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Orchard insights: UMN's Summer Field Day discusses GAPs and IPM topics

 Madeline Wimmer, Extension Educator, fruit production & Annalisa Hultberg, Extension Educator, food safety

Earlier this growing season, educators from the University of Minnesota Extension hosted a field day focusing on Good Agricultural Practices (GAPs) and orchard Integrated Pest Management (IPM) at Apple Jack Orchard, located near Delano, MN (Zone 4b). Topics covered included information on food safety, composting, and scouting and pest monitoring in orchards. The following summarizes the key points discussed throughout the day.

Food safety in orchards

Every fruit grower can benefit from using Good Agricultural Practices that reduce the spread of diseases from microbial contaminants such as E. coli, Salmonella and Listeria. These practices include avoiding harvesting apples contaminated with bird feces, cleaning and sanitizing pick bags regularly, placing compost operations at a safe distance away from growing sites, and ensuring that handwashing facilities are available to workers and visitors who may be harvesting fruit.

Composting in an orchard setting

Image: A compost pile at Apple Jack Orchards with a thermometer measuring its internal temperature, which can indicate if the compost is getting hot enough to kill pathogens, but not too hot to slow biological activity.

Apple Jack Orchards currently practices making compost on site with a mixture of wood chips, manure, and other plant materials. This compost is fully treated following guidelines from the National Organic Program (NOP.) The compost is then applied to the base of the trees, and covered with mulch.

Making compost is an active process for growers as it requires monitoring both temperature and moisture levels and turning of the compost pile to encourage its consistent decomposition and heating. The staff at Apple Jack Orchards have a thermometer that can read temperatures within the center of their compost pile. To be considered treated, temperatures must be maintained between 131F and 170F. Below that temperature range pathogens may not be adequately killed, and biological activity is obstructed at temperatures above 170F. When this temperature range is maintained for a minimum of 15 days and the pile is turned at least 5 times within that time period, the presence of pathogens drops dramatically and the compost is considered a “treated” product. It can then be used without restriction on produce and apple trees for fertility and soil health.


If the compost containing manure is not made following this method, and simply ages in a pile, it cannot be considered fully treated. You can still use this compost, but to reduce risks you should apply it well before harvest. Work it in well in the fall, and make sure to allow at least 90 days between application of the compost and harvest if the product grows above the soil (e.g., apples, grapes, blueberries, trellised tomatoes), and 120 days if the product grows on the soil (e.g., strawberries, lettuce, melons). This will allow time for the potential pathogens to die and greatly reduce risks to your vegetables or fruit crops.

Orchard scouting and pest monitoring

The IPM portion of the field day emphasized the importance of knowledge in relation to creating a pest management plan. Some knowledge stems from having good resources like compendiums and field guides to learn about insect and pathogen life cycles and symptoms, learning how to use degree day models, or knowing how to use spray guides for making management decisions. But none of this knowledge would be useful without knowing what is actually present within an individual orchard setting. Field scouting involves actively going out with intention to find plant symptoms, evidence of insect pests, or the pests themselves to gather the presence or extent of damage at a certain point in time.

Images: Two examples of apple resources that can assist in pest and disease identification: A pocket guide for IPM Scouting in Michigan Apples and Compendium of Apple and Pear Diseases and Pests, Second Edition. Image (left) retrieved from Michigan State University Extension website.

Monitoring pests with traps can greatly enhance this process. If you’re purchasing any pest-specific trap for the first time, consider the following:
  • What is the optimal trap shape, color, and placement for the targeted insect pest?
  • How many traps are required per acre?
  • At what time of the growing season should traps be installed? Traps can be set up before the anticipated insect pest activity window begins and removed after the insect pest’s life cycle has ended, or when it is no longer needed for monitoring.
  • Would a lure increase the trap’s effectiveness? If it makes sense to add a lure, it helps to know how long that lure lasts and whether or not it requires refrigeration for storage before use.

Images: (left) Ben Fontana, orchard manager at Apple Jack Orchards taking a delta trap set up with a codling moth pheromone and sticky sheet out of its position to show two codling moths exhibiting in the trap.

Apple Jack Orchards is one of the Minnesota apple orchards participating in the MDA’s apple insect catch report, which means they monitor for codling moth, apple maggot, lesser apple worm, obliquebanded leafroller, dogwood borer, redbanded leafroller, and spotted tentiform leafroller. At the very last part of our field day, our group walked out to view Apple Jack Orchards’ codling moth trap, which had two codling moths in it that day.

Maintaining good agricultural practices related to food safety and best practices related to pest management is a process that takes time, preparation, and thoughtful intention, but is also rewarding. It ensures worker and consumer safety, can reduce the use of expensive pesticide applications, and creates a whole systems approach to creating a legacy for any orchard or farming business. Look out for more UMN Extension upcoming learning opportunities, which are often announced in our UMN Fruit and Vegetable News newsletter and on the UMN Extension website.

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