WSU Whatcom County Extension

Integrated Pest Management for Blueberries

Introduction

 

This manual is intended to be used as a tool to aid in sampling and decision-making for managing key insect, mite, and disease pests in Northwest Washington blueberry fields. It compiles information from numerous written sources and practical pest scouting experience of growers in Whatcom County.

This manual is based on crop stage and pest development because this is the way the grower or scout encounters blueberry pests and decides how to manage them. The crop stages are divided into five periods:

Pre-Bloom (link)

Bloom (link)

Pre-Harvest (link)

Harvest (link)

Post-Harvest (link)

Key pest biology, sampling methods, and treatment thresholds are presented in a narrative form for each of the five crop stages. Scouting sheets for each of these crop stages are available in pdf form which can be printed out and used for each scouting trip. A matrix is provided for each crop stage which shows identification, monitoring, decision points, and management options in a convenient layout (link to these pages at left). Pest profiles are provided for each insect, disease, and weed pest – these sheets provide information on the identification, life history, and management of the pest as well as pictures and links to other relevant web pages. The weed management section is a new addition to this manual and incorporates a weed inventory scouting method. As in the apple and raspberry IPM manuals, this manual provides a section on “Pesticide Selection” and “Pesticides and Water”. Additional resources, such as books and websites, are provided in the section relevant to that resource.

It is our hope that growers, chemical company field representatives, private consultants, extension agents and others who are interested in blueberry IPM will use this manual. This manual is directly developed from previous manuals produced from the Nooksack IPM Project. This manual has been designed in a compact disc and online format, which will allow the user to easily navigate through the manual and print pages where required. New information will be added to the web version as it is developed. The development of IPM in blueberries, as in other crops, will continue to change and improve; it is a dynamic process affected by many factors. The design of this manual reflects the evolving field of Integrated Pest Management.

 

Rationale

Regular field scouting is an important component of any IPM program. Blueberry growers have an active role to play in gaining a better understanding of pests and beneficial insects and mites in their fields. By performing some of the basic scouting and record-keeping procedures outlined in this manual, growers can be more informed and more involved in pest management decision-making.

 

General Guidelines for Scouting in Blueberry Fields

Regular systematic scouting and record keeping are fundamental components of Integrated Pest Management. The scouting season typically begins in early March prior to the onset of bloom with four to five trips during pre-bloom and bloom, two to three trips pre-harvest, and two to three trips during harvest and post-harvest. Eight to ten well-timed trips through the field for the entire season are usually enough to provide valuable information on which to help make decisions. Experience with the Nooksack IPM program shows that scouting and record keeping takes about an hour for each field visit. This represents a total season-long investment of about eight to ten hours per block. It is important to be systematic and use your time efficiently, concentrating on the key pests and tasks at hand which vary with the crop stage and target pest.

Scouting involves performing two or three tasks at each of three to five sites in a block (field or portion). A minimum of three sites should be checked in small blocks (< 5 acres) and five sites are usually adequate in larger blocks (10 acres or more). Sampling in several sites rather than just in a spot or two will illustrate the range or variation in pest abundance found across a block. Recording information on a site by site basis allows the sampler to return later to determine trends in pest population which are helpful in making decisions and in evaluating treatments that have been applied. In general, sites should be distributed throughout the block and effort should be made to return to those approximate areas for each visit.

At each site, visit 10 to 20 bushes. These bushes should be spaced 3-5 plants apart and on both sides of the row, in order to cover a larger area at each site.

 

Scoutting Pattern of Blueberry Field

 

At each plant, follow the monitoring guidelines as described in each crop stage section. This will include inspecting leaves for aphids, leafrollers, and gall midge; inspecting the soil for mummy berries and weevil larvae; and inspecting the stems for evidence of disease. Some diseases, such as scorch virus, should be identified in a field even during non-scouting events. When performing other duties in the field, the grower or other trained field worker should keep a notepad handy to record locations of plants showing suspicious symptoms. Scouting for pests and disease should occur during regularly planned scouting trips, but can, and should, also occur during general trips to the field.

 

Scouting Equipment

The tools used in scouting are quite simple. For most of the field visits, you should have the following equipment with you when you enter the orchard:

 

Magnifying Hand Lens (10 to 14X power) or an OptiVisor® (3.5X power)

Hand Lens and Optivisor

For convenience, a hand lens should be tied to a small nylon line (loop) and hung from the neck so it frees up the hands and is accessible when needed. It is used most often for identifying and counting spider mites and their predators in the field. The extra power of a 14X is useful mite scouting but is not essential. Some growers prefer using an OptiVisor®, which has lower but adequate magnification. These fit around the head with an adjustable head band and have a flip-down lens, so both hands are free to hold and examine an object.

 

Clipboard with Scouting Sheet Attached or a Small Notebook (3 X 5”)

Scouting Sheet with Clipboard

Scouting sheets are provided for printing for each crop stage. For each key pest, a box is provided to record pest numbers or level of damage. These sheets contain a location for a field map to be drawn to indicate site locations as well as space for notes on other pests seen in the field. These sheets can be used with a clipboard to take into the field for recording data. Some may find it more convenient to use a small notebook that can be used to record data and observations from each site and then transcribe the data into the scouting sheet or onto the computer for future reference.

 

Carpenter’s Apron or Nail Pouch

Carpenter's Apron

A carpenter’s apron provides additional pockets for holding a small notebook, penknife or pruning shears, pencil, and small containers such as empty film canisters or plastic bags for collecting insect specimens or foliage.

 

Traps for Key Pests

Sticky Trap for Pests

Sticky traps and pheromone traps for specific pest species are important tools for monitoring the flight activity of these pests. Pheromone traps and lures can be purchased from various suppliers. Check with your extension office for information on these traps.

 

Digital Camera

Digital Camera

Small digital cameras can be used to document symptoms or pests seen in the field and to further identify the problem when returning to the office. These pictures can easily be sent to an extension professional or field representatives via email to aid in identification. Furthermore, these photos can be used as a way to train field workers in identification of pest issues. Digital cameras with a macro setting will be able to produce the best pictures of small objects, such as insects.

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WSU Whatcom County Extension • 1000 N. Forest St., Bellingham, WA 98225 • (360) 778-5800 • whatcom@wsu.edu