If you plan your growing operation for one temperature range, and if you specialize in one or two or at most, several types of plants and flowers, you will automatically reduce to a minimum the number and kinds of pests and diseases that you might encounter if you grew many different kinds of plants with quite different cultural requirements.
It is easier to prevent trouble than to cure it. A program of prevention should be part of the regular operating routine of your greenhouse. To establish such a program, you should know something about the various insects and diseases that might be troublesome, though it is not likely that any one greenhouse could be plagued by all of the afflictions that will be mentioned below. While these are by no means all the kinds of pests and diseases that affect plant growth, they are the ones that hobby gardeners will most likely encounter at one time or another.
Investigate the various insecticides, miticides, fungicides, and general pesticides available before you start your gardening program, and keep informed of new ones as they are marketed. For Garden Pest Control, select one or two that you feel you can use with confidence. Some plants are adversely affected by certain chemicals, so particular attention should be paid to each manufacturer's instructions about how and where to use his product. Orchid blossoms, especially, are easily spotted, and sprayed materials should not be used in their immediate vicinity.