Augmentative Biological Control of Spider Mites on Hops

Project Overview

Project Type: Graduate Student
Funds awarded in 2016: $11,432.00
Projected End Date: 06/01/2018
Grant Recipient: Ohio State University
Region: North Central
State: Ohio
Graduate Student:
Faculty Advisor:
Celeste Wetly
Ohio State University


  • Agronomic: hops


  • Education and Training: extension, on-farm/ranch research
  • Pest Management: biological control, integrated pest management

    Proposal abstract:

    The twospotted spider mite, Tetranychus urticae (Acari: Tetranychidae), is one of the biggest challenges to hop production in Ohio.  As the production of hops is a new industry in the Midwest, research has not yet been done on the effectiveness of the pest management tactic known as augmentative biological control, where predators are released into a system to help control pest populations.  In our project, “Augmentative Biological Control of Spider Mites in Hops”, we will work with four hop growers in central and southwest Ohio to evaluate the ability of two predatory mite species, Galendromus occidentalis (Acari: Phytoseiidae) and Neoseiulus fallacis (Acari: Phytoseiidae), to successfully manage twospotted spider mite populations when released in a hop yard.  We will release these two predators at both a low and an intermediate prey density to determine at which density the predatory mites are better at managing spider mite populations.  As hop growers in the Ohio and throughout the Midwest need a cost effective pest management strategy to manage twospotted spider mites, we will compare the cost of augmentative biological control to the use of both organic and chemical pesticides currently being used.  Another key part of spider mite management is proper scouting techniques.  We will work with the same four growers to establish effective scouting programs in their hop yards.  These growers will also help us to produce extension videos that explain proper scouting techniques as well as the proper predator release techniques used in augmentative biological control.  These resources will be made available through the Ohio State Extension as well as the Ohio Hop Growers Guild.   The hop industry in the Midwest continues to grow and proper scouting techniques and the use of augmentative biological control will allow growers to improve production to keep up with the growing demands for locally produced hops.  The adoption of these tactics will be evaluated by a series of online surveys.

    Project objectives from proposal:

    Expected Outcomes




    Evaluation/Monitoring Plan, Measurement Methods


    100 growers will learn about proper scouting techniques.


    100 growers will learn about the use of augmentative biological control to control spider mites.



    20 growers will develop and use proper scouting protocols that help them to better manage their pest populations.


    20 growers will incorporate augmentative biological control tactics into their pest management strategy


    Supply of locally produced hops will begin to meet demand



    Profits increase


    Use of augmentative biological control leads to a decrease in the use of chemical pesticides protecting the health of growers as well as increasing the presence of natural predators


    Higher quality of life for growers, their families and their communities

    Researched-based recommendation on the use of predatory mites G. occidentalis and N. fallacis in augmentative biological control to manage twospotted spider mites in hops


    Economic analysis on augmentative biological control versus organic pesticides versus conventional pesticides


    2 videos – proper scouting techniques, augmentative biological control


    2 Printed Fact Sheets on

    proper scouting techniques, augmentative biological control


    2 extension bulletins (available on OSU website and Ohio Hop Grower Guild website)


    1 research article (Journal of Economic Entomology)


    1 on-farm trial on four farms


    2 presentations at “First Friday Hop Tours”


    1 presentation at  “Ohio Hop and Malting Barley Conference and Trade Show”



    SARE funding


    Time - Grad Student, Advisor, and Student Research Assistant


    Cooperating growers for on-farm trials




    Pre and post project survey of hop grower’s pest management tactics.


    Pre and post project survey of hop grower’s scouting methods.



    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.