Scale

Scale-like insect [ Phytoparasitology ]	Dictionary of botanic terminology - index of names
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The scale insects are small insects of the order Hemiptera, generally classified as the superfamily Coccoidea. There are over 7,000 species of scale insect.

Scale is a diseased condition of plants caused by scale insects that usually lives and feeds on plants and secretes a protective waxy covering. Scale insect sucks plant fluids for nutrition. It coats itself with a covering (hence scale) that makes it quite resistant to pesticides, which are only effective against them when they are in the juvenile crawler stage. Scale, however can be controlled with horticultural oil, which suffocates them, or through biological controls.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994