Weeds affect farmers directly through burdensome production costs. This economic impact is a direct result of the high costs of manufactured herbicides, tillage equipment and machinery, fuel costs, yield loss, and land value loss. A second negative impact is impaired quality of the harvested product. A few examples include; weeds in leafy green vegetables, the staining of cotton, and aflatoxins forming when certain weeds are stored with peanuts while drying. These aspects do not include how the crop plant is weakened from having to compete for nutrients, sunlight, water, and space. This competition causes a very direct yield loss on the crop. Incorporating an integrated weed management (IWM) approach is one way to overcome pressure from problematic plants.
Integrated weed management (IWM) is a long-term management approach which utilizes several techniques such as: preventative measures, cultural control techniques, biological control methods, mechanical control, and chemical control.
Some general points to remember when it comes to weed prevention are: avoid allowing weeds to reach a reproductive stage and produce viable seeds, avoid planting infested crop seeds or transplants, never allow livestock to feed on matter contaminated with weedy seeds, clean farm machinery thoroughly, and kill weeds in surrounding areas.
Cultural control involves manipulating farming practices to suppress weed growth and production, while promoting the overall health and development of the crop plant. Some items to remember to reinforce plant health and ward off weeds include: using a system of crop rotation, selecting appropriate planting date for the crop, strategic spatial arrangement and row spacing of the planted crop, suitable seeding rate, and adequate soil fertility and pH. Proper weed identification and scouting to determine threshold levels are also key in making the right weed management decision at the optimum time.
This means of control involves incorporation of a parasite, predator, or pathogen of the pest in order to decrease density and maintain more stable levels of weed population. This method of control works well for perennial systems like forage grasses or scenarios where rapid and complete control is not necessary. Biological control works well when there is an infestation of one target weed.
Mechanical control is the oldest of all methods and involves utilizing techniques such as mowing, handpicking, tilling, mulching, and fire. The mechanical method used often depends on the area of weeds to be managed, what the land is used for, and the land’s physical characteristics. These techniques can seem very practical and convenient at times, but have the ability to increase erosion, and compaction if overused without an integrated management approach.
Lastly, is the option for chemical control using herbicide application. In some situations, herbicides offer the only practical, cost-effective (and selective) method of managing certain weeds. In addition to this perk, herbicides can reduce the need for cultivation, they help prevent soil erosion and water loss, and they are widely used in conservation farming methods. In many cases, a weed is only weakened or killed by one specific herbicide, and it is important to use the correct product/active ingredient and application rate for control of that particular weed. The most common mistakes include incorrect identification of the weed or using inappropriate products. Carefully reading the label will help prevent these mistakes. Also if a chemical herbicide is used over a long period of time continually, the weed may build up a resistance to the chemical. Using an integrated approach will help reduce chances of that occurring.
The presence and management of invasive plants and various weed species causes millions of dollars in yield loss annually. In addition, these problem plants cost Florida’s overall economy several billion dollars annually to manage. Combining several techniques to control plant pests using the integrated weed management (IWM) approach decreases the chance that a weed can adapt to a control method. Ongoing maintenance requires a long-term commitment, but with careful management, weed problems will reduce over time. If you have a plant that needs identification, call your local UF/IFAS Extension Office for help and recommendations on management.
UF/IFAS Extension in Suwannee County is an Equal Opportunity Institution.