Pests and Disease  PEST PROBLEMS Insects are a natural visitor to any garden. But not all insects are bad for your plants and flower gardens. In fact, many are beneficial because they eat other insects that can be a problem. However, some bugs are harmful and, if not detected and treated properly, can cause severe damage to your garden. Good gardening practices will deter pest problems before they begin Ensure your soil is healthy by enriching it with homemade compost and other appropriate nutrients. This builds strong plants which are more resistant to most pests. See soil smarts. Avoid planting the same crops in the same location year after year. This is especially important in vegetable gardens. Keep your garden clean and tidy. Insects may start on nearby weeds or dead foliage and then migrate to your healthy plants. Experiment with companion planting by growing certain varieties next to others. Marigolds, for example, actually deter insects. Feed and water your plants regularly as directed (most annuals need weekly fertilizing). Properly nourished plants stay vigorous and are less susceptible to infestation and disease. In spite of good pest prevention, some conditions might prevail that promote insects. Click on any of the following to determine if this pest is your problem. Aphids • Tiny yellow, green, or dark colored soft bodied insects cluster on the leaves,    stems, and flowers. • Leaves are curled, distorted, and yellowing. Flowers are often malformed. • A shiny, sticky substance may coat the leaves. • Aphids are extremely prolific and populations can rapidly build up to damaging    numbers during the growing season. • Ants feed on honeydew, a sweet, sticky substance excreted by these insects.    Picture and remedy Mealy bugs • Oval, white insects up to 1/4 inch long. • Cluster in white cottony masses, on stems and leaves. • Eggs and some adults can survive through the winter in warm climates. • Leaves may be deformed and withered. • Infested leaves are often shiny and sticky. • Begonias and coleus are susceptible to several mealy bug species. • Ants feed on honeydew, a sweet, sticky substance excreted by these insects.    Picture and remedy Scale • Tiny sap sucking insects that look like tiny bumps on plant leaves and stems. • They hide under a shell cover that acts as a shield. • They can kill plants if present in large numbers. • Ants feed on honeydew, a sweet, sticky substance excreted by these insects.    Picture and remedy Thrips • Tiny insects resembling brown or straw colored wood slivers. • Found at the base of petals in a flower bud. • In cold climates thrips feed and reproduce from spring until fall. • They are especially troublesome during prolonged dry spells. • There are often silvery white streaks on the leaves. • Flower buds turn brown and die before they open. • Flowers that have opened are often streaked and distorted.    Picture and remedy White flies • Nymphs are oval, flat insects with short, sucking beaks. • Nymphs are usually found on lower leaf surfaces. • White flies are common to greenhouse vegetables and flowers but in warmer    climates, they attack citrus and many ornamentals as well. • Ants feed on honeydew, a sweet, sticky substance excreted by these insects.    Picture and remedy  PLANT DISEASES If by examining the above list of pests you have not discovered an obvious cause for your plant problem, perhaps you need to consider the possibility of disease. Although there are numerous diseases that can attack your plants, home gardeners are likely to only experience a few of the more common ones. Click on any of the following to determine if this disease is your problem. Botrytis blight • Common to tulips, it's caused by a fungus. • Light to dark colored spots appear on part or all leaves and flowers. • In cool, moist weather a fuzzy brown or grayish mold forms; leaves and stems    distort, and often rot off at the base. • Bulbs have dark, circular, sunken lesions; and dark brown pinhead sized pellets    form on the bulb husks.    Picture and remedy Crown rots • Most severe in overcrowded plantings, above 70 degrees F and moist conditions. • Leaves irises grown from rhizomes die, leaf tips form downward. • The leaf bases and possibly the rhizomes are dry brown, and rotted. • Leaves and stems at soil level are rotted, and bulbs are soft and crumbly.    Picture and remedy Leaf spots • Several disease and environmental factors contribute to spotting and blotching    of leaves. The most common are the fungal and bacterial left spots. • Fungal leaf spots are 1/4 inch yellow, red, tan, gray, brown, or black circular    spots on leaves. • Bacterial leaf spots are usually tiny, angular dark colored and may be    accompanied by rotting and oozing.    Picture and remedy Powdery and downy mildews • Flour like patches on the surface of leaves, buds, young stems and fruits. • They thrive in both humid and dry weather. • The spores are spread by the wind to healthy plants. • They cause leaf yellowing, dwarfing, stunting and deformation. • Common on roses, zinnias, phlox, lilacs, cucurbits, apples and grapes    in shaded, crowded areas.    Picture and remedy  OTHER PROBLEMS If you still can't discover what is wrong with your plants, perhaps you need to examine your methods. Click on any of the following to determine if it is your problem. Iron deficiency • The newest leaves turn pale green or yellow. • In extreme cases, leaves are small and completely white or yellow. • Older leaves may remain green. • Iron deficiency can result from over liming or lime leached from cement or brick. • Often in regions where soil is derived from limestone and in areas with low rainfall.    Picture and remedy Nitrogen deficiency • Older leaves turn yellow. • A continuing shortage of nitrogen results in overall yellowing. • Nitrogen is leached from the soil by excessive moisture and is used up rapidly    by micro-organisms found in organic compounds.    Picture and remedy Transplant shock • Flowers drop their buds before they open. • Blossoms and leaves may drop prematurely. • Wilting may occur during the hot part of the day, even if the soil is moist.    Picture and remedy A collection of the top selling perennial ferns