344 T. Venkatesan and S. K. Jalali
The number of larvae also reduced drasti-
cally due to higher parasitism in MIHTTS plots.
The larvae per plant was significantly less 0.8 in
MIHTTS plots compared to 2.5, 6.2, and 20.3/
plant in susceptible strain, farmers’ practice and
untreated control plots. Feeding punctures were
also significantly less in MIHTTS released plots
as compared to other treatments and in untreated
control feeding punctures recorded were 80.1/
plant, which was significantly higher than all
treatments. This indicates that it may not be pos-
sible to raise cabbage without control measures.
The yield recorded was highest in MIHTTS + in-
secticides plots 295.0 compared to 230.0, 265.0,
and 110.0 q/ha in susceptible strain + insecticides
plots, farmers’ practice plots and untreated con-
trol, respectively (Table 14 ).
During the 2nd year trial, no egg parasitism
was recorded by Trichogramma in any treat-
ments. The post treatment egg parasitism in MI-
HTTS plots was significantly higher (46.53 %)
than egg parasitism by susceptible strain
(0.80 %), farmers’ practice (0.0 %) and untreated
control (3.70 %). The MIHTTS released indi-
cated its ability to survive in higher proportion
than susceptible strain. The higher parasitism by
MIHTTS compared to susceptible strain could
be due to its tolerance to various insecticides in
sprayed situation in the field (Table 15 ).
The number of larvae also reduced drastically
due to higher parasitism in MIHTTS plots. The
larvae per plant was significantly less 0.33 in MI-
HTTS plots compared to 5.75, 2.10, and 12.75/
plant in susceptible strain, farmers’ practice and
untreated control plots, respectively. Feeding
punctures were also significantly less in the MI-
HTTS released plots (10.9/plant) as compared
to susceptible strain plot (94.7/plant), farmers’
practice (15.10/plant) and in untreated control
feeding punctures recorded were 134.16/plant,
which was significantly higher than all treat-
ments. This indicates that it may not be possible
to raise cabbage without control measures. The
yield recorded was highest in MIHTTS + insecti-
cides plots 315.0 q/ha compared to 228.0, 278.0,
and 128.0 q/ha in susceptible strain + insecticidesTable 15 Effect of field release of MIHTTS of T. chilonis on its efficacy against diamondback moth of cabbage at
Malur (Karnataka) during 2nd year trial
Treatments Egg parasitism of stem
borer (%)
No. of larvae/plant Feeding punctures/plant Yield (q/ha)MIHTTS of T. chilonis 46.53 0.33 10.90 315.0
Susceptible strain 0.80 5.75 94.70 228.0
Farmers’ practice 0.0 2.10 15.10 278.0
Untreated control 3.70 12.75 134.16 128.0
SEM. (±) 0.78 0.32 1.12 6.45
LSD (0.05) 2.78 0.95 1.78 12.36
LSD (0.01) 5.17 2.23 3.12 19.56
CV (%) 15.99 8.79 12.65 8.86
Table 14 Effect of field release of MIHTTS of T. chilonis on its efficacy against diamondback moth of cabbage at
Malur (Karnataka) during 1st year of trial
Treatments Egg parasitism of stem
borer (%)
No. of larvae/plant Feeding punctures/plant Yield (q/ha)MIHTTS of T. chilonis 35.0 0.8 2.4 295.0
Susceptible strain 1.2 2.5 39.0 230.0
Farmers’ practice 0.0 6.2 35.0 265.0
Untreated control 2.0 20.3 80.1 110.0
SEM. ( ± ) 0.53 0.12 0.69 4.89
LSD (0.05) 1.16 0.27 1.50 10.66
LSD (0.01) 1.62 0.38 2.1 1 14.94
CV (%) 8.78 2.61 2.78 3.44