Clomazone 96%: A Pre-Emergence Herbicide for Broad-Spectrum Weed Control

Technical Introduction

Clomazone (IUPAC: 2-(2-chlorobenzyl)-4,4-dimethyl-1,2-oxazolidin-3-one) is a selective, pre-emergence herbicide widely used for controlling grassy and broadleaf weeds in crops such as rice, soybeans, maize, cotton, and vegetables.

It works by inhibiting carotenoid biosynthesis, causing bleaching of young shoots and leaves in susceptible weeds, ultimately stopping growth. Clomazone is highly effective at early stages and prevents weed competition before crops establish.

• Mode of Action: Inhibits 1-deoxy-D-xylulose 5-phosphate (DOXP) pathway, affecting carotenoid synthesis (HRAC Group 13).

• Systemicity: Primarily soil-active with limited translocation in plants.

• Spectrum: Controls both broadleaf and grass weeds during pre-emergence.

Applications

• Cereal Crops:

  • Applied to rice, maize, and wheat for early control of grasses and broadleaf weeds.

• Legume and Cotton Crops:

  • Used in soybeans and cotton fields to prevent weed establishment.

• Vegetable Crops:

  • Effective in pre-planting application for crops like tomato, pepper, and beans.

• Application Timing:

  • Best applied pre-emergence or immediately after planting. Rainfall or irrigation is needed to activate herbicidal action.

Advantages

• Broad-Spectrum Weed Control: Controls both grassy and broadleaf weeds effectively.

• Early-Stage Activity: Protects crops by eliminating competition during initial growth.

• Low Application Rate: Effective at low doses (0.5–1.5 kg a.i./ha).

• Soil Activation: Works through soil absorption and root/shoot contact of emerging weeds.

• Crop Safety: Selective for major crops like rice, maize, soybean, and cotton.

Specifications (Typical Parameters)

FAQ

Q1: When should Clomazone be applied?
A: It is most effective pre-emergence or immediately after planting before weeds germinate.

Q2: What crops are safe for Clomazone use?
A: Safe for rice, maize, soybean, cotton, and several vegetables when applied at recommended rates.

Q3: Does Clomazone control emerged weeds?
A: No, it is primarily a pre-emergence herbicide; post-emergence control is limited.

Q4: How does Clomazone affect weeds?
A: It inhibits carotenoid biosynthesis, causing bleaching of young leaves and shoots, preventing further growth.

Q5: Is Clomazone safe for mammals?
A: Yes, it has low mammalian toxicity, but care should be taken to avoid contamination of water bodies due to aquatic toxicity.

Q6: Can Clomazone be used in integrated weed management (IWM)?
A: Yes, it is effective as part of pre-emergence weed control programs, especially when rotated with other herbicides to delay resistance.