Isoprothiolane 40% EC Fungicide Uses

Isoprothiolane 40% EC is a CIB & RC-registered systemic fungicide from the dithiolane/thiolcarbamate group, used specifically for blast disease control in rice (paddy). This page lists its mode of action, key benefits and the recommended dosage as per available label and registration information.

Mode of Action

Isoprothiolane is a systemic fungicide (FRAC Group 6) that moves both acropetally and basipetally within the plant, giving it true two-way translocation. It disrupts phospholipid biosynthesis in the fungal cell membrane and specifically blocks appressorium formation — the specialised infection structure that the blast fungus (Magnaporthe oryzae) needs to penetrate leaf and stem tissue. Because of this dual preventive-and-curative action, it can be applied both proactively during high-risk periods and at the first appearance of symptoms, and its distinct mode of action makes it a useful rotation partner against strobilurin/triazole-resistant blast populations.

Features & Benefits

• True systemic, two-way (acropetal + basipetal) movement protects new growth that emerges after spraying.
• Dual preventive and curative action against rice blast disease.
• Covers the full blast disease cycle — leaf blast, neck blast and node blast.
• Distinct FRAC Group 6 mode of action makes it a valuable rotation partner for resistance management.

Recommended Usage of Isoprothiolane 40% EC

The table below gives the recommended dose and water volume per acre for rice (paddy) blast. Waiting period figures marked "unverified" come from a single secondary source and should be confirmed against your product's own label before harvest.

The CIB label rate is 300 g a.i./ha (750 ml product/ha at 400 g a.i./L formulation strength) in 500–1,000 L water/ha. Converted per acre (1 ha ≈ 2.47 acres), this works out to roughly 300 ml product in 200–400 L water per acre. Always confirm against the product label/CIB registration before spraying, and follow your local agricultural extension advice.

How to Use

1. Scout the crop regularly from the tillering stage onward for early blast symptoms.
2. Apply preventively during high disease-risk periods, or immediately at the first appearance of leaf blast symptoms.
3. Mix 300–400 ml per acre (up to 400–480 ml per acre for neck/node blast protection) into 150–400 L of water, as per the table above.
4. Apply as a fine, uniform foliar spray; for neck blast control, time the second spray just before panicle initiation.
5. Spray during calm morning or evening hours, avoiding wind and rainfall within 4–6 hours. Repeat after 10–15 days if disease pressure continues — typically 2–3 sprays per season — and rotate with a fungicide from a different FRAC group.

Precautions & Safety

• Wear full protective gear (mask, gloves, full-sleeve clothing) while handling and spraying — the label places this product in Toxicity Category II.
• Observe a minimum 24-hour re-entry interval (REI) after spraying.
• The pre-harvest interval shown above is drawn from a single secondary source and is unverified — always confirm the actual waiting period on your product's own label before harvest.
• Wash hands, face and exposed skin thoroughly after use, and launder sprayed clothing separately.
• Store in original, sealed containers away from direct sunlight, food and children.
• Toxic to fish — avoid use near ponds, aquaculture systems or paddy-fish culture.
• Belongs to FRAC Group 6; avoid consecutive sprays of the same product and rotate with strobilurin/triazole-group fungicides to manage resistance.