Bamboo Scale: Appearance, Territory, Damage, and Life Cycle

Latin Name: Asterolecanium Bambusae

Appearance: The roundish depression that frequently develops in plant tissue where each scale nymph feeds is how pit scales get their name. In California, there are at least eight species. Except for a brief period when they are first instars that have just emerged, these scales are round to oval (crawlers). Most species’ mature pit scales have a diameter of between 1/10 and 1/20 inches. The color of the pit scales can range from whitish to brown, gold, green, tan, and green. Typically, their damage, the circular depressions, is what makes them stand out (pits).

Hosts Plants: The bamboo pit scale, Bambusaspis Bambusae, is often harmless to its numerous other hosts but frequently infests bamboos, such as the Bambusa, Dendrocalamus, and Phyllostachys species.

Territory: Between 1995 and 2012, this species was stopped 12 times at U.S. ports of entry, with specimens coming from Vietnam, Australia, China, French Polynesia, Jamaica, and Trinidad and Tobago.

Damage Insect Cause: Bamboo pit scale can be seen in high numbers on leaves and stems, although it does not form pits. This species is frequently ignored because its transparent green to the yellowish body takes on the color of the host leaves or stems where it feeds. Late instars (older nymphs) have a waxy fringe around their bodies that makes them seem like certain kinds of whiteflies.

Life History and Habits: Pit scales go through three phases of development: egg, nymph, and adult. Nymphs resemble adults in appearance but are smaller and have less wax in species that discharge wax. Crawlers’ scales remain fixed in the same position for the remainder of their life after they settle to eat. They have one generation each year for the species with well-known biology.

This family of pit scales has five male and three female instars. They frequently result in deformation and are typically detected on the leaves or shoots of the host plant. A clear or transparent test typically covers the body. The mature female shrinks and dies in the fall, leaving a hollow that is filled with eggs. Males are rarely detected, but when they do, they grow in a test in a way that is identical to how the females do.