116 TRINIDAD AND TOBAGO BULLETIN. [XX.2,3&4. 



A FUNGUS DISEASE OP CABBAGES. 



By F. Stell, Mycologist. 



Reports and specimens recently received from growers of 

 cabbages in the San Juan district show the presence of a highly 

 Important fungus disease. The affection is known as Cabbage 

 Yellows and is caused by a soil fungus, a species of Fusarium^ 

 Evidence of the disease in the cabbage plot is often found on very 

 young seedlings ; it is shown by the rapid wilting of the leaves and 

 dying of the roots, while externally the stem appears to be sound. In 

 more mature plants, the striking feature is the yellowing of the leaves 

 hence the common name of the disease is " yellows." Sometimes the 

 yellowing may affect the whole plant ; at other times only one side is 

 diseased. In any case, once the plant is affected the effect is fatal. 



The parasite, which lives in the foil, gains access through the 

 young roots. Once established, the fungus invades the vessels of the 

 stem and leaves. These become discoloured and gradual starvation 

 results. 



In the United States, where cabbages are grown on a large 

 commercial scale, much investigation and experimental v/crk has been 

 earned out in connexion with this disease. As a result it has been 

 found that the cnly satisfactory method of dealing with the c.ffeclion 

 is tD grow resistant varieties. 



Once the soil is infected, the parasites can hve for years in the 

 same soil so that it is practically useless to grow varieties of cabbages 

 which are susceptible to the disease. 1 herefore local growers will 

 do well to determine carefully the varieties they grow and their history. 



Steps have since been taken by this Department to secure 

 information from the United States as to the best varieties of cabbage 

 which are immune to "yellows," and "Wisconsin' a variety reported, 

 o be immune is now under trial at St. Clair Experiment Station. 



