Publication 360, Fruit Production Recommendations: Pest Management Tools

Excerpt from Publication 360, Fruit Production Recommendations 2010-11,
Order this publication

1. Pest management tools
2. Cultural pest controls
3. Biological control
   • Table 2-4. Examples of Classical Biological Control in Ontario Fruit Crops (PDF 109 kb)
   • Table 2-5. Examples of Augmenting Natural Enemies from Commercial Sources (PDF 117 kb)
4. Control with pesticides
   • Table 2-6. Efficacy Ratings for Pesticides
5. Other topics in Pest Management
   • Integrated Pest Management - Monitoring
   • 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
6. Chapter 2 - Pest Management - PDF 240 kb
7. Related Links

• Choose sites less favourable for pest development. Avoid planting in poorly drained locations.
• Select cultivars less susceptible to disease or insect pressure (see Table 5-23. Strawberry Variety Disease Ratings, and Table 6-5. Relative Susceptibility of Grape Cultivars to Diseases).
• Where possible, rotate to a non-host crop to break the pest cycle. Some insects and many diseases overwinter in crop debris.
  Use plants tested and determined to be free from virus diseases, and grown according to guidelines that minimize the presence of other pests.
• Remove all sources of the pest, such as cull piles and dropped fruit, from the field or orchard.
• Maintain good weed control and eliminate wild hosts from within as well as the perimeter of the planting. Weeds and wild fruit trees, grapevines and brambles often act as alternate hosts for many crop pests.
• Use non-related crops planted in close proximity as a barrier to insects and diseases. Avoid inter-cropping plants with similar pest complexes.
• Modify insect habitat through the introduction of cover crops to promote beneficial organisms.
• Prune and remove infected plant material to reduce pest pressure. Pruning and training plants to improve air movement within the canopy will also improve spray coverage.
• Timely irrigation can reduce plant stress during drought and increase plant tolerance to pests. Schedule irrigation so that plants are not wet overnight.
• Manage nutrients to avoid excessively lush growth, which is more susceptible to some diseases and more attractive to some insect pests.
  

Biological control uses a pest's natural enemies to help suppress pest populations. These biological control agents may be predatory insects, parasites, pathogens or nematodes.

Predatory and parasitic insects are most effective against indirect pests such as aphids, leafhoppers and mites. They are less effective at keeping populations of direct pests, which attack the harvested product, at levels acceptable for commercial production. Important insects and mites for biological control include ground beetles, mullein bugs, minute pirate bugs, lacewings, lady bird beetles and phytoseiid mites.

Natural pathogens of insects and mites include bacteria, viruses, fungi and protozoa. Pathogens circulate naturally in insect populations. Under the right conditions, they can cause disease outbreaks in insects, which can significantly reduce insect populations. Aphids and caterpillars are routinely infected by cycles of viral or fungal disease, which thrive when the environment is moist.

Several approaches to biological control are used in Ontario fruit crops: classical biological control, augmentation of natural enemies from commercial sources, and conservation of existing natural enemies.

Classical biological control is based on importation of natural enemies, in hopes that they will become established in their new environment (Table 2-4. Examples of Classical Biological Control in Ontario Fruit Crops). This method is generally used to manage introduced or exotic pests, which have few natural enemies in their new habitat. Classical biological control is a long term strategy that can take years or decades to become effective. Strict protocols are in place to ensure that introduced species of beneficial insects do not become pests in their new location.

Augmentation involves increasing the populations of natural enemies using periodic releases from commercial sources:

This practice is very successful in greenhouses and controlled environments. Control is less consistent in outdoor settings and is affected by pesticide use, environmental conditions, pest density and the crop. Some species of biological control agents require alternative food sources to prevent starvation when pest populations are low. Product quality and shelf life are important considerations when using biological control agents. For sources of beneficial insects and mites, see Appendix A. Suppliers of Pest Monitoring Equipment and Biological Control Agents, or check Sources of Crop Inputs at www.ontario.ca/crops.

When using biological controls is it important to monitor pest and predator populations to determine the need for reapplication. Choose pesticides carefully as they can have short and long-term negative effects on one or more stages of predatory mites. For detailed information on how to use biological control in fruit crops, contact the product supplier. See Appendix A. Suppliers of Pest Monitoring Equipment and Biological Control Agents.

Conservation involves protecting natural enemy populations. This is achieved mainly by careful choice and timing of pesticides. IPM programs attempt to minimize adverse effects of pesticides on beneficials. For example, avoiding the use of organophosphate insecticides after petal fall will help conserve Pholetesor ornigis, an important parasite of tentiform leafminer in apples. The use of certain fungicides can negatively affect the performance of certain fungal diseases of aphids, beetles, and other pests.

The crop environment and surrounding habitat can affect natural enemy populations. IPM programs also aim to provide habitat for beneficial insects. Border crops and hedgerows provide refuges for natural enemies and flowering plants in these habitats provide nectar for food.

Follow these practices to conserve beneficial insects in fruit crops:

• Avoid use of pesticides that are toxic to the most important beneficials in a cropping system. See Prevent bee poisoning.
• Encourage a diverse habitat around the perimeter of the field where beneficial insects can live. Small flowering plants are an important food source for parasitic wasps.
• Avoid ultra-clean cultivation. Crop residue, mulch or ground cover will encourage ground beetles and other important predators in the soil.
• For additional information on predators and parasitoids, see OMAFRA Publication 208, Predatory Insects in Fruit Orchards.