This is first seen by its causing small yellowish semi-transparent patches on the leaves, easily noticed by looking at the foliage against the light. If taken in time it can be stopped by sponging the patches with one of the spider killers advertised for the purpose. A moist atmosphere, a growing condition of the Vines, and the use of the Campbell's sulphur vaporizer are the best preventives. Most important of all is thorough attention to the cleaning of the house and rods in the dormant season. Red spider is caused by checks to the growth, dry borders, and general weakness through overcropping.

Warty Leaves are caused by sour borders or too moist an atmosphere. The sulphur vaporizer will kill the warts. Give a dressing of lime to the borders, and maintain a slightly drier atmosphere.