Michigan Researches Use Flowering Plant Strips to Support Beneficial Insects and Increase Crop Productivity
Beneficial insects are valued on farms for their abilities to perform services like pollination and pest control. Researchers at Michigan State University are exploring whether plantings of native Midwest flowers can support beneficial insects and lead to improved crop productivity and quality.
“There has been a growing interest in recent years about the economic and ecological benefits of re-incorporating natural resources into agricultural systems, in part because of the documented declines in populations of beneficial insects,” said Rufus Isaacs, Professor of Entomology and Small Fruit Extension Specialist at Michigan State University’s (MSU) Department of Entomology. “Providing a broad range of flowering plants is an essential component of rebuilding a strong beneficial insect community in farmland.”
Isaacs, and Brett Blaauw, a research assistant at MSU, have been exploring ways to help conserve beneficial insects on farms while simultaneously helping to enhance pollination and pest control within crop fields. They each applied for NCR-SARE grants to support their complementary research. Blaauw was awarded $9,910 through the NCR-SARE Graduate Student Grant Program, and Isaacs was awarded $148,837 through the NCR-SARE Research and Education Program to work with Blaauw and MSU extension educators Nikki Rothwell, Carlos Garcia, and David Epstein. As specialists with experience in small fruit production, Blaauw, Isaacs, and the team at MSU were learning about the resources insects need to thrive on farms, and wanted to share the results of their research with growers and the public.
“In order to understand how to best conserve beneficial insects and their services, it is not only important to do scientific research, but to also inform growers and the public so that this approach can be adopted,” said Blaauw. “As a funding source, SARE’s mission fits perfectly with our plan to advance sustainable agriculture through research and education.”
Blaauw and Isaacs conducted their research on Michigan fruit farms, working with producers of blueberries, cherries, and apples. Research at MSU had previously evaluated native Midwest flowers for their attractiveness to bees and insect natural enemies, so they selected species from that list for their research. They found that the abundance of both native bees and insect natural enemies increased while pest insects did not change in crop fields adjacent to conservation strips.
“There were significantly more of these beneficial insects in fields and orchards adjacent to the wildflower plantings compared to those adjacent to control (unenhanced) perimeters,” said Isaacs. Additionally, after two years of wildflower establishment, in the third year of measuring the ecosystem services from the beneficial insects, they found a significant increase in percent fruit set and berry weight in blueberry fields adjacent to the conservation strips, compared with the control fields. They used these numbers to calculate a predicted fruit yield for blueberry farms, and Isaacs reported that the fruit yield was 10- 20% higher in blueberry fields adjacent to the wildflower plantings.
Blaauw found that densities of both insect natural enemies and pollinators increased with wildflower plot size. He also found that for each of three wildflower species he measured (sand coreopsis, cup plant, and New England aster) there was an increase in pollination with an increase in wildflower plot size.
Isaacs pointed out that the establishment of native, perennial wildflowers along the borders of crops fields in the form of conservation strips can be an initially costly practice, but said that with time these conservation strips can lead to an increase in the number of native bees and natural enemies, and with the measured yield benefits they may also pay for themselves in the long run. This happens even more quickly if the planting costs are supported by one of the NRCS conservation programs to increase habitat for beneficial insects. In order to share information with producers and the public about the use of flowering plant diversity in farms to conserve beneficial insects, Isaacs and Blaauw have presented information at numerous extension meetings and conferences. These presentations included information about using wildflower plantings to support beneficial insects and current results from this SARE funded project.
They also developed many tools for public use. They contributed to a website called “Native Plants and Ecosystem Services” that shows how Michigan growers can use native plants to produce win-win situations for agriculture, communities, and the environment. Their 2-page, at-a-glance “Beneficial Insect Guide” identifies common crop pollinators and common natural enemies. Along with the website and the 2-page guide, their video, “A Quick Guide to Establishing Wildflower Plantings for the Conservation of Beneficial Insects,” is available on NCR-SARE’s YouTube channel.
According to Isaacs and Blaauw, growers’ interest in insect conservation has increased. At their blueberry grower meeting in 2009, 18% of those in attendance had an area of their farm dedicated to beneficial insect conservation. At their 2012 grower meeting, 90% of the surveyed growers responded that they were somewhat or very likely to implement wildflower plantings at their farms to help conserve beneficial insects. One of their grower cooperators on their project has independently implemented a third wildflower planting at his farm. Two of their other grower cooperators, who produce blueberries and cherries, are preparing to establish more wildflower plantings at their farms, with support from the Farm Service Agency’s SAFE program for pollinators.
“These meetings have generated much interest in the use of conservation strips to help conserve beneficial insects, with growers taking the initiative to adopt this approach on their own,” said Isaacs. “Adoption of this practice is increasing in Michigan, with increasing sales of native plant seed, and greater enrollment in government programs for pollinator conservation.”
In addition to presenting this information to producers and the public, Blaauw has presented this work at numerous national entomology meetings, and will be presenting at the annual meeting of the Entomological Society of America in Tennessee this fall. Based partly on his work for this project, Blaauw has been awarded the graduate student award of the International Organization of Biological Control Nearctic Regional Section.
Isaacs has presented his research to Michigan’s House of Representatives as part of an effort to improve policy options for supporting sustainable pollination practices. According to Blaauw, the results of this project have also helped MSU secure a new $1.7 million USDA Specialty Crop Research Initiative Grant to lead a national crop pollination research and extension project.
Want more information? See the related SARE grant(s) GNC09-116, Evaluation of Plant Composition and Strip Size on the Effectiveness of Native Plant Conservation Strips for Sustainable Enhancement of Beneficial Insect Communities , and LNC08-297, Native Plant Conservation Strips for Sustainable Pollination and Pest Control in Fruit Crops .
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This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture through the Sustainable Agriculture Research and Education (SARE) program. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.