Although diseases can appear despite your best efforts, if you're familiar with their symptoms and the controls that can be used against them, you'll have a better chance of stopping them before they can become a problem.

While good gardening practices will fend off many diseases, you can't always prevent a disease from attacking a prized plant. To help keep plant problems under control, try taking the following steps:

• Transplant Carefully - This minimizes root damage. When broken, roots are susceptible to certain soil born diseases.
  
  
• Keep Plants Healthy - Give them the water, light and fertilizer they need to flourish.
  
  
• Keep the Garden Clean - Do a thorough fall cleanup each year. Remove weeds, since pathogens may over-winter on them. Strip off any diseased leaves remaining on plants and rake up and discard all diseased leaves on the ground. You may also want to rake up other garden debris, though, if not diseased, it can serve as good mulch. Leaving some of the old non-diseased debris can also act as a shelter from ground-dwelling pests.
  
  
• Buy Disease-Resistant Plants - Vegetable seed packets are labeled to indicate the particular plant's disease resistance. Plant tags on fruit trees or ornamental trees and shrubs also contain this information.
  
  
• Take Care Not To Injure Plants - An open wound on a plant stem or tree trunk readily admits bacteria and fungi.
  
  
• Avoid Wet Weather Garden Work - You may unwittingly spread water-born pathogens as you move about from one spot to the next.
  
  
• Remove Diseased Plants - If certain plants are constantly afflicted by disease, eliminate them from the garden and replace them with less troublesome choices. This solution is simpler than trying to control the disease, and it removes the source of further infection.
  
  
• Install A Drip Irrigation System - Minimize the splashing water that can spread water-born pathogens.

Fungi, bacteria and viruses are the pathogens most often responsible for plant diseases. Unlike green plants, these organisms are incapable of manufacturing their own food and must instead take it from a host plant. Fungi can live in the soil, but the bacteria and viruses that cause plant problems cannot survive outside of their host.

Fungi multiply by tiny reproductive bodies called spores, which they produce in great quantity. Spores of some fungi enter plants through the roots; others land on leaves, where they attach and complete their life cycle.

Bacteria need water and warmth to multiply, so the diseases they cause tend to be more prevalent in warm, wet climates. These single-celled organisms enter plants through wounds and cuts.

Viruses are even smaller than bacteria; they can reproduce only within the actual cells of the host organism. Some viruses are transmitted by insects such as aphids, leafhoppers and thrips; others are carried by infected seeds and pollen. Viruses also enter plants through wounds and cuts.

There are both chemical and non-chemical controls for solving disease problems. It should be noted that fungicides should be used only as a last resort, when all other control tactics have been exhausted. Many of these products are highly toxic, rating a signal word of "danger" or "warning."

The following are some of the most common diseases you'll be faced with along with some information on the plants they attack and some remedies - both chemical and non-chemical:

• Bacterial Wilt - A common disease of cucumbers, bacterial wilt also afflicts muskmelons, squash and pumpkins. Most troublesome east of the Rockies, it is prevalent during moist weather. Cucumber beetles feeding on foliage usually spread it. Symptoms include rapid wilting of plants and death of young seedlings. Check for the disease by cutting a stem near the base and squeezing it; if present, bacteria will ooze out in a sticky mass. Try using floating covers to keep beetles off plants or spray with pyrethrin.
  
  
• Gummosis and Cankers - These are both terms used to describe various bacterial or fungal diseases that cause oozing, sunken lesions on trunks or limbs of afflicted trees and shrubs. The problem is most commonly seen on fruit trees, and often gets its start when the disease organism enters through a wound or borer entry hole. To prevent this problem, avoid over watering and take care not to injure plants. Protect young trees from sunscald by wrapping the trunks loosely in burlap. If the plant is generally healthy, it will usually seal off the cankers. If the canker appears on a small limb, prune it out well below the canker; disinfect tools between cuts.
  
  
• Powdery Mildew - This fungal disease attacks a wide variety of plants, including all sorts of beans, clematis, dahlia, grape, rose, strawberry, tomato, and zinnia, and trees such as apple, maple, oak, peach, and sycamore. It is favored by moist air, shade, and poor air circulation, but needs dry leaves to become established. The first symptoms are small gray or white circles on leaves, stems and flowers; then entire leaves or blooms become powdery white and distorted. Some plants remain vigorous despite the infection, but others decline or fail to set fruit. Some flowering plants can become so disfigured that they must be removed from the garden. To prevent powdery mildew, plant resistant varieties and routinely spray plants with jets of water to wash off fungus spores. Increase sunlight to plants by avoiding overcrowding. In the fall, discard infected flowers, fruits, and plants. Sulfur may help; on roses and other flowering plants, try a baking soda and summer oil spray. Some gardeners report success with the anti-transpirant sprays sold to protect tender plants from cold. Such sprays keep the surface temperature of treated leaves somewhat higher than that of the surrounding air; apparently, they also prevent mildew spores from attaching to foliage.

Hopefully the above information will help you to maintain a beautiful and healthy garden. When disease is handled quickly and properly, you can keep your garden at its best with just regular care. A garden can add joy and therapy to your life, and a healthy garden leads to a happy gardener.