| dc.description.abstract | Plant diseases and plant pests are major constraints to plant growth and development, resulting in severe crop losses annually. Plant pathogens can be a variety of things, living and non-living. Non-living pathogens exist as physical conditions that plants are exposed to- climatic conditions can cause damage to plants and there are various agricultural practices that can also be harmful to the plant. Living pathogens are called parasitic or infectious diseases and are extremely contagious and can spread from plant to plant very quickly. Insects, nematodes, mites and higher animals can be considered as pathogens, as are slime mold, bacteria, fungi and parasitic higher plants. Viruses and viroids are also considered pathogens (URL ). Fungal diseases, in particular, severely limit the production of major crops, as do insect crop pests. Effective control of pathogens has led to widespread use of chemical fungicides and insecticides, but with potentially deleterious environmental and human health consequences associated with this practice, strategies to utilize natural host plant resistance mechanisms for disease control are being pursued (Yun e/ a1.,1997). The agrochemical industry has been actively looking for less damaging ways to control insect pests, and has introduced a number of more environmentally friendly pesticides. In addition, alternative strategies for
pathogen and pest control have been pursued, such as biological control, and the use of plant varieties with inherent resistance | en_US |
