New Horizons in Insect Science Towards Sustainable Pest Management

340 T. Venkatesan and S. K. Jalali

Field Efficacy of the Multiple

Insecticides and High Temperature

Tolerant and Susceptible Strains

of T. chilonis on Cotton, Tomato

and Cabbage Pests in Comparison

with Insecticides Alone

Cotton

The larval population recorded in tolerant T. chi-
lonis plots was 0.5 larva/plant compared to 0.8

in laboratory population and 1.2 larvae/plant in

farmers practice plots. The significant reduc-

tion in larval population in tolerant T. chilonis

plots indicated tolerant T. chilonis survival in the

sprayed cotton field and their ability to parasitize

the eggs in greater numbers than the laboratory

population.

During 1st year of trial, the mean boll damage

was significantly lower in MIHTTS of T. chilonis

plots compared to susceptible strain and farm-

ers practice plots. The bad open bolls recorded

Table 5 GST activity in susceptible insecticide tolerant and MIHTT strain
Strain Activity (nmol CDNB conjugated mg sample−^1 min−^1 )
Susceptible 11.5
Endosulfan tolerant 20.0
Monocrotophos tolerant 20.5
Fenvalerate tolerant 20.3
MIHTTS 24.5

Table 6 Carboxylesterase activity in lab susceptible and insecticide tolerant strains treated with insecticides
Strain Insecticide treated Pesticide treated for
(minutes)

Specific activity

Susceptible Nil Nil 180
Endosulfan tolerant Nil Nil 179
Susceptible Endosulfan 30 61.4
Endosulfan tolerant Endosulfan 30 143
Susceptible Endosulfan 120 61.27
Endosulfan tolerant Endosulfan 120 120
Monocrotophos tolerant Nil Nil 200
Susceptible Monocrotophos 30 19.72
Monocrotophos tolerant Monocrotophos 30 35.53
Susceptible Monocrotophos 120 18.15
Monocrotophos tolerant Monocrotophos 120 20
Fenvalerate tolerant Nil Nil 164
Susceptible Fenvalerate 30 61.5
Fenvalerate tolerant Fenvalerate 30 131
Susceptible Fenvalerate 120 61.27
Fenvalerate tolerant Fenvalerate 120 117

Table 7 Michaelis constant (Km) values of Carboxyl-esterase activity for 1-NA for susceptible and insecticide tolerant
strains
Strain Km (mM)
Lab susceptible 0.02
Endosulfan tolerant 0.1
Fenvalerate tolerant 0.032
Monocrotophos tolerant 0.0735
MIHTTS 0.02