The conditions under which many floral and foliage crops are produced, i.e., high humidity, low light intensity and frequent watering are favorable for the development 0£ fungal and bacterial diseases. If insects are uncontrolled in the greenhouse, viruses can become a major problem. Nematodes may be introduced on infected plant material or unsterilized soil.

Sanitation in propagation and growing will reduce the incidence of disease. Soil-less culture, healthy plant material, clean containers and benches, and pathogen-free water are important. considerations. Plant culture on wire benches will avoid soil-borne pathogens. Most fungicides are protectants and require frequent re-application. Early correct identification of causal agents is important in preventing heavy disease losses and avoiding improper use oi pesticides.