This year producers are already fighting Palmer Amaranth, or pigweed, which is now 3 to 5 inches tall and flowering. The anomalous weather pattern has this plant confused on what time of year it is, behaving like it is late August or September.
The short day lengths of March and April along with the record breaking warm temperatures has triggered emergence and flowering across the southeast. This brings new concerns on how to control the growing herbicide-resistant Palmer Amaranth population.
Dr. Ramon Leon, UF/IFAS weed specialist, said pre-emergence herbicide can play a major role in controlling this persistent agronomic pest. Producers need a weed management program to assure they are rotating chemicals as well as crops.
Unfortunately the herbicide resistance is forcing many growers to abandon traditional conservation tillage practices in an effort to better suppress this fast growing, prolific weed. Researchers are currently studying the effects of cover crops reducing enough sunlight to promote more control of the Palmer Amaranth’s emergence.
Palmer’s seeds are relatively weak and do not last long in the ground. To germinate, the seeds need plentiful sunlight which a cover crop may block.