Uses of Captan

Uses of Captan

 

It is a heterocyclic nitrogenous compound with its chemical name N-trichloromethyl-thio-4cyclohexene-1,2-dicarboximide. Kittleson prepared this compound and first reported its fungicidal activity. Hence, it was called Kittleson’s killer in the beginning.

 

Captan is commercially sold under different trade names. Some are Captan 50W or Captan 75W, Captaf, Esso fungicide 406, Dhanutan, Orthocide 406, Kohicap, Vancide 89, Mastan, Captax, Capgold etc. Shamir comes in combination of Tebuconazole 8% + Captan 32 % SC, Rinzex comes in combination of Tebuconazole 6.7% + Captan 26.9 % W/W SC.

 

It is mainly act as a protectant but in some cases, it is claimed to have acted systemically. It has been proved that captan gets degraded on sunlight exposure. It also gets decompose at higher pH.

 

Captan is not compatible with materials like Kaolin, Attaclay, all alkaline material, lime-sulphur and Bordeaux mixture. It is compatible and can be safely used with other common fungicides and insecticides.

 

Comparatively, Captan is a safe fungicides. In USA, its tolerance limit has been fixed at 100 ppm as against 7 ppm of most of organic sulphur fungicides. It has shown no harmful effect when animals fed with captan treated grains. It has been suggested that caution might be necessary in the use of captan in countries where the diet is low in protein. It may shows oral toxicity at low protein diet, as per experiment on rats.

 

Captan is used as spray, dust, seed dresser and soil drenching in nurseries. It is used as seed protectant for agronomic crops, vegetables, flowers and grasses. Captan has also been reported to repel “seed pulling by birds”.

 

In the spray schedule for apple and stone fruits issued from department of horticulture, Himachal Pradesh, India, Captan at the rate of 600 gm per 200 litre of water has been recommended at green tip and pre-harvest stage to control scab, fly speck and bitter rot diseases in apple. For stone fruits such as peach, plum, apricot, it has been recommended on similar dose to control brown rot disease in the month of May.

 

Captan at the rate of 2 gm per litre (0.2 %) controls following fungal diseases:-

• Leaf spot in banana and coconut, weekly nursery spray.
• Damping off and fruit rot in chilies. Dry seed dressing and six spray at 15 days interval.
• Blight disease of cumin and okra.
• Phomopsis fruit rot in egg plant, five sprays at 15 days interval from first week of October.
• Leaf spot in fig, 5 sprays at 15 days interval from first week of May.
• Black rot, Grey mould or Botrytis rot and Downy mildew in Grapes.
• Peach brown rot, spray in full pink bloom, petal fall and pre-harvest spray and for peach leaf curl, one dormant spray & another just before opening the bud.

Seed treatment of beans at the rate of 2.5 gm per litre (0.25 %) can be done to control damping-off disease. 3.0 gm per litre (0.3 %) can be sprayed to control beans blight and seedling rot in chilies.

 

For leaf spot and brown rot in citrus, 6 gram per litre of water (0.6 %) can be sprays at three weeks interval.

 

Seed dressing/ treatment with 10 gm per kg seeds can be done for Pythium wet rot disease and 2.5 gm per litre water (0.25 %) for soil borne fungus in cow pea.

 

In ground nut, seedling rots caused by Aspergillus, Rhizopus & Rhizoctonia can be checked with seed treatment with 2.5 to 3.0 gm per kg seeds. Three parts of 75 % captan and one part of 75 % Quintozene.

 

Anthracnose disease of mango, captan at the rate 2.0 – 2.5 gm per litre water (0.2 to 0.25 %) can be sprayed. Seven sprays of captan alone or captan with zineb sprays at flowering at 1 to 3 weeks interval.

 

In onion, storage rot cause by different causal organisms, can be controlled by 10 minute dip of bulbs in 2 gm per litre water (0.2 %) solution. For smut disease in onion, furrow application at 25 to 30 kg per hectare.

 

3.5 gm per litre of water can be sprayed for anthracnose disease in papaya.

 

Seedling blight and damping off in Pea can be controlled with the help of spray with captan 2.5 gm per litre of water (0.25 %) and benomyl should be mixed to control seedling blight.

 

For fungal seed piece decay in potato, seed treatment with 2 gm per litre water (0.2 %) has been recommended. For early and late blight of Potato, spray with 3 to 4 Kg per ha (2.5 – 3.0 gm per litre water). 5 – 6 Kg per hectare (4.0 – 5.0 gm per litre water) can be used in case of severity. Repeat at 5 to 7 days interval.

 

Strawberry disease like late blight, fruit rot and leaf spot spray with 4 to 6 Kg per ha (3.0 – 5.0 gm per litre water) can be done. Spray should be done uniformly and started with start of new growth. Repeat the spray at 7 days interval and continue through harvest.

 

In case of damping off, grey leaf spot and stem rot of tomato, soil application at the rate of 15 gm per sq meter has been recommended. The early blight, late blight, anthracnose and leaf spot in tomato can be controlled with the spray of 4 to 6 Kg per ha (3.0 – 5.0 gm per litre water) and 6 – 8 Kg per hectare (5.0 – 6.5 gm per litre water) can be used in case of severity. Repeat at 7 to 10 days interval. The spray should be started when first fruit are formed.

 

Anthracnose and Downy mildew in watermelon can be controlled with the spray of 4 Kg per hectare (3.0 gm per litre water). Spray must be uniform coverage and start with the first sign of infection and repeat at 5 to 7 days interval.

 

Authentic literature resources have been consulted for preparing the above article. Some books which are consulted viz. “Fungicides in Plant Disease Control by Y. L. Nene and P. N. Thapliyal” and “Plant Pathology by George N. Agrios” etc and Spray schedules issued from department of horticulture, Himachal Pradesh, Shimla 171002 at their website and other authentic material issued from authorized agencies.

 

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