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Weed Management Questions and Answers

1.

First herbicide produced in the world is :

Exam Year(s)

JPSC Civil Services - 2021,

Answer: A

The first herbicide produced is 2,4-D.

2,4-D (2,4-dichlorophenoxyacetic acid) was developed during the Second World War and released commercially in 1946. It was the first successful selective herbicide, killing broadleaf weeds without harming cereal crops, and it is still widely used.

2,4,5-T is a related phenoxy herbicide that came slightly later and is now banned in many countries. Pendimethalin and simazine (spelt 'Semazin' in the paper) are much later herbicides of the dinitroaniline and triazine groups.

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2.

World's most problematic aquatic weed is _____.

Exam Year(s)

JPSC Civil Services - 2021,

Answer: C

The world's most troublesome aquatic weed is Eichhornia, the water hyacinth.

Eichhornia crassipes, introduced to India from South America in the nineteenth century, spreads so fast that it chokes lakes, ponds and canals, blocks light, depletes oxygen and harms fish. It is often called the 'Terror of Bengal'.

Wolffia is the smallest flowering plant, a harmless duckweed. Azolla is a useful water fern that fixes nitrogen and is used as biofertiliser in paddy. Trapa is the water chestnut (singhara), grown as a crop.

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