Visualizing vegetable pests

UNIVERSITY OF MINNESOTA EXTENSION - www.extension.umn.edu

Marissa Schuh (center) points out mock pest damage on a craft cabbage with Dalia Macias (left) and other Farm at the Arb apprentices.

University of Minnesota Extension educator Marissa Schuh used decorative craft models and art supplies to prepare a lesson on food crop pest scouting.

Acrylic paint and pipe cleaners aren’t usually the kind of props Marissa Schuh puts to use in her role as a University of Minnesota Extension educator in integrated pest management (IPM). But during the chilly winter and spring months, she got creative. 

On a chilly day in May, Schuh sat on the floor of a small classroom at the Robert J. Jones Urban Research and Outreach Engagement Center in north Minneapolis, facing a collection of fake cabbages. She had finished her presentation to Farm at the Arb apprentices with the Minnesota Landscape Arboretum, and moved onto the hands-on part of the lesson. 

“We’re practicing how to identify potential pest problems,” Schuh said, gesturing to the colorful cabbages, “especially since we can’t scout in the field for a couple more months.”

Art meets disease and insect pests

Pest damage can be easier to find than the pest itself, in this case, a caterpillar crafted out of a pipe cleaner to blend in with the plant.

Schuh purchased the pieces of her makeshift cabbage field from the internet, then used art supplies to represent various plant diseases and pest damage. 

She wanted a visual tool that could help people understand what to look for. “I painted these cabbages with symptoms of different diseases and added some pipe cleaner caterpillars to show pest infestations,” said Schuh. “I teach so many people who are just getting into farming for the first time, and they may be taking a class before they’ve even grown more than a garden-sized plot.” 

“Our apprentices are placed at one of four sites for the growing season,” said Madeline Carter, apprenticeship instructor at the Minnesota Landscape Arboretum. “They will help identify plant pests and diseases, and we will use the continuum of IPM intervention strategies to make ecologically-minded decisions about how to maintain the health of our crops and our growing spaces.” 

Hands-on-cabbage learning

Apprentices had to look closely to see the start of pathogen symptoms, whereas Marissa Schuh’s painted illustration grew with further disease onset.

The apprentices gathered around, inspecting the cabbages. One cabbage had holes that Schuh had poked or burned into its leaves, while another displayed dark spots representing common diseases. They consulted guides on the Extension website to identify the problems.

Scouting is essential for effective pest management.

“The earlier you catch a problem, the easier it is to address,” said Schuh. “Scouting involves anticipating future issues, not just reacting to what you see now.”

Apprentice Dalia Macias has a degree in botany, but is participating in the Farm at the Arb program to get experience managing horticultural crops. She picked up a cabbage. “This one has a leaf spot disease,” she observed, pointing to a dark splotch. 

“Exactly. What do you think could cause that?” Schuh prompted, encouraging critical thinking.

“Too much moisture,” another apprentice suggested. They discussed other contributing factors, then moved to the next cabbage, covering various pests and diseases.

“Some diseases won’t become apparent until later in the season,” Macias noted. “We need to be proactive and recognize the signs early.”