Dendrobiums are an epiphytic type of orchid , with long , narrow-minded , sarcoid leaves that grow in alternating layer on either side of the thick pseudobulb fore . Whether grown indoors as houseplant or outdoors in temperate climate , a routine of conditions can manifest distraint in the leaves of the plant . Insufficient or excess watering are uncouth issues , as are over - fertilizing , too much direct sunlight , fungus or insect pests .
Under- or Over-Watering
Too little moisture around the industrial plant roots can manifest in yellowing leaf , which shrivel , brown along the perimeter , desiccate and finally put down off . Too much moisture at the root word , either from extra lachrymation or unsuitably ponderous potting mixture such as soil , can suffocate the roots and make the leaves to fade to yellow and set down from the pseudobulb .
Phyllosticta Capitalensis Fungus
little circular maculation in yellow or fateful will take shape on dendrobium leaves when fungus spores are present . A particular fungal form that dendrobium are susceptible to is Phyllosticta capitalensis . It will spread from leaf to flip with the spots multiply and when the plant life is denuded of leaves , it will die .
Scales
One of the most frequently seen pests on dendrobium leaf are scales that colonise the bottom surface of the foliage . Scales appear as little troll or ovoid spots that are white , tan or dark brown . Scales colonize and reproduce speedily and can only be controlled if catch early and arrested with chemical substance insecticides . Most dendrobium orchids with obtrusive and established scale infestations can not be pull through and must be destroyed .
Too Much Sunlight
Excessive bright , direct sunlight can burn leaves and cause severe drought focus in the orchid plant , delivering a one - two lick that can quickly yellow and dehydrate the orchid leaves . Only expose orchid to verbatim sunshine when it is weakly in the morning time or good afternoon . brilliant , indirect light is always the preferent vulnerability .
Excess Fertilizer
Too heavy or too frequent fertilizing can burn the orchidaceous plant fragile epiphytic roots cause rapid leaf discoloration and cliff . Fertilizer practice right away to the potting medium or roots without first being heavily diluted in water can stimulate enough stem damage to kill an orchid .
