Disease Prevention in Home Gardens

Photo from www.thefhd.com

I couldn't get over how quickly the ground had dried from all the rain we got a couple of weeks ago so the rain we had this past weekend seemed like it came at a good time.    The corn and beans already in the ground looks like they grew several inches just in a few short days.   Not to mention the plants in my garden seem to have shot up since last Friday.  Even though my garden looks to be growing at a good pace and appears to be healthy, that warm, wet soil is breeding grounds for fungi and diseases.  So this past Sunday morning and again on Tuesday morning (because of the Monday rain), I applied a fungicide to my home garden as a preventative measure.

Plants in the garden can be attacked and damaged by fungi, bacteria, nematodes and viruses.  Plant diseases can be prevented or controlled in a variety of ways. Rural home gardeners can often use nonchemical methods effectively because they are willing to bear time and labor costs. When chemicals must be used, home gardeners can get by with few chemical applications by spraying only when needed.

The number of chemicals labeled for use in home vegetable gardens is limited compared to the number available to producers of commercial vegetables. Gardeners should rely on preventive practices rather than pesticides to manage diseases. Use fungicides to supplement cultural controls—this will greatly reduce the need for chemicals in the garden.

Fungicides available to home gardeners are protectants by nature and will not cure existing infections or symptoms, therefore prevention is key.  Protectant fungicides should be applied in a preventive manner to plant parts ideally before pathogens arrive (or no later than development of first symptoms). This is very different from the approach taken with most insecticides. Don’t wait until severe damage has occurred before deciding to use a fungicide. The majority of plant diseases tend to develop quickly under favorable environmental conditions, and delaying applications of fungicides in these situations usually has little effect on the disease. Because fungicides are subject to weathering, they must be reapplied at regular intervals when disease organisms are active to keep plants adequately protected.

Growers using certified organic gardening practices can only use certain brands of sulfer or fixed copper, and they should be used very sparingly. Other organically approved fungicides exist though they may be difficult for the home gardener to find or are only available via mail order. Some of these organic fungicides include naturally occurring soil fungi that are antagonistic to disease causing pathogenic fungi, and when applied can kill or out compete the pathogenic fungi. Other organic fungicide products include potassium bicarbonate (baking soda), which may have a strong preventative effect against powdery mildew disease.

Non-restricted use fungicides for the home garden can be found in most any outdoor/gardening section at retail stores (ie Ace Hardware, Lowe’s, Wal-Mart, etc).  Chemicals should be applied only in the prescribed manner as recommended by the manufacturer. Read the label carefully and follow directions. Note the number of days required between the last fungicide application and harvest date. The days waiting may vary among crops. Recent changes in pesticide registrations have significantly reduced the number of chemicals labeled for use in home vegetable gardens. The user must accept responsibility for safe and legal pesticide use.

A complete list of fungicides for use in the home garden can be found at http://www2.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-GEN-07.pdf.

For more information on home vegetable gardening, contact the McLean County Cooperative Extension Service at (270)273-3690.  Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability or national origin.