Entomo-Pathogenic Nematode (EPNs), an assassinator of insect pests

Today, in the field of pest management the trend of Entomo-pathogenic nematodes (EPNs)

application is emerging globally. Research based literature supported that EPNs has prodigious

potential against different pest. EPNs are profound to be a target oriented bio-control assassinator

of insect pest. Many enigmatic and cryptic nature of insect cant resist against the assassination

of this bio control agent.

Mostly, Nematodes are soil inhabitants. Their soil dwelling activity is deemed to be playing a

significant role in soil fertility and aeration. From soil, EPNs are brought to laboratory for mass

culturing. In labs wax moth, Galleria mellonella (a lepidoptern pest of bee hive) is used as host

for their mass culture. Within this group are the so-called entomopathogenic or insect pathogenic

nematodes. Two nematode families fall into this category: Steinernematidae and

Heterorhabditidae. The species belongs to these two families are lethal and obligate pathogen of

insects, thats why many important insect pests of crops, such as the citrus weevil, , fungus gnats,

flowers thrips, Field crickets and scarab beetles have successfully been controlled by these

EPNs.

To save crops from pest prevalence, we are applying agricultural pesticides unconsciously. As

the matter of fact, the massive use of insecticides results into serious havoc of environmental

contamination, presence of residual effects in food commodities, mass killing of non-target

organisms, resistance and resurgence of insect pest populations. Alarmingly, these consequences

are pathetic and dreadful. Now, Food and Agriculture Organization (FAO) of the United Nations

has recommended the “Ecosystem Approach” in agricultural management, including IPM,

combining different management approaches to cultivate high quality crops and mitigate

pesticide use.

Therefore it is essential to introduce alternatives that should environmentally safe, host specific

and harmless to other biodiversity. Another alternative to the chemical control of pests is the use

of EPNs that works as competent pathogens (entomo -pathogenic nematodes). Nematodes have

no adverse effects for non-target organisms and environmentally safe, thats why it is become the

most preferable choice for insect pathologist. Moreover, insect pathologists are working to

explore its bio-efficacy and potency against various vermin. Different field and laboratory

experiments reveal that many EPNs species, for example Heterorhabditis bacteriophora have the

mutualistic association with other bio control agent like Beauveria bassiana.

EPNs have been declared as conservational, eco-friendly and augmentative microbial control

agents. EPNs are attaining preference among other entomo-pathogenic microbes due to

multidimensional attributes .i.e. peculiar mode of action, broad range of hosts and rapid

assassination of host. These are thought to be integral part of IPM program and sustainable

Agriculture. Due to its peculiar mode of action, pests are unable to resist its encounter and

become cadaver. The third juvenile stage of EPNs is considered to be the infective stage (IJs) or

Dauer Juvenile (DJ). The DJ ambush and enter in the host through orifice (mouth, anus or

spiracles) and develops into parasitic stage. Within the gut of the nematode gram-negative

bacteria are present and cause the mortality of the insect host.

Pakistan has experienced of ravaging episodes of pest borne diseases. Many dipterans,

lepidoterans and homopterns pests are responsible for pest borne diseases in humans, animals

and plants. These vector borne pests like mosquitoes, ticks, mites and flies are posing direct

threat to our survival on this planet. Many developed countries are strategically applying bio-

control agents to cope these notorious insect pests.

But regrettably we have sole reliance on insecticides for the annihilation of pest outbreak. As

mention above that the injudicious use of these chemicals perturbs our ecosystem. Furthermore,

it is observed insect pests are becoming resist to these chemicals. Although the biological control

management of pest has acknowledged EPNs since the 1980s, relatively little is understood

about their biology in natural and managed ecosystems. It is dire need of time to construct insect

pathological labs, where experts and scientist are provoked to explore the potential of EPNs

against these obnoxious pests.