Maine IPM Report, 2021

NEERA meeting: April 23, 2021

James Dill, Professor of Entomology and IPM Coordinator
Glen Koehler, Associate Scientist IPM
Griffin Dill, IPM Professional

The UMaine Cooperative Extension IPM Program delivers pest management education, monitoring, forecasting, diagnostics, and individualized problem solving. In addition to commodity-specific outreach programs, the Pest Management Unit within the UMaine Cooperative Extension Diagnostic & Research Laboratory provides local, statewide, and regional support. The efforts of the lab and program staff help a variety of commercial and non- commercial stakeholders with effective, efficient, environmentally sensitive, and safe pest management. The Extension IPM Program collaborates with the Maine Department of Agriculture, Conservation, & Forestry (ME DACF), grower organizations, other university departments, and other New England universities in order to best serve the people of Maine and the region. The IPM programs have reached a number of underserved audiences, including Somali farmers in central Maine, Maine’s Native American tribes, and Maine’s Amish population.

Tree Fruit

Apples are the dominant tree fruit in Maine. The main program components are the Maine Tree Fruit Newsletter (which covers horticulture, marketing, and other topics in addition to IPM), the Ag-Radar apple pest/horticultural tracking/forecast system, a pest scouting cooperative subsidized by the Maine State Pomological Society, webinars and in-person meetings, and individualized telephone and field visit support. Observations from the scouting coop are shared with over 500 commercial and hobbyist growers through the newsletter.

In the 2019 year-end program survey, 100% of the 27 apple growers who participated in the scouting co-op said that the visits were useful to their decision making. Ninety-six percent of surveyed growers said they had benefited from an Apple IPM Program presentation or consultation, and 100% said that the newsletter had helped them with pest management decisions. Growers estimated that support from the Apple IPM Program helped them reduce pest damage losses by 32%, while also reducing production costs by an average of $406 per acre, with an estimated $6.3 million benefit to Maine’s apple crop quantity and quality.

A new addition to the program in 2021 is site-specific weather forecast and observations at 1.5 mile spatial resolution and hourly temporal resolution for 79 Maine locations. Weather data service for another 79 sites beyond Maine is being provided to growers, consultants, and Extension programs, including the Purdue Extension Meloncast program. Data are delivered via twice daily email reports, real-time web charts and hourly CSV files. Data tables with additional elements not shown in the charts or email reports are in development. The weather data are also used as input for the AgRadar Tools decision support models for apple, with models for other commodities and IPM application sites in development.

Sweet Corn

Twenty farmers volunteered to have their cornfields used for pest monitoring and demonstrating IPM techniques for the major corn pests, including European corn borer, corn earworm, and fall armyworm. The number of farms included in the program was reduced from previous years in order to accommodate travel and safety regulations necessitated by the COVID-19 pandemic.

Insect traps were set up and maintained by IPM field scouts trained to identify and monitor corn pest populations. Due to pandemic restrictions, all communication with farmers was carried out electronically, primarily though cell phone texts and email. Information gathered from volunteer farms were summarized and shared with sweet corn growers, agricultural consultants and Extension educators around the state. In 2020, 136 farmers received weekly pest updates through our e-mail newsletter. Our sweet corn IPM blog received over 100 views per week, peaking at the height of the corn season. We also shared our observations with researchers, extension staff and growers throughout the region. At present, we believe this program is reaching well over one half of the commercial sweet corn growers in the state, and at least two thirds of the acreage. We estimate that the program has saved, on average, more than three insecticide applications over more than 3000 acres of sweet corn in each season.

In 2020, our monitoring sites indicated that corn earworm numbers were somewhat higher than the previous season, but populations were quite variable from site to site. As a result, some fields required more insecticides sprays than the previous season, while others required fewer. Fall armyworm, was found in lower numbers in most locations, similar to last season, although it arrived fairly early and became more intense at the end of the season. This situation illustrated to farmers the importance of local monitoring for pests, and how pest pressure can vary greatly from site to site, even when they are geographically quite close. We also monitored most fields for western bean cutworm, which has become a significant corn pest in the Midwest and southeast regions in recent years. In 2019, numbers were much higher than observed in previous years of trapping this new pest, and 2020 continued this trend, strongly suggesting that this is becoming a new pest problem for corn in Maine.


The Potato IPM Program maintained 30 specialized insect traps, coordinated a statewide network of electronic weather stations, and surveyed 30 potato fields on a weekly basis during 2020. A series of five, sixteen foot high tower traps in Aroostook County was also operated from May through September 2020 to monitor the timing of aphid flights and the presence of certain aphid species. Through this trapping, approximately 6,000 individual aphids were examined and identified. During the 2020 growing season in Maine, potato colonizing aphid populations were at relatively low levels and although non-colonizing aphid populations were active, their activity was also relatively low. Outreach to potato growers was conducted through approximately 3,000 individual grower contacts and a weekly newsletter with current regional pest updated was emailed to over 460 industry staff in Maine, New Brunswick, and the eastern United States.

Through active field monitoring and outreach to growers, management strategies for multiple potato pests including Colorado potato beetle, European corn borer, and aphid species capable of spreading potato virus Y (PVY) were implemented. These recommended management strategies helped reduce potential crop losses and reduced the unnecessary application of pesticides. The estimated economic impact of the Potato IPM Program’s insect monitoring for Maine potato growers in 2020 was approximately $10.6 million. The program distributes information through a potato pest hotline, weekly growing season newsletter, the annual Maine Potato Conference, and the annual Maine Potato Pest Management Conference,

Small Fruit

Six volunteer farmers worked with Extension to provide monitoring sites and pest information for the major strawberry pests, including tarnished plant bug, strawberry bud weevil, two spotted spider mites, cyclamen mites and gray mold. The sites were scouted weekly by the Extension Specialist and/or a trained student scout. The number of farms included in the program was reduced from previous years in order to accommodate travel and safety regulations necessitated by the COVID-19 pandemic. The pest data collected at the sites were shared with growers via weekly electronic newsletters, our web site and a blog. Due to pandemic restrictions, all communication with farmers was carried out electronically, primarily though cell phone texts and email. In 2020, 161 people received the weekly Strawberry IPM Newsletter during the growing season.

Insect pest pressure in most strawberry fields was moderate in 2020, with two-spotted spider mites being the most common problem requiring action. Most growers were able to reduce insecticide sprays by one or two applications, due to very low pressure from strawberry bud weevil and tarnished plant bug. Although early spring conditions were quite wet, and threatened to increase incidence of fungal diseases, dry weather prevailed through bloom and harvest, reducing the need for fungicide applications for fruit rots.

Traps for the invasive small fruit pest Spotted Wing Drosophila were set out at nine volunteer farms in southern and central Maine. The number of farms included in the program was reduced from previous years in order to accommodate travel and safety regulations necessitated by the COVID-19 pandemic. The traps were monitored weekly for spotted wing drosophila by the Extension Specialist and/or a trained IPM scout. During the summer and fall, weekly updates of spotted wing drosophila populations were sent out 1015 growers, consultants and Extension staff, with management recommendations. Our webpage and blog also supplied information on how to monitor spotted wing drosophila in fruit plantings and directed farmers to further resources for management strategies. Data and observations were shared with other state and regional programs. In 2020, spotted wing drosophila was observed early in the season (~7/20), and soon built to damaging levels, threatening all ripening fruit in most parts of the state. As a result, regular protective sprays were recommended through much of the season for raspberries, blueberries and fall strawberries. Growers who followed five to seven day spray intervals on ripening fruit were able to keep infestations from developing and maintained good quality for the season.

Public Health

University of Maine Cooperative Extension conducts surveillance of ticks and tick-borne pathogens to track their distribution, detect trends or changes in tick activity, and to identify areas of risk for tick-borne disease in Maine. A total of 3,273 ticks were submitted to the UMaine Extension Tick Surveillance Program in 2020, with samples submitted from each of the state’s 16 counties and from 354 towns. The majority of the ticks submitted were identified as blacklegged ticks (Ixodes scapularis), the primary vector of Lyme disease and other tick-borne pathogens, while American dog ticks (Dermacentor variabilis) also made up a significant portion of the submissions. In 2020, possibly as a result of increased outdoor human activity associated with COVID-19 combined with warm spring temperatures, adult deer ticks were encountered at exceptionally high rates during spring and early summer. Nymph numbers usually peak in June and early July. Nymphal deer tick activity was down in 2020, possibly due to the hot, dry weather during mid-summer.

Nearly 2,500 blacklegged ticks were tested for the causative agents of Lyme disease, anaplasmosis, and babesiosis with an infection prevalence of 37%, 7.5%, and 7.3% respectively. Borrelia burgdorferi, the causative agent of Lyme disease, was identified in ticks from each of the state’s 16 counties, while the pathogens that cause anaplasmosis and babesiosis were more prevalent in southern and coastal counties.

In addition to tick surveillance, program staff also provided outreach to the general public on the management of tick populations and personal protection from tick bites. Approximately 750 clients contacted the lab directly for guidance on handling tick-related issues. Although travel and safety regulations necessitated by the COVID-19 pandemic decreased the number of public presentations on ticks, presentations were still conducted virtually for a variety of stakeholder groups including businesses, hospitals, gardening clubs, etc. Through these presentations, over 1,100 people were trained on the biology, ecology, and management of ticks and their associated pathogens.