Improvement In Food Resources — Science STD 9 — Question

Effect of weeds on crop plants:

1. The growth of weeds in the crop fields is harmful because they compete with the crops for nutrients, water, space and light.
2. The weeds spread crop pests and diseases by acting as alternate host to insects and microorganisms.
3. Some weeds may produce toxic substances which may interfere with the growth of crop plants.
4. During harvesting weeds get mixed with crop's produce to downgrade its quality.