Many home owners derive a great deal of satisfaction from growing their own fruit. This endeavor, however, is not as simple as one might hope. There are many insect and disease organisms, and pruning and cultural management functions that must be considered in both planning and maintaining a home orchard. Many problems can be avoided before planting fruits. It is important to consider site selection, soil fertility, size and type of plants, and especially varieties of fruits, since they all relate to pest control. Many aspects of pest control can be facilitated by the use of dwarf or semi-dwarf trees, insect and disease resistant cultivars, and by purchasing plants certified to be disease-free. Additional information on planting fruits can be obtained from the Rhode Island Cooperative Extension Service.

Introduction to Pesticides & Application
Apples
Pears
Stone Fruit
Blueberries
Strawberries
Brambles
Grapes
Insect Trap Suppliers
Insecticides
Fungicides

 

Pesticides:

Fruits can be attacked by many insect and disease organisms that often require either insecticides or fungicides for control. These chemicals can be purchased separately or mixed together as a multipurpose fruit spray. A multipurpose fruit spray usually contains three pesticides: Methoxychlor for chewing insect control, Malathion for sucking insect control and Captan for disease control. The main problem with a multipurpose fruit spray mix is that you may need a fungicide or an insecticide at various times during the growing season, but not both. This is especially true during bloom when you may not apply an insecticide but a fungicide may be necessary. Insecticides cannot be applied during bloom because bees are pollinating the flowers.

As a result, you may want to purchase chemicals separately, since you may not always need a fungicide when an insecticide is needed and vice versa. Most of the insecticide recommendations are based on phosmet (Imidan). The fungicides available to home owners include Captan, Benlate, sulfur, fixed copper and Bordeaux mixture. See notes on pesticides at the end of this bulletin.

To insure pesticides will work for you over the years, it is important to prevent pests (insects and diseases) from becoming resistant to chemicals. Pests develop resistance to chemicals most rapidly when they are constantly exposed to the chemical. For this reason, use pesticides only when necessary and at labeled rates. Benlate is especially prone to resistance development, so you should use Captan, Sulfur, fixed coppers or Bordeaux mixture whenever possible.

Pesticide Application:

Pesticides are poisonous, therefore, applicators should be aware of any hazards associated with pesticides they are applying. Take appropriate steps to minimize exposure to yourself, neighbors, and the environment. Although chemicals listed in this guide are relatively low in toxicity to humans and warm blooded animals, safety measures should be followed carefully. Keep pesticides in a locked cabinet, away from children and pets. THE LABEL MUST BE READ IN ITS ENTIRETY BEFORE SPRAYING! Particular attention should be paid to the antidote/treatment in case of an accidental poisoning. Pesticide applicators should avoid breathing mist or allowing mist to contact skin. If the label instructs you to do so, wear protective clothing.

Purchase wettable powder formulations where possible, especially if pesticides will be stored in an unheated garage during the winter. Do not store pesticides at high temperatures (more than 86 degrees F) or allow liquid formulations to freeze. Optimum storage temperatures are between 65 and 80 degrees F.

Pest Management:

Before spraying, learn the pests that may be present at various times during the development of the fruit. It is also helpful to learn insect and disease life cycles so you can time your applications for optimum control. Identify damage to your fruit at harvest and learn when to control the problem in subsequent years. You can tolerate more damage to leaves by aphids, leafminers, mites and leafhoppers than direct damage to the fruit. This is a general guide for pest control for apples, pears, peaches, plums, cherries, apricots, blueberries, strawberries, brambles and grapes. Your fruit may have additional problems that need attention. To aid in identification of insect and disease problems, contact the University of Rhode Island's Plant Protection Clinic. For a small fee, an insect or disease problem will be identified, and a control recommendation given. The address is: Plant Protection Clinic, Greenhouse Conservatory, Cooperative Extension Education Center, Kingston, RI 02881.

APPLES:

The first step in apple pest management is to plant trees that are resistant to apple scab. This will eliminate the need to apply up to eight fungicide treatments during the growing season. There are many disease resistant cultivars available, such as Liberty, Freedom, Macfree, etc. (see below for suppliers). Using disease resistant trees, a dormant oil spray and sticky red spheres to catch apple maggot flies, you can limit your pesticide sprays to two or three applications per season. To control summer diseases (sooty blotch and fly speck) you need to apply Captan or Captan/Benlate starting in early June and continue every two to three weeks until mid-August.

DISEASE-RESISTANT APPLE PROGRAM

Red sticky spheres can control apple maggot flies without the use of pesticides. Spheres should be placed within the canopy between 4-6 feet high. Use 1-8 traps per tree, depending on tree size (1 per dwarf tree, 2-4 per semi-dwarf or 4-8 per full size standard tree). Ideally, set out one trap for every 150 apples (see end of bulletin for insect trap suppliers).

If the use of red sticky spheres for control is impractical because of size or number of trees, the red sticky spheres can still be used to monitor apple maggot fly activity for proper timing of an insecticide application. One or two spheres per home orchard can be used to determine presence of apple maggot flies. When 1-2 flies per trap are captured, a half-rate spray of phosmet has been shown to control apple maggot flies.

Disease Resistant Apple Trees:
Liberty, Redfree, Nova-Easyro, Macfree and Jonafree are all resistant to both apple scab and cedar apple rust. Make certain the cultivar you choose is resistant to both diseases, since we have both in Rhode Island.

Disease Resistant Apple Tree Suppliers:
1. Hilltop Nurseries Inc., Hartford, MI 49057 616-621-3135 1-800-253-2911 or 1-800-632-2951

2. Stark Brothers Nursery, Box B248CA, Louisiana, MO 63353 1-800-435-8733

3. Kelly Brothers, Dansville, NY 14337

4. Raintree Nursery, 391 Butts Rd., Morton, WA 98356 360-496-6400

5. Miller Nurseries, West Lake Road, Canandaigua, NY 14424 1-800-836-9030

6. Cummins Nursery, 18 Glass Factory Bay Rd., Geneva, NY 14456 315-789-7083

7. Rocky Meadow Orchard and Nursery, 360 Rocky Meadow Rd. NW, New Salisbury, IN 47161 812-347-2213

DISEASE-SUSCEPTIBLE APPLES
Disease susceptible apple trees require the same insect control as disease resistant trees. They also require use of a fungicide to protect against apple scab. Captan or Captan/Benlate should be applied as soon as green tissue is showing in April, and should be applied every 7-10 days until the beginning of June. Continue with Captan or Captan/Benlate every two to three weeks until mid-August or early Sept. (depending upon cultivar harvest date) to protect against summer diseases.

CAUTION - DO NOT MIX OIL AND CAPTAN, AS SERIOUS FOLIAGE INJURY CAN RESULT. DO NOT USE CAPTAN WITHIN 7 DAYS OF AN OIL SPRAY.

As with disease resistant trees, an insecticide may be needed at petal fall and again 10-14 days later. Begin apple maggot fly control at the end of June with red sticky spheres, or with half-rate phosmet applications. Two or more sprays may be required for apple maggot flies depending upon your cultivars and insect pressure.

PEARS:

Pears are relatively pest free compared to apples. Pears may require a dormant oil application for pear psylla, an insecticide application (phosmet) for plum curculio, and usually no fungicides for the entire season. Pear psylla is the biggest insect problem because it is resistant to most insecticides. Apply a dormant oil in early April just as the flower buds begin to swell. Spray oil again 7-10 days later. Apply an insecticide at petal fall if plum curculio is a problem. Pears will occasionally have disease problems, but protectant fungicide applications are not warranted unless you know you have susceptible varieties, or are in an area with heavy disease pressure.

PEAR PROGRAM

STONE FRUITS:

The stone fruits may be difficult for the home orchardist to grow because of a disease called brown rot, which affects the fruits. Brown rot attacks all stone fruits (see GreenShare Factsheet on brown rot for more information on this disease).There are no disease resistant varieties available at this time. To aid in the control of brown rot, remove and destroy all diseased and mummified fruits after harvest and mulch in early spring with 3-4 inches of sawdust or other good mulching material. Blighted twigs and cankers should also be pruned out. This will eliminate much of the disease inoculum.

The first fungicide spray for brown rot control should be applied just before bloom when many of the pistil tips (stigmas) extend above the buds. The number of sprays required during bloom varies from year to year. Spray a fungicide every 4-5 days if damp, cool weather persists through bloom. Plan on a total of three fungicide treatments, just before bloom or early bloom, mid-bloom, and late bloom.

Black knot is another fungus of plums and cherries. It affects twigs, branches and fruit spurs. Prune out and destroy all diseased wood during late winter. Make cuts 6-8 inches below any visible black knot swellings. Apply Captan in the spring just before the buds open to control black knot or, plant resistant cultivars. Of the European varieties, Damson, Lombard, Shropshire and Stanley are very susceptible. Bluefre is also susceptible. Bradshaw, Early Italian, Fellenburg, Methley and Milton are moderately susceptible. President is a resistant variety. Japanese varieties are generally less susceptible than most American varieties.

There are many insects that also attack stone fruits. Apply phosmet at petal fall and again 10 days later.

STONE FRUIT PROGRAM

BLUEBERRIES:

Blueberries are perhaps the easiest fruit for homeowners to grow. Blueberries generally require no insecticides or fungicides. The blueberry maggot fly may need to be controlled with sphere traps (see section on use of sphere traps for control of apple maggot flies). One red or green sticky sphere baited with ammonium acetate or ammonium carbonate placed within the canopy of each bush will capture flies. Ammonium baited yellow sticky cards placed in a øVÓ orientation over the canopy will also capture many flies. One other problem with blueberries is that birds love them too. To keep birds away place a net over the plants prior to the berries turning blue. During years of high gypsy moth populations, an insecticide containing Bacillus thuringiensis may be needed at petal fall.

STRAWBERRIES:

When growing strawberries many problems can be avoided before planting. Choose a site which was not recently planted in turf and has well drained soil. Turf harbors many root grubs and root weevils that may be troublesome to strawberries. Choose varieties that are resistant to root diseases (verticillium, black root rot, and red stele), and buy plants that are certified virus free. Renovate strawberry beds yearly. In the fall, mow plants to 2-3 inches and rototill between rows. Remove mowings and dispose of all old debris to remove disease spores (do not compost). Avoid applying too much nitrogen to strawberry plants. Apply fertilizers after harvest.

Gray mold is a common disease that becomes visible on maturing fruit. Many homeowners plant a few extra strawberries, figuring that if some get grey mold, they will still have plenty of fruit. Using this strategy, no fungicide applications are required. If you do not mind spraying fungicides, grey mold can be controlled by applying Benlate during bloom. If cool, rainy weather persists to prolong bloom, plan on three fungicide treatments, early-, mid-, and late-bloom.

Some strawberry growers may need to apply one insecticide pre-bloom against tarnished plant bugs, which feed on strawberry buds and blossoms causing damage that results in small, deformed, seedy berries. If you have had significant tarnished plant bug injury in the past, apply one spray of malathion just before the flower buds open.

STRAWBERRY PROGRAM

Strawberry Cultivars Resistant to Red Stele:
Darrow, Delite, Earliglow, Guardian, Midway, Pathfinder, Redchief, Redglow, Sparkle (Paymaster), Stelemaster, Sunrise, Lester, Scott and Surecrop are resistant varieties. Not all of these cultivars are resistant in all infested soils due to different strains of the fungus.

BRAMBLES (Raspberries, Blackberries, etc.):

Brambles are an excellent choice for the home grower because pesticide treatments are generally not needed. The best prevention against diseases and insect pests is a clean berry patch. Start with healthy certified stock from dependable nurseries. Keep the canes thinned out to maximize light penetration for photosynthesis, and air circulation for disease control. Canes should be thinned to about 6-8 inches apart. All old canes should be removed as soon as they finish bearing, and the prunings should be destroyed (do not compost).

Brambles are shallow-rooted and thus poor competitors for water and nutrients, making a mulch desirable. Straw or sawdust maintained at a depth of 4-6 inches will retain moisture and suppress weed growth. Weed control also improves aeration and reduces disease occurrence. Avoid applying too much nitrogen.

Brambles are also susceptible to gray mold. One or two fungicide applications may be needed to control this disease. If it is a particularly wet bloom, three fungicide treatments may be needed. As with strawberries, no fungicide treatments are needed if you plant a few extra plants so you can tolerate some fruit with grey mold.

BRAMBLE PROGRAM

GRAPES:

Growing grapes may be difficult due to several grape diseases. If the growing site is located in a wet area with poor air circulation, grape diseases can be troublesome. If on the other hand, the vines receive good aeration, fungicide sprays may be reduced to two (or fewer) per season depending upon the cultivar. To encourage good air circulation, plant rows parallel to prevailing winds, remove all weeds from around the vines, and keep vines well pruned. There is also evidence that removing one leaf above and below the fruit cluster can greatly reduce disease pressure. Planting varieties that are less susceptible to grape diseases will also help manage grape pests. Cascade, Dechaunac, Delaware and Ives are grape varieties that are only slightly susceptible to black rot and botrytis bunch rot.

Sanitation is an important part of grape disease and insect management. Remove and destroy all diseased clusters from vines at the end of the season. Prune out old or diseased wood on the vines and rake all prunings and leaves from beneath the trellis and destroy the material. Continue to prune out diseased or injured fruit and foliage during the growing season. Mulching or cultivating beneath the trellis will cover or destroy any mummified berries lying on the ground. These berries provide the black rot disease inoculum for spring infections. Powdery mildew may develop during some seasons but it is not necessary to apply preventative fungicides. If leaves become covered with the white powdery fungus, a sulfur spray may be applied. Do not apply sulfur to Concord or other sulfur-sensitive varieties.

Several insects attack grapes, but many of these can be removed by hand during the growing season. Grape tomato galls can be removed and destroyed when they are first noticed (mid-June). Berries infested with grape berry moths can be pruned out and destroyed when the grapes are forming. Another pest, grape phylloxera is an aphid-like insect that forms galls on leaves and causes new leaves to curl. Remove and destroy leaves infested with grape phylloxera. Japanese beetles and rose chafers can also be removed by hand if especially numerous. Grapes can tolerate a great deal of Japanese beetle leaf feeding with no damage to grape cluster quality.

GRAPE PROGRAM

Insect Trap Suppliers:

1. Gempler's IPM Buyer's Guide, 100 Countryside Dr., P.O. Box 270, Belleville, WI 53508
1-800-382-8473

2. Great Lakes IPM, 10220 Church RD NE, Vestaburg, MI
517-268-5693

3. Ladd Research Industries, Inc., PO Box 1005, Burlington, VT 05402
802-658-4961

4. Gardens Alive, 5100 Schenley Place, Lawrenceburg, IN 47025
812-537-8650

The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by the University of Rhode Island Cooperative Extension Service is implied. The authors have assembled the most reliable information available to them at the time of publication. Due to constantly changing laws and regulations, the University of Rhode Island can assume no liability for the recommendations.

Insecticides:

Horticultural (Superior) Spray Oil

APPLICATION/USE: Horticultural oils are used as dormant sprays to control scale insects, aphid and spider mite eggs.

Malathion

APPLICATION/USE: For control of many insects including aphids, spider mites, scale insects, house flies, and mosquitoes. Malathion will also control a large number of other sucking and chewing insects attacking fruits, vegetables, ornamentals, and stored products.

HANDLING AND STORAGE CAUTIONS: Harmful by swallowing, inhalation, or skin contact. Avoid breathing spray mist. Avoid contact with skin. Wash thoroughly after handling. Change contaminated clothing. Biological activity of malathion remains practically unvaried for 2 years in undamaged original containers in cool storage. Recommended storage temperature 77-86 degrees F.

Methoxychlor

APPLICATION/USE: Widely used because of long residual action against many species of insects and low toxicity to humans and warm-blooded animals. HANDLING AND STORAGE CAUTIONS: Store in a cool, dry place.

Imidan (phosmet)

APPLICATION/USE: Effective against a wide range of insects. Incompatible with Bordeaux mixture and lime, but compatible with most other pesticides. May cause severe leaf injury to sweet cherries. High bee poisoning hazard.

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Fungicides:

Captan

APPLICATION/USE: Controls scab, black rot, botrytis, sooty blotch, fly speck, summer rots on apples. Brown rot, leaf spots on stone fruits. Dead arm, downy mildew, black rot on grapes. Controls wide variety of fungus diseases on small fruits, berries, ornamentals, vegetables. Compatible with most insecticides but cannot be used with oil sprays. Captan has been listed by EPA as a probable human carcinogen. HANDLING AND STORAGE CAUTIONS: Avoid contact with skin or clothing. Wash hands and face thoroughly with soap and water after use and before eating or smoking. Store in a cool, dry place. Persons entering a treated area within four days following application must wear protective clothing.

Benlate (benomyl)

APPLICATION/USE: Controls a wide range of diseases of fruit. HANDLING AND STORAGE CAUTIONS: Do not contaminate water, food, or feeds by storage or disposal. Keep benlate dry during storage to avoid certain chemical changes affecting fungicidal effectiveness. Keep container tightly closed when not in use. Benlate is toxic to beneficial predatory mites, therefore, use only when alternatives are not available. Fungicide resistance to benlate has been noted where it has been used extensively. Benlate has been listed by EPA as a possible human carcinogen.

THE FOLLOWING FUNGICIDES ARE PHYTOTOXIC UNDER CERTAIN CONDITIONS.

Bordeaux Mixture (hydrated lime + copper sulfate)

APPLICATION/USE: Primarily a fungicide, acts as a repellent against many insects. Bordeaux mixture has a long residual action and has been used for control of many fruit diseases, including black rot, downy mildew, and powdery mildew of grapes. However, it has problems with causing plant injury and due to the lime (high pH), it is not compatible with many other pesticides. Bordeaux mixture is generally unsafe to use on fruit crops after the 1/4 inch green stage (New York State Pesticide Recommendations 1988). Bordeaux mixture is prepared according to a three part formula (e. g. 2-6-100). The first number is pounds of copper sulfate (not fixed copper), the second number is pounds of hydrated lime, and the third number is gallons of water. Bordeaux mixture is generally regarded as safe as far as mammalian toxicity is concerned.

Fixed Copper (copper hydroxide, copper oxychloride sulfate, copper tetra calcium oxychloride and tri-basic copper sulfate)

APPLICATION/USE: These formulations are referred to as "fixed" because the toxic copper ion is relatively insoluble, making them safer than Bordeaux mixture for use on fruit crops. However, the addition of spray (hydrated) lime is still required to obtain the necessary degree of safety for use on many fruit crops, depending on the time of application. Fixed coppers are effective against many diseases but are limited in use to certain sprays on grapes, pears, and sour cherry because of injury to fruit and foliage. In general, the fixed copper compounds are more compatible than Bordeaux mixture with other pesticides. All fixed coppers are generally regarded as safe as far as mammalian toxicity is concerned.

Sulfur

APPLICATION/USE: The most commonly used form of sulfur is the wettable form. Wettable sulfurs are finely divided elemental sulfur particles with a wetting agent added, allowing the sulfur to be mixed with water and remain in suspension. The wettable sulfurs are most readily available as dry wettable powders containing 95% sulfur or as fused bentonite sulfur containing 30% or 81% sulfur depending on the brand. Flowable sulfur products are also available. They have the advantages over wettable sulfur of being effective at slightly lower rates, and having better retention on foliage.

Dry wettable sulfur can be used with moderate effectiveness in early season sprays for apple scab control. It may be used up to and including bloom without substantially reducing fruit set. Fruit russeting and reduction in yield may result if used under high temperature conditions which often occur during post-bloom sprays.

Sulfur is very effective against powdery mildew of apple, cherry and grape. Sulfur is used on stone fruits for control of brown rot but has not been as effective as most other brown rot fungicides. It also provides good control of peach scab, but is not effective against Rhizopus rot. All sulfur fungicides are generally regarded as safe as far as mammalian toxicity is concerned.

 

Prepared by Heather H. Faubert, Steven R. Alm, David B. Wallace, Richard A. Casagrande and Lisa Tewksbury. Revised July 21, 2000