Experimental Herbicides and Desiccants in Dry Edible Beans
February 21, 2007
KIH-485: Kumiai America Chemical Company is developing KIH-485 for preemergence weed control in corn. The compound has not been registered by the EPA but is currently under review. Registration in corn may occur in 2008 followed by registration to other crops with adequate safety. It is of unknown mode of action and unique chemistry. The NDSU Extension Weed Science Project has conducted 3 years of research in corn. Grass weed control is excellent and comparable to Dual, Outlook, Harness, Surpass and other soil-applied herbicides labeled in corn but control of broadleaf weeds is much greater. Greater than 90% control of foxtail, redroot pigweed, common lambsquarters, wild buckwheat, kochia, wild mustard, marshelder, and common ragweed was observed. Studies from other areas in the mid-west show it will control more weeds than those listed above. Preliminary research from Colorado State University and University of Guelph, Ontario, Canada reported selectivity of KIH-485 on some dry bean types. The compound is different than any other soil-applied herbicide registered in dry bean by controlling grass and many broadleaf weeds. Research on KIH-485 rates and application timings in dry beans types at multiple locations is needed to document weed control at rates safe on dry bean.
In 2006, experiments were conducted near Hatton and Thompson, ND, to evaluate dry bean type response to soil-applied KIH-485. Ensign, Maverick, T-39, and Montcalm were planted followed by soil application of KIH-485 treatments.
KIH-485 was applied at 1x, 1.5x, and 2x the rate for the soil type at each location. The dry beans in all treatments were hand harvested and there were no significant difference in yield from the weed-free check.
Results -- Hatton and Thompson:
Both studies were evaluated 12, 21, 28, 43, and 70 days after application for dry bean safety. No visual injury was observed for any treatment at any evaluation. The four dry bean types showed good emergence. There was no stunting, chlorosis, burning, deformed leaves or injury symptoms. There was little to no rain after PRE applications which may limited the amount the soil-applied herbicide was activated. Redroot pigweed emerged after application which also demonstrates lack of moisture activation because pigweed is susceptible to KIH-485 and controlled easily. These studies should be conducted again next year to observe dry bean response when
KIH-485 has been adequately activated with sufficient rainfall. (Dept. of Plant Sciences, North Dakota State University, Fargo).
Permit (Halosulfuron): Gowan Chemical Company recently bought the marketing rights of Permit (halosulfuron) from Monsanto for use in minor and speciality crops. Halosulfuron is labeled as Permit in corn and as Sandea in minor/specialty crops. Permit is a mid-residual, sulfonylurea herbicide with activity on many broadleaf weeds, including wild mustard, smartweed, sunflower, cocklebur, marshelder, and ragweed. The herbicide has a residue but all crops can be planted the year following application except canola (15 months), sunflower (18 months), and sugarbeet (36 months). Gowan is seeking registration of Permit on potato, dry beans, and some vegetable crops. Almost no research has been done with dry bean crop tolerance, adjuvant enhancement, and weed efficacy with Permit in the main dry bean growing area of North Dakota and Minnesota. Registration of soil-applied Permit on dry bean occurred in 2007 with postemergence registration to follow after sufficient data has shown adequate safety. Research should be conducted to develop a database of information to answer grower questions about Permit and to develop a use program wherein crop safety is protected and weed control is efficacious.
In 2006, experiments were conducted near Thompson and Hatton, ND, to evaluate dry bean type tolerance to Permit. Ensign, Maverick, T-39, and Montcalm were planted after which soil-applied Permit treatments were applied and postemergence treatments were applied on June 14 to V2 to V3 (1 to 2 inch) navy, pinto, black bean, and kidney bean.
Results -- Hatton: At June 14, pinto, navy, kidney, and black beans were in the unifoliate stage and showed good emergence. No injury was observed with any treatment. This rating is approximately 21 days after planting. There was no stunting, chlorosis, burning, deformed leaves or injury symptoms. No weeds were emerging except volunteer wheat in the treated plot area which was a light infestation. There was little to no rain after PRE applications.
At June 29, (7 DAT after the Permit POST treatments), there was no visible injury.
At July 14, there was no visible injury. Pinto beans were 8 to 10 inches tall and flowering, navy beans were 6 to 8 inches tall and flowering, kidney beans were 10 to 12 inches tall and flowering, and black beans were 6 to 9 inches tall and flowering.
At August 9, there was no visible injury in any treatment. All bean types were green without any indication of beginning senescence and no indication of stress from any herbicide treatment as exhibited in delay in physiological maturity.
Results -- Thompson: At June 7, pinto, navy, kidney, and black beans were all in the unifoliate stage and showed good emergence. No injury was observed with any treatment. This rating is approximately 14 days after application. There was no stunting, chlorosis, burning, deformed leaves or injury symptoms. Very little rain occurred after application. Redroot pigweed was emerged which Permit has some activity. This may indicate that the herbicide applied PRE was not activated by rain. Almost all weeds were in the wheel tracks of our tractor from seeding.
At June 15, no visible injury and beans were in the 1st to 2nd trifoliate. Redroot pigweed was emerging to 2 inches tall.
At July 14, there was no visible injury. Pinto beans were 14 to 18 inches tall and flowering, navy beans were 10 to 12 inches tall and flowering, kidney beans were 12-14 inches tall and flowering, and black beans were 14 to 18 inches tall and flowering.
At August 9, no injury was observed in any treatment. Beans were green without any indication of beginning senescence and no indication of stress from any herbicide treatment as exhibited in delay in physiological maturity. (Dept. of Plant Sciences, North Dakota State University, Fargo)
Dry bean desiccation: Through Northavest Dry Bean Grower funding, Valor was found to be an effective desiccation and Valent, in collaboration with IR-4 are seeking full Section 3 labeling anticipated in 2008.
Carfentrazone: FMC labeled Aim (carfentrazone) in 2005 as a desiccant in several crops, including dry bean. One year of testing in 2005 found it to be similar to Gramoxone in speed dry bean leaf but not vine desiccation. Preliminary research also shown enhancement of Aim by certain adjuvants. Research is proposed to test Aim in a graduated rate range and with adjuvants to determine speed and extent of desiccation.
In 2006, an experiment was conducted near Hatton, ND, to evaluate dry bean desiccation from Aim and Valor with adjuvants. ‘Ensign’ navy bean was planted on June 1, 2006. Desiccation treatments were applied on August 23 to beginning of naturally senescing dry bean. Dry bean senescence at application was quantified in the following manner: 50% green pods, 50% yellow pods, 0% leather pods, 5 to 10% top leaf drop, and 50 to 60% bottom leaf drop.
Generally, Gramoxone Inteon increased desiccation faster and quicker than other treatments which was better than previous years. Over 0.75 inches of rain occurred following application. From 0 to 7 DAT the weather was sunny, warm, and breezy with 55F lows and 80F highs. At 10 DAT, there was less differences between treatments. Valor slightly increasing control over Aim. Desiccation from Gramoxone and glyphosate was better than previous years. At 10 to14 DAT, 0.2” rain occurred with sunny and highs were in the 70F which may explain the increased desiccation.
Dyne-Amic + Valor desiccated vines well but it was until 10 DAT for Gramoxone to equal Valor+Dyne-Amic vine control of 73%. Valor increased control over Aim over time and all treatments desiccated dry bean greater than the untreated. Dyne-Amic and Superb HC with Valor and Aim and Gramoxone had 94% or better leather pods at 14 DAT. (Dept. of Plant Sciences, North Dakota State University, Fargo).