Bean Mold Management Tools and Rotational Systems Management Planning

Bean Mold Management Tools and Rotational Systems Management Planning

Summary

Our goals for 2012 were to 1) further investigate the impact of past Contans applications and at-bloom applications on white mold incidence and sclerotial colonization and survival and 2) explore rotational systems management on organic vegetable farms.

In 2012 we demonstrated that at-bloom applications of Contans, although not currently a registered use, is very effective. We also demonstrated that sclerotia generated on beans grown in fields with a recent history of Contans applications are colonized by Cm.

This year we started the rotational systems management and planning aspect of the proposal. We are developing two farm systems analyses in which we and the farmer describe how the farm plans and implements systems soil and pest management and the impact of systems management.

Objectives/Performance Targets

Our goals for 2012 were to 1) further investigate the impact of past Contans applications and at-bloom applications on white mold incidence and sclerotial colonization and survival and 2) explore rotational systems management on organic vegetable farms.

Accomplishments/Milestones

Objective 1) to further investigate the impact of past Contans applications and at-bloom applications on white mold incidence and sclerotial colonization and survival

In 2010 we showed that in bean fields that had a recent history of Contans applications, sclerotia developed on beans died much more rapidly than in fields in which there was no recent history of Contans application; 6% of surface-incubated sclerotia were viable in Cm+ fields the following May, compared to 72% in Cm- fields; in September, almost no sclerotia were viable in Cm- fields and 8% were viable in Cm- fields

Two snap bean fields were planted in 2012; one had a history of Contans application and the other did not. Contans (1 lb per acre), Topsin (highest recommended rate), a Contans (1 lb/A)/Topsin (half rate) tank mix, and a water (Control) treatment were applied at early (late popcorn) and mid-bloom. Foliar disease severity and pod disease incidence were evaluated at harvest. Sclerotia were picked from disease plants in each plot and evaluated for viability and colonization by Cm and other fungi.

There was no difference in foliar white mold incidence between the water and Contans treatments (on average 55% of plants had white mold symptoms) and no difference in foliar white mold incidence between the high rate Topsin and the Contans/half-rate Topsin treatments (average of 6% of plants had white mold symptoms).

In both fields, Contans application resulted in the highest Cm colonization of sclerotia (70-80% of sclerotia were colonized) of all treatments, high rate Topsin application resulted in the lowest colonization (15-21%), and the Contans/half rate Topsin tank mix resulted in an intermediate level of colonization (45-50%).

In the field with no history of Contans applications, the water treatments resulted in 17% colonization, and in the field with a history of Contans application, the water treatment resulted in 50% colonization.

Objective 2) to begin to explore rotational systems management and planning on organic vegetable farms

We are developing farm systems analyses of two long-term organic vegetable farms that practice biologically-based systems management of soil and pests (insect, weed, disease). These analyses include an introduction to the farm and its goals and resources, its record-keeping strategies, all farm data sets (soil analyses, rotation histories, pest damage, yield, profitability), data collected on the farm by researchers, the farmer’s description of his/her approach to systems soil and pest management and their soil and pest management practices over time, and the farmers analysis of how the system has performed over time including problems (that have decreased, stayed the same, or increased over time), and successes. These analyses are currently in draft form but will be published in some form through eOrganic in 2013.

Impacts and Contributions/Outcomes

A presentation on integrating biological control into bean mold management systems is being given at the processed vegetable grower meeting, and a workshop on farm systems analyses and systems soil/pest management will be coordinated in February. Journal articles and extension bulletins/web articles on biological control of white mold with Contans will be published in 2013. At least one farm systems analysis and an article on systems management of at least one pest will be published to eOrganic in 2013.

Collaborators: