Most pests lurk under leaves and close to the growing tip where tissue is softest. Most of these pests can be washed off with a spray of water. Several washes over a period of two or three weeks, plus isolation for the infested plant to prevent the pest from moving to other plants, generally eliminates the problem. Some pesticides are hazardous, not only to the general environment, but to the plant tissue. Ferns are extremely sensitive to all forms of chemical spray, and infested fronds are best removed and destroyed.
Diseases are rare on foliage and flowering plants.
The only ones likely to be encountered are Botrytis, the gray mold fungus that invades dead and dying tissues, and soft leaf spot or crown rot fungi which thrive in moist atmospheres. Tiny white or yellow spots on leaves, later becoming mottled and dusty. Fine webs under leaves and in growing tips. Leaves may curl up. Thrive in dry climates.