IPM

IPM Basics

Integrated Pest Management, IPM, is the foundation of this guide. The word “Integrated” indicates that several types of management tactics are used against pests, and combined to make them more effective than any one tactic alone. It also means orchard management decisions impact each other, and that pest management decisions must be part of overall orchard management. 

Commonly, people think of pests as insects, but in IPM the word “Pest” has a larger meaning: a pest is any living thing that threatens the crop. Insects are pests, but so are mites, weeds, fungi, bacteria and animals such as deer, rabbits and voles.

The word “Management” implies less than complete control of pests.  Rather, IPM manages their potential risk, and keeps damage at acceptable levels. Instead of total eradication, the IPM approach stresses suppression of pest populations to levels that do not cause economic damage. Pesticide sprays and other pest control tactics suffer diminishing returns - applying more costs more and and comes with negative side-effects, such as environmental pollution. For some insect pests, it may be important to have at least some pests around an orchard to ensure that other insects, natural enemies, or natural biological controls, will be there to suppress subsequent pest infestations. A viable IPM approach attempts to minimize pollution problems, and decrease the risk of pest resistance, while maximizing the economic and environmental sustainability of an orchard.

IPM depends on growers and their pest management advisors understanding pest biology and ecology. That is, knowing when a pest is active and likely to damage a crop, and when it is most susceptible to treatment. An IPM approach combines available management tools in complementary ways to create an overall management plan that is efficient, effective, and sustainable. By using multiple tactics, the chance of successful results goes up, and the chance that a pest will adapt and overcome a management tactic decreases. Cultural practices, such as sanitation and habitat management, are a first line of defense in preventing many types of pest problems. Similarly, if feasible, an orchard can be planted with cultivars that are resistant or at least less attractive to important pests. Increasingly, commercial biological controls are being developed, and may be used as part of an IPM plan. Using forecasting models and employing weather information in pest management decisions has become easier with development of online decision support systems, which give growers a clearer picture of important pest risks at any given point in the growing season.

 

Generally, IPM follows this process:

  • Determine how much, if any, damage may be acceptable - a threshold for damage.
  • Identify pest problems that are most significant from year to year, the key pests.
  • Know when and how to monitor for these pests, and do it.
  • Treat with an appropriate management tactic at an appropriate time.
  • Evaluate results during the season and at harvest.
  • Adjust tactics if needed to improve results.

 

Monitoring. A good IPM program depends on having a careful observer in an orchard throughout the growing season. The word “monitoring”, or sometimes "scouting", in IPM means making regular observations of pest activity, such as the first appearance of an important insect pest, the types of weeds in tree rows, or a daily set of weather observations. Monitoring methods differ for different pests. For insects, specific traps make it much easier to tell whether a pest is reaching a potentially damaging level. For diseases, it’s generally necessary to use weather conditions to determine risk. There are times in the growing season when key pests are most likely to cause problems, as indicated by the Apple Pest Chronology Diagram for Southern New England. However, every year is different, and checking the pest management situation requires regular, even daily, updates. 

 

Basic IPM Tactics


 

Apple IPM Elements

Apple IPM Elements are at a minimum a guide/checklist for you to consider when implementing IPM in your orchard. Rarely, are all Elements achieved nor should they necessarily be. How you practice/implement IPM depends on other factors, but at least you should be considering these Elements and which of them you can effectively adopt. For an alternative, more interactive Apple IPM Elements, visit elements.ipipe.org

Insect management - monitoring

  • Monitoring is done in a systematic manner according to accepted IPM guidelines. Records are kept of all monitoring information collected.
  • Bark of rootstock, trunk and limbs is monitored for San Jose scale, winter moth, woolly apple aphid or borers, where appropriate.
  • Tarnished plant bug is monitored by white visual sticky traps or visual inspection of buds.
  • Leafminers are monitored by foliar inspection for first generation mines.
  • Foliage is sampled for mites and mite predators.
  • Fruit clusters are examined pre-bloom for pug moth and/or winter moth.
  • Fruit is monitored for fresh plum curculio injury following initial cover spray to time additional sprays, if needed.
  • European apple sawfly is monitored by white visual traps.
  • Pheromone traps are used to monitor Oriental fruit moth, codling moth, and oblique banded leafroller, and for determining biofix (first sustained trap catch).
  • Terminal foliage is monitored for aphids and aphid predators.
  • Monitoring for leafhoppers (fruit clusters for white apple LH and rose LH; terminal growth for potato LH) is conducted.
  • Brown marmorated stink bug is monitored with pheromone traps
  • Apple maggot fly is monitored by red sticky spheres that can be either unbaited or baited with an apple-based lure.
  • Fruit and foliage are monitored for codling moth, fruitworm and leafroller larvae or injury, where appropriate.

Insect management - tactics

  • Application of insecticides corresponds to pest threshold ranges specified in state apple IPM publications such as the UVM Quick Guide to Monitoring Arthropod Pests.
  • One application of oil is made in early spring.
  • A second application of late spring oil is applied.
  • A border-row application is used in lieu of one or more whole-orchard sprays against plum curculio (border sprays generally follow a cover spray).
  • Biological control by naturally occurring predators is used for control of aphids.
  • Resistance management is considered when making insecticide applications following all label resistance management guidelines and rotation of insecticides.
  • Summer oil is used in part as a substitute for other miticides used to suppress mites in early season.
  • Biological control by naturally occurring predators is used for control of mites; no miticide is applied.
  • Synthetic pyrethroids are not applied as they are likely to induce outbreaks of mites and woolly aphids.
  • A border-row spray is used in lieu of one or more whole-orchard sprays against apple maggot.
  • Orchard is surrounded by odor-baited red sphere traps at a rate of 1 trap per feet in lieu of pesticide application against apple maggot.
  • All abandoned apple trees within 300 feet of the orchard border are removed to prevent codling moth immigration.
  • Efforts are made to establish the mite predator, T. pyri.
  • Bases of trees on dwarfing rootstocks are kept clean (free of weeds, debris, etc.) to reduce dogwood borer infestation.

Disease management

 

  • Leaf chopping (flail mowing) is done in fall or early spring to reduce scab inoculum.
  • Urea treatment is applied in fall or early spring to reduce scab inoculum.
  • Trees are pruned annually to remove diseased wood (primarily fire blight and black rot) and apple mummies (rot disease inoculum).
  • A dormant to green tip copper compound application is made to suppress fire blight.
  • First fungicide spray is delayed an appropriate time according to previous year's scab incidence using potential ascospore dose evaluation, and ascospore maturity level in the current season.
  • Unless visible infections develop, fungicides for scab management are applied only until the end of primary scab season, using 100% ascospore maturity and release and sufficient time to allow symptoms from the last infection to be visible.
  • Apple scab infection periods are measured using leaf wetness and temperature.
  • Fungicide treatments for primary apple scab are made according to infection periods, tree growth and estimates of the remaining effectiveness of the previous fungicide application.
  • Resistance management is considered when making fungicide applications, by either tank-mixing two or more modes of action in a single spray, or rotating modes of action such that materials in the same FRAC group are not applied consecutively.
  • Treatments for fire blight follow a fire blight forecast model (e.g. Maryblyt or CougarBlight), or specific Extension or consultant recommendations based on such a model.
  • Fungicide applications exclusively targeting powdery mildew or rusts are not made unless there is a history either disease in the block.
  • Where rust diseases are a problem, alternate hosts (primarily red cedar and juniper) within 300 feet surrounding orchard are removed.
  • Fungicides for sooty blotch/flyspeck are applied based on an accumulated wetting hours and estimated fungicide depletion.
  • Plantings are located so that trees are least 75 feet away from wooded or shrubby borders to reduce pressure from sooty blotch and flyspeck fungi.
  • Orchards are replanted with a minimum three-year gap between tree removal and new tree planting. During the gap, cover-crops selected to suppress nematodes, reduce soil compaction, improve weed suppression, and benefit soil health in general are planted.
  • On sites prone to flooding or with heavy soils, trees are planted on raised berms and/or drainage is installed.
  • Experimental block of disease-resistant trees is planted.

Nutrient management & horticulture

  • Orchard Best Management Practices, such as those for Massachusetts, are followed.
  • A soil test is done at least every 3 years on a per block and variety basis.
  • A complete leaf tissue analysis is done at least every 3 years on a per block and variety basis.
  • Fertilizer and/or soil amendments are applied according to leaf tissue analysis and/or soil test.
  • A written nutrient management plan is in place with nutrient application records.
  • Trees are pruned during dormancy so that spray penetration and air circulation are adequate, and diseased wood and fruit mummies are removed.
  • Pruning debris is removed or destroyed using flail chopping or another method such that no residue is present after one year.
  • Summer pruning is done on densely-foliated, vigorous trees.
  • Orchard plantings include dwarfing rootstocks planted at high density using a training system that will reduce spray volume and improve spray deposition.

Weed management

  • In-row weed control is maintained/supplemented by use wood chips or mechanical cultivation.
  • A weed survey is conducted, recorded, and updated with weed problems noted on orchard block maps.
  • Herbicide rate, selection and spot applications are based on the results of the weed survey.
  • Herbicides are rotated base on mode of action in order to avoid herbicide resistance development.
  • Herbicides are banded only in the crop row and a seeded ground cover is used in the row.
  • Clean herbicide strips are maintained where young trees on dwarf rootstocks susceptible to dogwood borer infestation.
  • Orchard middles are mowed frequently to prevent flowering groundcover, reduce vole/rabbit habitat, and prevent weeds from going to seed.

Wildlife management

  • Fencing is used to exclude deer from the orchard.
  • Mowing is frequent, weeds and grass are not allowed to grow in the tree row, and orchard blocks are not planted close to wild field edges in order to minimize rodent cover and maximize distance to habitat.
  • A monitoring program for voles is conducted to determine the need for rodenticides.
  • Where rodenticides are applied, bait stations, rather than broadcast treatments, are used.
  • Wire mouse guards are used where vole pressure is high and/or other measures are not used to reduce the likelihood of vole damage.

Weather and tree monitoring

  • Orchard has a weather station and data is collected to guide pest management decisions.
  • Orchard uses a Decision Support System to aid in making IPM decisions, such as
  • Bud stages and other critical tree development stages are observed and dates of occurrence recorded.

Pesticide application & records

  • Pesticides with Reduced Risk (RR) or Organophosphate (OP) Alternative rating in the EPA listing are chosen as an alternative to non-RR or OP pesticides.
  • Orchard sprayer, including hoses, nozzles and pumps, is inspected at least once per season and replaced as needed. Equipment is calibrated at the start of the season and the procedure is recorded.
  • Calibration of orchard sprayer is subsequently checked at least once during the growing season and equipment is recalibrated as needed.
  • A written pesticide drift management plan is in place, and/or air-induction nozzles are used to reduce pesticide drift.
  • Herbicide sprayer is calibrated at the start of the season. Procedure is recorded.
  • The grower has calculated tree-row volume for each block and applications conform to tree-row volume calculations (unless rate per acre specified on pesticide label).

Education

  • Orchard owner/manager subscribes to University/Extension fruit program including newsletter and other forms of messaging.
  • Orchard owner/manager attends one or more twilight meetings/workshops during the current year.
  • Orchard owner/manager consults New England Tree Fruit Management Guide when selecting pesticides and for other IPM practices.
  • Orchard contracts/employs/uses professional crop consultant.

Resistance Management

Resistance to pesticides originally drove the development of Integrated Pest Management, and today reducing the risk that insects, pathogens, and weeds will develop resistance to pesticides remains a primary goal of IPM. Modern pesticides generally have much more specific modes of action than older pesticides. A pesticide developed fifty or more years ago often has multiple ways that they can kill a pest, while today pesticides often have a single, specific aspect of pest physiology that they disrupt. Pests are more likely to develop resistance to single-site pesticides than to multi-site pesticides, so in terms of potential to develop resistance, single-site pesticides are considered “high risk” and multi-site pesticides termed “low risk”.  Some key pests, such as the apple scab fungus, have developed resistance to many types of high-risk fungicides. In order to maintain a full set of management options, it’s critical that growers manage pesticides resistance.

There are several ways that IPM addresses resistance, starting with only applying a pesticide when needed. In addition, IPM incorporates non-chemical tactics in addition to pesticides, rather than focusing exclusively or heavily on chemical control. When chemicals are required, a good IPM program recommends tactics for pesticide selection and application that reduce the chances of resistance development.

Tank Mixes. One way to manage resistance with pesticide selection is to apply mixtures of pesticides in a single application. Each pesticide must have a different mode of action, as indicated by different FRAC, IRAC or HRAC codes. Usually, these codes are on the pesticide label, and this guide lists them with pesticides as well. In recent years, companies have developed pesticides that come pre-mixed, with two, or even more, different modes of action. Usually, the mixes are made up of high-risk pesticides. While this is better than applying only one high-risk pesticide, putting a low risk, multi-site pesticide into a tank mix provides more powerful resistance management. Even with a pre-mix, it is worthwhile adding a low-risk partner.

Alternate Pesticide Modes of Action. Another way to manage resistance is to alternate the modes of action used in consecutive applications. This may be done by selecting a high-risk pesticide for one spray, a different high-risk pesticide in the next spray, and returning to the first mode of action for a third application. Even better would be alternating applications of a high-risk pesticide with a low-risk pesticide. Better still, apply a high-risk pesticide, then a low-risk pesticide, then a high-risk pesticide with a different mode of action from the first, then a low-risk pesticide. The more often the mode of action changes, the better it is for resistance management.

Limit the Use of Any Single Mode of Action in a Season. The more often a given mode of action is used, the more likely it is that a pest will develop resistance to it. By using a variety of modes of action in a year, the chances of resistance development go down. Pesticide manufacturers have increasingly put label restrictions on the number of applications per year, the total amount of a material that may be applied in a year, or both. This is to prolong the useful life of their products.

Use the Highest Recommended Rate. At the beginning of the modern drug era, the famous microbiologist Paul Ehrlich recommended that drugs be used to “hit hard and hit fast”. That is, use high rates of drugs as early as possible in the infection to prevent bacteria from becoming resistant to them. The same holds true for pesticides. Use the highest rates on the label to reduce the chances of resistance development in insects, pathogens or weeds.

Treat Early - Avoid Using Pesticides as a “Bail Out”. Similarly, address pest problems as soon as it is clear that a pesticide application is needed. For diseases, using post-infection or eradicant treatments increases the risk of resistance. Treating insects after they have had a chance to build up their populations, or treating more mature weeds, particularly if they go to seed, is also boosting the chances of resistance.

 

The Insecticide Resistance Action Committee (IRAC)

IRAC is dedicated to prolonging the effectiveness of insecticides and acaricides by countering resistance problems. IRAC provides a coordinated industry response to prevent or delay the development of resistance in insect and mite pests. The IRAC Mode of Action (MoA) Classification Scheme is recognized globally as the authoritative reference for defining the MoA of commercial insecticides. This information provides growers, advisors, extension staff, consultants and crop protection professionals with a guide to the selection of acaricides or insecticides for use in an effective and sustainable acaricide or insecticide resistance management (IRM) strategy.

IRAC has just published the latest version of the MoA Classification (https://www.irac-online.org/latest-version-of-the-moa-classification-inc...), now incorporating bio-insecticides.

In addition to presenting the MoA classification, this document outlines the background to, and purposes of, the classification list, and provides guidance on how it is used for Insecticide Resistance Management (IRM) purposes. IRAC has taken the step to systematically integrate non-chemical and biological products with insecticidal activity into the IRAC MoA Classification Scheme. This is one of the most significant updates to the scheme since its creation. Now included are bacterial agents, plant-derived extracts and unrefined plant oils, fungal agents, non-specific mechanical disruptors, peptides, and viral agents.