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.
Sooty 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.ike most mites, the citrus red mite is an extremely tiny pest, only 1/50th of an inch long and red or purple in color. These mites infest leaves and fruit. Intense infestations during hot, dry weather can cause leaf drop. To control Citrus Bud Mites spray the tree with Bug Buster or Trounce.