Factors Influencing Soybean Tolerance to Diflufenican
Diflufenican (DFF) is a selective, contact, residual herbicide under development by Bayer Crop Science for use in corn and soybean. It is a novel active ingredient and site of action for field crop production in North America and is highly effective on Amaranthus species. Differential soybean tolerance to DFF was observed at several field locations with cultivar selection, cultural practices, and environmental conditions all thought to influence tolerance. Field and growth room studies indicate no differences in tolerance exists among soybean cultivars and that crop response is instead related to rainfall timing and intensity. Rain splash from intense rainfall was shown to be a key mechanism for increased DFF exposure on soybean seedlings. Preplant applications were successful at reducing soybean phytotoxicity to DFF. This may permit the use of increased field rates, achieving improved residual weed control while maintaining crop safety.