223 



specimens examined were found to be remarkably healthy. The few 

 unhealthy specimens were attacked by soft rot, or were bruised, 

 while not a single instance of black heart was found. 



Fruit Rot : To return to the subject of diseases found in 

 Hawaii, the fruit rot or soft rot is undoubtedly the most important 

 according to the account of them given by L. D. Larsen in the Bulletin 

 referred to above. This disease attacks ripe pine-apples in the field, 

 and occurs at the cannery to some extent, but is most destruc<-ive on 

 crated fruits during shipment. Such fruits, as well as those in store- 

 houses, are often attacked when still quite green. In the field, direct 

 infection usually commences at the base of the fruit. Here a moist 

 chamber is formed between the bracts which occur on the stem, and 

 the base of the pine-apple; the moisture enables the spores of the 

 fungus Thielaviopsis paradoxa to germinate, and the existence of the 

 chamber prevents them from being killed by the sun. Infection in 

 the field may also occur on other parts of the fruit where there is 

 a wounded surface. On crated fruit during shipment, the rot com- 

 mences at the top or on the sides, almost as frequently as at the 

 base. Here again, the presence of wounds favours the entry of the 

 fungus, but, under the dark, moist conditions that prevail in this 

 case, the fungus is able to penetrate the fruit directly. This it does 

 espesially at points in the cracks between the individual fruitlets of 

 which the pine-apple is composed. The dry conditions and the 

 destructive effect of sunlight on the spores of the fungus prevent 

 direct penetration of the fruit in the field except, as already stated, 

 at the base. 



The symptoms of this disease are as follows. The affected tissue 

 has a water-soaked appearance, is of a slightly darker shade of 

 yellow than the normal, and has a characteristic odour. It is very 

 soft, even in the early stages of decay, and, as the disease progresses, 

 becomes so disintegrated as to yield to the slightest pressure. The 

 rot spreads very rapidly, and is found to destroy half the fruit in 

 four days from the date of inoculation. On cutting open a diseased 

 fruit and exposing the infected tissues to the air, an immense number 

 of black macroconidia of Thielaviopsis is formed, giving all the por- 

 tion attacked a black appearance. These symptoms agree very closely 

 with those of the disease described by Howard on packed pines in 

 Antigua, which was attributed by him to the macro- and rnicro- 

 conidial stages of Trichosphaeria sacchari, which was then regarded 

 as almost certainly identical with Thielaviopsis paradoxa. This 

 fungus was found in at least one instance on ripe pine-apples from 

 the same island, in the examination carried out during last season, 

 and refered to above; the symptoms of the rot produced was similar 

 to those observed in Hawaii. 



The wounds which enable the fungus to gain an entry, especially 

 in the field, may be due to sun scald, or damage by animals, or by 

 implements during field operations. One considerable source of 

 injury is that inflicted by insects, of which the most important in 



