F. Protecting Key Ecosystems through Integrated Pest Management (IPM) in Maine

Insights from IPM research, application, communication and outreach initiatives

Morning Session – 8:30AM-10:30AM
Cumberland Room (1st floor)

Session Co-Chairs

This conference session will be focused on understanding the role of integrated pest management (IPM) methods in keeping the health of key ecosystems such as forests, marshes, estuaries, vernal pools, other freshwater shorelines, and coastal ecosystems. IPM is a science-based approach that combines diverse pest control techniques (e.g., biological, cultural, chemical, etc.) to reduce the impact of pests on ecosystem health, local economy, and human wellbeing.

Researchers and program managers in IPM have a crucial role in informing public policies (and the public) about the effectiveness of integrating diverse pest control practices. Researcher’s and program manager’s role is key to demonstrating the impacts of IPM on human and natural systems and to bring new insights about which IPM techniques can be more effective ecologically, economically, and socially. During this conference session we will discuss IPM experiences in the field and how communication and outreach programs can contribute (and are contributing) to protect key ecosystems in Maine.

Session Overview

  • 8:30AM-8:50AM – IPM as a Necessity: Managing Potato Virus Y. Andrei Alyokhin
  • 8:55AM-9:15AM – Pesticide Occurrences in Water Bodies of Maine Cities. Does Increasing Population Size Effect Pesticide Detections? Pamela J. Bryer
  • 9:20AM-9:40AM – The effects of timber harvesting on small mammal abundance, tick burden, and foraging behavior with implications for tick densities. Stephanie Hurd (student)
  • 9:45AM-10:05AM – Getting the Word Out About the Worm: How Integrated Pest Management Communication Initiatives May Assist in Slowing the Spread of Jumping Worms. Regina Smith
  • 10:10AM-10:30AM – Sweet Corn Integrated Pest Management in Maine: An Extension-Farmer Partnership. David T. Handley

Session Abstracts

Presenters are indicated in bold font.

8:30AM-8:50AM
IPM as a Necessity: Managing Potato Virus Y

Andrei Alyokhin
School of Biology and Ecology, University of Maine

Potato virus Y (PVY) is an economically important plant virus that is transmitted by aphids and can cause significant decline in tuber yield and quality. Management of insect-borne diseases often relies on suppressing their vectors with insecticides. However, this approach does not work for PVY because it is transmitted by numerous aphid species most of which arrive from outside of potato fields, and because the process of transmission happens so quickly that insecticides do not have enough time to kill them. Instead, successful crop protection must rely on a combination of reducing initial inoculum through a variety of methods, using resistant cultivars, and reducing vector efficacy by applying mineral oils. However, commercial growers often do not fully appreciate the complexity of the problem and still rely almost exclusively on insecticides in an attempt to suppress PVY spread. This results in excessive chemical applications that are both useless and damaging to the environment. The PVY-aphid-plant pathosystem illustrates the importance of both developing integrated solutions in pest management, as well as educating stakeholders on their benefits.

8:55AM-9:15AM
Pesticide Occurrences in Water Bodies of Maine Cities. Does Increasing Population Size Effect Pesticide Detections?

A pdf of this presentation is available. Please contact Pamela Bryer with any questions.

Pamela J. Bryer
Board of Pesticides Control, Department of Agriculture, Conservation, & Forestry

Surface waters around urban areas are frequently degraded due to non-point source pollutants. One aspect of this contamination originates from the use of pesticides, both inside and outside of the home. While Maine is a rural state, many of our towns and cities were built alongside rivers, placing these aquatic resources at risk for contamination. Recent work elsewhere has demonstrated greater numbers of pesticide detections in areas with higher concentrations of people. We surveyed the rivers and streams of 10 cities in Maine during the summer of 2019 for the presence of pesticides. We collected grab samples of water and sediment as well as deploying a passive sampler in the water column of each city’s major river. We found detectable levels of pesticides in each city. We found a greater variety of pesticide types in areas with more people. In the sediments, the pyrethroid bifenthrin was found in eight out of ten locations. In two locations, pesticide concentrations were above threshold values, indicating that negative ecological changes are predicted to start occurring at those sites. The two pesticides exceeding threshold values were bifenthrin in sediment and imidacloprid in water. Additional sampling at these locations could verify the patterns found and more fully explore the scope of the issue.

9:20AM-9:40AM
The effects of timber harvesting on small mammal abundance, tick burden, and foraging behavior with implications for tick densities

A pdf of this presentation is available. Please contact Stephanie Hurd with any questions.

Stephanie Hurd (student), Allie Gardner
University of Maine

Forest management occurs across spatial scales (e.g., property, landscape) to meet varied stakeholder objectives. This range of management affects wildlife habitat differently and has the potential to interrupt stages in the lifecycle of disease vectors, like ticks. The blacklegged tick, Ixodes scapularis, vectors Lyme disease, the most common tick-borne disease in the United States that threatens public health. Maine is among the states with the highest incidences of Lyme disease. Lyme disease transmission is heavily influenced by tick densities, which may depend on the abundance of wildlife hosts parasitized by I. scapularis. Forest management alters host habitat, yet little research has determined the effects of common, property scale practices like timber harvesting on these host populations. This project investigates the impact of timber harvesting on small mammal behavior and population sizes and its implications for tick-host encounter frequencies. Using a combination of techniques (i.e., live trapping, track plates, and foraging trays), this study assessed small mammal foraging and population sizes in forest stands with varied structural attributes. Results show the number of trees per acre positively correlates to small mammal population size, negatively correlates to the average larval tick burden on each individual, and has no effect on foraging behavior. Previous work showed higher I. scapularis densities in these forest stands with increased trees per acre and small mammal populations, indicating that host population size may be driving tick densities. These results suggest a biotic mechanism relating forest management practices to tick-borne pathogen transmission via host population size.

9:45AM-10:05AM
Getting the Word Out About the Worm: How Integrated Pest Management Communication Initiatives May Assist in Slowing the Spread of Jumping Worms

A pdf of this presentation is available. Please contact Regina Smith with any questions.

Regina Smith
Program Manager, University of Maine Cooperative Forestry Research Unit

Nearly all earthworms in the eastern United States and Canada are non-native. Around 10,000 years ago, glaciers reset the clock and wiped out any native earthworms in the area. Jumping worms (Amynthas spp.) are a type of earthworm native to East Asia that are now found in the United States. Jumping worms are considered an invasive species due to their destructive cascading environmental impacts once populations are established. They alter the physical, chemical, and biological characteristics of soil by voraciously colonizing the uppermost layer of soil where organic material is found. By accelerating the decomposition of leaf and plant material, jumping worms expose mineral soil and turn otherwise healthy soils into dry worm castings (feces) that cannot support native plants in our gardens and forests. Soils take on a texture similar to coffee grounds and become highly susceptible to erosion and compaction. Jumping worms decrease soil biodiversity, disturb mycorrhizal connections, and create opportunities for invasive plants to take hold in soils devoid of structure and nutrients. This may further exacerbate the loss of species diversity. Currently, there are no known controls for irradicating jumping worms. Integrated pest management (IPM) may help slow the spread of jumping worms, with a primary focus on education and prevention. The Jumping Worm Working Group of Maine has developed communications materials to aid in informing gardeners, horticulturists, foresters, and the general public, and further research is being conducted on methods of control. Prevention is the best control: sanitation suggestions include starting plants from seed to avoid introduction, buying bare root, and cleaning equipment that may harbor worm cocoons or adults.

10:10AM-10:30AM
Sweet Corn Integrated Pest Management in Maine: An Extension-Farmer Partnership

A pdf of this presentation is available. Please contact David Handley with any questions.

David T. Handley, James F. Dill
University of Maine Cooperative Extension

Fresh sweet corn is an important retail vegetable crop in Maine, with very high consumer demand during the summer months. However, an aggressive insect pest complex, including European corn borer, corn earworm and fall armyworm, combined with very low consumer tolerance for insect damage, make this crop challenging to grow profitably. High rates of insecticides used in the past to achieve high crop quality are no longer considered economically, environmentally or socially tolerable. For more than 30 years, the University of Maine Cooperative Extension has been working with Maine farmers to develop and support integrated pest management (IPM) practices for sweet corn. This program was the first to introduce pest monitoring techniques and the use of economic action thresholds to Maine sweet corn growers. The program now reaches over 100 farms statewide, and has joined a network providing information throughout the Northeast region. More than twenty farmers work with Extension to provide monitoring sites and pest information each season, which is shared with over 100 growers via weekly electronic newsletters and blogs. Farmers have participated in applied research projects throughout the program, including insect trap types and placement, pesticide alternatives, and parasite releases. Program evaluations indicate that most Maine sweet corn growers have now adopted IPM strategies and as a result have significantly reduced of pesticide use, and seen an improvement in crop quality and profitability.

About the Session Chairs

Hillary Peterson is the Integrated Pest Management Specialist with the Maine Department of Agriculture, Conservation and Forestry. The DACF IPM Program seeks to minimize the use of pesticides across all stakeholders in Maine involved with dealing with pest-related issues, including insects, non-insect arthropods, and some vertebrate pests. To do so, Hillary creates educational materials and workshops for the public, pesticide applicators, and school IPM coordinators to aid in the prevention of pest issues, and works to help identify areas where IPM education are needed across the state. Hillary earned her Ph.D. in Entomology at Penn State University in 2020, and her B.S. in Biology with a concentration in Ecology in 2015 at the University of Maine.

Andrés Urcuqui-Bustamante is a postdoctoral research associate at the University of Maine, School of Forest Resources. Andrés is currently developing a social-ecological systems model to study the impacts of diverse forest management practices (e.g., timber harvesting, pesticide application and invasive species removal) on tick density and tick-borne disease prevalence. Andres holds a Ph.D. in Environmental Science from SUNY College of Environmental Science and Forestry, a Master in Rural Development from Pontificia Universidad Javeriana (Bogota, Colombia) and a Master in Conservation of Biodiversity from CEU San Pablo (Madrid, Spain).