Cyperinus and Parthenium are types of I. Diseases II. Pesticides III. Weeds IV. Pathogens
Option c. Weeds are unwanted plants which grow along with the crop plants in the cultivated field. Some common weeds in India are Amaranthus (Chaulai), Parthenium (Gajar ghas), Cyperus rotundus (Motha), Chenopodium (Bathua), Xanthium (Gokhroo). Weeds compete with the crop plants for nutrients, space, light and water. This results in lowering the food grain quality and reduction in crop yield. Weeds may produce toxic substances which may interfere with crop growth. During harvesting, weeds get mixed up with crops to lower down its quality. So, the correct answer is 'Weeds'.
