal tubes.  However, to kill their host successfully for food and development, the infective juveniles of both Steinernematid and Heterorhabditid nematodes eventually need to penetrate by puncturing digestive track (gut) or tracheal tubules (currently, the process of puncturing is unclear) into insect’s body cavity (an open circulatory system) and release symbiotic bacteria, Xenorhabdus spp. and Photorhabdus spp., respectively from their gut in insect blood generally called hemolymph.  In the blood, multiplying nematode-bacterium complex causes septicemia and kill their insect host usually within 48 h after infection.

To enlarge, click the pictures.

Fig. 1. Infective juveniles of entomopathogenic nematodes- Photo by Ganpati Jagdale

Fig. 2. Points of infection by entomopathogenic nematodes into body of their insect hosts: Photo by Ganpati Jagdale

Stored grain/ product pests: Nematode Information

Several stored grain/product insect pests like Indian meal moth (Plodia interpunctella), Mediterranean flour moth (Ephestia kuehniella), Sawtoothed grain beetle (Oryzaephilus surinamensis), Mealworms (Tenebrio molitor), Red flour beetle (Tribolium castaneum) and Warehouse beetle (Trogoderma variabile) attack and destroy large quantities of stored grains and products during long-term storage in farm bins, grain processing facilities, warehouses, retail stores, and eventually also on the consumer shelves. The insect pests of stored grain/products have a major economic impact on the food industry due to the costs associated with their management, monitoring, rejection and return of contaminated shipments and failure to meet regulations that required to and pass inspections.  Therefore, there is a need to protect stored food products from attack by insects.  However, stored grain/product pests are generally difficult to control using traditional method as they hide in cracks and crevices, under perforated floors, and inside machinery used for processing of stored-products.  Chemical pesticides are not advisable to use against stored-product pests because of health and environment pollution risks.

The Indian meal moth (Plodia interpunctella): The larval stages infest and feed on different kinds of cereal grains, rice and processed dry foods like pasta, bread and spices.

The Mediterranean flour moth (Ephestia kuehniella): The larval stages mainly feed various types of flour.

The Sawtoothed grain beetle (Oryzaephilus surinamensis): This insect feed on broken seeds and seed germs.

The Mealworm (Tenebrio molitor): Larvae feed on flour and cereals.

The Red flour beetle (Tribolium castaneum): Feed on flour, cereal grains and dried food products like pasta, biscuits etc.

The Warehouse beetle (Trogoderma variabile): Larvae feed on dried cereal grains and food products such as noodles and spaghetti, and dried spices.

Entomopathogenic nematodes:

Entomopathogenic nematodes also called as insect-parasitic nematodes are commercially available and have potential to use as a biological control agent against above stated stored product pests because of their different host finding strategies.

For example, entomopathogenic nematodes, Steinernema carpocapsae use ambush foraging called “sit and wait” strategy to attack highly mobile insects including stored-product pests. After application, infective juveniles of Steinernema carpocapsae will generally remain near or at the surface of the stored-products.  When infective juveniles of Steinernema carpocapsae sense that there is an insect host passing by them, they will attack and infect it by standing on their tails (behavior called ‘nictation’) and jumping on the host.

Ambush foraging entomopathogenic nematode, Steinernema carpocapsae have a capacity to cause over 85% larval mortality of indian meal moths, mediterranean flour moths, mealworms and red flour beetles (Ramos-Rodriguez et al., 2006).

Entomopathogenic nematodes such as Heterorhabditis bacteriophora, Heterorhhabdtits megidis, Steinernema glaseri and Steinernema kraussei are considered as cruiser nematodes because they generally move actively in search of hosts and can easily find and attack their insect hosts that are hiding in deep in the soil or in case of stored-products hiding in cracks and crevices and under perforated floors. Cruiser nematodes never nictate but use carbon dioxide released by insect hosts as cues to attack them. Cruiser entomopathogenic nematodes, Heterorhabditis bacteriophora and Heterorhhabdtits megidis can kill larvae of Indian meal moth (Mbata and Shapiro-IIan, 2005).

Some entomopathogenic nematodes such as Steinernema feltiae and Steinernema riobrave have adapted a strategy in between ambush and cruise strategies called an intermediate strategy to attack both the mobile and sedentary/less mobile insects at the surface or deep in the soil and in case of stored-products, pests that hiding in cracks and crevices and under perforated floors or remaining at the surface of the product.

Intermediate foraging entomopathogenic nematode, Steinernema riobrave have a potential to kill over 65% larvae of indian meal moths, mediterranean flour moths, sawtoothed grain beetles, mealworms, red flour beetles and warehouse beetles (Ramos-Rodriguez et al., 2006).

Another intermediate foraging entomopathogenic nematode, Steinernema feltiae can cause over 90% larval mortality of only indian meal moths, mediterranean flour moths, red flour beetles (Ramos-Rodriguez et al., 2006) and over 79% larval mortality of the confused flour beetle,  Tribolium confusum (Athanassiou et al., 2008).

Publications:

Athanassiou, C.G., Palyvos, N.E. and Kakoull-Duarte, T. 2008. Insecticidal effect of Steinernema feltiae (Filipjev) (Nematoda : Steinernematidae) against Tribolium confusum du Val (Coleoptera : Tenebrionidae) and Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) in stored wheat.  Journal of Stored Products Research. 44: 52-57.

Athanassiou, C.G., Kavallieratos, N.C., Menti, H. and Karanastasi, E. 2010.  Mortality of four stored product pests in stored wheat when exposed to doses of three entomopathogenic nematodes.   Journal of Economic Entomology 103: 977-984.

Mbata, G.N. and Shapiro-Ilan, D.I. 2005. Laboratory evaluation of virulence of heterorhabditid nematodes to Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Environmental Entomology 34: 676 – 682.

Ramos-Rodriguez, O., Campbell, J.F. and Ramaswamy, S.B.  2006.   Pathogenicity of three species of entomopathogenic nematodes to some major stored-product insect pests. Journal of Stored Products Research 42: 241-252.

Ramos-Rodríguez,O.,Campbell, J. F.,and Ramaswamy, S. 2007. Efficacy of the   entomopathogenic nematodes Steinernema riborave against the stored-product pests Tribolium castaneum and Plodia interpunctella. Biological Control 40:15 -21.

Tradan, S., Vidric, M., and Valic, N. 2006. Activity of four entomopathogenic nematodes against young adult of Sitophilus granarious (Coleptera: Curculionidae) and Oryzophilus surinamensis ( Coleoptera: Silvanidae ) under laboratory condition. Plant Disease and Protection. 113: 168 – 173.

Fayyaz S. and  Javed , S. 2009.  Laboratory Evaluation of Seven Pakistani Strains of Entomopathogenic Nematodes against a Stored Grain Insect Pest, Pulse beetle Callosobruchus chinensis (L.).  Journal of Nematology 41: 255-260.

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 from Egypt

The occurrence and distribution of entomopathogenic nematodes including Heterorhabditis indica, Steinernema abbasi and Steinernema carpocapsae have been reported from four geographical regions (Northern, Middle, Southern and Sinai Peninsula) of Egypt.

These findings were presented by Abu-Shady, N.M., Shamseldean, M.M., Abd-Elbary, N.A. and Stock, S.P. at the 50th annual meeting of the Society of Nematologists held in Corvallis, Oregon from July 17-20, 2011.

• 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 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.

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.

Recently, Deol et al. (2011) demonstrated that entomopathogenic nematodes, Steinernema carpocapsae, can be delivered via infected Galleria mellonella or Tenebrio molitor cadavers in the Scotts commercial growing medium, Miracle-Gro ^(R).

Read following papers for more information on delivery of entomopathogenic nematodes using nematode infected cadavers

Ansari, M.A., Hussain, M. and Moens, M. 2009.  Formulation and application of entomopathogenic nematode-infected cadavers for control of Hoplia philanthus in turf grass. Pest Management Science. 65: 367-374.

Bruck, D.J., Shapiro-Ilan, D.I. and Lewis, E.E. 2005.   Evaluation of application technologies of entomopathogenic nematodes for control of the black vine weevil.  Journal of Economic Entomology 98: 1884-1889.

Deol, Y.S., Jagdale, G.B., Canas, L. and Grewal, P.S. 2011. Delivery of entomopathogenic nematodes directly through commercial growing media via the inclusion of infected host cadavers: A novel. Biological Control 58: 60-67.

Shapiro-Ilan, D.I., Morales-Ramos, J.A., Rojas, M.G. and Tedders, W.L. 2010.  Effects of a novel entomopathogenic nematode-infected host formulation on cadaver integrity, nematode yield, and suppression of Diaprepes abbreviatus and Aethina tumida. Journal of Invertebrate Pathology. 103: 103-108.

Spence, K.O., Stevens, G.N., Arimoto, H., Ruiz-Vega, J.,   Kaya, H.K. and Lewis, E.E. 2011.   Effect of insect cadaver desiccation and soil water potential during rehydration on entomopathogenic nematode (Rhabditida: Steinernematidae and Heterorhabditidae) production and virulence. Journal of Invertebrate Pathology 106: 268-273.

Spence, K.O., Stevens, G.N., Arimoto, H., Ruiz-Vega, J., Kaya, H.K. and Lewis, E.E. 2011.  Effect of insect cadaver desiccation and soil water potential during rehydration on entomopathogenic nematode (Rhabditida: Steinernematidae and Heterorhabditidae) production and virulence. Journal of Invertebrate Pathology 106: 268-273.