11.7.1 Mode of Action of EPN
• The non feeding infective third stage juveniles (0.4–1.5 mm in length) enter into
an insect through natural openings, such as mouth, anus or breathing holes.
• Nematodes enter insect body cavity and release their symbiotic bacteria into the
intestine of the host. Toxins produced by the bacteria kill the insect in a week.
• It feeds on the cadaver and liquefies its host. Nematodes reproduce and generate
to three-generation descendants on host cadaver.
• Infective juvenile nematodes leave the dead insect and seek for a new host. Under
optimal conditions, nematode-infected pest stages should be present 5–7 days
after application. Insects killed by Steinernematidae become brown or tan; ones
killed by Heterorhabditidae turn red. Dead insects, however, are not always
visible (Fig.11.4). Table 11.5 represents the list of commercially available EPN
based biopesticides.
11.7.2 Advantages of EPN
• They are considered safe to humans, plants and animals and relatively safe to the
environment. It does not require personal protective equipment, safety masks and
re-entry intervals. It leaves no residues.
• It is effective against field pests such as cranberry girdler, root weevil, black vine
weevil, webworms, cutworms, armyworms and wood-borers.
Fig. 11.4 Mode of action of nematodes
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M. Rajamani and A. Negi
• The non feeding infective third stage juveniles (0.4–1.5 mm in length) enter into
an insect through natural openings, such as mouth, anus or breathing holes.
• Nematodes enter insect body cavity and release their symbiotic bacteria into the
intestine of the host. Toxins produced by the bacteria kill the insect in a week.
• It feeds on the cadaver and liquefies its host. Nematodes reproduce and generate
to three-generation descendants on host cadaver.
• Infective juvenile nematodes leave the dead insect and seek for a new host. Under
optimal conditions, nematode-infected pest stages should be present 5–7 days
after application. Insects killed by Steinernematidae become brown or tan; ones
killed by Heterorhabditidae turn red. Dead insects, however, are not always
visible (Fig.11.4). Table 11.5 represents the list of commercially available EPN
based biopesticides.
11.7.2 Advantages of EPN
• They are considered safe to humans, plants and animals and relatively safe to the
environment. It does not require personal protective equipment, safety masks and
re-entry intervals. It leaves no residues.
• It is effective against field pests such as cranberry girdler, root weevil, black vine
weevil, webworms, cutworms, armyworms and wood-borers.
Fig. 11.4 Mode of action of nematodes
250
M. Rajamani and A. Negi