Brown Spot

Concerns about health, the environment and the increasing resistance of pests to chemicals have forced people to reconsider practices they once took for granted. The regular preventive application of traditional pesticides is one example. Most people don't realize that, in general, nature takes pretty good care of itself. Healthy plants can usually fend off pest attacks, while predatory insects and birds may keep undesirable insects under control. Thus, the preventive use of pesticides is unnecessary. Also, many insects are beneficial with less than 1 percent of all insects being harmful to plants.

Think before you plant. It takes considerable amounts of pesticides to protect plants weakened by unfavorable growing conditions. Know which plants can tolerate the conditions in your yard and plant them. Concentrate on pest-resistant varieties.

Go easy on water and fertilizer. Over watering and over fertilizing cause excessive growth, making them vulnerable to insects and disease. Encourage healthy growth and maintain the quality of your landscape by applying fertilizer and water only when needed and in moderate amounts.

Mowing grass too short and severely shearing trees and shrubs weakens them, inviting pests. Mow to the proper height and prune selectively. Remember, leaves are necessary to produce food for the plant.

Scout the yard for pests. Inspecting plants for pests helps identify problems early, before they get out of hand. Common plant pests in this area include aphids, mealybugs, scales, whiteflies, thrips, spider mites and caterpillars. Detecting small insects and mites can be difficult; life cycles as short as one week add to the problem.

To detect small pests, strike the leaves of small branches against a sheet of white paper and use a ten-power (10X) magnifying glass. Scales and whitefly larvae attach to the plant. Look for them on branches and the undersides of leaves.

Sooty mold on foliage is a good indicator of infestation by insect pests that pierce the plant and suck sap. These insects often secrete a sugary product known as honeydew. This substance encourages the growth of black fungi which appear as sooty mold.
Ants are another good indicator of the presence of pest insects as they feed on honeydew and care for insects that produce it.

Extensive plant damage with few pests may signal the decline of a pest population. Beneficial insects may already be doing the job for you. These may include lady beetles (commonly called lady bugs), lacewings and parasitic wasps.

Tolerate some insect damage and leaf disease on plants. No one can maintain an insect- and disease-free landscape, and a little damage won't hurt your plants. Remember, to have the "good guys" there must be some "bad guys" as a food source.
Handpicking, pruning or spraying with water are effective controls of some insect pests if you catch the damage early. Many insect problems can be reduced or eliminated by removing a few affected leaves or plant parts.

Protect the beneficial insects in your landscape by avoiding blanket applications of pesticides. Treat for specific pests and only treat the affected plant. Avoid using broad-spectrum pesticides. Remember, broad-spectrum pesticides are not selective; they also kill beneficial insects.

Safer alternatives to traditional, chemical pesticides include insecticidal soaps, horticultural oils and products containing a bacterium called Bacillus thuringiensis.


For more information go to:
A Guide to Environmentally Friendly Landscaping: Florida Yards and Neighborhoods Handbook
Allen Garner, John Stevely, Heidi Smith, Mary Hoppe, Tracy Floyd and Paul Hinchcliff. Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Agriculture Sciences, University of Florida. Publication date: May 2001