Session 3: Weed Management
Unit 6: Insect Pests, Diseases, and WeedManagement
Textual Question-Answers
Check Your Progress
Fill in the Blanks
1. Undesirable plant in the field that is responsible for economiclosses to the human is called a………………
Ans: weed
2. Weeds are harmful as these compete with the …………………for nutrients, water, light and space.
Ans: crop plants
3. Blue grass and chick weed are commonly seen in …………………soils.
Ans: fertile
4. Spurge pusley and knot weed show the presence of………………… in soil.
Ans: compaction
5. Young shoots of …………… can be used against asthma andblood disorders.
Ans: Chenopodium
Multiple Choice Questions
1. Leguminous weeds are commonly seen on ……………………(a) soil rich in nitrogen content
(b) soil poor in nitrogen content
(c) soil rich in phosphorus
(d) soil rich in calcium
Ans: (b) soil poor in nitrogen content
2. Examples of weed that can be used as mycoherbicide………………
(a) Phytophthora sp.
(b) Colletotrichum sp.
(c) Both (a) and (b)
(d) None of the above
Ans: (c) Both (a) and (b)
3. Herbicides which are applied after weed emergence arecalled……………
(a) pre-emergence herbicides
(b) post-emergence herbicides
(c) pre-planting herbicides
(d) None of the above
Ans: (b) post-emergence herbicides
Subjective Questions
1. What are weeds and their various types?
Ans: Weeds are unwanted and undesirable plants that grow along withcrops and cause economic losses by competing for nutrients, water, light, andspace. Weeds are classified into different types based on their life cycle suchas annual weeds, biennial weeds, and perennial weeds. They are also classifiedbased on morphology into monocot weeds, dicot weeds, and sedges.
2. Describe pre-emergence and post-emergence herbicides.
Ans: Pre-emergence herbicides are applied after sowing of crops but beforethe emergence of weeds. These herbicides prevent weed seed germination orkill young seedlings. Post-emergence herbicides are applied after weeds haveemerged in the field and are used to control actively growing weeds.
3. Describe selective and non-selective herbicides.
Ans: Selective herbicides kill only specific types of weeds without affecting the crop plants. They are used when weeds and crops are growingtogether. Non-selective herbicides kill all types of vegetation and are used forclearing land, bunds, and non-cropped areas.
4. What are the different methods of weed control?
Ans: Weed control can be done by different methods such as cultural methods like crop rotation and timely sowing, mechanical methods like handweeding and hoeing, chemical methods using herbicides, biological methodsusing insects and pathogens, and integrated weed management which combinestwo or more methods.
Match the Columns
A
1. Monocot weeds
2. Dicot weed
3. Sedges
4. Wild onion
5. Pallister beetles
B
(a) Perennial weeds
(b) Biennial weeds
(c) Feeding on the weeds
(d) Taproot system with broad leaves
(e) Stem is hollow and round, internodes are short
Ans:
1 – (e)
2 – (d)
3 – (a)
4 – (b)
5 – (c)
