Asian Cockroach

Scientific Name: Blattella asahinai Mizukubo (Insecta: Blattodea: Blattellidae)
CLASS/ORDER/FAMILY: Insecta/Hymenoptera/Formicidae
METAMORPHOSIS:Complete

Introduction:

As its name suggests, the Asian cockroach (Blattella asahinai) is most commonly found in Southeast Asia. However, the Asian cockroach has spread significantly and is now known to infiltrate houses worldwide. First documented in the United States in the 1980s, the Asian cockroach has since spread through most of the Southeastern United States. Like other species, the Asian cockroach is omnivorous and feeds on any available food source. They have been known to carry germs and can spread diseases to humans. Asian cockroaches are prolific breeders and reach peak populations in spring and summer.

The Asian cockroach is nearly identical to the German cockroach (Blattella germanica) except for a few minor morphological differences. Like the German cockroach, it is about 1.6 cm (0.63 in) long, is tan to brown in color, and has wings. However, its wings are longer than the German cockroach, and there is a difference between a groove in the abdomen between the two species. There are other differences. The quickest way to tell the difference between the two species is that the Asian cockroach is a strong flyer (almost like a moth) and is attracted to light, unlike the German cockroach.This species tends to prefer the outdoors, whereas the German cockroach prefers living indoors.

Distribution and Habits:

The Asian cockroach was first described in 1981 from insects collected on Okinawa Island, Japan. It is most likely that B. asahinai was introduced into the United States through imports from Japan. Since the first identification of B. asahinai in Lakeland (Polk County), it has been reported from Marion County in central Florida to Broward County in southwest Florida.

The primary habitat of the Asian cockroach is outdoors in shaded mulched or composted areas, such as landscaping and gardens, where fresh plant litter accumulates. Populations of 30,000 to 250,000 insects per acre have been reported. Members of this species are strong fliers, unlike their close relative, the German cockroach. They may invade structures but indoor infestations are rare occurrences. They become active at sundown and are attracted to light-colored surfaces and brightly lit areas. Adults will take flight during the day if disturbed. The presence of this pest is obvious since their peak activity period coincides with our leisure time.

This species has been observed feeding on various commercial agricultural crops such as lettuce, cabbage, roses, and strawberries. However, the Asian cockroach does not cause any major damage because commercial crops are routinely treated with insecticides for other pests. Therefore, damaging populations of Asian cockroaches in commercial plantings have not occurred (Koehler et al. 1990).

Description:

The Asian cockroach was first described in 1981 from insects collected on Okinawa Island, Japan. Blattella asahinai was most likely introduced into the United States through imports from Japan. Since the first identification of Blattella asahinai in Lakeland (Polk County), it has spread through much of Florida and is reported in Alabama, Georgia, South Carolina and Texas.

The primary habitat of the Asian cockroach is outdoors in shaded mulched or composted areas, such as landscaping and gardens, where fresh plant litter accumulates. Populations of 30,000 to 250,000 insects per acre have been reported. Members of this species are strong fliers, unlike their close relative, the German cockroach. They may invade structures but indoor infestations are rare occurrences. They become active at sundown and are attracted to light-colored surfaces and brightly lit areas. Adults will take flight during the day if disturbed. The presence of this pest is obvious since their peak activity period coincides with our leisure time.

In 2008, the USDA published reports that the Asian cockroach might also have a possible beneficial role, as an egg predator, in controlling lepidopteran pests of annual crops (USDA 2008). However, as it is primarily a pest, there are no plans to distribute it as a biological control.

Life Cycle:

The Asian and German cockroach life cycles are similar to one another. (Atkinson et al. 1991a). Immature development in females took 67.8 days and 65.7 days in males. Females were much longer lived than males with adult longevity at 103.5 and 48.5 days, respectively. Female Asian cockroaches produce an average of 3.7 oothecae with 37.5 offspring in each. Ross and Mullins (988) indicated that oothecae from older females resulted in fewer offspring. The first oothecae is produced 13 days after becoming an adult with approximately eight days between subsequent oothecae. The female retains the oothecae for about 19 days and deposits it near the time of hatching. The Asian cockroach female can produce about 80 offspring in her lifetime which is significantly less than that of the German cockroach.

Management

Control of Asian cockroaches is difficult due to their mobility and abundance of population sites. Traditional treatments using residual sprays inside and around the perimeter of a structure are ineffective due to numerous infestations in mulched and wooded areas. Plus, adults enter homes through windows and doorways, avoiding areas typically treated for control of German cockroaches. Sodium vapor lamps for security lighting and yellow incandescent bulbs for porch lighting are both less attractive to adults and would thereby reduce attraction of adult insects to lighting near buildings. Although Asian cockroaches are susceptible to all pesticides, toxic pelletized baits scattered outdoors have provided the most reliable control. Insect Management Guide for cockroaches Least Toxic Methods of Cockroach Control