The surname Nguyen is believed to have originated in the Chinese surname Ruan (in the Mandarin language) or Yuen (Cantonese), owing to Chinaâs long domination over Vietnam.
Tinea nigra is a fungal infection that is mainly seen on the palms of the hands or soles of the feet causing a dark brown to black discoloration of the affected skin. The word tinea means a fungal infection and nigra means black.
Brown Soft Scale. Brown soft scale is a common problem on citrus trees, as well as many other types of trees. Soft scale insects are small, non-mobile insects that attached themselves to the wood, foliage and sometimes the fruit. Scale is most common on the new tender woody growth.ooty Mold. Sooty mold is a fungus, which causes the blackening of the leaves of citrus trees. The mold forms on the leaves as a result of honeydew secretions from insects such as whiteflies, aphids and mealybugs. Insect control is the most effective way to prevent the incidence of this disease.