Refinement of Dry Bean Harvest-aid Herbicides to Protect Seed Quality

Crop Dry Bean
Start Date2009
End Date2012
Principal InvestigatorGillard, Chris, University of Guelph
MPSG Financial Support$32,000
Report

Research Objectives

Develop harvest-aid strategies that provide uniform and rapid dry-down of dry beans, result in minimal herbicide residues levels in the seed at harvest, have no adverse effect on seed quality and yield, are efficacious on weed species that are commonly found in the dry bean production areas, and have low environmental impact.

Project Description

Seed maturity at harvest time is critical in dry bean production; however, due to variations within the field not all beans mature at the same time. To help reduce such variation and dry-down weeds that potentially can stain beans and interfere with harvesting operation, growers often use herbicides such as glyphosate as a harvest-aid (desiccant) to ensure adequate weed control and more uniform and rapid dry-down of beans. Desiccant chemistry and application timing is critical as it may cause crop yield losses and leave unacceptable herbicide residues in the seed.

Currently, there are few registered harvest-aid herbicides [glyphosate (Roundup), carfentrazone-ethyl (Aim), glufosinate ammonium (Ignite), and diquat (Reglone)] available to dry bean growers. Glyphosate is the most commonly used harvest-aid herbicide since it provides a uniform, gradual dry-down of the crop, it dries down existing weed foliage in the field, it provides control of emerged winter annual, biennial and perennial weeds, and it controls bean regrowth. There is little information available on the effect of desiccant chosen, desiccant tank-mixes, application timing and application rate on seed yield, seed quality and desiccant residues within the seed.