Weeds are the unwanted plants which growing with the crop.
Weeds act as competition for the same space and nutrients that crops need to grow. If and when weeds are allowed to grow in the field, the farmer will more often than not get lower grain yeilds. In crops where the seed is harvested and sold as a cash crop, this is a serious threat. In crops where the plants are to be chopped up into silage, this is not as big as a threat because the silage is going to be eaten by livestock anyway.
Methods of Pest control.
We will not attempt to discuss in depth the various methods of pest control. Our intent here is to simply give you an overview of the available alternatives and to present some characteristics of each.
Resistant Varieties. Frequently, pest problems can be avoided or minimized simply by planting resistant varieties. The degree of resistance to a particular pest may be either partial or complete. These varieties possess genetic defenses such as protective physiological or physical characteristics which reduce their susceptibility to pests. Selecting resistant varieties makes the environment less favorable for pests and keeps them below harmful levels. Frequently, pest problems can be avoided or minimized simply by using resistant varieties.
Crop Rotation. Crop rotation can be an effective mean of maintaining pest populations at manageable levels; oftentimes it is a necessity. If a crop which is susceptible to a particular pest is grown year after year on the same land, pest infestations can become devastating. Rotation to other crops not desired by resident pests may offer at least a partial solution and may at the same time provide additional benefits such as increased soil fertility and a reduction in soil erosion.
Cultural Control. Many pest problems can be avoided or minimized by using appropriate cultural control techniques. Cultural control includes a number of practices designed to create optimal growing conditions for the crop and/ or unfavorable conditions for the pest. Cultural control involves, normal farming operations such as varying the planting time, cultivating, fertilizing, irrigating, and harvesting which may alter somewhat in response to particular pest problems. Sanitation practices, such as removal of crop residues which harbor pests, can also be an effective means of cultural control.
Biological Control. The foundation of biological control focuses on maximizing the effects of the natural enemies of pests. Biological controls are most commonly used to manage insects, mites, and some weeds. These natural enemies should be preserved in the field, as they are beneficial. This requires a careful choice of pest control measures, particularly an informed selection and judicious use of pesticides. Special consideration needs to be given to select insecticides that will not harm your beneficial insects. You can also help to ensure the continued presence of these species by preserving appropriate habitats in surrounding vegetation.
Chemical Control. Despite their potential hazards, chemical are essential components of pest control programs and will remain so for the foreseeable future. Chemical controls use naturally derived or synthetic chemicals called pesticides which kill, repel, attract, sterilize, or otherwise interfere with the normal behavior of pests. Chemicals act quickly and are effective against large pest populations. In many cases, the application of pesticides may be the most effective and feasible control tactic. However, pesticides should be used only when needed and in such a manner that you, your family, your neighbor, and the environment are adequately protected.
