Chlorothalonil 75% WP Fungicide Uses

Chlorothalonil 75% WP is a broad-spectrum, multi-site contact (protective) fungicide from the chloronitrile chemical group, registered for use in India under the Insecticides Act, 1968, formulated as a wettable powder (WP) for foliar spraying. It is registered for the control of tikka leaf spot and rust in groundnut, early and late blight in potato, fruit rot in chilli, scab in apple, anthracnose and downy mildew in grapes, leaf spot in cauliflower, and downy mildew and leaf spot in watermelon. This page lists its mode of action, key benefits and the recommended dosage as per the Central Insecticides Board & Registration Committee (CIB&RC) official list of approved fungicide uses (Government of India).

Which Problem Is This For? (Symptom Guide)

Not sure whether what you're seeing in the field matches this fungicide's use case? This guide helps match symptoms to this fungicide's approved crop-wise uses.

Mode of Action

Chlorothalonil belongs to the chloronitrile group of fungicides — FRAC Group M05 (multi-site contact activity). It stays on the surface of the leaf and fruit and reacts with thiol (sulphur-containing) groups in many different fungal enzymes at the same time, especially those involved in respiration and energy production. This stops fungal spores from germinating and prevents infection from starting. Because it acts at many sites at once, the risk of fungi developing resistance to it is low. It is a protective fungicide: it does not move inside the plant and does not cure infections already established in the tissue, so it works best when sprayed before or at the very first appearance of disease.

Features & Benefits

• Broad-spectrum protective control of leaf spots, blights, rust, scab, anthracnose, downy mildew and fruit rot across field crops, vegetables and fruit crops.
• Multi-site mode of action (FRAC M05) with a low risk of resistance development — a useful partner in rotation with systemic, single-site fungicides.
• Forms a protective layer on the leaf surface that stops spore germination before infection starts.
• Wettable powder (WP) formulation that is easy to measure and mix in the spray tank.

Recommended Usage of Chlorothalonil 75% WP Fungicide

The table below gives the recommended dose, water volume and waiting period per acre, converted from the CIB&RC-registered per-hectare rate — see the note below the table for conversion details. Always confirm against the current product label before use.

Figures above are converted from the CIB&RC-registered per-hectare rate (1 ha ≈ 2.47 acres): groundnut (tikka leaf spot, rust) 0.66–0.863 kg a.i./ha, 0.88–1.150 kg formulation/ha, 600–800 L water/ha, waiting period 14 days; potato (early & late blight) 0.66–0.937 kg a.i./ha, 0.875–1.250 kg formulation/ha, 600–800 L water/ha, waiting period 14 days; chilli (fruit rot) 600 g a.i./ha, 800 g formulation/ha, 750 L water/ha, waiting period 10 days; cauliflower and watermelon 1.5 g a.i./litre, 2.0 g formulation/litre, 500 L water/ha, waiting period 3 days; apple (scab) 0.150% a.i., 0.200% formulation (200 g/100 L water), 10 L water per tree, waiting period 45 days; grapes (anthracnose, downy mildew) 0.15% a.i. (150 g/100 L water), 0.2% formulation (200 g/100 L water), 100 L water/ha, waiting period 60 days. *Doses marked with an asterisk are fixed mixing concentrations, not fixed per-acre quantities — keep the stated concentration and adjust the total spray volume to the crop or tree size. For grapes, the ~40 litres is the conversion of the 100 L/ha listed by CIB; the actual spray volume needed depends on canopy size. Always confirm the current dose on your specific product's label before use.

How to Use

1. Identify your crop and target disease from the symptom guide above and confirm the dose from the table.
2. Make a smooth paste of the measured powder in a small quantity of water first, then add it to the half-filled spray tank and top up to the full volume while stirring.
3. For cauliflower, watermelon, apple and grapes, prepare the spray at the stated concentration (grams per litre or per 100 litres of water) and spray enough to cover the whole crop or tree canopy.
4. Spray uniformly with a knapsack or power sprayer, covering both sides of the leaves, stems and fruit — as a contact fungicide it protects only the surfaces it covers.
5. Start spraying as a preventive at the first sign of disease or when weather favours disease (cloudy, humid conditions), and repeat as advised by your local agricultural extension office.
6. Spray in calm weather in the early morning or late evening, and avoid spraying if rain is expected within a few hours.

Precautions & Safety

• Wear appropriate PPE — mask/respirator, gloves, goggles and full-sleeved clothing — while mixing and spraying, and avoid inhaling the powder or spray mist.
• Chlorothalonil can irritate the eyes and skin — avoid contact, and wash off any splashes immediately with plenty of clean water.
• Respect the waiting period (PHI) given in the table before harvesting the treated crop — 14 days for groundnut and potato, 10 days for chilli, 3 days for cauliflower and watermelon, 45 days for apple and 60 days for grapes.
• Follow the recommended dose strictly; do not mix with other pesticides unless specifically recommended.
• Do not let spray wash or rinse water reach ponds, fish tanks, streams or drinking-water sources.
• Store in the original, tightly closed container in a cool, dry place away from direct sunlight, food and feed, and out of reach of children and livestock.
• Wash hands, face and any exposed skin thoroughly with soap and water after handling, and change out of contaminated clothing before eating, drinking or smoking.

Brand names mentioned on this page are registered trademarks of their respective owners and are referenced here for identification purposes only; FarmMate is not affiliated with or endorsed by these brands. This page is for general information only — always consult your local agricultural extension office and confirm the current product label before use.