Bamboo Powderpost Beetles
Order:
Coleoptera
Family: Bostrichidae
Scientific Name: Dinoderus minutus
The bamboo powderpost beetle, also known as the bamboo borer, infests fabrics, foodstuffs, and, as expected, bamboo furniture. Although endemic (native) to Asia, this pest beetle is commonly encountered in the United States.
Signs
of feeding activities of these Bostrichids, or false powderpost beetles,
indicate active infestations. Infested
items have tiny, round exit holes along with tightly packed frass (powder-like
material produced by the feeding larvae) in the excavated tunnels.
Bostrichid infestations are usually limited; thus, reinfestation
is rare.
Biology and Habits
Adult female bamboo powderpost beetles create tunnels for egg deposition by boring into bamboo or other suitable material. A female may lay over 200 eggs in 11 days. Egg hatch occurs in 3 to 7 days, and the newly emerged larvae begin feeding inside the infested material. The larval stage averages 33 to 63 days, depending on the time of the year. The pupation period is short, only lasting from 3 to 5 days before mature adults emerge. The life cycle from egg to adult varies from 44 days to 73 days. In general, the warmer the temperature, the slower the developmental period.
The adult is a small, cylindrical, brown beetle. As the drawing depicts, the head is hidden from above by the pronotum (the dorsal or top surface plate of the prothorax, the first thoracic segment), which has rasp-like teeth protruding from its front edge. Size is about 1/8 inch (3 to 4 mm) in length. At twilight, the adults often fly towards artificial lighting.
Common
characteristics of the bamboo powderpost beetle include overlapping generations
with peak emergence in 3 months, and 2 to 4 generations per year.
Due to these characteristics, an infestation may seem to undergo
a population explosion and falsely depict a more intense infestation.
Control
The bamboo powderpost beetle may infest bamboo and rattan furniture, ornaments, curtains, cotton fabrics, drugs and foodstuffs such as chestnuts, sweet potatoes, rice, sugarcane, chocolate, wheat flour, corn and dried bananas. Control of this beetle pest largely depends on the type of material or product infested.
In general, the beetles attack bamboo within 24 hours of harvesting, when it still contains high starch content. Previously infested bamboo is not an attractive oviposition site; therefore, it is rarely reinfested. As a result, infested bamboo items probably do not require treatment. Removing adult beetles and sealing the round exit holes limit the effects of the cosmetic damage to the infested material.
When foodstuffs are infested, the adulterated material may receive treatment according to label requirements, or may have to be discarded. Sanitation also limits the potential of the infestation spreading to other products.
Accurate identification of the bamboo powderpost beetle is very important to avoid misidentification with a powderpost beetle that causes structural damage. Since this beetle is so small, magnification and possibly expert opinion is needed for identification.
(Courtesy of the National Pest Control Association.)