Pest control technical note – Number 2 Updated February 2018

Cockroaches • A torch or pyrethrin aerosol may be used to flush cockroaches out of their harbourages. Sticky traps can be effective for long-term monitoring of Cockroaches belong to the order . populations. There are over 4000 species of cockroaches worldwide, only a few of which are considered major 2. Measures to reduce access to food, water and pests. The high pest status of cockroaches is largely shelter, including: attributed to their wide distribution, close association  Maintaining a high standard of hygiene with humans and potential to carry disease.  Reducing water availability by removing The faeces of some species of contain a unnecessary containers of water and repairing pheromone. These cockroaches press or smear their leaky taps and pipes. faeces onto surfaces to mark feeding and aggregation sites.  Storing food in sealed airtight containers, emptying garbage bins regularly and keeping garbage bin Conditions that favour cockroach infestations are those lids tightly closed. that provide abundant food, water and shelter. Cockroaches eat virtually any or vegetable  Sealing cracks and crevices where possible. material, including paper, fabric, leather, starches and 3. Application of pesticides to areas that will grease particles. target the cockroaches, may consist of any or a Cockroaches are generally nocturnal. Any active combination of: cockroaches observed during the day are often  Surface sprays applied to cracks, crevices and indicative of a large infestation. Cockroaches are voids that may harbour cockroaches, and surfaces gregarious (they congregate together), and frequently where cockroaches travel. Food-handling surfaces groom themselves. This behaviour is exploited by must not be treated. Cupboards and pantries pesticides such as dusts that come in contact with the should be emptied before treatment. feet or body of the cockroach and are ingested during grooming.  Space sprays or ULV (ultra-low volume) machines to treat an entire indoor area. It should be noted Cockroach eggs are enclosed in a purse-shaped egg that space sprays are unlikely to effectively case, which may be carried, dropped or glued to a penetrate harbourages and the trend is toward surface. When hatched, the nymphs congregate with using fewer sprays and more dusts and baits. adult cockroaches and mature after a number of moults. The number of nymphal moults, time taken for  Dusts are used in areas that cannot be treated with maturation and the adult lifespan depends on the wet sprays. Dusts can be applied to cracks and species of cockroach. crevices, in electrical equipment, and in wall and roof voids. They should always be applied lightly and carefully to avoid the risk of humans coming in Control Methods contact with the dust. Effective cockroach control relies on the education and  Baits may be in the form of gels, pastes, particles co-operation of the residents of the infested area. This or bait stations. Baits are becoming increasingly requires: useful in cockroach control and the use of baits can offer safety advantages if treatment is required in 1. A thorough inspection of the infested area. commercial food-handling areas, schools or hospitals.

Chemicals must always be used according to label length. They are reddish-brown in colour with a pale directions and the effectiveness of chemical control yellow border around the upper part of the thorax and may be limited by poor hygiene. pale legs. They have wings and males can be distinguished from females as their 4. Follow-up inspection and monitoring. wings extend beyond the tip of the abdomen. American cockroaches are capable of flying short distances in Major pest species warm conditions. Females produce up to 50 large egg German cockroach capsules in their lifetime, each containing German cockroach (Blatella germanica) 12 to 16 eggs. They usually carry these German cockroaches are amber in around for about 2 days, then drop them colour, 12-15 millimetres long when fully or glue them to surfaces close to food grown, with two dark longitudinal stripes. and water. Nymphal development takes They have wings that extend beyond the 6-12 months and the adult lifespan is 6- abdomen, but do not appear to fly. They 12 months. are the most prolific breeder of the pest American cockroaches prefer to feed on decaying cockroaches; generally having three to organic matter, but will eat most other organic foods, four generations per year, with up to 40 offspring per including paper and clothing (particularly if soiled). generation. They take as little as 40 days to develop Their desire for fermented liquids, such as beer, is very from hatchling to adult. Adults often carry egg sacs. strong. They will often travel for food, but adults with a German cockroaches will eat almost any organic water source can survive for 2-3 months without it. material, ranging from crumbs to built-up grease. They American cockroaches usually congregate in warm, can survive for up to a month without food, provided moist, dark locations. They prefer coastal areas, but that water is available. are a widespread pest, living indoors in cool regions, German cockroaches congregate in warm, undisturbed and outdoors in warm regions. Buildings commonly areas of high humidity. Most infestations are found in infested include hospitals, bakeries, food stores, kitchens. Cockroaches may be found under sinks, in factories and houses. They tend not to infest dwelling and under cupboards and drawers, and around areas in buildings, but rather the roof, wall and subfloor electrical equipment such as refrigerators. They hide in areas, and in and around sewers, grease traps and cracks and crevices during the day and feed at night. rubbish dumps. Sightings in other areas of the house, for example bedrooms, may indicate a large infestation. When inspecting for German cockroaches a torch should be used to search for live or dead cockroaches, faecal Australian cockroach pellets (small, dried faecal particles), faecal smears, Australian cockroach ( australasiae) cast off skins and empty egg cases. A thorough treatment of all cracks and crevices, voids and surfaces These are darkish-brown cockroaches, on which cockroaches are likely to travel is required in about 35 millimetres long with yellow infested areas. markings on the upper part of the thorax and on the fore margins of the German cockroaches generally spread to new locations forewings. Females produce up to 20 as stowaways in cardboard boxes or crates of food and egg cases, each containing up to 24 drink. A few individuals can establish themselves in a eggs. Development takes 6-12 months new location and rapidly breed to huge numbers. and adults live for 4-8 months. Australian cockroaches are most commonly found in warm sub-tropical to tropical environments and usually live outside in greenhouses, in and around shrubs and trees, around woodpiles and under bark or leaf litter in American cockroach (Periplaneta americana) gardens. They sometimes come indoors and will inhabit American cockroaches are the largest common pest subfloor, wall and roof voids. They prefer food of plant species of cockroach, reaching 35-40 millimetres in

Technical Note Number 2 – Cockroaches 2

origin, becoming a pest when they enter homes and eat is slender. The male’s wings extend beyond the holes in clothing and books. abdomen but the female’s wings are smaller, exposing the abdomen, whereas nymphs have underdeveloped As Australian cockroaches are usually found outdoors, wings. Females produce up to 13 yellow to reddish applications of insecticides to foundation plantings, brown egg cases, which may contain up to 18 eggs. woodpiles and mulch may be required. Residual barrier They are usually carried around for 1-2 days before sprays can substantially reduce Australian cockroach being glued to surfaces. Development from nymph to populations around houses. Dusting sewage lines, roof adult takes only 2-4 months and adults usually live for and wall voids is an effective method of control if 3-6 months. Australian cockroaches are infested in these areas. Baits and other formulations better suited for damp Brownbanded cockroaches tend to be an indoor pest. locations can provide control in cellars and They like to feed on starchy materials such as books greenhouses. and wallpaper paste, but have also been known to eat clothing items such as nylon stockings. They hide in warm areas near the ceiling, behind wall decorations and loose wallpaper, in piles of paper in cabinets, Smokybrown cockroach beneath or inside upholstered furniture, and in electrical appliances such as stereos, and toasters. Activity may Smokybrown cockroach (Periplaneta fuliginosa) be scattered throughout the building, making control Smokybrown cockroaches are about difficult. 30 millimetres long, a shiny dark These cockroaches may leave tiny, dark droppings and brown-black colour and fully winged. cast skins on cabinets and shelves. They are Egg cases contain up to 26 eggs and commonly transported in furniture, luggage, and other are dropped or glued to surfaces. items in houses and can develop into persistent When hatched, nymphs take 6-12 infestations during warm, humid conditions. It is not months to develop to adulthood. Adults live for 6-12 unusual to see them during the day. They are active months, during which time females produce up to 17 and may fly in warm conditions, or if disturbed. egg cases. When locating these , look for faecal smears, Smokybrown cockroaches are susceptible to losing cast skins, alive or dead individuals and egg cases moisture through their cuticle, and so are usually found glued to places in higher and drier areas than other in damp, dark, poorly ventilated environments. They cockroaches normally occupy. Brownbanded rarely infest the dwelling parts of buildings, and are cockroach control often requires extensive treatment instead found in sheds, wall and roof voids, subfloors, throughout an entire building, with particular attention to mulched areas, in and around grease traps and in furniture, cupboards, bookshelves and other such drains. They prefer food of plant origin, and are harbourages. therefore often a pest in greenhouses, nurseries and gardens. They can fly short distances in warm weather, and are often attracted to lights at night. Oriental cockroach Oriental cockroach (Blatta orientalis) Brownbanded cockroach Oriental cockroaches are of medium size (20-25 millimetres long) and are uniformly dark brown to black.

Male wings cover most of the abdomen, female wings Brownbanded cockroach (Supella longipalpa) are reduced, and nymphs have no Brownbanded cockroaches are small wings. These cockroaches generally do (10-15 millimetres long) and pale glossy not fly. The female may produce up to 14 brown with very pale bands across the egg cases in her lifetime, each thorax and abdomen. These bands may containing up to 16 eggs. She carries appear irregular or broken, but are her egg case around for about one day usually quite apparent on nymphs and before gluing it to a surface. Nymphal females. Nymphs and females are broad development may take 6-18 months and when viewed from above, while the male adults live for 3-6 months.

Technical Note Number 2 – Cockroaches 3 Oriental cockroaches prefer cool climates and are often found outdoors under leaf litter and bark, in damp subfloors and around drainage systems. They are relatively sluggish and are usually located at or below ground level in buildings where they eat a range of decaying organic matter. Starches and books may also be attacked. Inspections for these cockroaches should concentrate in areas of high humidity and cool temperatures. Cellars, crawl spaces, and around plumbing in kitchens and bathrooms should be inspected for faecal smears, live or dead cockroaches and egg cases.

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© State of Victoria, Department of Health and Human Services February, 2018.

Available at https://www2.health.vic.gov.au/public- health/environmental-health/pesticide-use-and-pest-control