Chemical Class and Anti-Penetration Mechanism
Tricyclazole belongs to the triazolobenzothiazole chemical class (FRAC Group 16.1), functioning as a Melanin Biosynthesis Inhibitor (MBI-D).
It inhibits the polyhydroxynaphthalene reductase enzyme, preventing fungal appressoria from forming the dark melanin pigment required to generate mechanical turgor pressure for leaf cuticle penetration.
- Active Ingredient: Tricyclazole 75% WP (Wettable Powder)
- MBI Mechanism: Blocks melanin synthesis, preventing fungal penetration pegs from breaching the plant surface
- Fast Systemic Uptake: Rapidly absorbed through roots and foliage, translocating acropetally to protect newly expanding leaves
- Rainfastness: Highly rainfast within 1 hour of application, providing reliable protection during continuous monsoon showers
Target Diseases in Paddy Cultivation
Rice blast is one of the most destructive fungal diseases of paddy, capable of causing total crop failure under cool, humid conditions.
Tricyclazole provides protective and systemic defense against all developmental phases of blast infection.
- Leaf Blast: Spindle-shaped lesions with grey centers that coalesce to destroy active photosynthetic leaf area
- Node Blast: Blackened, rotted stem nodes causing tillers to break and lodge easily
- Neck Blast: Black necrotic rings at the panicle base, resulting in completely chaffy, empty white ear-heads
- Application Window: Spray proactively at the tillering stage for leaf blast, and at boot leaf to 5% panicle emergence for neck blast
Application Standards and Stewardship
Tricyclazole is most effective when applied preventively before full-scale fungal sporulation occurs.
Dissolve recommended doses in clean water, ensuring thorough coverage of both vegetative canopies and emerging panicles.
- Foliar Dilution: Apply according to CIBRC label rates using 200 liters of water per acre with fine hollow-cone nozzles
- Panicle Protection: A prophylactic spray at early heading is critical to shield vulnerable panicle necks from blast spores
- Resistance Management: Rotate with broad-spectrum multi-site protectants like mancozeb or strobilurin fungicides
Official source
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Central Insecticides Board & Registration Committee ↗Related on KisanPe
Common questions
What disease is primarily controlled by tricyclazole 75% WP?
It specifically targets rice blast disease (leaf blast, node blast, and neck blast) caused by Pyricularia oryzae.
How does tricyclazole stop rice blast?
It inhibits melanin biosynthesis in fungal appressoria, preventing the fungus from generating the physical pressure needed to penetrate leaf tissues.
When is the best time to spray tricyclazole for neck blast prevention?
Apply at the boot leaf stage to early panicle heading (5% to 10% flowering) before fungal spores colonize panicle necks.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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