Bruce A. Barrett
Division of Plant Sciences
Fruit plantings can be a source of beauty as well as fresh produce. However, for the inexperienced grower, they also can be a source of frustration and expense. Nursery catalogs are full of brightly colored advertisements depicting bountiful harvests of unblemished fruit. Harvests like these are possible, but only with careful selection of the fruit cultivar (cultivated variety) and diligent pest management. Weather conditions in Missouri , such as high humidity, abundant rainfall and warm temperatures, increase disease and insect populations. With few exceptions, home fruit plantings require treatment with pesticides to control a variety of serious diseases and insect pests. Pesticides needed and frequency of application depend on the cultivars planted, location of the planting, weather conditions and cultural practices.
Table 1 is subdivided into pome fruits, stone fruits and small fruits. Within each section are listed the major developmental stages of the plants and the associated pests (insects and diseases) frequently occurring during each plant stage. These developmental plant stages are also referred to as “spray periods” when an application of a given pesticide is recommended in order to control a specific pest(s). Effective control of fruit insects and diseases depends on the proper timing of pesticide applications, and these spray periods indicate to the homeowner when certain sprays may be applied.
Not all insects or diseases listed in each plant’s developmental stage, or spray period, will be present in your fruit plantings. We have listed the most commonly encountered fruit insects and diseases in Missouri. For many pests, we have also provided brief descriptions of the damage they cause. The presence of the key symbol in the table indicates the most important sprays that should be applied against key pests or pest complexes.
We have tried to list only the pesticides readily available to the homeowner at most nursery and garden, hardware, and home improvement centers (Table 2). The pesticides are not listed in any particular order of effectiveness, although some products may be more effective against some types of pests than another product. In many cases, one or two pesticides listed in a given spray period will be effective against all the pests listed for that time of the season.
Several commercial fungicide-insecticide combinations are available for the homeowner. These may be more desirable for fruit growers not wanting to make their own combinations of pesticides that are recommended in this publication. Commercial home fruit spray mixtures are convenient to use but may not control all of the insects and diseases found on all fruit crops because each product usually contains only one type of insecticide and fungicide.
Choose a cultivar with care. Consider adaptability to Missouri soils, climate and intended use. Remember, the cultivar planted may often determine the amounts of pesticides needed to produce a crop. For example, Jonathan apples are an eating favorite but must be sprayed to prevent mildew, scab, fire blight and rust diseases. On the other hand, several recently developed disease-resistant varieties have a flavor similar to Jonathan and have the advantage of requiring fewer fungicide sprays. Differences in cultivar susceptibility to diseases exist within each fruit crop. All cultivars must be treated for certain insect pests.
The following MU Extension publications, available online and from your local University of Missouri Extension center, can help you select the best fruit crop varieties for your situation: G6021, Home Fruit Production: Apples; G6026, Disease-Resistant Apple Cultivars; and G6085, Home Fruit Production: Grape Varieties and Culture.
In most situations, apply a fine spray to all parts of the plant until some of the spray liquid runs off. For most brambles, grapes, strawberries and small fruit trees, the conventional pump garden sprayer is adequate. For larger plantings, you may prefer a motorized sprayer.
Whatever type of sprayer you decide to use, rinse it thoroughly and allow it to dry after each use
Many pesticides are corrosive. During a single season, corrosive action can ruin many types of equipment. In addition, pesticide residues remaining in the tank after one spraying may break down or interact with the materials used in the next spraying in ways that can damage plants.
Too often, home fruit growers think that if a small amount will control the pest for one week, then twice that amount will give twice as much control. This is a dangerous assumption and can put both the applicator and the plants in unnecessarily dangerous situations. Recommended rates are based on the amounts needed for control (Table 3).Applications that exceed recommended rates contribute needlessly to environmental contamination without increasing control. Repeated applications at 7-, 10- or 14-day intervals (cover sprays) generally are required to protect growth developed since the last spray, or to replace spray residues that are no longer effective because of weathering and chemical breakdown.
Pesticides are poisonous to people and animals. Handle with care. Read the label. The label is the most important piece of information you will find on both the proper use and the hazards of the material. Follow these precautions with all pesticides used:
- Read the label
Be aware of the toxicity of the material you are using and wear appropriate protective clothing.
- Observe any days-to-harvest or reentry precautions
- Store pesticides only in their original labeled containers
Keep all pesticides and utensils used to measure them in a locked storage area out of reach of children and pets.
- Wear rubber gloves and protective eyewear when measuring chemicals, preparing spray mixtures and applying pesticides
- Accurately measure the amount to be used each time
Guessing can be hazardous and expensive.
- Do not prepare more spray mixture than is required for the job
Do not attempt to store unused mixtures for later use.
- Spray small amounts of excess spray mixture onto the fruit tree(s) being treated
Rinse water from the sprayer away from food plants, water supplies and children’s play areas.
- Do not attempt to reuse any pesticide container
Rinse cans and bottles (add the rinse to the spray tank), and then dispose of them by delivering containers to an approved disposal site.
- Do not buy larger quantities of pesticide than you expect to use in a single season
- If a pesticide concentrate from a bag, can or bottle is spilled on you or others, wash it off immediately
Change clothing if it becomes contaminated.
- Save the bees
Bees are often very sensitive to pesticides. Avoid applying insecticides or miticides during the bloom period when bees may be pollinating flowers.
See MU Extension publication G1917, Personal Protective Equipment for Working With Pesticides, for more information.
This publication contains pesticide recommendations subject to change at any time. Before purchasing any materials, make sure they are still approved for recommended use.
Missouri Poison Center, 800-222-1222
All Missouri Poison Centers are coordinated through SSM Cardinal Glennon Children’s Medical Center in St. Louis. This facility has a 24-hour Poison Help Line staffed by professionals. The expert taking your call will refer you to the closest poison center for treatment.
In case of accidental poisoning involving a pesticide, follow the first-aid directions printed on the label of the container and consult your physician immediately. Additional information concerning treatment and course of action can be obtained from your nearest poison center.