Improving IPM

Published Feb 14, 1997

In 1996 we continued the project begun the previous year, a study of alfalfa weevil and other insects in alfalfa supported by the Leopold Center for Sustainable Agriculture. We worked with the ISU entomology Department through graduate student Kris Giles, who was on the farm regularly.

We monitored alfalfa weevil populations weekly during May and June to see if parasites or diseases of the weevil affected their populations. When we harvested the first cutting of hay, we left a windrow unharvested in the center of the field.

Our unseasonably wet weather allowed the fungus disease Zoopthora phytonomi to drastically reduce weevil populations. When the wet weather turned abnormally dry, our focus shifted to the potato leafhopper. We hoped the adult leafhoppers would congregate in the uncut hay strip in the center of the field, allowing the new growth to develop unhindered. We believe we lessened the leafhopper impact, but we’re not sure how much.

Farmer involvement was a very important part of this project. Early in 1995, we invited neighbors in to talk with Kris about the project, and there has been continuing interest in what the research was finding. Last August we held a field day to share results and talk about our diversified farming system.

IPM and sustainable farming practices have been useful to us. We are appreciative of PFI, and the IPM Issues Team of the Leopold Center for their work on this project.