• Korean journal of applied entomology
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• v.33 no.4
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• pp.207-215
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• 1994

The brown planthopper (BPH), Nilaparuata lugens, is the major pest 01 nce in Asla. Cument control tactics rely pnmalily on chemical ~nsecticides and resistant nce varieties In Korea, the most important biolog~cal conb-ol agent appears to be the naturally-occuning, mermlthid nematode, Agarnermrs unka. Although parasitism of BPH is highly variable from place to place and from year to year. the rnermithid is a promising biological control agent because it reduces the fecundity of the host and ultimately causes its death. The memithid has only one generation per year compared to the three to four generations of BPH, but the mermithid lemales stagger their egg production so that many individuals in all BPH generations are parastized. Augmentation of this rnermithld into BPH populations is only psslble on a limited scale because it is an obligate parasite and mass production technology has yet to be developed. Conservation of naturally-occumng populations through cultural techniques and the use of compatible resistant rice varieties and chemical insecticides may lead to an effective integrated pest management program for BPH.

• Korean journal of applied entomology
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• v.27 no.4
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• pp.185-189
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• 1988

Laboratory trials were conducted for control of onion maggot and tobacco cutworm with ento¬mogenous nematodes. The onion maggot, Delia antiqua, was exposed to Steinernema feltiae at concentration of 0,30,60, 120 or 240 nematodes per larva, and to Heterorhabditis heliot-hidis at concentration of 0, 10, 20, 40 or 80 nematodes per larva. Mortalities of the maggot ranged from 80 to 100% in S. feltiae and from 63.3 to 100% in H. heliothidis. The tobacco cutworm, SpodoPtera litura was exposed to S. feltiae at concentration of 0,50,100,200 or 400 nematodes per larva and to H. heliothidis at concentration of 0,20,40,80 or 160 nemat¬odes per larva with or without kale in petri dish. The 3rd instar larvae of the tobacco cutworm was more susceptible to both nematode species than the 4th or 5th instar at low concentration. Mortalities of the 3rd instar were 100% in S. feltiae and 67.7-100% in H. heliothidis while those of 4th and 5th instar ranged 76.7-100% and 43.3-100% in S. feltiae, and 36.7-90% and 3.3-90% in H. heliothidis, respectively. Mortalities of the tobacco cutworm larvae decreased when the nematodes were sprayed on the kale leaves in petri dish except 3rd instar.