Investigations on tritrophic interaction in integrated management of okra pod borer complex
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Date
2008
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UAS, Dharwad
Abstract
Investigations on tritrophic interaction, screening of okra accessions against pod
borers, bio-efficacy of biorationals, evaluation of marigold as trap crop and development of
IPM modules for the management of okra pod borer complex were carried out at Agriculture
Research Station, Main Agriculture Research Station and Narendra village of Dharwad
district during 2004-05 and 2005-06.
In tri-trophic relationship, parabhani kranti, Shakti-303, Shagun and Rasi-5 were least
preferred hosts for oviposition for all three pests and permitted greatest parasitisim by the egg
parasitoid, thereby resulted in least per cent egg hatching. However, on the contrary
Mahalaxmi-Amisha, Ankur and L-177 supported highest oviposition and least parasitism by
the parasitoid due to their higher trichome density. Irrespective of accessions trichome
density was positively correlated with oviposition preference while parasitism was negatively
correlated.
Among different accessions screened, accessions shakti-303, Shagun and Rasi-5 were
recorded lowest pod borer incidence and produced 33.38, 26.41 and 22.95 per cent increase
in yield over commercial check Arka Anamika.
Among different bio-rationals, NSKE 5%, econeem plus (1000 ppm), Beauveria
bassiana + econeem plus (1000 ppm) and B. bassiana @ 2g/l were found to be superior by
registering less number of eggs and larvae of Earias vittella (Fab.) and Helicoverpa armigera
(Hubner) which resulted in lowest per cent pod damage and highest yield of 68.91, 67.78,
67.44 and 60.57 q/ha, respectively and were comparable with the standard check malathion
50 EC (71.17 q/ha).
Among different row proportions used, okra + marigold @ 10:2 and 10:1 proved to be
effective in reducing the pod damage and produced highest yield of 61.28 and 54.97 q/ha,
respectively.
Adaptable IPM (M2) module involving biorationals and selective insecticide was
found to be effective and resulted higher net profit of Rs.57926 compared to rest of the
modules tested.
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Keywords
Agricultural Entomology