UPSC Weed Science Previous Year Questions (PYQs) – Year Wise & Topic Wise

Weed Science

Weeds – their characteristics

1. Classify parasitic weeds on the basis of their parasitism. Explain the preventive measures and integrated management practices for orobanche. (20M CSE 2023)
2. What are different types of noxious weed? Describe with suitable examples. Enumerate the measures to prevent noxious weed entry in the country. (8M, IFoS-2022)
3. Differentiate and elaborate Relative and Obnoxious weeds (10M/15M, 150W, CSE 2013, 2001)
4. Relative and Obnoxious weeds (10M, CSE 2013)
5. Short notes on Allelopathy (20M, 200W, CSE 2007, 2001)

Dissemination and association with various crops; their multiplications

1. Discuss the factors affecting crop-weed competition. (10M, IFoS 2020)
2. Define crop weed competition. Describe various factors affecting crop weed competition. Explain the factors affecting the efficacy of herbicides. (20M, CSE 2020)
3. What do you mean by dormancy and dissemination of weed seed? Give their significance in spread and survival. (8M, 150W, IFoS-2019)
4. Explain the critical period of crop-weed competition with suitable examples (10M, CSE 2016)
5. Describe crop-weed competition (20M, CSE 2014)
6. Write the importance of quarantine check of week seeds in importing food grain (10M, CSE 2014)
7. Persistence of weeds (12.5M, 200W, CSE 2013)
8. Discuss the factors affecting crop-weed competition. What do you mean by critical period of crop-weed competition? (10M, 200W, CSE 2013)
9. What is crop-weed competition? Give principles of integrated weed management (12M, 150W, CSE 2012)
10. What is crop-weed competition? Examine the significance of critical period of weed control. Critically assess the use of herbicides in weed control in rice and wheat (60M, CSE 1999)
11. Enumerate the ill-effects of weed competition in field crops and briefly describe the methods of their control. (CSE 1995)
12. What is crop-weed competition? How dose integrated weed management approach help in crop production under different cropping systems? Mention weedicides commonly used and their methods of application in direct seeded and planted rice crop. (60M, CSE 1994)
13. What is crop weed competition? What is the significance of critical period of weed control? Critically assess the use of herbicides in weed control in rice and wheat. (CSE 1992)
14. Integrated weed management. (200W, CSE 1989)

Cultural, biological, and chemical control of weeds

1. Describe in detail about the weed control measures in Black Gram and Sesame. (10M, CSE 2024)
2. Discuss the cultural methods of weed control. (10M, CSE 2024)
3. Describe the good cultivation practices for short-term initial control of weeds in crops. (15M, IFoS-2023)
4. Briefly write cultural and chemical weed control methods of soyabean and wheat. (10M 150W CSE 2023)
5. How do herbicides control weeds selectively? Write down the classification of herbicides with suitable examples. (10M, IFoS-2022)
6. Discuss about the types of herbicide resistance in weeds with specific example in Indian perspective. Discuss the management practises dealing with herbicide resistance in weeds. (20M, CSE 2022)
7. Discuss selection criteria of successful bioagent and bio-herbicides. State at least two examples of biocontrol of weeds. (10M, CSE 2022)
8. Discuss the activity and selectivity of herbicides. (10M, CSE 2021)
9. Describe the major biological control methods of weeds. (10M, CSE 2021)
10. The major weeds of rice and their management practices under both upland and lowland conditions. (10M, 150W, CSE 2021)
11. Enlist the methods of weed control and discuss the physical control of weeds in detail. (15M, IFoS 2021)
12. Discuss the herbicide selectivity phenomenon with the factors affecting it. (10M, IFoS 2020)
13. What are the advantage and limitations of biological weed control? (8M, IFoS 2020)
14. Describe the causes of increasing threats of Parthenium weed in the country. Write integrated methods of weed management with suitable examples. (20M, CSE 2020)
15. Current status of biological weed management (10M, CSE 2019)
16. Differentiate narrow spectrum and broad-spectrum herbicide (20M, CSE 2019)
17. Calculate the weed index in wheat crop with the given information and draw the inference (20M, CSE 2019)

18. What are the advances in chemical weed management? (10M, CSE 2018)
19. Mention the principles of weed management and give their merits and demerits. (10M, IFoS-2018)
20. What is the phenomenon of herbicide resistance in weeds? Discuss the factors responsible for development of herbicide resistance. (10M, CSE 2018)
21. Describe aquatic weeds and their control management. (10M, IFoS-2018)
22. Describe Innovations in biological weed management. (10M, 150W, CSE 2018)
23. Describe crop-weed-competition. Discuss the different factors affecting the efficiency of herbicides (20M, CSE 2017)
24. What are the problems of herbicide –resistance in wheat crop? (8M, 150W, IFoS-2017)
25. Soil solarization is an important tool for weed control. Justify. (10M, 200W, IFoS-2017)
26. Describe the method of biological weed control with suitable examples (10M, CSE 2017)
27. List out the factors affecting efficacy of herbicides (10M, CSE 2016)
28. Describe the integrated weed control measures involving both pre- and post-emergence herbicides in rice and cotton. (8M, 150W, IFoS-2016)
29. Bio-fertilizers and bio-herbicides and their benefits. (10M, 200W, IFoS-2016)
30. Discuss about the factors affecting the efficacy of herbicides. (20M, CSE 2015)
31. Elaborate the problems of residual toxicity of herbicide and its management. (10M, 150W, CSE 2015)
32. Significance of pre-sowing, pre-emergence and post emergence in weed control. (10M, IFoS-2015)
33. Write the approaches of biological weed control with suitable examples (15M, CSE 2015)
34. Classification of herbicides on the basis of their chemical nature. (10M, IFoS-2014)
35. Describe biological weed control with suitable example. (10M, 150W, CSE 2014)
36. Write about the factors of development of herbicide resistance in weeds. What are the management options? (15M, 250W, CSE 2013)
37. Explain Mode of herbicidal action (10M, 150W, CSE 2013)
38. What are the factors of herbicide selective herbicides for rice and wheat? (15M, 200W, CSE 2012)
39. Differentiate Selective and non-selective herbicides (10M, CSE 2011)
40. Short notes biological weed control. (15M, 150W, CSE 2011)
41. Short notes Herbicide Residue Management (20M, 200W, CSE 2009)
42. Differentiate between biological and chemical method of weed control. Suggest suitable weed management practices in soybean and maize crop. (60M, CSE 2008)
43. Define integrated weed management. Suggest integrated weed management for rice-wheat, and groundnut pigeon pea, inter-cropping systems (60M, CSE 2007)
44. Short notes on Weed control in wheat (20M, 200W, CSE 2006)
45. Short notes biological methods of weed control (20M, 200W, CSE 2005, 2004)
46. Classify herbicides used for weed control with examples. Discuss the advantages and limitations of using herbicides in crop production. What precautions should be taken during their application? (60M, CSE 2004)
47. What are the losses caused by weeds? Suggest chemical control of weeds in direct sown and transplanted rice, wheat, maize, sugarcane and soybean (60M, CSE 2003)
48. Short critical notes on Classification of Herbicides (20M, 200W, CSE 2000)
49. Short critical notes on Integrated Weed Control in Wheat (20M, 200W, CSE 2000)
50. Classify the herbicides used for weed control in field crops. Discuss the integrated weed management practices for paddy-wheat rotation of North-Western India (60M, CSE 1996)
51. How does cropping pattern affect the weed flora? Discuss the management approach under sequential cropping. (CSE 1993)
52. Herbicide residues (200W, CSE 1991)
53. Selective herbicides. (200W, CSE 1990)