Within the complex network of chemical signals used by termites, trail pheromones and sex pheromones are among the best known. Numerous recent papers map the chemical identity and glandular origin of these pheromones in nearly all major isopteran taxa. In this study, we aimed to describe the sex pheromone and the trail pheromone of a poorly known sand termite, Psammotermes ... Read more

The role of esterase in pyrethroid resistance was studied in the final larval instar of different strains of the cotton bollworm, Helicoverpa armigera. The resistant strains viz., Nagpur strain and the Delhi strain were found to have elevated midgut esterase activity in comparison to the susceptible strain. Nagpur strain and Delhi strain have 2.24 and 1.73-fold higher esterase activity, respectively, ... Read more

Microplate assay technique for estimation of esterase activity in a single insect was used in combination with dose mortality bioassays to detect pyrethroid resistance in three strains of Helicoverpa armigera and to study the frequency of pyrethroid resistant individuals within the population of the same strain at two larval stages, third and fifth instar. The third and fifth instar larvae ... Read more

Pyrethroid insecticides were first introduced into India in 1980, primarily for the control of Spodoptera litura, which by that time had become resistant to organophosphate, carbamate and organochlorine insecticides (Ramakrishnan et. al., 1984). Within few years, pyrethroids became popular with cotton farmers and were indiscriminately used and replaced all other insecticides (Reddy, 1987). Resistance of the cotton bollworm, Helicoverpa armigera ... Read more