Maine IPM Report, 2020

NEERA meeting: May 12, 2020

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 Insect and Plant Disease Diagnostic Lab and the newly instituted Tick ID Lab, provide 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 different programs have reached a number of underserved audiences, including Somali farmers in central Maine, Maine’s Native American tribes, and Maine’s growing Amish population.

Tree Fruit

Apples are the dominant tree fruit in Maine, with peaches a distant second. 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, an annual full-day preseason IPM meeting, presentations at other meetings, and individualized telephone and field visit support. Observations from the scouting coop are shared with over 400 commercial and hobbyist growers through the newsletter.

In the year-end program survey, 100% of the 27 apple growers who participated in the scouting coop 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. On average, 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. The Apple IPM Program had an estimated $6.3 million impact on Maine’s apple crop.

Sweet Corn

Twenty-three 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 University of Maine Cooperative Extension set up insect traps and trained student field scouts to monitor corn pest populations and report to participating farmers. Information gathered from volunteer farms were summarized and shared with sweet corn growers, agricultural consultants and Extension educators around the state. Presently over 150 farmers receive weekly pest updates through our e-mail or hard copy newsletter. Our sweet corn IPM blog received over 100 views per week, peaking at the height of the corn season. We share 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 during the season, resulting in over $700,000 crop impact.

Our monitoring sites indicated that corn earworm numbers were higher than the past three years so, although higher number of pesticide applications were recommended for most farms compared to the last three years, growers were able to keep earworm damage to a minimum in spite of higher pressure. Fall armyworm, however, was found in lower numbers in most locations, and appeared later than normal, requiring a less intensive spray program for this pest. This situation illustrated to farmers the importance of both monitoring for pests, and understanding the behavior all the pest species affecting the crop. All of the farmers responding to our post season survey stated that following program recommendations helped improve crop quality and said that they want to continue receiving this type of information in the future.


The Cranberry IPM Program includes monitoring for insect pests and providing online educational resources for growers. As a result of the program’s outreach, Maine cranberry growers had seen an industry wide increase in annual yield of approximately 20-30% (roughly $250,000-$400,000 in berry value or $1,000-$1,500 additional yield per acre through 2017). Unfortunately, Maine’s acreage has been reduced by approximately 50%, because of various cropping and value issues.

In the year-end grower survey, over 70% of growers surveyed wanted even more information regarding cranberry pest management and would greatly appreciate additional Extension pest monitoring. Expected outcomes of the proposed activities include pesticide minimization, increased crop yield, and increased implementation of IPM.


The Potato IPM Program maintains 200 specialized insect traps, coordinates a statewide network of electronic weather stations, and surveys 100 potato fields on a weekly basis.

During the 2019 growing season in Maine, potato colonizing aphid populations were at very low levels during most of the season. Non-colonizing aphid populations were active during the entire growing season, however, activity was lower than most years. The Potato Industry was alerted to this activity level. Some seed growers utilized stylet oil, a non-traditional insecticide which interferes with virus transmission. Non-colonizing aphids are capable of transmitting Potato Virus Y and traditional insecticides do not prevent these aphids from transmitting virus. Also during the 2019 growing season, no fields scouted exceeded threshold level for European corn borer via pheromone trapping or scouting.

The estimated economic impact of the Potato IPM Program’s insect monitoring in 2019 was approximately $17,000,000. 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

Eight 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 and gray mold. The sites were scouted weekly by the Extension Specialist and/or trained student scouts. The pest information data collected at the sites were shared with over 100 growers via weekly electronic newsletters, our web site and a blog. Insect pest pressure in most strawberry fields was moderate, with pests only showing up late in the season, and most growers were able to reduce insecticides applications. Extensive rain during bloom, however, did increase the need for fungicide applications to prevent losses due to gray mold infections. Outreach is also conducted through Small Fruit and Vegetable Field Day, Twilight meetings (6), and Vegetable and Small Fruit Schools (2). A recent focus has been field trapping and weekly reports on spotted wing drosophila.

Our post season program evaluations indicated that farmers modified their pest management practices as a result of the program (85% of those responding), usually reducing the amount of pesticide used significantly (up to 50%). Most have seen an improvement in crop quality, and found that IPM has both reduced pesticide costs (up to $100/acre) and improved crop profitability. Additionally, we have worked with growers to adopt alternative strategies such as pest resistant cultivars, biological controls, and insect barriers. Growers now time sprays in response to pest monitoring results, and most have adopted at least one non-chemical alternative pest management strategy.

Spotted wing drosophila: Traps for this invasive pest of soft fruit were set out at 14 volunteer farms in southern and central Maine. The traps were monitored weekly for spotted wing drosophila by the Extension Specialist and/or trained student scouts. During the summer and fall, weekly updates of spotted wing drosophila populations were sent out to over 800 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. This year, spotted wing drosophila was observed early in the season but was slower to build to damaging numbers than in the previous season. As a result, some growers were able to reduce the number of insecticide sprays applied to fresh berry crops for this pest.

Public Health/Home & Garden

Through the continued outreach efforts of the Home & Garden IPM Program and the Tick Identification/Disease Surveillance Program, we have significantly increased the number of direct contacts with the general public regarding pest management options and the safe, judicious use of pesticides. An annual Tristate Greenhouse IPM Conference serves the commercial ornamental plant industry. Additional outreach has continued on a number of home and garden pests including Japanese beetles, white grubs, and brown-tail moth.

The initiation of the Tick ID Program in 2015 has allowed us to delve deeper into some of the vector-borne public health issues plaguing our state and region. In conjunction with the ID program, a tick website has been developed to increase public knowledge of tick biology, ecology, management, and personal protection. In 2019, we opened our new $12 million dollar Diagnostic and Research Laboratory, which is coordinated By Jim Dill. Also in 2019, we added tick disease testing to our program with over 2000 deer ticks being tested for Lyme, Anaplasmosis and Babesiosis. Outreach on ticks, mosquitoes and bed bugs through multiple public speaking engagements and media interviews has also helped increase public awareness.