DISTRIBUTION AND BIOCONTROL POTENTIAL OF ENTOMOPATHOGENIC NEMATODES AGAINST SOME LEPIDOPTEROUS PESTS
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Date
2014
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Publisher
CSK Himachal Pradesh Krishi Vishavavidyalaya, Palampur
Abstract
Survey for entomopathogenic nematodes (EPNs) was conducted in ten districts of Himachal
Pradesh during 2011-13. In all, 930 soil samples from 131 locations were analysed for the
occurrence of the nematodes. The frequency of occurrence of these nematodes was very low
(3.82%). The nematodes were found in five locations i.e. Sangla (Distt. Kinnaur), Kamand
(Distt. Kullu), Rajgarh (Distt Sirmour), Rajour and Sutkar (Distt. Chamba). These localities
are situated in mid hill/high hill zones of the state. The nematodes were recovered from fruit
orchards only having lighter soils. The nematodes from all the locations were identified as
Heterorhabditis. Nematode cultures from different locations were considered as isolates and
were designated as ‘Sangla isolate, ‘Kamand isolate’, ‘Rajgarh isolate’, ‘Sutkar isolate’ and
‘Rajour isolate’. Former three isolates, along with one commercial isolate i.e. H. indica
(procured from NBAII, Bangluru) were evaluated for their pathogenic effects against
Spodoptera litura, Helicoverpa armigera, Plutella xylostella and Agrotis segetum in Petri
plates/soil/screen house. All these three local isolates including the commercial isolate
proved pathogenic variably to different insect-pests. In screen house testing on cabbage,
‘Rajgarh isolate’ was found highly effective against S. litura, H. armigera and P. xylostella.
The virulence of these isolates was considered of the medium level. The bacterium,
Photorhabdus luminescence was associated with all the isolates and proved non pathogenic
to Achroia grisella when tested alone. Besides, host invasion studies in A. grisella revealed
maximum penetration through natural openings, other than mouth. For in vivo mass
production of local EPNs, Corcyra cephalonica, A. grisella and Bombyx mori were used.
The average yield of IJs/larva was minimum (23020-26030) in C. Cephalonica and
maximum in B. mori (463080-546840) for different EPNs. For in vitro production, chicken
offal medium was used. The yield was maximum for ‘Rajgarh isolate’ (17.70 x 106
IJs/flask).
Description
Doctoral Dissertation
Keywords
##Unable to generate tags sumit vashisth phd 2014.pdf, LEPIDOPTEROUS PESTS, ##Unable to generate tags sumit vashisth phd 2014.pdf, Insects