Scale Management to Promote Sustainable Southeastern Peach Production

Project Overview

Project Type: On-Farm Research
Funds awarded in 2017: $14,985.00
Projected End Date: 03/14/2019
Grant Recipient: University of Georgia
Region: Southern
State: Georgia
Principal Investigator:
Brett Blaauw
University of Georgia


  • Fruits: peaches


  • Crop Production: application rate management
  • Education and Training: demonstration, extension, on-farm/ranch research
  • Pest Management: chemical control, cultural control, integrated pest management


    Peach is not only a significant economic industry in the Southeast, but it is also an important and enduring cultural icon that is under a severe threat from San Jose scale (SJS). Scale insects can damage peach orchards, both acutely and over the long-term, but for decades growers were able to inadvertently control SJS with highly effective, but potentially dangerous insecticides directed toward the primary fruit-feeding insect pests. Thus, with the loss of these effective pesticides (eg. methyl-parathion) and increased regulations on other organophosphate insecticide use, growers have to seek a more integrated pest management approach. Growers need a management strategy that more effectively utilizes environmentally friendly insecticides, such as horticultural oils, and support the beneficial insects to help naturally control scale. We therefore investigated horticultural oil volume (100, 200, and 400 gpa) and application timing (pre- and post-pruning) for improving management of SJS and their impact on insect natural enemies in southeastern peach orchards. Both application timing and oil volume were important for increasing spray coverage of peach trees. All combinations of pruning-time and volume had fewer SJS crawlers than did 100 gpa applied to pre-pruned trees. Additionally, no combination of treatments had a negative impact on insect natural enemies. Thus, if growers are able to apply their delayed-dormant oil spray post-pruning, 100 gpa may be effective at suppressing SJS crawlers, but if the oil sprays are applied prior to pruning, volumes greater than 100 gpa are needed to effectively manage SJS.

    Project objectives:

    1. Investigate the effectiveness of horticultural oil coverage through increased volume applied for San Jose scale suppression;
    2. Compare the effectiveness of horticultural oil coverage applied for San Jose scale suppression pre-peach tree pruning and post-pruning;
    3. Identify the natural enemy communities of San Jose scale in southeastern peach orchards and how they are impacted by management practices.
    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.