Uses of Dodine

 Uses of Dodine

 

Dodine was developed by the American Cyanamid Company and released for commercial use in U.S.A. with chemical name n-dodecyl guanidine acetate.

 

It is a crystalline solid, soluble in hot water, ethanol and low molecular weight alcohols. It is generally insoluble in most of solvants. It is a salt of strong base and weak acid and is a surface active compound. Being a surface active compound, it ensures automatically a better coverage.

 

It comes in market under various trade names from different companies. Some examples are Cyprex 65% W.P., Sylit, Himdin, Tohfa, Noor, Dodino FIL 40 % SC etc. Cyprex 65% W.P. is its former name, which has been withdrawn later.

 

It is an excellent fungicide against apple scab and also controls certain foliage diseases of cherry, strawberry, pecan and roses etc. It gives long lasting protection and is also a good eradicant. It appears to have local systemic action in leaves.

 

It is compatible with most of pesticides but incompatible with strongly alkaline compounds like Bordeaux mixture or lime, and also with oils. Malathion may reduce its eradicant action. It causes shot holes peaches. It is not compatible with Streptomycin.

 

In the mode of action of dodine, it first saturates the cell wall and then reacts with the protoplast membrane. Physical disruption of the membrane or inhibition of enzymes located there may be ultimate toxic mechanism. It has been observed that it interferes with RNA synthesis and inhibition of degradation of lipids during conidial germination.

 

Phytotoxity

 

It is normally safe for foliar sprays, but sometimes it may produce certain undesirable effects. Tolerance limit of 5 ppm has been fixed in the U.S.A. for several fruits.

 

Dodine may cause russet in apple fruits at 60 gm per 100 litre of water under low temperature and poor drying conditions. The green skinned varieties are more susceptible. It can also cause damage to peaches, plums, pear, roses and watermelons etc.

 

In high sun varieties of peaches, fruit spotting is caused by dodine spray. This fruit spotting can be eliminated by using dodine plus captan mixture. A mixture of 60 gm dodine and 120 gm of captan in 100 litres did not cause any phytotoxicity. Injury increases with increase in concentration of the mixture and temperature between 22 degree and 37 degree Celsius.  

 

Dodine is highly active against apple scab. It also shows its activity against black rot disease in tea, Nectria canker, Sclerotinia rot in soyabean, Botrytis neck rot in alliums (onion, garlic etc). It also shows anti bacterial properties. It inhibits both growth as well as sporulation in case of Sclerotinia and Botrytis. Strains of the apple scab fungus resistant to dodine have appeared and predominate in some areas.

 

Dodine at the rate of 180 gm per 100 litres is effective against powdery mildew at low disease incidence, but partially effective at low rate of disease and high disease incidence.

 

As per recommendation from department of horticulture, Himachal Pradesh, India through their spray schedule of apple, dodine 65 % WP has been recommended for apple scab disease at the rate 200 gm per 200 litre water at pink bud stage and dodine 40 % SC at the rate of 150 gm per 200 litre water at fruit development (walnut size) stage for scab, Alternaria and premature leaf fall disease.

 

Other instructions have also been given for dodine. The dodine should not be sprayed when temperature is 30 degree Celsius & above and when slow drying condition prevails. Dodine should not be mixed with other pesticides or chemicals and hard water.

 

For leaf spot of cherry, 1 gm per 2 litre of water (0.05 %) can be sprayed at 7 to 10 days interval. 3 to 4 sprays are sufficient. Application can be started at petal fall stage.

 

Bacterial canker in citrus can be controlled by spraying 1.5 to 2.0 gm per litre water (680 gm per 400 litre water per ha), 2 to 3 sprays at 14 days interval.

 

Seed treatment with 2 gm per litre water (0.2 %) can be done to control foot rot disease in grams.

 

Black spot, scab and fleck diseases can be controlled by spraying 150 gm per 200 litre water (0.075 %) at pre bloom stage and repeat at 14 days interval.

 

Leaf blight in mustard can be controlled with the spray of dodine at the rate of 2 ml per litre water (0.2 % a.i.). 5 sprays at 10 days interval and spray should be started at disease appearance.

 

Bacterial leaf spot in peach can be controlled with spray of 1 gm per litre water (0.1 %) during the season at 10 days interval. Mixture with captan 3 gm per litre (0.3 %) gives better control of several diseases.

 

For pear scab, spray with dodine at the rate of 150 gm per 200 litre (0.075 %) has been recommended at pre bloom and repeat after 5 to 7 days interval.

 

Downy spot & scab in pecan can be controlled with the spray with 120 gm dodine per 100 litre water at post pollination stage.

 

In the black spot of rose, 1 gm dodine per 2 litre water (0.05 %) can be sprayed with the start of first sign of disease and repeat the spray at 7 days interval.

 

To control leaf spot of strawberry and Anthracnose of walnut, dodine at the rate of 2.0 gm per litre water (0.2 %) can be sprayed.

 

Efforts have been done to consult the reliable literature material for preparing this article. Books or literatures such as “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, have been consulted.

 

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