Author ORCID Identifier

https://orcid.org/0009-0004-3668-6048

Date Available

4-26-2024

Year of Publication

2024

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department/School/Program

Entomology

First Advisor

Dr. David Gonthier

Abstract

The success of many integrated pest management (IPM) strategies is limited by trade-offs with economic, cultural, and environmental factors. While some IPM strategies reduce pests, they may harm pollinators, reduce the efficiency of weed or disease management, or may increase costs relative to revenue. Pest protective row covers, in the form of fine-mesh netting (referred to as mesotunnels), are an effective alternative to pesticide use, but they are not without their challenges. While row covers exclude insect pests and the pathogens they vector, it is unknown how well non-vectored diseases can be managed underneath the row cover. The exclusion of insects also includes pollinators, creating difficulty ensuring that pollinator dependent crops such as acorn squash are sufficiently pollinated. Furthermore, weed management can be especially challenging when it may involve removing hoops and row covers to cultivate and then replacing materials which are time and labor intensive. Lastly, the cost-effectiveness of fine-mesh netting row covers is unknown.

In chapter 2, I address management of non-vectored diseases and cost effectiveness of fine-mesh netting row covers (referred to as mesotunnels) and acorn squash. I found that powdery mildew was less severe beneath the mesotunnels compared to uncovered treatments. Further, the material and labor costs of implementing mesotunnels were lower or roughly equivalent to the pesticide-only treatment, but there was higher revenue for the mesotunnel-only treatment compared to the uncovered-untreated treatment and pesticide-only treatment.

In chapter 3, I address the management of pollination with the use of fine-mesh netting row covers and acorn squash. I found that marketable yield was most consistent under the “open ends” treatment where the ends of the row covers were clipped open to the hoops to allow wild pollinators access to squash flowers. The “open ends” treatment also excluded most insect pests from the squash plants and did not impede pollinators from accessing the flowers.

In chapter 4, I address weed management in the furrows of raised plastic beds under fine-mesh netting row covers for acorn squash. For the first experimental year, I compared three different densities of teff and one density of buckwheat as living mulches and found that the high teff seeding density (40.75 kg per hectare) provided the best weed suppression. In the second and third years, I compared the high teff seeding density mowed versus un-mowed and compared living mulch treatments to landscape fabric. Mowing the living mulch did not impact weed suppression or marketable yield. I also found that landscape fabric suppressed weeds and increases yield compared to living mulch cover crops in 2022. However, despite the increase in yield, landscape fabric was the least cost-efficient treatment according to an economic analysis.

In chapter 5, I explore further strategies for increasing the use of row covers in diversified vegetable operations via reusing netting on spring, summer, and fall crops within the same growing season. I compared three different types of row covers (remay-fabric, 60-gram fine-mesh netting and 85-gram fine-mesh netting) to organic and conventional pesticides and an uncovered, untreated control across two years and a total of six crop plantings to learn which provides the most consistent benefits. I found 85-gram fine-mesh netting and conventional pesticide treatments generated higher revenue than the untreated control treatment across six crop plantings and two years. Furthermore, I found that row covers performed best for spring greens, were equivalent to all treatments for muskmelon and underperformed in fall broccoli.

The results from these experiments partially address the trade-offs with economic and environmental factors of using one IPM strategy – pest protective row covers. My research demonstrates row covers can be an economically viable option for pest management in organic vegetable production and has provided evidence of best management practices for the use of row covers to address issues with diseases, pollination, weeds, and profitability.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2024.207

Funding Information

This research was supported by Organic Research Extension Initiative ‘Resilient Systems for Sustainable Management of Cucurbit Crops’ Grant # 2019-51300-30248 in 2019-2023 and United States Department of Agriculture Hatch grant (KY008079) in 2018-2023.

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