With the increasing concern about use and misuse of pesticides in commercial agriculture and home gardens, more and more inquiries for "organically grown" commodities are received every year. Non-chemical practices for plant diseases have been known and recommended for years. The backbone of any integrated pest control program must always include culture and sanitation practices, two important components of non-chemical disease control. Unfortunately, disease problems may begin as soon as seeds are planted and can continue into harvest and storage.

    Plant diseases may be caused by several different living pathogenic organisms such as fungi, bacteria, viruses, phytoplasmas, and nematodes. In addition to these parasitic organisms, non-living factors such as deficiencies or excesses of water, light, temperatures, air pollution, pesticides, and nutrients can either predispose a plant to disease or directly cause plant injury. Fortunately, many disease problems can be prevented or controlled without the use of pesticides.

    Effective plant disease control must begin at the onset of disease or even before symptoms appear. Several non-chemical practices that can reduce plant loss are as follows. First is resistance. Effective plant disease control through resistance (or a plant's tolerance or immunity to a disease) is based on the knowledge of disease known to occur in an area. Selection of resistant plant may eliminate many disease problems.

    Exclusion, another non-chemical practice, is preventing the entrance and establishment of disease causing garden. Use certified, disease-free seeds or transplants. Examine the leaves and root systems of transplants and eliminate or destroy diseased plants. Either raise your own transplant in sterilized beds or buy them from a reputable dealer. Also, avoid transporting soil or tools from known disease areas to disease-free areas.

    Last but not least is eradication. Eradication is the elimination of the disease-causing organism after it has become established on a plant. Eradication can be accomplished by sanitation, crop rotation, fallowing, and soil sanitation treatments.

(Adapted from: http://factsheets.okstate.eduidocuments/epp-7652-non-chemical-methods-for-controlling-disease-in-the home-landscape-and-garden/)

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