Question

Dichloral urea is used as a

• A. Soil herbicide for pre emergence treatment
• B. Soil herbicide for post-emergence treatment
• C. Soil nematicide for pre emergence treatment
• D. Soil fungicide for post emergence treatment

Hint:

Pre-emergent herbicides target weeds before germination; Dichloral urea is one such example.

Answer 1

The Correct Option is A

Dichloral urea is primarily used as a pre-emergent herbicide to prevent weed growth before seeds germinate.

Answer 2

Alternate approach — Mode-of-action elimination:
Dichloral urea belongs to the chloral derivative group of herbicides that act by inhibiting cell division in newly germinating weed seedlings, a mechanism that only works before or immediately as the weed emerges from the soil, not on already-established plants. This immediately rules out any post-emergence classification. It also has no nematocidal or fungicidal activity, since it does not target nematode nervous systems or fungal cell walls and membranes, ruling out the nematicide and fungicide options.
Since its documented action is restricted to inhibiting germinating weed seedlings before emergence, it is correctly classified as a soil herbicide for pre-emergence treatment.