158 HISTORY AND CAUSE OF THE COCONUT BUD-EOT. 



restricted dried areas are found both bacteria and fungous filaments. 

 It has not been possible always to prove that fungous filaments were 

 present, but it has always been demonstrated that bacteria were present. 

 This is not conclusive evidence one way or the other as to the cause 

 of the spots. In case the spot remains restricted it is evident that 

 the bacteria have gained no foothold to thrive; but wdien the spots 

 have elongated and become slimy, then the bacteria are flourishing. 

 Diseased areas may occur not only in the upper parts of the mature 

 leaves but also near the base of the leafstalks and on the adjacent 

 part of the trunk. These spots commonly develop as brown areas 

 with a water-soaked appearance. They vary in size from minute 

 ones to those a decuneter or more in length on the main part of the 

 stalk, or they may extend indefinitely into the strainer when it is in 

 a moist condition. These spots, as a rule, are slightly below the 

 general level of the tissue. If a piece of the diseased leaf tissues, the 

 surface of which has been washed clean, is pressed, a cloudy juice 

 oozes out, consisting of the ordinary juice from the tissues made 

 cloudy by the crushed cell tissues and myriads of bacteria. Hand 

 sections of this tissue are difficult to make, but not impossible. 

 These sections show a general brown staining of the tissues and shght, 

 if any, collapse of the cell walls. The contents are granular in appear- 

 ance. What appear to be bacteria occur in these cells scattered 

 unevenly throughout the diseased parts; they swarm in some of the 

 cells, but are apparently absent from others. No fungous filaments 

 have been found in these water-soaked areas, although fungous 

 infections frequently take place near the base of the leafstalks. 

 Such places present dry, gray, hardened surfaces with tiny pustules 

 here and there. It often happens that spots occur on the upper part 

 of the middle leaves when the heart is perfectly sound and no bud- 

 rot is apparent. These spots have been described above m that they 

 were said to be brown, becoming dry, and to contain either bacteria 

 or fungi, or both. The diseased spot seldom if ever spreads more 

 than 5 to 8 centimeters unless the leaves are very young or have been 

 injured. If the leaves arc young or fleshy the rot will spread down- 

 ward from the bacterial action, causing typical bud-rot at the heart. 

 Until tlie leaf where the infection first occurred becomes old and mem- 

 branous the fungous infection will spread either upward or down- 

 ward, but it will not spread m a healthy unmjured leaf. The fungi 

 that occur on these tissues are various, but the most common are 

 Pestalozzia imlmarum Cke. and what has been called Botryodiplodium 

 sp. They appear at maturity as an irregular sooty mass on the 

 surface of the leaves, or they break out from slender elongated 

 ])ustulcs, or they may appear as tiny black dots in the centers of 

 the dry spots. The Pestalozzia is common on diseased palms and 



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