Entompathogenic nematodes used as biopesticides by Ganpati Jagdale

Entomopathogenic nematodes such as Steinernema carpocapsae and Heterorhabditis bacteriophora have been used to control white grubs that feed turfgrass in your yard. When applied in turf these nematodes search and infect white grubs. They infect grub insects through the natural openings and once inside they release symbiotic bacteria in the body cavity of grub. Bacteria multiply and kill insect within 48 hours of infection.

Biological control of grape root borer Vitacea polistiformis using entomopathogenic nematodes. by Ganpati Jagdale

Efficacy of two entomopathogenic nematodes including Heterorhabditis zealandica strain X1 and H. bacteriophora Strain GPS11 was studied in the field against grape root borer Vitacea polistiformis (Williams et al., 2010).  This borer can damage roots of both wild and cultivated Vitis and Muscadinia grapes and is considered as a major pest of grapes grown in the eastern United States.  According to Williams et al. (2010), both H. zealandica and H. bacteriophora can cause up to 92% control of grape root borer and they can also persist in the soil for a extended period after their application. Read following literature for more information on interaction between entomopathogenic nematodes and the grape root borers.

Williams, R.N., Fickle, D.S., Grewal, P.S. and Dutcher, J. 2010.  Field efficacy against the grape root borer, Vitacea polistiformis (Lepidoptera: Sesiidae) and persistence of Heterorhabditis zealandica and H. bacteriophora (Nematoda: Heterorhabditidae) in vineyards. Biological Control. 53: 86-91.

Williams, D.S. Fickle, P.S. Grewal and J.R. Meyer. 2002.  Assessing the potential of entomopathogenic nematodes to control the grape root borer, Vitacea polistiformis (Lepidopetera: Sesiidae) through laboratory and greenhouse bioassays. Biocontrol Science and Technology 12: 35-42.

Manage insect pests of Strawberries with entomopathogenic nematodes by Ganpati Jagdale

Strawberries are one of the most economically grown crops throughout the world and in North America with annual yields ranging from 4-20 tons per acre and average monitory values between $2,800 to $14000 per acre.  There are several kinds of insect pests have been reported that attack and cause significant economic losses (over 60%) to this crop.   Different species of entomopathogenic have been used as biological control agents against different  insect pests of strawberries. It has been demonstrated that  the entomopathogenic nematode, Steinernema kraussei can reduce over 81%  population of black vine weevil (Ansari et al., 2010; Susurluk and Ehlers, 2008; Willmott et al., 2002). Entomopathogenic nematodes, Heterorhabditis megidis and H. downesi also can reduce 93 and 51% population of black vine weevil, respectively (Boff et al., 2001, 2002; Lola-Luz et al., 2005; Fitters et al., 2001). Populations of black vine weevils were also reduced by application of infective juveniles of Steinernema carpocapsae and S. glaseri (Booth et la., 2002). Steinernema carpocapsae can reduce 51% population of strawberry crown moth (Bruck et al., 2008). Please read following literature for more information on interaction between insect pests of strawberries and different species entomopathogenic nematodes.

Ansari, M.A., Shah, F.A. and Butt, T.M. 2010.  The entomopathogenic nematode Steinernema kraussei and Metarhizium anisopliae work synergistically in controlling overwintering larvae of the black vine weevil, Otiorhynchus sulcatus, in strawberry growbags. Biocontrol Science and Technology. 20: 99-105.

Berry, R.E., Liu, J. and Groth, E. 1997.  Efficacy and persistence of Heterorhabditis marelatus (Rhabditida: Heterorhabditidae) against root weevils (Coleoptera: Curculionidae) in strawberry. Environmental Entomology. 26: 465-470.

Boff, M.I.C., van Tol, R.H.W.M. and Smits, P.H. 2002.  Behavioural response of Heterorhabditis megidis towards plant roots and insect larvae. Biocontrol. 47: 67-83.

Boff, M.I.C., Wiegers, G.L. and Smits, P.H. 2001.  Influence of insect larvae and plant roots on the host-finding behaviour of Heterorhabditis megidis. Biocontrol Science and Technology. 11: 493-504.

Boff, M.I.C., Zoon, F.C. and Smits, P.H. 2001.  Orientation of Heterorhabditis megidis to insect hosts and plant roots in a Y-tube sand olfactometer. Entomologia Experimentalis et Applicata. 98: 329-337.

Booth, S.R., Tanigoshi, L.K., Shanks, C.H. 2002.  Evaluation of entomopathogenic nematodes to manage root weevil larvae in Washington state cranberry, strawberry, and red raspberry. Environmental Entomology. 31: 895-902.

Bruck, D.J., Edwards, D.L. and Donahue, K.M. 2008.  Susceptibility of the strawberry crown moth (Lepidoptera : Sesiidae) to entomopathogenic nematodes. Journal of Economic Entomology. 101: 251-255.

Curran, J. 1992. Influence of application method and pest population-size on the field efficacy of entomopathogenic nematodes. Journal of Nematology. 24: 631-636.

Fitters, P.F.L., Dunne, R. and Griffin, C.T. 2001.  Vine weevil control in Ireland with entomopathogenic nematodes: optimal time of application. Irish Journal of Agricultural and Food Research. 40: 199-213.

KakouliDuarte, T., Labuschagne, L. and Hague, N.G.M. 1997.  Biological control of the black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae) with entomopathogenic nematodes (Nematoda: Rhabditida). Annals of Applied Biology. 131: 11-27.

Lola-Luz, T. and Downes, M. 2007.  Biological control of black vine weevil Otiorhynchus sulcatus in Ireland using Heterorhabditis megidis. Biological Control. 40: 314-319.

Lola-Luz, T., Downes, M. and Dunne, R. 2005.  Control of black vine weevil larvae Otiorhynchus sulcatus (Fabricius) (Coleoptera : Curculionidae) in grow bags outdoors with nematodes. Agricultural and Forest Entomology. 7: 121-126.

Simser, D. and Roberts, S. 1994.  Suppression of strawberry root weevil, Otiorhynchus-ovatus, in cranberries by entomopathogenic nematodes (Nematoda, Steinernematidae and Heterorhabditidae). Nematologica. 40: 456-462.

Susurluk, A. and Ehlers, R.U. 2008.  Sustainable control of black vine weevil larvae, Otiorhynchus sulcatus (Coleoptera: Curculionidae) with Heterorhabditis bacteriophora in strawberry. Biocontrol Science and Technology. 18: 635-640.

Vainio, A. and Hokkanen, H.M.T. 1993.  The potential of entomopathogenic fungi and nematodes against Otiorhynchus-ovatus L and O. dubius strom (Col, Curculionidae) in the field. Journal of Applied Entomology-Zeitschrift fur Angewandte Entomologie. 115: 379-387.

Willmott, D.M., Hart, A.J., Long, S.J., Edmondson, R.N. and Richardson, P.N. 2002.  Use of a cold-active entomopathogenic nematode Steinernema kraussei to control overwintering larvae of the black vine weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae) in outdoor strawberry plants. Nematology. 4: 925-932.

Wilson, M., Nitzsche, P. and Shearer, P.W. 1999.  Entomopathogenic nematodes to control black vine weevil (Coleoptera : Curculionidae) on strawberry. Journal of Economic Entomology. 92: 651-657.

Entomopathogenic Nematodes as excellent biocontrol agents by Ganpati Jagdale

Both Steinernematid and Heterorhabditid nematodes are considered as excellent biocontrol agents against soil dwelling insect pests of many economically important crops.  This is because they have a broad host range, the ability to search actively for hosts, the ability to kill their hosts rapidly within 24-48 hours, the potential to recycle in the soil environment, no deleterious effects on humans, other vertebrate animals, non-target organisms and plants and no negative effects on environment.  In addition these insect parasitic nematodes can be easily mass produced using both in vivo and in vitro methods and applied using traditional insecticide spraying equipments.  Since these nematodes are compatible with many chemical insecticides and biopesticides, they are easily included in IPM programs. Entomopatogenic nematodes also been been exempted from registration and regulation requirement by US Environmental Protection Agency (EPA) and similar agencies in many other countries.

    Why entomopathogenic nematodes are safe to use as biological control agents against insect pests? by Ganpati Jagdale

    Because....... 1. Entomopathogenic nematodes and their symbiotic bacterium have no detrimental effects on animals and plants. 2. Both nematodes and their symbiotic bacteria do not cause any harm to the personnel involved in their production and application. 3. Entomopathogenic nematode treated agriculture products are safe to handle and eat. 4. Entomopathogenic nematodes and symbiotic bacteria do not have any pathogenic effects on humans or animals. 5. When applied in the soil, entomopathogenic nematodes have also no negative effect on beneficial nematodes (bacteriovore, fungivore, omnivore and predatory) and other microbial communities. 6. Finally, entomopathogenic nematodes are non-polluting and thus environmentally safe.

    Beneficial Nematodes: Steinernema and Heterorhabditis species by Ganpati Jagdale

    Entomopathogenic nematodes in the genera Steinernema and Heterorhabditis are recognized as insect-parasitic nematodes, beneficial nematodes, biocontrol agents, biological control agents, biological insecticides or biopesticides. These nematodes are also recognized as pathogens or microbial control agents because of their symbiotic association with bacteria (Xenorhabdus and Photorhabdus spp.) that are mainly pathogenic to insects. Because of mutualistic relationship with pathogenic bacteria these nematodes are named as entomopathogenic nematodes.

    These beneficial nematodes contribute to the regulation of natural populations of insects.  However, the population of naturally occurring entomopathogenic nematodes is normally not high enough to manages soil dwelling plant pests. Therefore, during last 3-4 decades, these live nematodes have been commercially mass produced and inundatively applied to control many garden insects, turfgrass insects, nursery insects, greenhouse insects and insects that feed on different field crops.

    Use of this natural control of insects is beneficial for both the environment and humans because it reduces use of chemical insecticides/pesticides.

    These biopesticides (entomopathogenic nematodes and their symbiotic bacteria) are safe to produce and not harmful to users, application personnel, mammals, most beneficial insects or plants.

    Since entomopathogenic nematodes do not cause any health risk to the consumers of nematode treated agricultural produce and damage to the environment, they are exempted from registration requirements in most countries.

    These biological control agents have also no detrimental effect on other benefical nematodes including bacterial feeders, some fungal feeders (Aphelenchus sp.), predatory nematodes and other soil microbial communities.

    But entomopathogenic nematodes can be detrimental to plant-parasitic nematodes that are responsible for causing a tremendous economic loss to our agriculture industry throughout world. It has been demonstrated that entomopathogenic nematodes can suppress the populations of many economically important plant-parasitic nematodes including foliar nematodes, potato cyst nematodes, ring nematodes, root-knot nematodes,  root lesion nematodes, sting nematodes, stubby root nematodes and stunt nematodes.