I remember when I used to get cockroach control done from godrej hicare I learnt that they were using the injection gel from PCI, It was a path breaking application, no messing etc etc and after first application within three days cockroaches vanished and couldnt be sighted for 6-8 months.
Impressed with the product and closure of that div of Godrej I switched tp PCI for cockroach treatment which was good till the last year, however, this time the application seems to have gone to the dogs even after 2 weeks of application cockroaches were roaming all over, after complaining another round was undertaken by PCI and its again al;most a month and cockroaches are roaming freely, as if the treatment was for getting rid of humans and make good environment for cockroaches.