Publication 360, Fruit Production Recommendations:
Biopesticides and Reduced Risk Products for Insect Control

Publciation 360, Fruit Production Recommendations > Chapter 2, Pest Management > Biopesticides and Reduced Risk Products for Insect Control

Excerpt from Publication 360, Fruit Production Recommendations 2010-11,
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1. Kaolin Clay (Surround WP)
2. Bacillus thuringiensis var. kurstaki (Bioprotec CAF, Bioprotec 3P, Dipel 2X DF, Dipel WP, Foray 48BA)
3. Insecticidal soaps - potassium salts of fatty acids (Opal Insecticidal Soap, Safer's Insecticidal Soap)
4. Spinosad (Entrust 80W, Success 480), Spinetoram (Delegate WG)
5. Cydia pomonella granulosis virus (Virosoft)
6. Spinosad + bait (GF 120)
   • Table 2-8. Characteristics of Biopesticides and Some Reduced Risk Products Registered on Fruit Crops (Disease Controls)
7. Other topics in Pest Management
   • Integrated Pest Management - Monitoring
   • Thresholds
   • Pest Management Tools
   • Reduced Risk Pesticides
   • Using Mating Disruption in Fruit Crops
   • Pest Management for Organic Fruit Growers
   • Pest Resistance to Insecticides, Fungicides, Miticides
   • Resistance Management Strategies
8. Chapter 2 - Pest Management - PDF 240 kb
9. Related Links

Bacillus thuringiensis products are registered on pome fruits, stone fruits, grapes and berry crops for control of various caterpillars, including leafrollers and fruitworms. The active ingredients in these products are proteins produced by the bacteria Bacillus thuringiensis, or Bt. Bt. is commonly found in soil, dead insects, plants and other locations. There are many subspecies, and some have proteins that are toxic to specific groups of insects. The kurstaki subspecies is toxic only to caterpillars, although it is not equally effective against all species of caterpillar. Insects affected by Bt. stop feeding within a few hours and die in 2-5 days.

Bt. products must be consumed by the insect to be effective. Consequently, they must be applied to plants where and when caterpillars are actively feeding. Because some caterpillars feed in cryptic locations, thorough coverage is essential. The active ingredient in Bt. is sensitive to ultraviolet radiation, and efficacy may be reduced after prolonged exposure to sunlight. To maximize the effectiveness of these products, apply in the evening, on cloudy days, and when no rain is forecast for 24-48 hours after application. Evening applications may be particularly important if the target pest feeds predominantly at night. Younger larvae are more susceptible to these products, so applications should be targeted at early instar larvae. Because there is not a long residual activity with these products, repeat applications will often be required to obtain effective control.

For best results using Bt. products, acidify spray tank solution to below pH 7. Do not apply in high volumes of water. For example, use no more than 600 L water/ha for Bioprotec and Foray.

Crop Specific Strategies

Apple - Due to its photosensitivity, Bt. products are often used early in the season prior to petal fall. However, they can be used later in the season to manage obliquebanded leafroller where populations are low.

Grapes - When hatching, larvae must consume egg shell treated with Bt. in order for the product to be effective. Apply Bt. to coincide with grape berry moth egg hatch, earlier than the traditional timing for organophosphate and pyrethroid insecticides.

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Insecticidal soaps - potassium salts of fatty acids (Opal Insecticidal Soap, Safer's Insecticidal Soap)

Opal and Safer's insecticidal soaps are registered for use on a wide variety of fruit crops for control of aphids, scale and other soft-bodied insects and mites.

Soaps work by coating the bodies of soft-bodied insects, smothering them and interfering with their cuticles. They must be sprayed directly onto the target insect and have no effect once the soap deposits have dried. Thoroughly cover all plant parts, including under leaf surfaces, where soft-bodied insects such as aphids are found. Apply these products when drying conditions are slow, in the early morning or evening, or when it is cloudy. Avoid using hard water with insecticidal soaps.
Insecticidal soaps often will not give complete control because it is difficult to cover 100% of the pests present in a crop. They are generally most effective when pest populations are small. Combine the use of insecticidal soaps with other pest management techniques (other chemicals or cultural controls). Repeated application of these products may be necessary; however take care to avoid phytotoxicity when using insecticidal soaps. To avoid damage, do not allow soap to accumulate at the base of fruits.

Do not apply within 3 days of a sulfur product.

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Spinosad (Entrust 80W, Success 480), Spinetoram (Delegate WG)

These products are registered in a number of fruit crops for control of various insect pests. Entrust is OMRI listed, while Success is not. The active ingredients, spinosad (Entrust and Success) and spinetoram (Delegate), are derived from the fermentation of the soil bacterium Saccharopolysora spinosa. They kill susceptible insects by exciting their nervous symptoms, causing death from exhaustion within 1-2 days of ingestion.

Spinosad kills insects primarily by ingestion. Spinosad is partly taken up in leaf tissue, which enhances its effectiveness over time. However, residues on the surface of the leaf are broken down by sunlight. Direct contact with spinosad is toxic to honeybees. Do not use these products when honeybees are actively foraging.

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Spinosad + bait (GF 120)

GF-120 NF Naturalyte Fruit Fly Bait is registered for control or suppression of various maggot pests in cherries, blueberries and apples. It consists of spinosad, the active ingredient in Entrust and Success, plus a feeding attractant that serves as a bait to draw adult flies to the product. Because the bait attracts insects to the spray deposits, only a small amount of insecticide is required. It has low toxicity to mammals and birds, but is toxic to adult flies of various pest species. The product is OMRI listed.

Large droplet sizes optimize the attractiveness and longevity of the bait. Apply this product using an all-terrain vehicle fitted with the appropriate sprayer and nozzle to ensure large droplets. GF-120 has relatively short residual activity in hot, dry conditions. This product loses effectiveness if exposed to rain or overhead irrigation. Re-apply every 7-10 days or after rainfall.

Crop Specific Strategies

Apples - Research conducted in Ontario has shown suppression of apple maggot in organic orchards. However, GF-120 does not provide adequate management of this quarantine pest in orchards where there is zero tolerance for damage. Monitor apple maggot emergence using sticky traps and apply GF-120, at a rate of 1.5 L per 6 L water, after the first fly is caught. To improve efficacy, prune trees to ensure penetration of the product to the cooler shaded, inner canopy where its residual activity may be prolonged. Uniform spray coverage of foliage is not critical.

Blueberries - Begin application when first blueberry maggot flies are trapped, or when berries begin to turn blue (about 2-3 weeks before fruit begins to ripen). Repeat application at least every 7-10 days.

Cherries - Spray as soon as traps indicate flies are present or 2-3 weeks before ripening.

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Cydia pomonella granulosis virus (Virosoft)

Virosoft is a microbial insecticide registered for control of codling moth in apples. The active ingredient is the Cydia pomonella granulovirus, a naturally occurring pathogen which is highly specific to codling moth larvae. When caterpillars ingest virus particles, the virus invades through the gut wall, attacking and degrading the insect's tissues. The insect eventually stops feeding, becomes discoloured, grows swollen and dies a few days later, essentially liquefying into a mass of virus particles.

Several factors are important when determining how to use this product:

• Larvae must consume the virus for it to be effective.
• Death may take several days.
• The virus is most effective against younger larvae.
• This product is very sensitive to sunlight, so applications should be made late in the day or when it is cloudy.
• Virus particles do not persist long in the environment, so sprays will be effective for only a week or so.

Apply Virosoft when young larvae either are on the surface of the fruit or will encounter the virus before entering the fruit. The best method is to have the virus present on the eggs as they hatch, so that hatching codling moth larvae consume the virus particles as they eat their way out of the egg. If Virosoft is to be the only control, apply the first application at 139 DDC, base 10°C after biofix (first sustained moth catch), followed by subsequent applications to cover the egg hatch period.

This product is most effective when used in conjunction with other materials. For organic growers, Virosoft together with mating disruption may provide acceptable control. Conventional growers may opt to rotate this product with other pesticides for resistance management. One option would be to apply a chemical insecticide at the start of egg hatch (139 DDC, base 10°C after biofix), with the virus serving as the second spray, when more eggs are present to be covered by the virus. Follow this with another rotation of insecticide and virus, or simply with additional applications of the virus.

Another option is to target only the first generation with the virus product. Although some virus-infected larvae will not die immediately, very few of these larvae will actually pupate and emerge as summer generation adults. Using Virosoft for the first generation greatly reduces the size of the summer generation, which can be controlled with other pesticides.

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For more information, see Table 2-8. Characteristics of Biopesticides and Some Reduced Risk Products Registered on Fruit Crops (PDF 50kB)

• Insect/Mite Controls
• Disease Controls