MSU Extension Fruit & Nuts

Michigan State University (MSU) has many scientists who prioritize their research based on the most urgent needs of Michigan’s fruit industries. This article highlights some of the exciting projects recently funded across MSU fruit researchers. This article is not an exhaustive list, and there are many excellent MSU research projects currently underway that are not mentioned here. This list is meant to serve as a way of highlighting some of the great new work being done by MSU scientists that you may not have heard about yet through Michigan State University Extension programs.  

Apples 

Creating a digital decision aid tool to improve apple pesticide programs 

Project lead: Jackie Perkins
Funding: MSU Project GREEEN 
MSU collaborators: Julianna Wilson, George Sundin, Emily Lavely and Lindsay Brown 

There is a great need for the creation of an online platform that provides all relevant integrated pest management (IPM) strategies and aids in decision making for selecting the best management options for a given pest or pest complex. Our team of apple IPM specialists and Extension educators at MSU will work to develop an online IPM database that includes all management options for key apple pests and provides recommendations based on scouting information, efficacy and environmental risk (toxicity). The information in this database will be primarily based on the existing MSU E-154 resource, “Fruit Management Guide.” The creation of an apple IPM database based on the E-154 guide will allow for the development of an interactive online tool where apple growers can access this information in a user-friendly format that aids in effective IPM decision making. 

Growing fruit trees in digital environments to improve resilience against labor and climate challenges 

Project lead: Daniel Uyeh
Funding: Michigan Department of Agriculture and Rural Development (MDARD) Farm Innovations 
MSU collaborators: Daniel Morris and Jackie Perkins 

The main focus of the project is to utilize a technology called "digital twins" coupled with artificial intelligence (AI) to tackle fruit industry-wide challenges such as labor and climate change. This technology essentially serves as a digital environment where we can simulate different growing strategies, environmental conditions, etc. to guide farm management decisions. The exciting part of this is that because it is guided by simulations, we are not confined by the restraints of traditional in-field studies, allowing more rapid advancements toward things like robotics, farm automation and risk mitigation. 

Pest risk and management in high-density apples and cherries 

Project lead: Catherine Lindell 
Funding: MDARD Specialty Crop Block Grant – Michigan Tree Fruit Commission 
MSU collaborators: Nikki Rothwell 

This project is generating information on pest risk and management in high-density ‘Honeycrisp’ and sweet cherries. The work focuses on bird pests, apple maggot and codling moth (in Honeycrisp) and spotted wing drosophila (in sweet cherries). We are conducting fruit and insect sampling and a netting experiment. The netting experiment compares bird damage and insect infestation in netted and unnetted trees in high-density plantings. Also, we are assessing the effects of netting on fruit quality. With the growing importance of high-density production, information on pest risk and management will help Michigan growers increase yield and efficiency of resource use. 

Mulching under rows of honey crisp 

Project lead: Chris Bardenhagen 
Funding: Northwest Michigan Horticulture Research Center (NWMHRC) 
MSU collaborators: Nikki Rothwell, Karen Powers and NWMHRC 

We are testing how three different kinds of mulch affect soil nutrients and biota, tree growth, fruit yield and fruit quality. Woodchips, straw mulch and alfalfa/grass hay are tested against a control. 

Blueberries 

Demonstration of biological control of the blueberry fruitworm complex and SWD with the egg parasitoid Trichogramma platneri and entomopathogenic nematodes 

Project lead: Carlos Garcia-Salazar 
Funding: MSU Project GREEEN 
MSU collaborators: Rufus Isaacs, Marisol Quintanilla-Tornel, Anamaria Gomez-Rodas and Cheyenne Sloan  

Before the arrival of spotted wing Drosophila (SWD) in 2010, Michigan’s blueberry IPM program was a sustainable system with no more than five insecticide applications per season against the fruitworm complex, blueberry maggot and Japanese beetle. After the arrival of SWD, insecticide applications increased to more than 10 per season, and pest management expenses increased from $75 to $456 per acre in 2014. From 2021 to 2023, the MSU blueberry IPM program started developing biological control alternatives for fruitworm and SWD control using Trichogramma egg-parasitoids and entomopathogenic nematodes. The main objective is developing an IPM program incorporating egg-parasitoid and entomopathogenic nematode and biological insecticides for fruitworm and SWD control 

BLUE-DYNAMO: An interactive platform to deliver blueberry disease and horticultural management strategies for fruit rots 

Project lead: Tim Miles 
Funding: United States Department of Agriculture (USDA) Specialty Crop Research Initiative 
MSU collaborators: Josh Vanderweide, Yuzhen Lu and Cheyenne Sloan 

Pre- and post-harvest blueberry fruit diseases such as anthracnose (caused by Colletotrichum spp.) and botrytis fruit rot (caused by Botrytis spp.) have a significant impact on fruit quality and consumer acceptance. These are also among the most difficult diseases to control in the blueberry cropping system. These latent pathogens can cause significant losses both in the field, and especially during transport and marketplace storage. Although both diseases result in rotted fruit, the biology and infection strategies of the causal pathogens are very different and the management strategies differ. Innovations for management, such as improved molecular detection assays for fungicide resistance, postharvest imaging, breeding resistant cultivars, and biopesticides have been developed for improved fruit quality. Development and integration of new strategies is critical for the long-term success of the blueberry industry. 

Cherries 

Developing export-ready pest management programs for Michigan tart cherries 

Project lead: Jackie Perkins 
Funding: Michigan Cherry Committee 
MSU collaborators: Chris Bardenhagen, Emily Lavely and Erin Lauwers 

This project will explore current pest management programs in tart cherry to determine 1) how well they control key pests like SWD, and 2) if these programs meet maximum residue limits (MRLs) for target export markets. Evaluating the pests and residues of current standard pest management programs will inform where there might be potential barriers to export and identify areas where pest management programs need to be adjusted. We can then test how effective these adjusted programs are at controlling key pests and meeting MRL requirements. This information will be used to create and update MSU Extension resources and programming. This will allow Michigan tart cherry growers to ensure their fruit can be sold in a diversity of global markets. 

Evaluation of current and future strategies to manage cherry leaf spot disease sustainably and effectively in Michigan 

Project lead: Erin Lauwers 
Funding: Michigan Cherry Committee 
MSU collaborators: George Sundin and Nikki Rothwell 

Currently, there are few commercial fungicides available for orchard use due to lack of new research and development of products and to fungicide resistance development in fungal pathogens. Thus, new disease management tools are critical for Michigan cherry growers to effectively control cherry leaf spot disease. This project evaluates best practices for using copper to control disease and minimize phytotoxicity. We are also evaluating spray programs with new biopesticides. Biopesticides and broad-spectrum copper fungicides have reduced risks of developing resistance and are commercially available but need to be evaluated to be successfully integrated into current disease management programs. 

Understanding the evolution of pathogenicity in epiphytic Pseudomonas on sweet cherry 

Project lead: Michelle Hulin 
Funding: MSU Project GREEEN 
MSU collaborators: Erin Lauwers 

Bacterial canker is a major disease of cherry and top priority for the Michigan industry. The disease is caused by multiple species within the Pseudomonas syringae species complex. This complicates management strategies as controls must be effective against all pathogens. Pathogenicity on cherry has evolved multiple times in P. syringae and new species may emerge as pathogens. Bacteria share pathogenicity genes via gene transfer agents such as bacteriophage viruses, which may accelerate new pathogen emergence. This project will examine Pseudomonas and their prophage in Michigan cherry orchards. With this knowledge we can design targeted control measures for these important pathogens. 

Evaluating novel control measures for Pseudomonas cherry canker and identifying new pathogen targets for future management 

Project lead: Michelle Hulin 
Funding: MSU Project GREEEN 
MSU collaborators: George Sundin, Lindsay Brown and Erin Lauwers 

Bacterial canker is a major disease of cherry. The industry urgently needs novel controls. In this project we will test System Acquired Resistance inducers and biological sterilants in the field to see if they can reduce disease. Developing control measures rely on a sound understanding of how the pathogen causes diseases. To improve understanding of the canker pathogen, we will employ a technique called Random Barcode Transposon Sequencing. This involves generating a bacterial mutant library where all bacterial genes are individually mutated to become non-functional. This library of bacteria will be inoculated onto cherry to determine important pathogenicity genes. 

Grapes 

Innovative canopy management strategies to improve grape specialized color metabolites synthesis 

Project lead: Paolo Sabbatini 
Funding: USDA National Institute of Food and Agriculture 
MSU collaborators: Ilce Medina 

Grape secondary metabolites significantly impact wine quality, but cool viticultural regions like Michigan face challenges in their development due to seasonal factors. To enhance grape quality in such climates, agricultural strategies were developed. The project is investigating the impact of early leaf removal on grape berry metabolites, focusing on color compounds. Different treatments were applied to Merlot, Pinot Noir and Cabernet Franc at various growth stages. The study aims to understand how these treatments influence plant growth and production. Insights gained from analyzing metabolite patterns could inform agronomic strategies for improving grapevine quality, particularly through enhancing color compound accumulation. 

Modeling Michigan grapevine cold hardiness 

Project lead: Esmaeil Nasrollahiazar 
Funding: MSU Project GREEEN and Michigan Craft Beverage Council 

This project aims to develop the Michigan Grapevine Cold Hardiness Model (MGCHM) tailored to local conditions to help grape growers minimize cold damage and ensure sustainable production. By monitoring bud cold hardiness, establishing cold limits for key grape varieties, and providing timely updates through the MGCHM hosted on Enviroweather, the project addresses a critical industry concern and supports informed decision-making for resilient vineyards in Michigan's changing climate. 

Measuring and modeling the benefits of regenerative agricultural practices in three agroecosystems in Michigan 

Project lead: Paolo Sabbatini 
Funding: MDARD Farm Innovations Grant 
MSU collaborators: Bruno Basso and Jason Rowntree 

Field experiments in agronomic research offer insights into crop yield responses to weather, soil, management and genetics, though knowledge gaps persist. Variability in weather, soil types, landscape and management practices affects trial results. Such experiments are time-consuming and costly, with effects often taking years to manifest. Integrating field observations with crop simulation models enhances understanding and model accuracy. This project assesses regenerative practices' impact on yield, soil health and greenhouse gas emissions in Michigan's croplands, vineyards and grazing sites. It focuses on cover crops in croplands and vineyards, and rotational grazing in grasslands. Model predictions aid farmers' decision-making towards climate-smart and regenerative agriculture. 

Fruit-related research at MSU consists of a mixture of short- and long-term projects that each contribute to applied knowledge and practice. The above listed projects are projects starting in 2024 and may take a few seasons to complete. In the meantime, Extension educators and researchers are creating educational materials on studies that may have started several seasons back. Keep your eye on the MSU Fruit & Nuts updates!