William F. Lyon
| Common Name | Scientific Name |
|---|---|
| Pennsylvania Woodroach | Parcoblatta pennsylvanica (DeGeer) |
| Parcoblatta virginica (Brunner) | |
Almost every spring, homeowners that live in moist wood land areas become alarmed when suddenly, about dusk, large flying cockroaches enter their home. It is the large males, during their mating season in May and June, that seem to be attracted to night-lights. Should a female get indoors, numerous males may be attracted to her. These roaches live outdoors in hollow trees, under loose bark of dead trees, stumps or logs and in piles of firewood. They are simply an accidental invader and cause no damage to household possessions nor spread human disease. Once indoors, woods cockroaches wander during the daytime rather than at night compared to household roaches. Normally, they do not reproduce or establish themselves indoors nor have the repulsive odor commonly found in other cockroaches that live indoors. Their presence is temporary, perhaps a few weeks a year. They usually die within a few days in the house due to insufficient moisture.
Similar to other cockroaches, the Pennsylvania woodroach is flattened, oval-elongate shaped, has spiny legs and long, filamentous antennae. Males are large, up to 1-inch long, dark chocolate brown with light-brown wings. The pronotum (large shield-like area covering the body behind the head) is dark with a pale or transparent yellowish, light-brown outer margin surrounding the body. Males, with wings longer than the body, fly swiftly, but cannot sustain themselves in the air for long periods of time.
Females are smaller, 3/4-inch long, chocolate brown, and resemble immature oriental cockroaches. They have short wings covering about half the body and are unable to fly. Females migrate by crawling. Woods cockroaches have four large spines and several smaller spines on the femur of the front legs, whereas other cockroaches have several spines that gradually decrease in size.
Nymphs (immatures) are red-brown to dark brown and wingless. Egg cases are yellow-brown, about 1/2-inch long and curved in an inverted half-moon shape.
Females deposit their egg capsules outdoors under bark of old logs, stumps and firewood. Females produce about 30 capsules containing up to 32 eggs each. The egg incubation period is about one month, with nymphs hatching in the summer and maturing the following spring (May or June). There is one generation per year and, in some cases, the life cycle takes two years. At dusk, males may begin taking short flights and are often seen in the headlights of the automobiles by persons driving through wooded areas. Woods cockroaches are active during the winter and can be found in firewood after pulling the bark away. These cockroaches are usually found in groups. Compared to domestic roaches, woods cockroaches are less likely to flee when approached and do not survive indoors. Overwintering occurs outdoors as a partially grown nymph. When disturbed, nymphs are active even in freezing weather. Adults are present May through early October.
Since woods cockroaches do not establish themselves indoors and their presence is temporary (a few weeks) during the spring, chemical control measures are seldom needed, at least not every month of the year.
Practice exclusion techniques such as sealing any cracks, gaps or openings with caulking compound, putty or plastic wood. Maintain tight fitting screens, doors and windows. Store the firewood pile far from the house. Try not to carry over large quantities of firewood from season to season in order to reduce potential breeding sites. If practical, bring only enough firewood indoors for a day or two to prevent insects from later emerging in the house.
Use good night-light discipline since males fly to the lights during mating season. Females will crawl into areas around porch lights or yard lights, thus attracting numerous males. Avoid the use of unnecessary lights. Populations will be reduced by replacing a 100-watt mercury vapor light (ultraviolet energy) with a 50-watt, high-pressure sodium vapor light. (Least attractive to insects are sodium vapor or halogen lights with pink, yellow or orange tints and dichrom yellow bulbs.) Individual roaches found inside can be collected with a vacuum cleaner or a broom and dustpan and discarded.
It is not practical to treat firewood or other areas away from the dwelling because males can fly in from a distance. Also, to limit the risk of exposure to toxic chemical fumes when burning firewood, non-chemical preventive practices are preferred. Occasionally, populations build in crawl spaces under the house. Dusts and sprays can be effective. Outdoors, treat around the eves, gables, face boards, doors, windows, patios, porches, foundations and other potential entry sites with residual sprays of acephate (Orthene), chlorpyrifos (Duration, Dursban, Empire), diazinon (Knox Out), propoxur (Baygon), resmethrin or trichlorfon (Dylox). Restricted use pesticides would include bendiocarb (Ficam), bifenthrin (Talstar), cyfluthrin (Optem, Tempo), cypermethrin (Cynofff, Demon), deltamethrin (DeltaGard, Suspend), esfenvalerate (Conquer), lambda-cyhalothrin (Commodore, Demand), propetamphos (Catalyst, Safrotin), tralomethrin (Saga) and pyrethrin (X-Clude). Before using pesticides, always read the label and follow directions and safety precautions.
This publication contains pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registration, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned. The author, The Ohio State University and Ohio State University Extension assume no liability resulting from the use of these recommendations.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
TDD No. 800-589-8292 (Ohio only) or 614-292-1868