Aphids are common pests of landscape plants, such as this mandevilla vine. (Photo by Dan Gill, LSU AgCenter)

For Release On 07/24/15

By Dan Gill LSU AgCenter Horticulturist

Wherever you go in America, gardeners will tell you about the terrible pest problems they have to deal with. Still, it seems like we have more than our share of insects, diseases and weeds in Louisiana.

It is important to remember that pesticides are only one method for controlling pests. Gardeners also can use other techniques that can help prevent the severe infestations that make the use of pesticides necessary. Minimizing the use of pesticides, whether they are chemical or organic, is always a good idea.

Make it a point to inspect your landscape frequently for developing problems. Weed control is a prime example where early intervention is far easier and more effective than letting a situation get really bad before taking action.

One of the best defenses against pest problems is to keep your plants in tip-top condition through good culture. A healthy, vigorous plant is usually more resistant to disease and withstands insect attack better, and a healthy lawn resists weeds. Good culture includes giving your plants proper spacing, soil, drainage, water, light and nutrients.

An excellent way to avoid insect and disease problems is through plant selection. Simply do not plant those plants that are known to be prone to insect or disease problems. Instead, choose plants that are adapted to our climate and are naturally resistant to major problems, or choose those that have been bred and selected for insect and disease resistance. If you have plants that constantly seem to have something attacking them despite your best efforts, consider removing them and replacing them with plants you have found to be more care free.

In vegetable gardens and annual flower beds that are replanted every year, crop rotation is important. Planting the same type of plants in the same bed year after year can cause a buildup in the soil of disease organisms that use that plant as a host. Plant different things in your garden in different places every year whenever possible.

Proper sanitation is another important factor in controlling insect and disease problems. Stands of weeds growing near gardens and landscapes can serve as alternate hosts and places of refuge and breeding for pests. Always keep your yard, gardens and adjacent areas as weed-free as possible. Fruit and fallen leaves infected with disease should be collected, bagged and thrown away. Never leave rotten vegetables and leaves on the ground in your vegetable garden.

Some disease organisms live in the soil and are splashed onto plants by rain. Applying mulch to soil under plants can reduce incidence of these types of diseases. This is especially helpful when growing fruit and vegetable crops like tomatoes, squash and strawberries.

Keep dead branches regularly pruned out of fruit trees, shade trees and shrubs. Dead and rotting branches can serve as points of entry and sources of infection.

Mulches are also the best way to save work and reduce the use of herbicides to control weeds in beds. Weeds are certainly a leading garden pest. Weed control, whatever method you use, is always more effective when done regularly and before a weed problem becomes major.

When problems do occur, proper diagnosis is critical to correctly deal with the situation with the appropriate, safe control method. Unfortunately, diagnosing the cause of problems is not always easy for the average gardener.

The symptoms that a particular insect or disease causes are usually distinctive enough to make diagnosis possible by a capable professional. Agents at your local parish LSU AgCenter office are available to help you identify problems and recommend solutions. Many local nurseries and garden centers have individuals on staff who can help you identify the damage and decide on the proper action to take. Books and the Internet are also valuable resources for identifying pest problems.

If pesticides are recommended for control, always request the least-toxic material that will do the job, and ask if something you already have would work. It is helpful if you maintain a list of what you have and have it with you when asking advice.

Read the label of the recommended product completely and thoroughly before you purchase it to make sure it is appropriate for the situation and that you are comfortable using it.

Water from municipal water treatment facilities is often alkaline, and many pesticides break down rapidly when mixed with alkaline water. Whenever possible, adjust the pH to make the water acidic with products available where garden pesticides are sold.

Dealing with pests when necessary will always be a part of taking care of a landscape. But doing everything you can to prevent pest problems before they arise will reduce the time, effort and cost of controlling them.