Beneficial nematodes for control of termites
Following five different species of beneficial entomopathogenic nematodes are found to be very efficacious against eight different species of termites, the most economically important pests of wood in building structures and in forests. Termites also cause damage to many crops.
1. Entomopathogenic nematode, Heterorhabditis bacteriophora
Heterorhabditis bacteriophora nematodes are beneficial insect-parasitic nematodes that use cruise strategy to find insect hosts including termites. This means the infective juveniles of this nematode move actively in search of host throughout the soil profile and in cryptic habitats. They also use volatile cues to find and kill even sedentary insects like white grubs. Infective juveniles of H. bacteriophora nematodes always carry hundreds of cells of symbiotic bacteria called Photorhabdus luminescens in their gut and use as a weapon to kill their insect hosts.
Heterorhabditis bacteriophora nematodes and their associated bacteria found to be effective against workers and nymphs of six different species of termites such as Coptotermes formosanus, Gnathamitermes perplexus, Heterotermes aureus, Psammotermes hybostoma, Reticulitermes flavipes and R. virginicus. There are several strains of H. bacteriophora exists and these strains differ their efficacy against different species of termites.
Heterorhabditis bacteriophora nematodes are commercially available. Generally, 23,000 infective juveniles of H. bacteriophora are required to treat one square foot of termite infested area. These nematodes can be applied using traditional sprayers in the field or using simple water cans on the small area against various types of insect pests including termites.
2. Entomopathogenic nematode, Heterorhabditis indica
Heterorhabditis indica nematodes are warm adapted heat tolerant beneficial nematodes that work better against many insect pests when temperature is above 25oC. This nematode also uses a cruiser- type of foraging strategy to find their insect hosts.
Infective juveniles of H. indica nematodes also carry hundreds of cells of symbiotic bacteria called Photorhabdus luminescens in their gut and used as a weapon to kill their insect hosts.
Heterorhabditis indica and Photorhabdus luminescens complex found to be effective against three species of termites including C. formosanus, C. vastator and R. flavipes.
Heterorhabditis indica nematodes are commercially available and 23,000 infective juveniles of this nematode are required to treat one square foot of termite infested area. Nematodes can be applied using traditional sprayers in the field or using simple water cans on the small area against various types of insect pests including termites.
3. Entomopathogenic Nematode, Steinernema carpocapsae
Entomopathogenic Steinernema carpocapsae nematodes are ambush foragers meaning they are adapted to “sit and wait” strategy to attack highly mobile insects like billbugs, sod webworms, cutworms, mole-crickets, armyworms including termites when they come in their contact at the surface of the soil.
Infective juveniles of Steinernema carpocapsae generally do not respond to host released volatile cues but they can stand on their tails (nictate) and easily infect passing insect hosts by jumping on them. Since highly mobile insects live in the upper soil layer, ambushers are generally effective in infecting more insects on the surface than deep in the soil.
Infective juveniles of Steinernema carpocapsae are symbiotically associated with the bacteria called Xenorhabdus nematophila. Nematodes together with their symbiotic bacteria, X. nematophila are capable of suppressing population of eight different termite species including C. formosanus, C. vastator, G. perplexus, H. aureus, Psammotermes hybostoma, R. flavipes, R. virginicus, Zootermopsis angusticollis.
Steinernema carpocapsae nematodes are commercially available. About 23,000 infective juveniles of this nematode are required to treat one square foot of termite infested area. Nematodes can be applied using traditional sprayers or simple water cans against various types of insect pests including termites. It has been demonstrated that S. carpocapsae nematodes can cause 70% mortality of a termite species, Z. angusticollis.
4. Entomopathogenic Nematode, Steinernema feltiae
Infective juveniles of Steinernema feltiae nematode carry symbiotic bacteria Xenorhabdus bovienii in their gut as weapon to kill their insect hosts.
For searching insect hosts, Steinernema feltiae nematodes use intermediate foraging strategy that lies between ambush and cruiser foraging strategies. The temperature range for the activity and infection of Steinernema feltiae is ranging from 10 to 25oC.
Steinernema feltiae nematodes are known to suppress the population of three species of termites including G. perplexus, H. aureus and R. virginicus.
Steinernema feltiae nematodes are commercially available. For high effectiveness of these nematodes against termites, generally 23,000 infective juveniles are applied per square foot of termite infested area using traditional sprayers or simple water cans.
5. Entomopathogenic nematode, Steinernema riobrave
Entomopathogenic nematode, Steinernema riobrave has adapted a foraging behavior that lie in between ambush and cruise strategies called an intermediate strategy to attack both the mobile and sedentary/less mobile insects at the surface or immobile stages deep in the soil.
Infective juveniles of S. riobrave nematode carry symbiotic bacteria Xenorhabdus cabanillasii and their gut and use them to kill their insect host.
It has been reported that the four species of termites including C. formosanus, G. perplexus, H. aureus and R. virginicus are susceptible to entomopathogenic S. riobrave nematodes.
It has been also demonstrated that S. riobrave nematodes can cause over 75% mortality of workers of three termite species including G. perplexus, H. aureus and R. flavipes (Yu et al., 2006; 2010).
Read blogs about how entomopathogenic nematodes infect and kill their insect hosts including termites as well as about how, when and how many beneficial nematodes should be applied?
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Mankowskia, M.E., Kaya, H.K., Gracea , J.K. and Sipes, B. 2005. Differential susceptibility of subterranean termite castes to entomopathogenic nematodes. Biocontrol Science and Technology 15: 367-377.
Manzoor, F. 2012. Synergism of Imidacloprid and Entomopathogenic Nematodes for the Control of Eastern Subterranean Termite, Reticulitermes flavipes (Isoptera: Rhinotermitidae). Pakistan Journal of Zoology 44: 1397-1403.
Wang, C., Powell, J.E. and Nguyen, K. 2002. Laboratory evaluations of four entomopathogenic nematodes for control of subterranean termites (Isoptera: Rhinotermitidae). Environmental Entomology 31: 381-387.
Wilson-Rich, N., Stuart, R.J. and Rosengaus, R.B. 2007. Susceptibility and behavioral responses of the dampwood termite Zootermopsis angusticollis to the entomopathogenic nematode Steinernema carpocapsae. Journal of Invertebrate Pathology 95: 17–25.
YU, H. GOUGE, D.H., STOCK, S.P. and BAKER, P.B. 2008. Development of Entomopathogenic Nematodes (Rhabditida: Steinernematidae; Heterorhabditidae) in the Desert SubterraneanTermite Heterotermes aureus (Isoptera: Rhinotermitidae). Journal of Nematology 40: 311–317.
Yu, H., Gouge, D.H. and Shapiro-Ilan, D.I. 2010. A Novel Strain of Steinernema riobrave (Rhabditida: Steinernematidae) Possesses Superior Virulence to Subterranean Termites (Isoptera: Rhinotermitidae). Journal of Nematology 42: 91-95.