Smokybrown cockroach American cockroach Oriental cockroach

Public Health Significance of Urban Pests 59 than 60 years were infested with oriental cockroaches, whereas new apartments less than 10 years old were infested with German cockroaches. Oriental cockroaches have also been reported in sewers in Germany Pospischil, 2004 and Hungary Bajomi, Kis-Varga Bánki, 1993. In Germany, they are also pests in public baths, bakeries and breweries Pospischil, 2004. In the south-western United States, they are primarily found outside structures, around water meter boxes and woodpiles and under uplifted concrete walks Cornwell, 1968. Adult populations peak in late June and July. Oriental cockroaches have been observed feeding on garbage, dead insects, slugs, bird droppings and turf grass, but areas where pets are fed outdoors frequently become heavily infested. In central California, they were found in 7.1 of sewers inspected, whereas they are rarely encoun- tered in sewers in southern California Rust et al., 1991. Cold hardiness probably contributes to its northern distribution. Oriental cockroaches are not limited by temperature throughout much of the United Kingdom and western Europe, if it can avoid short-term exposures to extremely low temperatures le Patourel, 1993. Outdoor populations may survive in urban areas if heated buildings provide attrac- tive harbourages. During a two-week acclimation to 10°C, none of the nymphs success- fully molted. Acclimation, however, did result in increased survival at low temperatu- res. Critical temperatures for formation of ootheca, viability and successful hatch are between 15°C and 20°C le Patourel, 1995. If the temperature is reduced to around 15°C, the populations can be arrested and will decline. Oriental cockroaches remain close to preferred harbourages and existing refuge Mielke, 1996. Nymphs are most likely to initiate movement to new harbourages, depending on the distance. Increased temperature 29–38°C and relative humidity between 48 and 70 decreases activity and increases the radius of movement. In the eastern United States, oriental cockroaches remained near preferred harbourages, aggregating around crawl spaces and vents under structures and with only 2 moving indoors Thoms Robinson, 1986. Consequently, locating refuge and aggregation sites is essential to control them.

2.1.4. Smokybrown cockroach

The smokybrown cockroach is commonly found in the south-eastern United States, except in central and southern Florida where it is replaced by the Australian cockroach Atkinson, Koehler Patterson, 1991. It is also found outdoors in some coastal areas of California. The lower and upper temperature limits on their development are 15 ºC and 35 ºC, respectively Benson, Zungoli Smith, 1994. The distribution could extend to all subtropical areas of the world, and isolated infestations could survive in any modern city Appel Smith, 2002. Adults are dark shiny tan to ebony and 25–38 mm long Fig. 2.1 and Fig. 2.2. The unpat- terned pronotum – that is, the upper or dorsal surface of the prothorax – is distinguis- hable among the other species of pestiferous Periplaneta. Both sexes have full wings, unlike female oriental and Turkestan cockroaches that are brachypterous – that is, having very short or rudimentary wings. Early instars are easily recognized by distinc- tive white-banded antennae, white mesonotum the dorsal portion of the mesothorax Cockroaches 58

2.1.2. American cockroach

The American cockroach is probably of tropical African origin, where it lives both inside and outside of structures. Adult males and females will readily fly, especially in warm tropical conditions. The adult female’s ability to survive 90 days with water and no food, the deposition of oothecae and extended nymphal developmental periods probably contri- buted to their spread in maritime commerce before the age of steam powered ships. The American cockroach is now cosmopolitan and a significant pest in tropical and subtro- pical climates. Indoors, the American cockroach will inhabit food preparation and storage areas, but they are not as common as German cockroaches. In buildings, they are found around steam and heating pipes and in areas associated with high temperature and humidity Appel, 1995. They can be troublesome in greenhouses, damaging plants and feeding on pest insects. Outdoors American cockroaches frequent palm trees and vegetation around structures Roth, 1981. Their close association with latrines, cesspools, sewers and dumps increases the likelihood of them transmitting human pathogens. In the arid south-wes- tern United States, they are commonly found in sewer systems. Adult male and female American cockroaches are among the largest cockroach species found in urban settings. They are about 4 cm long on average and are reddish brown except for a pale brown band around the edge of the prothorax. The cerci – that is, pai- red appendages on the rear-most segments, which serve as sensory organs – are extre- mely long and slender Fig. 2.1–2.3. In the field, the nymphs of American and oriental cockroaches are difficult to separate without a hand lens, and the initial identification often depends on the habitat where they are collected. Outdoor surveys that use traps can be biased and depend on the species in the area. Appel 1984 has shown that American cockroaches are more likely to be trapped than are smo- kybrown cockroaches. However, traps with nymphal smokybrown cockroaches repel American cockroaches, resulting in an under-representation of American cockroaches in those areas of sympatry – that is, geographical areas where the different species of coc- kroach overlap without interbreeding – where smokybrown cockroaches predominate.

2.1.3. Oriental cockroach

The oriental cockroach is probably indigenous to North Africa, inhabiting climates that combine summer heat and moderate winter temperatures. Oriental cockroaches are a major domiciliary pest in England and are found in northern cities of the United States and throughout Europe. In the United Kingdom, the favourite localities in structures for oriental cockroaches are the cellar, boiler room and heating ducts Cornwell, 1968. Surveys of pest control service technicians throughout the United Kingdom indicated that oriental cockroaches were found indoors in all questionnaires and outdoors about 60 of the time Alexander, Newton Crow, 1991. In the Czech Republic and in Slovakia, the prevalence of oriental cockroaches has been declining, probably because of changes in building practices Stejskal Verner, 1996. In Hungary, apartments older Public Health Significance of Urban Pests 61 times. This might provide a useful monitoring tool in situations where brownbanded cockroaches are a problem. 2.2. Health hazards 2.2.1. Surveys and public opinion