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Tips for Preventing Garden Pests and Diseases


Growing healthy plants is the first step toward a great garden. In order to achieve this, it's important to prevent diseases and pests through careful plant selection, planting, and care. It also helps to use some of the new environmentally safe products and techniques described in this article. We'll start by taking a closer look at how to prevent disease from penetrating your garden.

  • Among the most important considerations when preventing diseases is soil drainage; soggy roots lead to rot in almost every instance (though there are some plants that need the extra water). Sunlight is also essential. It must keep the plant well nourished (by photosynthesizing) so it can stay robust enough to resist diseases that attack weak plants.

  • Plants with enough space to reach maturity without overcrowding are likely to be healthy. They suffer less competition with their neighbors for sun, water, and nutrients, and they enjoy plenty of fresh air. In an overcrowded garden, airflow stagnates, just as it does in an overcrowded room. Without free air circulation, foliage dampened by dew, rain, or sprinkling will stay wet longer and be more susceptible to fungus and other diseases.


    Giving your plant plenty of room to grow will help prevent disease.
    Giving your plant plenty of room to grow will help prevent
    disease. See more pictures of garden ideas.

  • Choose disease-resistant cultivars whenever possible. They are bred to resist infection -- an ideal way to avoid diseases. Growing disease-resistant vegetables prevents chemical tainting of your food. Disease-resistant varieties of popular flowers such as roses save you time, trouble, and expense.

    There are varying levels of protection available:
    • Some cultivars have multiple disease resistances for maximum protection. The 'Big Beef' tomato, for instance, resists various types of wilts: tobacco mosaic virus, nematodes, and gray leaf spot. Little is left that can harm it.
    • Some cultivars resist only one disease. But if that disease is a problem in your area, then these plants will be worth their weight in gold.
    • Other plants are disease tolerant, meaning they may still get the disease but should grow well despite it.

To find out more about disease-resistant cultivars for your area, ask your local Cooperative Extension Service or a knowledgeable professional grower. Or get your name on the mailing list for nursery and seed catalogues that describe disease-resistant cultivars.

  • Spray plants susceptible to foliage fungus with wilt-proofing solution before disease strikes. This product is a pine oil modified to spread into a film coating that protects evergreen foliage from drying out during winter. An unexpected side effect of the film is that it keeps fungus spores from penetrating into susceptible leaves.

    Mix according to label directions and try it on phlox, bee balm, cucumbers, watermelons, tomatoes, and apples. Do not, however, spray plants with hairy leaves.

  • Experiment with baking soda sprays to prevent fungus diseases. Mix 2 teaspoons baking soda in 2 quarts of water with 1/2 teaspoon corn oil. Shake well, put in a sprayer, and go to work. Spray susceptible plants often and always after rain to help keep diseases such as powdery mildew from getting started.

  • Thin stems on disease-prone plants to improve air circulation. Mildew-susceptible phlox and bee balm, for instance, can grow into clumps so thick that they block air flow. This encourages fungus attack, but it is easily corrected. When new growth is coming up in the spring, cut out every third stem, targeting those that are weak or in areas of the thickest growth.

Pests can also be detrimental to plants. Find tips on how to prevent garden pests on the next page.

Some Disease-Resistant Cultivars
These plants have been proven to be resistant to disease:
  • Roses: 'The Fairy,' 'Red Fairy,' rugosa roses, 'Carefree Delight,' David Austin English Roses, Town and Country Roses, Meidiland roses

  • Zinnias: 'Star Gold,' 'Star Orange,' 'Star White,' 'Crystal White,' 'Cherry Pinwheel,' 'Salmon Pinwheel,' 'Rose Pinwheel,' 'Orange Pinwheel'

  • Cucumbers: 'Park's All-Season Burpless Hybrid,' 'Fancipack,' 'Homemade Pickles,' 'Tasty King,' 'Sweet Success,' 'Salad Bush'
  • Peas: 'Super Sugar Snap,' 'Sugar Pop,' 'Maestro,' 'Green Arrow'

  • Beans: 'Florence,' 'Buttercrisp,' 'Jade'

  • Tomatoes: 'Celebrity,' 'Better Boy,' 'LaRossa,' 'Enchantment,' 'Sunmaster,' 'Mountain Delight,' 'Big Beef,' 'Beefmaster,' 'Sweet Million,' 'Viva Italia,' 'Roma'
  • Apples: 'Liberty,' 'Jonafree,' 'MacFree,' 'Freedom'

  • Strawberries: 'Surecrop,' 'Cavendish,' 'Redchief,' 'Allstar,' 'Guardian,' 'Scott,' 'Lateglow,' 'Delite'

Want more gardening tips? Try:

  • Gardening Tips: Learn helpful hints for all of your gardening needs.
  • Annuals: Plant these beauties in your garden.
  • Perennials: Choose great plants that will return year after year.
  • Gardening: Discover how to garden.