Archive

South American fruit fly, Anastrepha fraterculus: It has been demonstrated that an entomopathogenic nematode Heterorhabditis bacteriophora when applied at the concentration of 250 infective juveniles per square cm in the field can cause 28 to 51% mortality of South American fruit fly larvae. However, another entomopathogenic nematode, Steinernema riobrave can cause only 24% larval mortality when treated with the same concentration (Barbosa-Negrisoli et al., 2009).

Peachtree borer, Synanthedon exitiosa: This borer is most economically important pest of stone fruit trees in North America. Shapiro-Ilan et al. (2009) studied the effect of entomopathogenic nematode, Steinernema carpocapsae on population of peachtree borer, S. exitiosa in the peach orchard. These researchers applied S. carpocapsae at the rate of 150,000–300,000 infective juveniles/tree during egg laying seasons of borers and reported that these nematodes were as effective as chemical insecticide, chlorpyrifos in preventing damage caused by borers to peach trees.

Peach fruit fly, Bactrocera zonata: Soliman (2007) studied the efficacy of two entomopathogenin nematode species, Steinernema riobrave and Heterorhabditis bacteriophora against the peach fruit fly, Bactrocera zonata and reported that all the larval stages of this fly were susceptible to both nematode species under laboratory conditions. However, H. bacteriophora was comparatively more efficacious than S. riobrave against all the larval stages of peach fruit fly. Larvae of peach fruit fly are also susceptible to another species of entomopathogenic nematode, S. carpocapsae (Soliman, 2007).

Mediterranean fruit fly, Ceratitis capitata: Soliman (2007) studied the efficacy of two entomopathogenin nematode species, Steinernema riobrave and Heterorhabditis bacteriophora (Malan and Manrakhan, 2009) against Ceratitis capitata and reported that all the larval stages of this fly were susceptible to both nematode species under laboratory conditions. However, H. bacteriophora was comparatively more efficacious than S. riobrave against all the larval stages of C. capitata. These fruit flies are also susceptible to another species of entomopathogenic nematode, S. carpocapsae (Soliman, 2007).

Mediterranean flatheaded rootborer, Capnodis tenebrionis: The efficacy of four entomopathogenic nematode species including Steinernema feltiae, Steinernema affine, Steinernema carpocapsae and Heterorhabditis bacteriophora was studied against Mediterranean flatheaded rootborer infesting potted peach trees (Morton and del Pino, 2008). It has been demonstrated that all the four species of entomopthogenic nematodes have an ability to locate and kill larvae of C. tenebrionis after their entry into the peach roots. Morton and del Pino (2008) reported that strains of S. feltiae caused highest mortality of C. tenebrionis larvae (80% to 88%) followed by strains of H. bacteriophora (72 to76%), S. carpocapsae (62%) and S. affine (35%).

Plum curculio, Conotrachelus nenuphar: Shapiro-Ilan et al. (2004; 2008) demonstrated that the application of entomopathogenic nematode, Steinernema riobrave at concentration of 100 infective juveniles/ cm2 can achieve over 78% control of plum curculio in peach orchards. Shapiro-Ilan et al. (2002) also reported that adults of C. nenuphar are more susceptible to S. riobrave or S. carpocapsae than to S. feltiae. In contrast, larvae of C. nenuphar are more susceptible to S. riobrave or S. feltiae than to S. carpocapsae.

Oriental fruit moth, Grapholita molesta: According to Riga et al. (2006), four entomopathogenic nematode species including Steinernema carpocapsae, S. feltiae, S. riobrave and Heterorhabditis marelatus when applied at the concentration of 10 infective juveniles/ square cm can cause 63, 88, 76 and 67 mortality of oriental fruit moth, respectively in the laboratory.

Lesser peach tree borer, Synanthedon pictipes: Shapiro-Ilan and Cottrell (2006) reported that Steinernematid nematodes (Steinernema carpocapsae, S. feltiae, and S. riobrave) were virulent against lesser peach tree borers than Heterorhabditid nematodes (Heterorhabditis bacteriophora, H. indica and H. inarelatus) under laboratory conditions.

For more information, read following literature on interaction between entomopathogenic nematodes and insect pests of peaches.

Barbosa-Negrisoli, C. R. C., Garcia, M. S., Dolinski, C., Negrisoli, A. S., Jr., Bernardi, D., Nava, D. 2009. Efficacy of indigenous entomopathogenic nematodes (Rhabditida: Heterorhabditidae, Steinernematidae), from Rio Grande do Sul Brazil, against Anastrepha fraterculus (Wied.) (Diptera: Tephritidae) in peach orchards. Journal of Invertebrate Pathology. 102: 6-13.

Malan, A. P. and Manrakhan, A. 2009. Susceptibility of the Mediterranean fruit fly (Ceratitis capitata) and the Natal fruit fly (Ceratitis rosa) to entomopathogenic nematodes. Journal of Invertebrate Pathology. 100: 47-49.

Morton, A., del Pino, F. G. 2008. Effectiveness of different species of entomopathogenic nematodes for biocontrol of the Mediterranean flatheaded rootborer, Capnodis tenebrionis (Linné) (Coleoptera: Buprestidae) in potted peach tree. Journal of Invertebrate Pathology. 97: 128-133

Riga, E., Lacey, L. A., Guerra, N., Headrick, H. L. 2006. Control of the oriental fruit moth, Grapholita molesta using entomopathogenic nematodes in laboratory and fruit bin assays. Journal of Nematology 38: 168-171.

Shapiro-Ilan, D.I., Cottrell, T.E., Mizell, R.F., Horton, D.L., Davis, J. 2009. A novel approach to biological control with entomopathogenic nematodes: Prophylactic control of the peachtree borer, Synanthedon exitiosa. Biological Control. 48: 259-263.

Shapiro-Ilan, D.I., Mizell, R.F., Cottrell, T.E., Horton, D.L. 2008. Control of plum curculio, Conotrachelus nenuphar with entomopathogenic nematodes: Effects of application timing, alternate host plant, and nematode strain. Biological Control. 44: 207-215.

Shapiro-Ilan, D.I., Mizell, R.F. and Campbell, J.F. 2002. Susceptibility of the plum curculio, Conotrachelus nenuphar to entomopathogenic nematodes. Journal of Nematology 34: 246.

Shapiro-Ilan, D.I., Mizell, R.F., Cottrell, T.E and Horton, D.L. 2004. Measuring field efficacy of Steinernema feltiae and Steinernema riobrave for suppression of plum curculio, Conotrachelus nenuphar larvae. Biological Control 30: 496–503.

Shapiro-Ilan, D.I. and Cottrell, T.E. 2006. Susceptibility of the lesser peachtree borer (Lepidoptera : Sesiidae) to entomopathogenic nematodes under laboratory conditions. Environmental Entomology. 35: 358-365.

Soliman, N. A. 2007. Efficacy of the entomopathogenic nematodes, Steinernema riobravis Cabanillas and Heterorhabditis bacteriophora (native strain) against the peach fruit fly, Bactrocera zonata (Saunders) and the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Egyptian Journal of Biological Pest control. 17: 77-82.

Soliman, N. A. 2007. Pathogenicity of three entomopathogenic nematodes to the Peach fruit fly, Bacterocera zonata (Saunders) and the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera : Tephritidae). Egyptian Journal of Biological Pest control. 17: 121-124.

• The Japanese beetle, Popillia japonica, is a most economically important pest of many ornamental plants and turf grasses.
• Larvae of these beetles are called white grubs that generally feed on roots of over 300 plants but their primary food source is grass roots. Severe damage caused by these grubs can result in dead patches of turf that can be picked up like a loose carpet.
• Adults mostly feed on leaves and flowers by chewing the tissue between the veins, a type of feeding called skeletonizing.
• Chemical insecticides including Imidacloprid (Merit), Chlorpyrifos, Isofenphos, and Diazinon are generally used to manage white grubs but due to human health and environment pollution concerns their use is restricted.
• Currently, environmentally safe biological control agents including a milky disease causing bacterium Bacillus popilliae (Milky spores) and entomopathogenic nematodes have been used to control this pest.
• Three entomopathogenic nematodes including Heterorhabditis bacteriophora GPS11 and TF strains, H. zealandica X1 strain and Steinernema scarabaei have been considered to be the most effective species against Japanese beetle grubs.
• It has been demonstrated that the application of H. bacteriophora GPS11 and TF strains, H. zealandica X1 strain and S. scarabaei at rate of 2.5 billion infective juveniles per hectare can cause about 96, 98 and 100%, respectively control of Japanese beetle grubs infesting turfgrass (for more information read Grewal et a., 2005).
• Nematodes can be applied using traditional sprayers that are used for the application of insecticides.
• Nematodes perform better when they are applied to target small stages of grubs.
• Nematodes also survive better and remain efficacious when field/lawns are irrigated before and after nematode applications.

How Entomopathogenic Nematodes kill Japanese beetles

• When the infective juveniles are applied to the soil surface or thatch layer, they start searching for their hosts, in this case Japanese beetle grubs.
• Once a Japanese beetle grub has been located, the nematode infective juveniles penetrate into the Japanese beetle grub body cavity via natural openings such as mouth, anus and spiracles.
• Infective juveniles of Heterorhabditis also enter through the intersegmental members 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 grub blood.
• In the blood, multiplying nematode-bacterium complex causes septicemia and kills Japanese beetle grubs usually within 48 h after infection.
• Nematodes feed on multiplying bacteria, mature into adults, reproduce and then emerge as infective juveniles from the cadaver to seek new larvae in the soil.

References

1. Grewal, P.S., Koppenhofer, A.M., and Choo, H.Y., 2005.  Lawn, turfgrass and Pasture applications. In: Nematodes As Biocontrol Agents. Grewal, P.S. Ehlers, R.-U., Shapiro-Ilan, D. (eds.). CAB publishing, CAB International, Oxon. Pp 147-166.