Paclobutrazol is a highly effective, low-toxicity triazole plant growth retardant with broad-spectrum antifungal activity. It inhibits gibberellin biosynthesis, reducing cell division and elongation, and is absorbed by plant roots, stems, and leaves for translocation via xylem. It shortens internodes, dwarfs plants, enhances lodging resistance, increases chlorophyll content, and promotes tillering and fruit setting. Widely used in rice, wheat, fruit trees (apple, pear, citrus), vegetables (tomato, rape), and ornamental plants (chrysanthemum, geranium) to control vegetative growth, boost yield, and improve stress tolerance. It also controls fungal diseases like rice blast, cotton red rot, and cereal smut.

Paclobutrazol is moderately toxic with low acute toxicity but requires standard precautions. Inhalation of dust may irritate the respiratory tract, causing cough or throat discomfort. Skin contact may cause redness or itching; eye contact can lead to conjunctival congestion and burning pain—rinse eyes with plenty of water for ≥15 minutes if contact occurs. Ingestion may cause nausea or abdominal distension; seek medical attention if large amounts are swallowed. Operations require a fume hood, chemical-resistant gloves, safety goggles, and a dust mask. Store sealed at low temperature, separate from food and oxidants. Dispose of waste per hazardous waste regulations to avoid environmental pollution. Acute oral LD50: 1,300 mg/kg (rat, female); 490 mg/kg (mouse, male).