Study on the possibility of adopting a complex method in Blattella germanica (L.) control on board ships

Campaings to control the German cockroach, Blattela germanica, were conducted at 14-day intervals over a period of 5.5 months on two merchant vessels of similar size and type. On one ship only the chemical "Gertoks", carbamate insecticide containing 1% propoxur was applied, and on the second ship two preparations simultaneously, a chemical and a biological--"Biotrol 25 W" containing Bacillus thuringiensis. - In order to assess the success of the control, the extent of infestation in the accomodation was determined immediately before and 24 h after the spraying. - The susceptibility of the cockroaches caught on the ships, to the two preparations applied, was also determined. It was found that "Gertoks" was an efficient preparation, the biopreparation "Biotrol 25 W" being less efficient. - A certain increase in resistance of the cockroaches to both preparations, was noted. - The above observations indicate that a considerable drop in numbers of population of cockroaches can be achieved if the ship's crew carry out systematic thorough spraying of ships quarters infested by cockroaches, with Gertoks". They also confirm previous suggestions that complex method in B. germanica control on board ships is possible, using chemical and biological preparations containing Bac. thuringiensis spores simultaneously.