Lots of Questions on Dry Bean Desiccants
September 18, 2006
NDSU Extension Weed Specialist Rich Zollinger fielded a number of phone calls leading up to this years dry bean harvest, about using Aim (carfentrazone) as a dry bean desiccant.
Aim is registered for preharvest dry bean desiccation. In one years research data, Zollinger says Aim at 1 oz/ac usually gave similar desiccation as paraquat at 1 pt/ac but Aim at 2 oz/ac + MSO gave around 5% greater desiccation than paraquat.
Aim applied with MSO at 1 qt/ac usually increased desiccation as compared to adding petroleum oil (COC) at 1 qt/ac.
Aim at 2 oz/ac gave about 10% greater desiccation than 1 oz/A at 5, 7, and 14 days after application (DAA) (61/73, 63/74, and 71/75).
The highest rating of desiccation from Aim was 75% at 14 DAA.
According to the NDSU 2006 Crop Production Guide (www.ag.ndsu.edu/weeds)both paraquat (Gramoxone Inteon, Gramoxone Max Restricted Use Pesticides) and Aim should be applied when at least 80% of pods are yellow/brown. Apply when no more than 40% (bush type beans) or 30% (vine type) of the leaves are still green.
Sequential applications may be needed, and thorough coverage is essential. Allow a seven day pre-harvest interval for paraquat and three days for Aim.
Glyphosate products are labeled for weed control in dry beans only, not as a crop desiccant. Glyphosate products should be applied after dry bean pods have turned yellow in color and leather in texture; at hard dough bean seed stage and 30% or less seed moisture. Allow a seven day pre-harvest interval. Do not apply glyphosate products to dry beans grown for seed because reduced germination/vigor may occur.
Zollinger notes that Valor (flumioxazin) is not registered for dry bean desiccation and will not be registered until possibly 2007, more probable 2008. The 2006 Bean Day CD included with the March-April 2006 issue of the Northarvest Bean Grower (page 26) included experimental research data from Zollinger evaluating Valor to other desiccants.