Evaluation of entomopathogenic nematodes against Plutella xylostella (L.) on cabbage
Loading...
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
Present investigation on “Evaluation of entomopathogenic nematodes against
Plutella xylostella (L.) on cabbage” was carried out in laboratory and screen-house. The
investigation focused on the selection of appropriate indigenous strain of EPN, its
application as foliar spray and its compatibility with currently used insecticides and Bt
against Plutella xylostella on cabbage. EPN isolates (Steinernema asiaticum, Steinernema
sp. RB-5 and Heterorhabditis bacteriophora) were used to know the effectiveness against
P. xylostella. Third instar larvae of P. xylostella were susceptible to all three EPNs isolates.
Steinernema sp. (RB-5) was least virulent (larval mortality 15.62%) after 96h whereas
highest virulence was observed in S. asiaticum (larval mortality 65.62%) at 20±1ºC.
Nematode multiplication (no. of IJs recovered per larva) was recorded highest (1226) in S.
asiaticum. On the basis of highest mortality and maximum nematode multiplication S.
asiaticum was selected for further studies on its pathogenic potential, compatibility with
insecticides, effect of temperature on its growth and development, and its efficacy against
P. xylostella as foliar spray. LC50 value of S. asiaticum was worked out to be 11.2 by using
Probit analysis. At 20 and 25 ˚C, S. asiaticum caused 45 and 80 per cent mortality after 96
h. S. asiaticum caused significant insect mortality even at the high temperatures. S.
asiaticum was effective within 20-35 °C, with optimum insect mortality at 30 °C. Nematode
multiplication was maximum at 30 °C. Maximum IJs recovery was at 30 (279) and 35˚C
(228). Maximum nematode growth and development took place at 35 °C. S. asiaticum was
compatible with endosulfan, malathion and Bt and it can be incorporated in the IPM
programme for management of P. xylostella. Split application (15000 + 15000 IJs) of S.
asiaticum IJs proved better and resulted in 48.33 per cent mortality as compared to single
dose (30,000) that caused 36 per cent mortality.
Description
Keywords
Biological phenomena, Animal developmental stages, Plutella xylostella, Parasites, Insecticides, Cabbages, Irrigation, Concentrates, Biological control, Planting