Integrated Pest Management


Integrated Pest Management (IPM) is a systematic decision-making process that supports a balanced approach to managing crop and livestock production systems for the effective, economical and environmentally-sound suppression of pests. IPM is not a stand-alone concept but should be integrated into the production system since many other components of tree fruit production can impact the prevalence of unwanted plants and plant pests and diseases. The successful application of most IPM components is very dependent on the proper management of other production practices.

The elements of IPM include:

  1. planning and managing agricultural production systems to prevent insects, plant diseases and weeds from becoming pests; 

  2. identifying pests, their natural enemies and damage; 

  3. monitoring populations of pests and beneficial organisms, pest damage, and environmental conditions; 

  4. making control decisions based on potential damage, cost of control methods, value of production, impact on other pests, beneficial organisms and the environment; 

  5. using strategies that may include a combination of behavioural, biological, chemical, cultural and mechanical methods to reduce pest populations to acceptable levels; 

  6. evaluating the effects and efficacy of management decisions.

The IPM concept has evolved to reduce reliance on chemical pesticides by including alternative non-chemical methods and biological products in control programs. Adoption of IPM reduces risks to environmental and human health, reduces risk of pesticide resistance shortening the useful life of selective control products, improves opportunity for biological control and in most cases reduces crop protection costs.

IPM requires knowledge of how to identify pests and assess their damage, how to identify natural control agents, and how to select effective control methods that minimize undesirable side effects. Selection of controls for individual pests must be made with the entire orchard management system in mind. Many cultural control methods are carried out as part of normal crop production operations.

Identification of Damage, Pests, and Natural Enemies

The first step in applying IPM is to correctly identify pest damage or a specimen that might be a pest or a natural control agent (natural enemy). The Diseases and Insects & Mites chapters provide descriptions of individual pests and diseases including symptoms of disease and pest injury and the life cycle of pests and natural enemies. Each description also includes pictures to aid in identifying pests/diseases and/or their damage. The Weed Control chapter lists information sources for weed identification. 

Assistance is also available from packinghouse field staff and pest/crop management consultants.

Monitoring

Monitoring is an essential component of all IPM programs. Sampling /detection methods are used to estimate abundance and distribution of pests, their damage symptoms and natural enemies. The information is needed to help decide if and when control action is required. For example, sex pheromone-baited traps are used to monitor the prevalence of codling moth, leafrollers and eyespotted bud moth, fruit spurs and leaves are examined for presence and abundance of mites and aphids, and terminals are inspected to determine the prevalence of aphids and leafrollers, and the degree of powdery mildew infection. Pest and disease monitoring can be done by the grower, by an employee or by a hired pest management consultant, as long as it is done regularly and consistently. Monitoring is not only essential for deciding if control is necessary, but is also useful in evaluating the effectiveness of a control treatment or practice.

Monitoring of weather conditions (temperature, rainfall, relative humidity) and leaf wetness provides information that can be used in pest and disease development/infection models to predict the appearance and duration of pest life stages (e.g. codling moth and leafroller egg hatch, emergence of cherry fruit fly) and the risk of infection (e.g. apple scab). Growers’ Supply operates a network of weather stations in the Okanagan Valley that collects weather data used by the Okanagan Tree Fruit Company in its pest and disease development models. 

Techniques are available to monitor most tree fruit pests and diseases. These techniques are designed to be used at a particular time in the life cycle of a pest or disease (such as larval stage or spore release) or in tree development (such as pink bud or petal fall). These techniques also involve the use of specific sampling units (such as number of leaves or trees, one hour) and equipment (thermometer, pheromone trap, beating tray). Failure to follow the instructions as described can result in incorrect information and poor control decisions. 

The presence of damage alone is not a clear indication that treatment should be applied as the pest may be gone or not in a stage susceptible to control. Existing damage to fruit or leaves cannot be reversed, but it can signal the need for intervention to prevent further damage if the pest is still active.

A 10 to 20X hand lens is essential to detect, identify and count insect and mite eggs, mites, aphids and other small insects on trees. 

Beating trays and insect traps are useful for monitoring insect pests and their natural enemies. Beating trays are easily made using white or pale green preshrunk fabric stretched over a 45 cm x 45 cm piece of plywood or wooden or PVC pipe frame, to form a smooth, taut surface. Light coloured insects are easier to spot on darker cloth. A handle can be attached to one side or to the underside. The impact end of the beating stick should be covered by rubber or other soft padding to prevent injury to tree limbs. The beating tray is held under a limb which is then rapped sharply three times (= one limb tap) to dislodge any insects onto the tray for counting. All insects must be removed from the tray before doing the next limb tap. 

Insect traps can collect insect pests either by visual attraction (e.g. yellow cherry fruit fly trap) or by sex pheromone (e.g. codling moth and leafroller pheromone-baited wing or delta traps). Proper placement and maintenance of these traps is essential if they are to be effective.

Most monitoring and sampling equipment is available through local grower supply retailers. 

Monitoring results should be recorded on the Monitoring Record forms at the beginning of this Guide. See the discussion on record keeping below.

Control Decisions

The objective of IPM is not to control 100% of the pests in an orchard. This is neither possible nor desirable. The potential impact of a particular level of pests varies greatly depending on tree vigour and variety, crop value, weather conditions and abundance of natural enemies. For example, codling moth trap captures may reach two moths per trap per week for two consecutive weeks, but little fruit damage may result if weather then becomes too cold and rainy for the young larvae to survive. A block of very vigorous trees with a light crop may be able to tolerate much higher numbers of mites than another block suffering from inadequate nutrition. Severity of apple scab infections will vary according to temperature, moisture conditions and the degree of infection the previous year. Because of these influencing factors, the control action thresholds recommended in this Guide are only guidelines. 

Once the monitoring and other relevant information has been reviewed, the grower can then decide if a pesticide application is needed. The grower must weigh the economic benefit expected from the treatment against the direct and indirect costs of control. To estimate the benefit of control requires a prediction of loss from the pest(s) if no pesticide is applied as well as a prediction of the effectiveness of the spray. Direct costs of pesticide application include purchase and transport of pesticide, application and clean-up time, protective clothing and training and licensing requirements. Indirect costs are difficult to measure and include hazard to the applicator, workers, pollinators and other non-target organisms and risk of pesticide resistance development. 

To help the grower select the most appropriate pesticide for the crop and pest problem, reference tables are provided in Chapters 13 (Pesticides) and 15 (References) on some characteristics of most pesticides recommended in the Guide. These characteristics include toxicity to bees, pre-harvest and re-entry intervals, relative toxicity of pesticides to people and to beneficial insects and mites, product Group Number, and sensitivity to water pH. 

Spray effectiveness varies depending on quality of application equipment and technique, weather conditions during and the following 24 hours, timing with respect to presence of susceptible stage of pest or disease, and the status of pest resistance to the pesticide. Excessive travel speed while spraying is a common reason for poor control.

Record Keeping and Evaluation

A very important but often neglected component of IFP is evaluating the results of pest and crop management programs at the end of the season. Did the management decisions result in the expected outcomes? If not, why? Such evaluation is only possible by keeping accurate records of pest and crop management activities. Growers should record results and observations of pest, damage and beneficial species monitoring, and also record irrigation, fertilizer and pesticide applications. Keep separate records for each block to form a permanent record for future reference. Such information is useful to identify changes in pest and natural enemy prevalence, detect unscheduled loss of water (line leaks), changes in soil nutrient levels, etc.. Use these records to identify weaknesses and plan adjustments in the programs for the next growing season by consulting available technical publications and advisory services. Accurate record keeping is an essential component of IFP and these records may be required as part of any production certification programs developed for the commodity.

For various pest and disease monitoring activities, record the date, block/variety, pest/disease name, number found, sample size or unit, and any observations that could useful when the pest management programs are evaluated.

Record all pesticide and fertilizer application activities performed by you, an employee or consultant. Information to record includes the application date, block ID, tree development stage, pest controlled, product used (trade name) and amount per tank, rate used/ha, spray volume/ha, pre-harvest interval and re-entry interval (as stated on the label), and notes on weather conditions.

IPM Programs

As previously stated, IPM involves the combined use of chemical, biological, cultural and other control methods in association with monitoring procedures to minimize crop losses and undesirable side effects on people and the environment. Although the IPM programs used in tree fruit production differ in the number of control components used, they all involve some form of pest or pest damage monitoring. 
Examples of other pest management programs include:

  1. IPM of orchard mites basically involves application of dormant oil and preservation of predatory mites by avoiding the application of chemicals that are toxic to these beneficial mites. Growers can have their orchards monitored for pest and predatory mite numbers to avoid unexpected outbreaks due to lack of predatory mites. When a miticide application is required to reduce economic populations of plant-feeding mites, only products least toxic to the predatory mites are used. Most pesticides recommended in this Guide are selected to conserve predatory mites.

  2. IPM of leafrollers and bud moth involves some monitoring (egg hatch, larvae, adult flight or feeding damage), application of a least toxic control product as needed in the spring and summer, and proper pruning to ensure effective spray penetration and coverage.

  3. Apple scab IPM involves awareness of inoculum potential (produced from the previous year’s infections), monitoring air temperature and duration of leaf wetness periods to determine if and when sprays are needed. In selecting a scab spray, consideration should be given to the toxicity of the spray to predatory mites and to the risk of resistance development through repeated use. Use of scab resistant apple varieties will greatly reduce the need for scab sprays.

  4. Pear psylla IPM program involves application of dormant oil, preservation of natural enemies through reduced pesticide use or use of least harmful pesticides, and monitoring psylla and natural enemies to assess need for intervention. 

  5. Orchard floor vegetation management should apply a balanced approach to minimizing rodent damage and nutrient and water competition to fruit trees and preserving suitable habitat for some natural enemies of tree fruit pests. Also, destruction of floor vegetation may create a pest problem. For example, flowering plants should not be destroyed from about one week prior to, to one week after full bloom of apple to minimize western flower thrips movement up into the trees and subsequent damage (pansy spot). However this decision must be weighed against any possible effect on honeybees foraging in the trees.

  6. Codling moth area-wide pest management delivered by the OKSIR Program involves the release of sterile codling moths in every hectare of pome fruit orchard in the Okanagan, Shuswap and Similkameen valleys, monitoring codling moth levels using pheromone traps and damage assessments, communicating results to growers and industry advisors, undertaking enforcement actions where codling moth levels exceed acceptable levels, and removing unmanaged host trees.