Cultural and Mechanical/Physical
Integrated pest management incorporates cultural and mechanical/ physical practices to prevent or delay the development of pest outbreaks. Management tools include, but are not limited to:
- site selection
- resistant/tolerant cultivars
- crop rotation between orchard planting
- clean, certified nursery stock
- orchard sanitation
- elimination of alternative hosts
- encouraging natural enemies
- water management
- nutrient management
Biological control uses beneficial organisms to help suppress pest populations. These biological control agents may be predatory insects, parasites, pathogens or nematodes. Many beneficials occur naturally in the environment; others may be introduced.
Beneficials will not completely eliminate damage by pests. However, once they are established, they can maintain pest populations at lower levels. They can also be effective against indirect pests such as aphids, leafhoppers and mites, but may be 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 in a moist environment.
Follow these practices to conserve and encourage beneficial insects in fruit crops:
- Avoid use of pesticides that are toxic to beneficials in a cropping system. See Table 3–6. Toxicity of Pesticides to Honeybees and Mite/Aphid Predators.
- Encourage a diverse habitat within and/or around the perimeter of the orchard 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 Ontario CropIPM at ontario.ca/cropIPM or OMAFRA Publication 208, Predatory Insects in Fruit Orchards.
Behavioural control uses a pest’s natural behaviour to suppress the population. The most commonly used behavioural control in orchard systems is mating disruption, but also includes use of bait trap/crop or sterile insect release.
Managing insects using mating disruption is very different from using insecticides. Mating disruption products are highly specific, targeting a single or few very closely related insect pests. These products release large quantities of synthetically produced sex pheromone into the orchard, which confuses males and interferes with mate location. They do not kill the target pest, nor will they control immigration of mated females from untreated or poorly managed areas.
For more information on using mating disruption in tree fruit, see OMAFRA Factsheet 03–079, Mating Disruption for Management of Insect Pests. Refer to Chapter 3 of this publication for mating disruption products registered for use on apples in Ontario.
Chemical controls include synthetic, inorganic, botanical and biological pesticides. They kill/inhibit development of target pests and thus limit subsequent pest populations. Plant defence activators (e.g., Regalia Maxx) induce natural plant defences against crop pests, but do not directly impact the plant pathogen itself. Applications of plant defence activators to crops may “activate” the defence response of the plant, thus inhibiting infection.
Chemical controls are important tools for crop protection when used as part of an IPM program. Understand the pest’s life cycle and apply chemicals at the stage when the pest is most vulnerable. Select the appropriate product for the target pests. To control insects and mites, monitor blocks closely. Spray according to action thresholds, degree-day timing (see Degree-Day Modeling below) or at critical stages of crop development. To control disease, apply fungicides prior to disease infection and development. Use factors such as weather conditions, crop stage and disease prediction models (where available) to assist in fungicide spray timing.
Organic and Biopesticide Pest Control Products
All organic pest control products must be registered by the PMRA on the pest and crop on which they are used and meet the requirements of the Canadian Organic Standards and any additional requirements of the local organic certification body.
While organic and biopesticide products are used most widely by organic producers, they can be useful tools for conventional growers as well. Possible advantages include:
- lower potential for pest resistance
- providing a rotational option to help manage resistance development in other conventional products
- shorter re-entry and preharvest intervals
- potentially lower toxicity to non-target organisms
Although many organic and biopesticide products are formulated, packaged and applied in a very similar fashion to conventional pesticides, the active ingredients are different. They have unique, specialized modes of action that make them more susceptible to numerous biological and environmental factors.
Some of the possible challenges associated with using these products are:
- more frequent applications needed to control pests
- slower acting than conventional pesticides
- may provide suppression rather than control of the pest
- more expensive than conventional pesticides
- fewer pests controlled