Studies on some ecological factors affecting the multiplication, virulence and survival of entomopathogenic nematodes, steinernema abbasi, elawad et al., 1997 and heterorhabditis indica, poinar et al., 1992
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Date
2008
Authors
Sunanda B.S.
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
Present study was carried out with the objective to investigate the
impact of some ecological factors affecting the multiplication, virulence and
survival of entomopathogenic nematodes, Steinerema abbasi and
Heterorhabditis indica.
The studies on effect of temperature on life cycle of IJs the result
revealed that of S. abbasi and H. indica were able to penetrate at
temperatures ranging from 20-30ºC. Highest number of IJs penetrated was
observed at 25ºC after 24-48 hrs and IJs of S. abbasi and H. indica emerged
from Galleria mellonella larvae at 20-30ºC. The studies further revealed that
the time (days) taken for emergence of both the nematode species was least
at 20ºC and At 25ºC highest number of IJs of S. abbasi (138.89 IJs) and H.
indica (137.16 IJs) were emerged. Duration of first and second generation of
IJs of S. abbasi was 3-4 days and 7-8 days respectively and for H. indica 3-
and 6-10 days respectively. Number of male and female of amphimictic
generation was 10.9 : 123.9 and 12.5 : 132.5 observed at 25ºC, S. abbasi and
H. indica respectively. Sex ratio (male : female) was 1 : 11.3 – 1 : 14.9 and 1 :
10.6 – 1 : 14.7 S. abbasi and H. indica observed. Observation on longevity
were recorded at different temperatures viz. 10, 20, 30 and 40ºC and at
different interval viz. 15, 30, 45, 60, 75 and 90 days. At 30ºC highest survival
of IJs (97.76%) and (88.09%) Steinernema abbasi and H. indica respectively.
Longevity IJs at 10ºC and 40ºC was least in both species of nematodes. The
studies on effect of aeration on survival IJs the revealed that survival of IJ in
aerated condition and non aerated condition was 95.2 and 79.8% observed
respectively, but highest survival of IJs in 5000 (IJs/ml) than the 10000
IJs/ml in both species of nematodes. Among nematodes, H. indica survival
rate highest in aerated condition then S. abbasi but S. abbasi survival rate
highest rate in non-aerated condition than H. indica.
The studies on effect of antidesccants on survival of IJs revealed that
the maximum survival of IJs was obtained in liquid paraffin in both the
nematode species highest survival in (4%) concentration. Lower concentration
(1%) of Liquid paraffin, Glycerol and Tween 80 had increased the survival of
IJs of both the nematode species. Survival of IJs decreased as time of
exposure increased from 7-30 days. The studies on effect of UV light and
survival of IJs revealed that addition of optical brighteners, PABA and CRP
enhanced the tolerance of both the nematode species to UV light. Among two
UV light protectants, Para amino benzoic acid (PABA) provided excellent
protection to IJs than Congored Powder (CRP). Among the different
concentration of these optical brighteners 0.5% of both PABA and CRP
observed highest survival upto 60 minutes exposure to UV light. Among
nematodes H. indica was more tolerable to UV light then S. abassi.
Description
Keywords
Drying, Sapota, Dryers, Fruits, Selection, Productivity, copper, Solar radiation, Sampling, Seed boxes