Syngenta warns US farmers of HPPD resistance
Syngenta has reminded US farmers not to rely solely on herbicides with a single mode of action, following the first case of resistance to hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitors. A waterhemp ( Amaranthus spp) population in Illinois has been confirmed with resistance to several post-emergence HPPD herbicides, including Syngenta’s Callisto (mesotrione). The population occurred in a field used for maize seed production for seven consecutive years, with over-reliance on HPPD herbicides, the company points out. “The lack of diversity in both herbicide modes of action and crop rotation in this field led to the development of resistant waterhemp,” says Syngenta’s manager of resistance management strategies, Chuck Foresman.