Bean Mold Management Tools and Rotational Systems Management Planning

Bean Mold Management Tools and Rotational Systems Management Planning

Summary

In the first year of this project, our emphasis has been on demonstrating Contans (Coniothyrium minitans, Cm) efficacy in the field. In 2010 we demonstrated that fields treated with Contans the previous fall reduced white mold incidence and severity in beans planted the following summer. The combination of Contans treatment and a bean cultivar moderately resistant to white mold reduced white mold severity to almost zero; in contrast, white mold severity was 23% in the susceptible, industry standard bean planted in fields not treated with Contans.

Six months after a November Contans application to diseased bean residues, mean Cm colonization of sclerotia was 47% in Cm-treated fields, compared to 3% in control fields. Mean sclerotial viability in Cm and control fields was 67% and 98%, respectively.

Ten months after the Contans application, 8.5% of sclerotia (buried or on the surface) were alive in Cm treatment fields compared to 74% in the control fields (almost 9 times more living sclerotia in the control than in the Cm treatment fields).

Beans were planted in the fields in July 2010. At bean harvest in September, percent foliar white mold necrosis for 91G (white mold susceptible variety) and OR-6230 (moderately white mold-resistant) was approximately 23 and 7.5%, respectively, in the control fields, and approximately 7 and 1%, respectively, in the Cm treatment fields. The lowest foliar disease severity was observed in the moderately resistant plants grown in Cm-treated fields.

At harvest, pod white mold incidence in 91G and 6230 was approximately 17 and 11%, respectively, in the control fields, and 7 and 3% in the Cm treatment fields. The lowest pod disease incidence was observed in the 6230 plants grown in Cm treated fields.

The lower disease severity in the beans grown in the Cm-treated than in the control fields was likely due to lower Scelorotina inoculum levels. Lower disease severity in OR-6230 compared to 91G was due to higher genetic resistance.

Thirty farmers and ag professionals learned about and discussed this project at a field day in August 2010 that included a stop at the experimental fields at the OSU vegetable farm.

More than 100 farmers and agricultural professionals learned about project results at the processed vegetable grower meetings in January 2010 and 2011.

Grower and processor representatives discussed project results and plans at the Oregon Processed Vegetable Commission reports and presentations meetings in January and February 2010 and 2011.

• Methods results and figures

Objectives/Performance Targets

In 2010, our goal was to investigate and demonstrate efficacy of Contans, in combination with a moderately resistant bean cultivar, for management of white mold of snap bean.

Objectives:

To evaluate the impact of Contans applications and reduced tillage on:

1) sclerotial survival,
2) sclerotial colonization by Coniothyrium minitans and other fungi,
3) apothecia production in the field in subsequent years, and
4) disease incidence in subsequent susceptible and moderately resistant bean crops.

Accomplishments/Milestones

We demonstrated in 2010 that inoculum survival and white mold severity in snap beans was reduced in a bean crop planted 10 months after a low rate fall Contans application. In addition, we demonstrated that integrated white mold control through a combination of Contans and cultivar resistance was additive and reduced disease severity to almost zero.

A group of 15 farmer and processor representatives discussed project findings and plans at Oregon Processed Vegetable Commission meetings in winters 2009-10 and 2010-11. In addition, 30 farmers and agricultural professionals walked the field trials and discussed the results at a 2010 summer field day at the OSU vegetable farm, and more than 100 growers and agricultural professionals learned about project findings at the Oregon Processed Vegetable grower meeting in January of both 2010 and 2011.

Impacts and Contributions/Outcomes

Collaborators: