Category: Ailments

LEAVES: On Phalaenopsis, Show White Patches

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Damage by cold water causes sunken cell wall collapse; water dripping from the roof in winter causes it. F85-8 Read More

LEAVES: On Vandas Turn Yellow and Drop

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Repot the plant in loose medium dampen it and place in a plastic bag in indirect light. A75-35 Read More

LEAF BLIGHT: Also Known as Leaf Die-back, Tip Burn

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Caused by fungus invasion; spreads gradually through leaf; cut it out before treating; infected areas show watery before drying; control with Benlate, or Anti-Damp, or Tersan. RMH Read More

LEAVES: Wilting Without Changing Color, Leading to Death of Plant

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Too little light can cause it, or excessive wetness; check the roots for root aphids or fungus. A71-345 Read More

LEAVES: Shrivelling on Cattleyas

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Is caused by several things, such as dryness of culture, lack of high enough humidity, roots possibly dead from over-watering. A86-383 Read More

LEAVES: Sunburned

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago The best treatment is to remove only the badly burned ones; partly burned ones are unsightly but still functional. A69-130; A75-906; A79-334 Read More

LEAVES: White Patches

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Check the Mg and Fe levels in the fertilizer and increase one or both. Au84-204 Read More

LEAVES: White Patches on Phalaenopsis

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Most likely this is caused by cold damage which results in sunken cell-wall collapse, likely on plants too near a cold wall or under a cold-water drip; always use water for watering which is warmer... Read More

ALGAE: On Plant Leaves

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago Caused probably by too little light; low intensity of fertilizer on leaves promotes growth; it can cut down on photosynthesis. F68-187 Read More

PESTICIDES: Shelf Life

Author is Robert M. [Bert] Hamilton (Compiler), posted over 7 years ago They should be purchased for short-term use; mark the date of purchase on the container; most keep their effectiveness for two or more years if stpred properly; signs of ineffectiveness in dusts an... Read More