Tolerances to starvation and thirst in six cockroach species, including domestic and sylvatic ones, were investigated under laboratory conditions. Young stages of the German cockroach nymphs, Blattella germanica, died within three weeks without food and water. Older ones, however, could survive up to seven weeks under the same conditions. Large cockroaches, such as Periplaneta fuliginosa, P. americana or P. brunnea, could survive weeks longer than the German cockroach. The sylvatic cockroaches, such as lobster cockroach, Nauphoeta cinerea and Blaberus trapezoids, could survive more than four months in later stages and two months in earlier stages without food and water. Water management is important in cockroach control in food processing plants as is leftover management.

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This study presents details of the pests brought to Yokohama City Institute of Health from April 1992 to March 2009. A total of 608 pests was identified; the yearly average was 35.8 cases. Of the identified pests, Insecta accounted for 79.8%, and, subsequently, the other classes of Arthropoda (except Insecta) accounted for 14.3%. Insecta was divided into 14 orders. The dominant order was Diptera (120 cases, 24.7%), followed by Hymenoptera (109 cases, 22.5%), Coleoptera (102 cases, 21.0%), Lepidoptera (60 cases 12.4%), and Hemiptera (39 cases, 8.0%). The dominant family in Diptera was Muscidae, mainly Musca domestica, Fannia canicularis, while Formicinae was dominant in Hymenoptera; Anobiidae, Silvanidae, and Tenebrionida were dominant in Coleoptera.

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From April 2002 to March 2008, a total of 122 food samples were examined at the Yokohama City Institute of Health for possible contamination of insects. One hundred and two cases (83.6%) of insect contamination were found, and each case was identified. The insects found in the food samples consisted of 10 orders. Lepidoptera was most dominant (35 cases; 34.3%), followed by Diptera (26 cases; 25.5%) and Coleoptera (19 cases; 18.6%). The insect contamination was found in different kinds of food including box lunches, cooked side dishes, wheat flour, fish, rice, snacks, and sweets. The insect contamination appeared to be introduced in different phases of food processing: in ingredients (25.2%), in the manufacturing process (28%), during transportation or storage (7.0%), and at home (7.8%). The phase of contamination was undetermined for the remaining 36 cases (31%).

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The indoor oviposition of Aedes albopictus was examined by experiments of releasing fed females into a house. Gravid females laid their eggs in eight ovi-traps (first floor, 6 traps; second, 2) placed indoors during the first three days after the release. The oviposition of gravid females was remarkable when the traps were set in comparatively bright sites without shutters, that is, entrance, kitchen, and restroom. In contrast, oviposition by A. albopictus entering from outside was confirmed in only one ovi-trap (on the third floor) out of a total of 64 traps placed in a public institution where the general public moved throughout the observation period. The results suggest that gravid females would favorably use the breeding habitats found inside houses and enter the premises from outside to breed.

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