Studying Alternative Methods to Pesticides

When Cory Straub, Associate Professor of Biology, walks out into the fields of rolling alfalfa he notices the smallest things. Footsteps cause certain insects to scatter, among them, the tiny and very destructive Potato Leafhopper. This movement is significant because the more they hop from plant to plant; the more likely they are to meet up with a predator, says Straub. And that, it turns out, is a good thing because it eventually could mean using fewer pesticides to control the leafhopper.

Jamie Faselt 2015 and Phoenixia Rene 2017

This summer, students including Summer Fellow Jamie Faselt 2015, are working with Straub to research the effects of polyculture (growing multiple plant types together) and naturally occurring predatory insects on the leafhopper, a serious pest of numerous crops. “I am passionate about conservation, sustainability, and ecology,” says Faselt.  “This directly applicable research experience is invaluable to me.  I am so grateful that Ursinus College provides students with the opportunity to participate in undergraduate research. This is very important to me as I plan to pursue a Ph.D. and continue ecological research.”

Faselt, who will graduate next May, is working with six other students on a nine-acre field at Northern Star Farm, Trappe PA.  They are studying alfalfa, a main feed crop for cattle.  “We are examining alternative methods to pesticides with the ultimate goal of eliminating or reducing farmers’ reliance on chemical pesticides,” says Faselt. “The potato leafhopper is a pest of alfalfa and farmers spray harmful pesticides to control the leafhopper populations. The research I am doing this summer is unique and exciting because I get to be out in the world, working to ultimately reduce pesticides and foster a healthier environment.”

Jamie Faselt 2015 and Phoenixia Rene 2017

The Ursinus Summer Fellows project, says Straub, provides an opportunity for students to develop a deeper appreciation for sustainable agriculture while gaining valuable experience in field research. Straub’s fieldwork in Pennsylvania, and with colleagues abroad, has helped him study how planting grass­es with alfalfa has the potential to reduce leafhopper abundance and damage to alfalfa.  “Leafhoppers find grasses repulsive, and planting repulsive plants with their preferred food (alfalfa) causes them to move – and in doing so encounter predators more often,” Straub says. “The idea is so simple – if you move more as a pest you will get eaten – but it’s relevance for agriculture has not yet been explored.”  This movement-risk hypothesis has been studied in natural ecosystems, for instance, when elk move about to look for food they are more likely to be attacked by a wolf. But the concept has potential value for pest management in agro-ecosystems. Now Straub will have some extra help to explore the question with his students more thoroughly. He recently was awarded a $146,445 grant from the United States Department of Agriculture to support his research.

The field where they are conducting their research consists of plots of regular alfalfa, a possibly resistant strain of alfalfa, and a mixture of the ‘resistant’ alfalfa and orchard grass. The ‘resistant’ alfalfa strain should be less appealing to the leafhopper and the alfalfa-grass mixture should have the fewest leafhoppers because the leafhoppers don’t like the orchard grass. Faselt and the other students ‘sweep’ the field to see if there are fewer leafhoppers in the resistant plots and the least amount of leafhoppers in the mixed plots. They also will conduct an enclosed cage experiment to study  leafhopper movement and predation. Their guess? The leafhoppers will move more in the resistant and mixed plots, and as consequence they will be more vulnerable to insect predators that naturally occur in the field. Other students working on the project are; Damian Schell, Michael Melchiorre, Matthew Scott, Kimberly Realbuto and Phoenixia Rene. They are supported by the UC SF program, Straub’s USDA-NIFA grant, and the HHMI FUTURE program. Dr. Straub, Faselt and Phoenixia Rene 2017 will present their results at the Entomological Society of America’s annual conference in Portland, Oregon this coming November.

The Ursinus Summer Fellows program is an eight-week opportunity for some 70 students to work with a faculty mentor on an independent research project or creative project on or off campus. Fellows will present their research in a campus symposium July 25.