I. Glazer et al., IDENTIFICATION AND BIOLOGICAL-ACTIVITY OF NEWLY ISOLATED HETERORHABDITID POPULATIONS FROM ISRAEL, Fundamental and applied nematology, 16(5), 1993, pp. 467-472
The present study describes specific identification and characterizati
on of the biological activity of entomopathogenic nematodes which were
isolated from soil samples in a recent survey of the arid '' Negev ''
region of Israel. Morphological examination indicated that the nemato
de populations designated IS1, IS2 and IS3 represent strains of Hetero
rhabditis bacteriophora Poinar. Whereas IS4 is considered a strain of
H. megidis Poinar, Jackson & Klein. The identification for IS-3 and IS
4 isolates was confirmed by analysis of total DNA on restriction fragm
ent length differences of repetitive sequences, while the IS2 and IS3
isolates showed banding pattern different from that of H. bacteriophor
a. In infectivity assays the IS4 strain of H. bacteriophora was found
to be the most pathogenic of the four new population and the HP 88 str
ain of H. bacteriophora against the lepidopteran species Galleria mell
onella, Earias insulana, Spodoptera littoralis. IS, infectivity to the
lepidopteran strain was equivalent to that of the steinernematid Stei
nernema carpocapsae All strain. The superior infectivity of the IS4 wa
s also demonstrated against the scarab Maladera matrida. Viability of
the H. bacteriophora HP 88 infective juveniles was reduced to 20 % whe
n exposed to 37-degrees-C for 3 h. The level of survival of all other
heterorhabditids strains was 3-4.5 fold higher than the HP 88 strain.
The viability of S. carpocapsae All strain was not affected by the sam
e heat treatment. Exposure to low relative humidity conditions (3 h at
50-60 % RH) resulted in 55-85 % reduction in most of the various nema
tode populations. Relatively high tolerance to the desiccation conditi
ons was recorded with the IS1 and IS3 heterorhabditid isolates.