Optimizing Integrated Pest Management in Mesotunnels for Organic Acorn Squash

Project Director: Sarah Pethybridge, Cornell University

Project overview

Cucurbits, which include cucumbers, pumpkins, squash, and melons, are an important component of diversified, organic vegetable farms. However, cucurbits are susceptible to several diseases, including bacterial wilt (caused by a bacterium transmitted by striped and spotted cucumber beetles) and cucurbit yellow vine disease (CYVD; caused by a bacterium transmitted by squash bugs). These diseases can decimate cucurbit crop harvests; as such, disease and insect pest management is critical. Weed management is also critical for cucurbit production, as weeds compete with crops for nutrients and can negatively impact both crop yield and quality.

Mesotunnels, which are modified row cover systems consisting of nylon mesh fabric and hoops, can be effective, organic-compliant methods of excluding pests.

This study assesses the effectiveness of several pest and weed management practices (i.e. mesotunnels, furrow cover cropping, and landscape fabric) in reducing insect pest populations, disease incidence, fruit yield, and fruit quality in acorn squash.

Mesotunnel research plots. Photo courtesy of Cornell University

Farmer takeaways

  • Mesotunnels can reduce cucurbit disease incidence (CYVD) and insect pest populations (squash bug, cucumber beetle) compared to non-covered production systems. However, the financial costs associated with mesotunnel installation/maintenance may not be worth the minimal observed yield response differences.
  • Cover cropping within furrows may offer similar weed prevention properties as landscape fabric, with potential soil health benefits to the production system.

Project objectives and approach

Evaluate the effectiveness of mesotunnels (insect pest exclusion), furrow cover cropping (weed management), and furrow landscape fabric (weed management) in reducing disease incidence and insect pest populations.

  • Replicated field trials were conducted over two years (2021 and 2022) at the Gates West Organic Farm facility in Geneva, NY.
  • Non-treated acorn squash were seeded in a certified-organic greenhouse and transplanted.
  • Four treatments were established: (1) Mesotunnel w/ furrow landscape fabric; (2) Mesotunnel w/ furrow ryegrass/white clover cover crop; (3) Mesotunnel w/ furrow ryegrass cover crop; and (4) Non-covered (no-mesotunnel) w/ furrow landscape fabric.
  • Assessments of insect pest populations and disease incidence were made at regular intervals. Furrow cover crop and weed biomass were evaluated, in addition to harvest data (quantity and quality).

Key findings

Mesotunnels may significantly reduce cucurbit disease incidence (CYVD) and insect pest populations (squash bug, cucumber beetle) compared to non-covered production systems, but with little-to-no impact on cucurbit harvest quantity or quality

  • Cucurbit yellow vine disease (CYVD) was observed in the non-covered (no mesotunnel) plots an average of 20 days prior to in the mesotunnel plots.
  • CYVD incidence was significantly higher in the non-covered plots than in the mesotunnel plots, with no significant differences observed between the cover crop vs. landscape fabric mesotunnel treatments.
  • Squash bug populations were significantly higher in the non-covered plots than in the mesotunnel plots in both years. Similarly, cucumber beetle populations were significantly higher in the non-covered plots than in the mesotunnel plots in one of the two trial years (2022).
  • Treatment had no significant effect on marketable fruit weight, non-marketable fruit weight, total fruit, or number of marketable fruit.

Both cover crop treatments performed similarly as a natural weed control

  • Weed dry weight did not differ significantly between either of the furrow cover crop treatments (ryegrass & white clover, ryegrass only). No weeds were present in the landscape fabric mesotunnel.

Resources

Pethybridge, S., K. Damann, S. Murphy, K.Diggins, and M.L. Gleason. 2024. Optimizing Integrated Pest Management in Mesotunnels for Organic Acorn Squash in New York. Plant Health Progress 25:2

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Location

New York

Collaborators

Kellie Damaan, University of Vermont

Sean Murphy, Cornell University

Kaitlin Diggins, Cornell University

Mark Gleason, Iowa State University

Region

Northeast

Topic

Disease Management, Insect/Pest Management

Category

Vegetables/Fruits

Year Published

2023