A combination of circumstances paint a picture of fewer tools for growers fighting weeds. Herbicide-tolerant crops have proven to be far less than a magic bullet, Cardina explained. Problems include high technology fees and loss of overseas markets, particularly in Europe where there is widespread suspicion and fear about the safety of bioengineered products. Another major concern domestically is how the federal government plans to regulate these types of plants. Growers should understand the concept of the weed bank, he said, which is made up of all weed seeds in the plant, on or in the soil or in associated plant litter.
Weeds have an enormous capacity for seed production.
On the high end, each pigweed plant is capable of producing up to 117,400 seeds. Only one-quarter of these seeds survive in the soil, but that leaves enough potential for problems that a grower's management efforts must address the problem, Cardina said. The key is avoidance - protecting against seeds invading a field. Seeds can get into your fields and orchards in a variety of ways, including on machinery, crop inputs, infestation of crop seed, irrigation water, transplants and any corridor where seeds can enter. At the end of the season, collect weeds and litter, remove them from the field and burn them.