Pest management methods for western Washington fruit trees

Agricultural pest management research is an on-going endeavor, particularly when we consider how quickly pests can establish themselves in new geographic regions as the result of global transport and travel.  Here in Seattle, our climate allows us access to a wide array of fruit tree types and fruit varietals (with new varietals and hybrids being continually developed! ), making it a wonderful state for fruit enthusiasts.  However, while pomologists (fruit researchers) have begun to study fruit varietals that have resistance to some of our common insect and fungal pests (see the NW Fruit research on peach leaf curl), there are still thousands of fruit trees in our state that do not have natural resistance to these pests.  It is for this reason that pest management research and application of Integrated Pest Management (IPM) strategies by orchardists and tree owners alike are so critical.

As part of her internship with City Fruit, University of Washington student Justice Correa-West researched and compiled a report on the current pest management methods for fruit trees in Washington.  The report is clear and informative and can serve as a great first read for someone looking to build their knowledge in fruit tree IPM.  We hope you enjoy!  

Excerpt of the pest management report


Proper management of fruit tree pests is an integral part of producing a successful fruit yield and can help deter the spread of invasive pests. Washington State’s climate has been categorized into Hardiness Zone 8 as described by the United States Department of Agriculture (USDA). This zone describes the types of plants and agricultural crops that grow successfully in Washington. Many fruit trees thrive in zone 8, including apples, pears, peaches and figs. The climate in Washington is so conducive to fruit growth that it puts the state in the number one spot of apple production in the nation (USDA, 2020). Unfortunately, a wide range of pests and diseases also thrive in the State’s mild temperatures and moist winters and springs. Because of the abundance of pests, it is essential that orchards and individual backyard tree owners stay on top of managing their trees. In apple-producing regions of Washington State, such as Eastern Washington, it is even dictated by law that fruit tree owners manage for pests. This is due to the fact that many of the pests are fairly mobile and can travel from one unmanaged back yard tree into an orchard and cause an infestation (Brun & Bush, pg.7, 2013). These infestations can greatly harm the productiveness of the orchard and the farmer’s economic ability to continue growing fruit

This report will specifically discuss the current pest management methods of codling moth, spotted wing drosophila, and pear rust. The management methods will be discussed through a lens of integrated pest management (IPM). The main framework of IPM is utilizing multiple different methods, whether it be physical, cultural, chemical, or biological (Brun & Bush, pg.3, 2013). Cultural methods revolve around tree healthcare including sanitation, pruning, and initial careful selection of specific fruit trees (cultivars/dwarfing rootstock). Physical methods often include cardboard banding, pheromone trapping, or bagging of fruit trees. Chemical methods consist of the use of pesticides. There are two common types of pesticides used in orchards, conventional pesticides and organic pesticides. Conventional pesticides are synthetically derived materials that add additional and unnatural levels of elements into the soil. Organic pesticides are derived from natural materials that have been taken directly from the earth. This report will only discuss organic pesticides when suggesting chemical methods of management. Biological methods involve introducing beneficial organisms that prey on pests. An additional approach to pest management that will be discussed at the end of this report is the use of permaculture or ancestral farming, also known as guild building and companion planting. This method could be used in combination with IPM strategies and could decrease the number of methods that need to be utilized to combat the pests and diseases discussed below.

Interested in reading more? Click here to read Justice’s full report!