vrn 



DISEASES AND ENEMIES 



255 



strong hypertrophy, which makes them much thicker 

 than the healthy shoots and gives them a monstrous 

 appearance. They have also a tendency to grow more 

 vertically, and to make lateral twigs before they them- 

 selves have attained their full development. Such a 

 hypertrophied green twig, with undeveloped leaves and 

 bearing a great number of lateral twigs, has some 

 resemblance to the " witch -brooms" of other trees. 



FIG. 84. Three fruits attacked by the Surinam witch-broom disease. 



A, Young fruit with a lump on one side, due to local hypertrophied growth (| nat. size). 



B, Young fruit with an abnormally thick (hypertrophied) stalk ( nat. size). 



C, Fruit with a hard, dark-coloured spot ("hardening " or " induration ") (^ nat. size). 



The lifetime of the diseased twigs is always very 

 short. 



When the young fruits are attacked by the fungus, 

 they often show a hump on one side (Fig. 84, A), due 

 to the hypertrophied growth of that part of the fruit- 

 wall where the fungus has developed. The fruit stalk 

 is also sometimes hypertrophied (Fig. 84, B). Such 

 fruits fall off when still young. Often, however, the 

 fungus develops in the fruit more slowly, without 

 causing any of these symptoms ; the fruit develops 



