Development, Characterization and Field Assessment of Multiple Insecticides ... 341
were 2.4/plant in field-collected population com-
pared to 3.7 in laboratory population and 4.5 in
farmers’ practice plots, good open bolls record-
ed were 15.7, 11.0 and 12.0/plant, respectively.
Percent boll damage generally in plots receiving
MIHTTS of T. chilonis was significantly lower
2.2 compared to 3.3 and 3.5/plant in susceptible
strain and farmers practice plots, respectively.
The results showed that release of MIHTTS of T.
chilonis was useful in reducing egg hatch, which
resulted in lesser boll damage (Table 14 ). Plots
that received the combination of MIHTTS of T.
chilonis + insecticides recorded highest yield of
15.0 q/ha compared to 12.6 q/ha in susceptible
strain of T. chilonis + insecticides and 14.1 q/ha
in farmers practice plots. Besides, significant re-
duction in insecticide sprays was also observed
in MIHTTS of T. chilonis released plots.
The larval population recorded in MIHTTS
of T. chilonis plots was 0.3 larva/plant compared
to 0.9 in susceptible strain of T. chilonis and 1.3
larvae/plant in farmers’ practice plots. The sig-
nificant reduction in larval population in tolerant
strain plots indicated that tolerant strain’s ability
to survive in the sprayed cotton field and their
ability to parasitize the eggs in greater numbers
than the susceptible strain (Table 10 ).
During 2nd year of field evaluation, the mean
boll damage was significantly lower in MIHTTS
of T. chilonis plots compared to susceptible strain
of T. chilonis and farmers’ practice plots. The bad
open bolls recorded were 2.7/plant in field-col-
lected population compared to 4.2 in susceptible
strain of T. chilonis and 5.6 in farmers’ practice
plots, good open bolls recorded were 18.3, 10.0,
and 14.3/plant, respectively. Percent boll damage
generally in plots receiving MIHTTS plots was
significantly lower—3.5 compared to 4.8 and 4.1
in susceptible strain and farmers’ practice plots,
respectively. The results showed that release of
MIHTTS strain was useful in reducing egg hatch,
which resulted in lesser boll damage (Table 11 ).
Plots that received the combination of field-
collected population + insecticides recorded
highest yield of 14.8 q/ha compared to 12.4 q/
ha in laboratory population + insecticides and
14.3 q/ha in farmers’ practice plots. Besides, sig-
nificant reduction in insecticide sprays was also
observed in field-collected population released
plots.
The mean boll damage was significantly
lower in MIHTTS plots compared to susceptible
strain and farmers’ practice plots. The bad open
bolls recorded were 2.7/plant in MIHTTS plots
compared to 4.2 in susceptible strain and 5.6 in
farmers’ practice plots, good open bolls record-
ed were 18.3, 10.0, and 14.3/plant, respectively.
Percent boll damage generally in plots receiv-
ing MIHTTS plots was significantly lower 3.5
compared to 4.8 and 4.1 in susceptible strain and
farmers’ practice plots, respectively. The results
showed that release of MIHTTS was useful inTable 8 Microsomal p-Nitroanisole O-demethylase
activity
Strain Units: mole min−^1 mg−^1
sample
Susceptible 0.02
Fenvalerate tolerant 0.113
Table 9 Cytochrome C-reductase activity
Strain Units/ml
Susceptible 0.010
Fenvalerate tolerant 0.105
Fig. 3 Esterase isoenzymes banding pattern on native
PAGE (Lane 1( FF)- Fenvalerate tolerant strain exposed
to fenvalerate for 30 min; Lane 2 ( LFT) Susceptible strain
exposed to fenvalerate for 30 min; Lane 3 ( FUT) Fen-
valerate tolerant strain; Lane 4 ( LUT) Susceptible strain;
Lane 5 ( MMT) Monocrotophos tolerant strain exposed
to monocrotophos for 30 min; Lane 6 ( LMT) Suscepti-
ble strain exposed to monocrotophos for 30 min; Lane 7
( MUT) Monocrotophos tolerant strain; Lane 8 ( LUT) Sus-
ceptible strain; Lane 9 ( LUT) Endosulfan tolerant strain
exposed to endosulfan for 30 min; Lane 10 ( LUT) Sus-
ceptible strain exposed to endosulfan for 30 min; Lane1 1
( LUT) Endosulfan tolerant strain; Lane 12 ( LUT) Suscep-
tible strain)