Cockroaches are oval and flat. They can be black, brown, or tan. They have chewing mouth parts, and long flexible hairlike antennae. The adult stages have wings, but in some species just the male adults have wings.
Order: Orthoptera, Families Blattellidae and Blattodae
Cockroaches have 3 life stages (incomplete metamorphosis), egg, nymph and adult. The eggs are in bean like capsules called an ootheca. The ootheca may contain several dozen eggs.
Immature stages are called nymphs, several nymph stages occur, that are separated by a molt. Cockroach Nymphs are similar to adults but lack wings and are smaller. It takes 2 to 3 months for a roach to complete it’s life cycle.
Cockroaches are very good at adapting to different environments. They are omnivorous and they discover food by smell. They have developed resistance to commonly used pesticides.
Cockroaches can be transferred by grocery bags, cardboard boxes and food packages.They can also enter through cracks around doors and windows and they may travel through sewers.
Cockroaches like warm, dark, moist areas, and are found mostly in the kitchens and bathrooms. They are nocturnal, if they are seen in the day the infestation may be very heavy.
Large infestations have a foul odor, and some people can have allergic reactions to cockroaches. They are not direct carriers of human disease, but they are suspected of helping to spread disease such as food poisoning and dysentery.
Blatella germanica. Family: Blattellidae.
The German Cockroach is the most common species in Nevada. Adults are brownish tan and are less half an inch in length. They have wings that cover their abdomen and 2 dark stripes down their back. They have a high reproductive potential due to the amount of eggs laid and short lifecycle.
The females carry the ootheca for a month, then 2 days before hatching she will drop it. The ootheca changes colors depending how old it is, at first sight it is white, then changes to pink in a few hours, then turns brown after a couple of days. One female can produce 4 to 8 oothecas in it’s lifetime. Each ootheca has 30 to 50 eggs that will hatch in one month. The eggs will die if the mother is killed before dropping them.
They have 6 to 7 instars. If they are white they are newly molted. The young will be eaten by the females if no water is around. The lifespan is about 250 days, with 103 days to develop. They are usually found in the kitchen or bathroom, if they are in other areas of a home, that will indicate a very large infestation. They usually travel along wall intersections.
Brown Banded Cockroach
Supelia longipalpis Family:Blattellidae
The Brown Banded Cockroach is 12mm long and is slightly smaller than the German Cockroach. Females are tan to reddish brown or glossy dark brown, the male is a lighter brown. The Adults have 2 light colored bans at the base of the wings. Both the male and female have wings. Male wings cover the abdomen the female do not. The males can fly but the female can not.
The oothecas are 4mm x 2.5mm and yellow to a reddish brown and are usually glued to a surface in an dark area, which makes them easily transported to a new dwelling. Females can produce 14 oothecas in a lifetime with 18 eggs per capsule. Eggs will hatch in 50 to 75 days.
The adult female lifespan is 200 days. They prefer warmer temperatures 80 degrees or higher. They are more often found in homes and apartments than stores and restaurants.
Blatta orientalis Family: Blattidae
The adult Oriental Cockroach is reddish brown to black and 30mm long. Their wings are short. Females have small wing pads, males have wings that cover about 75% of their abdomen, and they can not fly.
The females drop oothecas in warm sheltered areas that are near food. The ootheca is 10mm x 5mm. The female can produce 8 oothecas that contain 16 eggs. The eggs hatch in 60 days.
The development time is in between 1 to 2 years. Nymphs are 6mm and are brown turning darker with each instar. They do not have cushion like pads between their claws, aka arolium, of the feet, aka tarsi, so they can not climb smooth vertical surfaces.
They are found in moist dark areas like drains, water meter boxes plumbing fixtures, sewers, and garbage cans. They are often called “the water bug”. They can survive outdoors during warmer months and can withstand colder temperatures than the German cockroach. They are sociable and can be clustered together.
Periplaneta americana Family: Blattidae
The Adult American Cockroach is 1 and half inches long, the largest species in domiciliary habitats. They are reddish brown in color. The wings extend 8 mm beyond the abdomen. Egg capsules are 8mm x 5mm brown when dropped and turn black in 2 days.They are dropped or glued near food.
Development is temperature dependent and can take 600 days. Egg sacks are produced in April or May. They have about 13 instars, the first instar consumes its cast skin. Wings are not noticeable until the 3rd instar.
Adults live 630 days. They are usually found in dark, damp locations. Like sewers and structures with inadequate ventilation. They can enter a building through the sewer system. They are omnivorous and they discover food through their sense of smell.
Blattella vaga Family: Blattidae
Field cockroaches look a lot like the German Cockroach, with the exception of being lighter in color. They are mostly found in irrigated fields in southern Nevada. The Adults have 2 dark parallel strips running down their back.
Their life cycle is similar to the German cockroach. They are not deterred by light and likely to be seen in the day. It is an outdoor pest but will invade homes in drier seasons. They feed on decaying vegetation.
Smokey Brown Cockroach
Periplanteta fuliginosa, Family: Blattidae
The Smokey Brown Cockroach is not typically found in Nevada, it is mostly commonly found in the southern states. It is the only all dark species of roach found in North America.
It is rarely found indoors, most common dwellings is in garages, woodpiles, outbuildings, and green houses. It will fly at night and is attracted to porch lights.
The wings completely cover the abdomen. It feeds on plants.
Blatta lateralis Family: Blattidae
The Turkestan Cockroach was first reported in the US in 1978. Since then, it has been seen in great numbers in California and Nevada, as well as in most southwestern states. It has replaced the oriental cockroach as the predominant roach in urban areas of the southwest. It is primarily found outdoors but can sometimes be an indoor pest.
The females are very similar to the Oriental Cockroach, being 1 inch long with no wings. The nymph are half black and red.
The Control Of Cockroaches
There are 3 basic steps for the control of Roaches. The first step is to inspect for them. The most common place for roaches to be are in dark damp places. Roaches are nocturnal, so inspecting for them can be quite a difficult task. The use of sticky traps can be helpful to find hiding spots. Place traps in areas where a roach infestation is suspected, and return in a few days to see if anything is there.
The second step is to use good sanitation practices. Make sure that the house is clean, where no food is available for them to eat. This includes crumbs, garbage and food on the counter. Cockroaches need water, make sure that there are no dripping faucets, or leaking pipes. Make sure cans and bottles ready to be recycles are left outside.
The last step is the use of chemicals. Roaches are not typically eliminated with one treatment, due to the fact that the sprays and fumigants cannot penetrate the eggs. You can spray and kill all the live roaches, but once the eggs hatch the problem will resurface again. That is why multiple treatments are necessary.
Treatments nearest to the regular hiding spots typically are the most effective. With that being said, roaches can become resistant to pesticide use, so different chemicals should be use with successive treatments. The most common types of chemical controls are sprays, dust and baits.